RESEARCH REPORT 458 - Health and Safety Executivedismantling the scaffold at risk, when the use of rope access may have been more appropriate. • Other organisations: specifying offsite

HSE Health & Safety

Executive

The global perspective in addressing construction risks

Prepared by BOMEL Limited for the Health and Safety Executive 2006

RESEARCH REPORT 458

HSE Health & Safety

Executive

HSE BOOKS

The global perspective in addressing construction risks

BOMEL Limited Ledger House

Forest Green Road Fifield

Maidenhead Berks SL6 2NR

This report describes a study into the global perspective in addressing construction risks. Global risks are defined as the overall risks resulting from all phases of a construction activity. These will need to be evaluated for each potential construction method in order to select the method with the lowest overall risk in relation to what is reasonably practicable. The present difficultly for HSE and industry is the absence of information on global risks which can be used in decision making. This project addresses that need and delivers a Global Risk Toolkit.

The Global Risk Toolkit contains a staged approach to ensure that global risk assessment is proportionate. The first stage is a HAZID with qualitative analyses of the results. If this generates sufficient information to allow a decision to be made on the appropriate construction method, then the task is complete. If further information or clarification is required, a methodology is presented for quantitative assessment of the global risks. Supporting data include a risk profile of the construction industry, probabilities of accidents and the financial consequences of those accidents.

This Toolkit has been applied to a range of scenarios involving work at height and workplace transport / material movements.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

© Crown copyright 2006

First published 2006

All rights reserved. No part of this publication may bereproduced, stored in a retrieval system, or transmitted inany form or by any means (electronic, mechanical,photocopying, recording or otherwise) without the priorwritten permission of the copyright owner.

Applications for reproduction should be made in writing to: Licensing Division, Her Majesty's Stationery Office, St Clements House, 216 Colegate, Norwich NR3 1BQ or by email to hmsolicensing@cabinetoffice.x.gsi.gov.uk

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CONTENTS

Page No.

EXECUTIVE SUMMARY xii

1. INTRODUCTION 1

1.1 INTRODUCTION 1

1.2 CONTEXT OF THE STUDY 1

1.3 AIMS 2

1.4 OBJECTIVES AND SCOPE OF WORK 2

1.5 SCOPE OF THIS REPORT 3

2. REGULATIONS ADDRESSING CONSTRUCTION RISKS 5

2.1 OVERALL REGULATORY FRAMEWORK 5

2.2 REGULATIONS RELEVANT TO CONSTRUCTIONACTIVITIES 8

2.3 CONSTRUCTION (DESIGN AND MANAGEMENT) REGULATIONS 10

2.4 WORK AT HEIGHT REGULATIONS 12

2.5 RISK MANAGEMENT GUIDANCE 16

3. RISK MANAGEMENT 17

3.1 INTRODUCTION 17

3.2 RISK MANAGEMENT OVERVIEW 17

3.3 RISK ASSESSMENT TECHNIQUES 20

3.4 ESTABLISHING LEVELS OF RISK 25

3.5 RISK CONTROLS 27

3.6 COST-BENEFIT ANALYSES 27

4. HAZARD IDENTIFICATION STUDIES (HAZID) 33

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4.1 OVERVIEW 33

4.2 HAZID TECHNIQUES 34

5. KEY CONSTRUCTION RISKS 37

5.1 INTRODUCTION 37

5.2 GLOBAL ANALYSIS 38

5.3 KEY RISK AREAS 46

6. HAZID WORKSHOP 71

6.1 INTRODUCTION 71

6.2 WORKSHOP ATTENDEES 71

6.3 METHODOLOGY 71

6.4 WORKSHOP FINDINGS 73

6.5 WORKSHOP ANALYSES 85

7. GLOBAL RISK TOOLKIT 89

7.1 INTRODUCTION 89

7.2 SCOPE OF THE TOOLKIT 89

7.3 KEY QUESTIONS 90

7.4 IDENTIFYING THE HAZARDS AND ASSOCIATED RISKS 90

7.5 QUANTITATIVE RISK ASSESSMENT 94

8. DATA SOURCES 97

8.1 INTRODUCTION 97

8.2 EXPOSURE 97

8.3 PROBABILITIES 97

8.4 CONSEQUENCES 100

8.5 RISK REGISTERS 106

8.6 RISK MODIFIERS 114

9. GLOBAL RISK SCENARIOS 115

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9.1 INTRODUCTION 115

9.2 WORK AT HEIGHT 115

9.3 WORKPLACE TRANSPORT AND MATERIAL MOVEMENTS 121

10. CONCLUSIONS 127

11. RECOMMENDATIONS 131

12. REFERENCES 133

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EXECUTIVE SUMMARY

INTRODUCTION AND OBJECTIVES

This report has been prepared by BOMEL Limited for the Health and Safety Executive as research contract 4539 / R72.093, and describes a study on the global perspective in addressing construction risks.

The implied hierarchy of risk controls within regulations may be open to simplistic and potentially inappropriate application. If falls from height and other construction risks are to be reduced, it is essential that more rational decisions are made. This requires global (or overall) risks to be considered, to ensure that risk reductions in one activity are not outweighed by greater risks in others, for example the risks incurred in erecting and dismantling scaffolding may outweigh the risk reductions gained from providing a short-term working platform. Global risks can thus be defined as the overall risks resulting from all phases of a construction activity. These will need to be evaluated for each potential construction method in order to select the method with the lowest overall risk in relation to what is reasonably practicable.

The present difficultly for HSE and industry is the absence of information on global risks that can be used in decision making. This project addresses that need and delivers a Global Risk Toolkit for construction activities, tasks and equipment. The applications presented in this report relate to construction. However, the principles extend beyond construction, and there is potential for wider application to address other risk areas.

The overall aims of this project are to:

1. To raise understanding of global risks in construction.

2. To provide a practical basis for addressing all significant risks when selecting approaches to construction work.

In order to achieve these aims, the following objectives were set and define the scope of work:

1. To set the context of this project in relation to the principles of risk management.

2. To obtain and present risk data on a representative range of construction occupations, activities and equipment.

3. To hold a HAZID workshop with staff from HSE’s Construction Division to address global risk scenarios.

4. To develop a Toolkit for addressing global risk issues in construction.

5. To apply the global risk methodology to a series of construction scenarios.

6. To develop material suitable for dissemination.

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RISK MANAGEMENT

Risk is defined as:

Risk = likelihood × econsequenc

Where: likelihood = the probability or frequency of an injury occurring

consequence = the outcome of an event (e.g. severity of injury)

An estimate of likelihood can be made from exposure data, whereby:

Likelihood = expsosure × injuryofyprobabilit

Where: exposure = the amount of time that worker(s) are exposed to the activity.

probability = the ratio of an outcome being an injury to the total number of of injury possible outcomes

The basis of risk management is generic and applicable to numerous scenarios across all industries. The approach is summarised in Figure 1.

Identify hazards

Analyse risks

Consequences

Establish level of risk

Consider feasibility, costs, benefits & risks

Identify construction activity

Risk controls

Likelihood

Identify hazards

Analyse risks

Consequences




Risk controls

Likelihood

Figure 1 Generic approach to risk management

Whilst a generic approach to risk assessment considering a construction activities on their own may give appropriate results in many instances, there are other instances where the wider (or global) implications of the risks need to be considered. In particular, issues may arise in terms of the unintentional transfer of risk to:

• Other workers: doing assembly work at height to avoid the risks associated with lifting the finished component exposes one group of workers to the risks associated with working at height, whilst other groups of workers are exposed to the risks of being struck by objects falling from height. Using a scaffold system to provide a safe

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Identify hazards

Analyse risks

Consequences


Likelihood

For each method at each stage

ofconstruction

work platform at considerable height for one group of workers puts those erecting and dismantling the scaffold at risk, when the use of rope access may have been more appropriate.

• Other organisations: specifying offsite construction of large units avoids the risks associated with onsite construction, but in doing so transferring the risk to those involved in manufacturing, loading, transporting, unloading and erecting the units.

• Other activities: using a ladder as a working platform as there are less risks associated with erecting and dismantling ladders than scaffolds, but the risks associated with working from a ladder are potentially greater.

• Members of the public: using mobile elevated work platforms to provide a safe working platform for work on a property adjacent to a busy highway can potentially put members of public (pedestrians and drivers) at risk.

The examples given may be the appropriate choices in some instances when they reduce the overall risk levels. However, the decision to adopt a particular construction method needs to be made explicitly with due consideration to the global (or overall) risks and the potential for transferring risks.

An alternative approach to that shown in Figure 1 is shown in Figure 2. The key difference is that alternative methods of undertaking the construction activity are identified, and for each of those methods the potential risks are assessed at each stage of the construction activity. Each of the methods is then ranked in terms of its global (or overall) risk profile. The method with the lowest overall risk that is compatible with the feasibility, costs and benefits is selected. Such an approach focuses more explicitly on the global risks associated with the methods of undertaking an activity.


Rank overall risks

Identify methods of undertaking activity


Select appropriate method

Identify hazards

Analyse risks

Consequences



Rank overall risks




Likelihood


of construction

Figure 2 Generic approach to risk management considering global risks

Whilst the approach outlined in Figure 2 may sound reasonable as a concept, determining the break point between, say, scaffold / platform access and abseiling options would be more

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challenging in the absence of specific risk (and cost) data. Indeed, considering time of exposure, risk level, impact on other contractors, cost and reasonable practicability is complex and presents significant challenges for all parties in maximising overall risk reduction and achieving clarity and consistency in assessments.

The present situation, therefore, is that those responsible for health and safety of others may make inappropriate decisions, creating greater risk on their sites than necessary. Even by raising awareness of the good sense in addressing global risks, they may, in the absence of guidance, be simply unable to weigh up the alternatives. Where the balance of risks may be apparent to HSE Inspectors, it would not be reasonable to expect the same level of knowledge within the industry as a whole. Whilst risk assessment is addressed in a range of regulations applicable to the construction industry, it is only the Work at Height Regulations that raise global risk issues directly, although the term global risk is not used explicitly. No methodology is presented.

The key barriers to undertaking global risk assessment are the lack of a methodology and the supporting data. This report is aimed at providing both a framework for assessing global risks and data to support those assessments.

KEY RISKS IN THE CONSTRUCTION INDUSTRY

In order to inform subsequent risk assessments, analyses were undertaken of the RIDDOR accident data to define the construction risk profile.

These analyses showed that he overall number of accidents reduced between 1999/2000 and 2003/04. This reduction resulted primarily from a reduction in the number of over 3-day injury accidents over that period. In terms of the readily identifiable industries, domestic construction, civil engineering construction and electrical installation work report the largest number of accidents. However, there has been a tendency to classify organisations under a catch-all industry description of construction building.

The largest number of accidents overall involved handling / sprain injuries. The majority of these involved over 3-day injury accidents. Trips, struck by falling objects, low falls and high falls were involved in the largest numbers of major injury accidents. High falls are the most significant accident kind in terms of severity as they are involved in the largest number of fatalities.

Of the readily identifiable occupations, carpenters / joiners are involved in the largest number of accidents overall and the largest number of major injury accidents. Handling and painting (surface treatment) activities are the work processes involved in the largest numbers of accidents. ‘Floors’ and building materials are the agents involved in the largest number of accidents overall. Moveable ladders are involved in the largest number of major injury accidents.

The age profile of the workers injured in these accidents indicates a distribution skewed towards younger workers, and with a peak at around 25 to 39. The largest variation is in the number of over 3-day injury accidents, with the major injury accidents numbering around 3,000 to 4,000 for the age groups between 20 and 60. Employees outnumber the self-employed by around ten to one in terms of overall accident numbers. The proportion of over 3-day injuries affecting the

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self-employed is smaller than that for employees. This may reflect differences in reporting between the two groups. There were few accidents involving trainees.

The most significant combination involves painters / decorators having low and high falls from moveable ladders whilst undertaking painting (surface treatment) work. Electric fitters also feature prominently in terms of low and high falls from moveable ladders, and trips on stairs and steps.

ASSESSING AND MANAGING GLOBAL RISKS IN CONSTRUCTION

A HAZID workshop was held with representatives of HSE’s Construction Division to address a variety of scenarios relating to work at height and workplace transport (including material movements).

As a result of this workshop, a qualitative method for addressing global risks was developed. One construction method is selected as the baseline measure, and judgements are made as to whether the frequency and consequences associated with the other construction methods are greater or less than those for the base method at each stage of construction.

Based on the experience of the HAZID participants, judgements can be made as to whether risks are slightly, somewhat or significantly greater or less than those of the base method. The relative frequencies and consequences can be combined by multiplying them together to give a risk index. By summing these risk indices over all stages of construction, an indication can be obtained of the global (or overall) risk level for each construction method.

The global risk indices can give an indication as to where the key risks lie for each construction method and stage of construction such that effort can be focussed on potential risk controls for those methods and / or stages of construction. However, the global risk indices will need to be considered in the light of other key information including cost, practicalities, environmental issues and available resources.

Whilst the global risk indices can give an indication of the global risks, they may not provide a sufficiently clear-cut answer and may need to be supplemented by quantitative analyses.

GLOBAL RISK TOOLKIT

A Global Risk Toolkit has been developed to permit the assessment of global risks in construction.

A staged approach is considered appropriate in order to ensure that the global risk assessment is proportionate. The first stage is a HAZID with qualitative analyses of the results. If this generates sufficient information to allow a decision to be made on the appropriate construction method, then the task is complete. If further information or clarification is required, a methodology is presented for quantitative assessment of the global risks.

Whilst a methodology is useful, it needs to be supported by guidance on the data to be used in both qualitative and quantitative risk assessments. Such data are readily available within the expertise contained in construction organisations, as the exposure of workers is a function of how long those workers spend working on an activity. Such information is readily used for

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estimating purposes. Data on the probability of accidents are presented in order to provide indications of how often construction accidents occur in relation to other accidents or causes of death. However, construction workers may well have a feel from their own experiences as to how frequently different forms of accidents occur in relation to one another. This data can be used for the quantitative risk assessments. Data on the consequences of accidents are presented in terms of the costs to society. This shows that the variation in consequences are much greater for accident kind than they are for occupation, work process or agent. The consequences vary least for occupations.

The quantitative risk assessment methodology allows potential risk reductions can be compared to the base method in terms of risk reduction per pound spent. This enables comparisons to be made in terms of costs and benefits.

The Global Risk Toolkit has been applied to the range of scenarios addressed in the HAZID workshop in order to provide comparisons of the qualitative and quantitative methods and to provide worked examples throughout the various phases of the Global Risk Toolkit.

The quantitative risk assessments for the work at height scenarios enabled some of the questions relating to length of exposure to be addressed. This showed consistent results for the construction method with the lowest global risk (MEWPs in this example). However, these analyses showed the positive effect of scaffolding reducing the construction period and thus exposure to risk compared with ladder access. These risk reductions outweighed the increases in risk incurred in erecting and removing the scaffolding.

For the workplace transport / material movements scenarios, the key difference from the qualitative results obtained from the HAZID presented in is that the tower crane is assessed to have a lower overall risk than telehandlers despite having the largest risk in most of the individual construction phases. This result is largely due to the risks presented by workers being struck by moving telehandlers over a relatively long construction phase. This risk outweighs the other higher risks imposed by tower cranes over shorter periods such as erection and removal.

The results presented are indicative and representative of the scenarios presented. They indicate the ability to consider risk trade-off and transfer between different construction methods and stages of construction. Sensitivity analyses are recommended in order to see if the results remain similar with variations in construction time and manning levels.

RECOMMENDATIONS

Based on the work undertaken, the following recommendations are presented:

1. The Global Risk Toolkit should be considered by both HSE and industry as a means of highlighting and addressing global risk issues in construction.

2. The Global Risk Toolkit should not be viewed as a prescriptive guide to assessing global risks, but as an aid to decision making based on experience gained in the construction industry and combined with other relevant information including practicalities, environmental issues and available resources. The Global Risk Toolkit will indicate where questions need to be asked and addressed.

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3. A phased approach should be taken to global risk assessment, starting with a qualitative risk assessment. Only if the qualitative approach does not generate sufficient information should a quantitative risk assessment be undertaken.

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1. INTRODUCTION

1.1 INTRODUCTION

This report has been prepared by BOMEL Limited for the Health and Safety Executive as research contract 4539 / R72.093, and describes a study on the global perspective in addressing construction risks.

The implied hierarchy of risk controls within regulations may be open to simplistic and potentially inappropriate application. If falls from height and other construction risks are to be reduced, it is essential that more rational decisions are made. This requires global (or overall) risks to be considered, to ensure that risk reductions in one activity are not outweighed by greater risks in others, for example the risks incurred in erecting and dismantling scaffolding may outweigh the risk reductions gained from providing a short-term working platform. Global risks can thus be defined as the overall risks resulting from all phases of a construction activity. These will need to be evaluated for each potential construction method in order to select the method with the lowest overall risk in relation to what is reasonably practicable.

The present difficultly for HSE and industry is the absence of information on relative risks which can be used in decision making. This project addresses that need and delivers a construction risk reference document for activities, tasks and equipment. Many of the examples presented in this report relate to work at height in construction. However, the principles extend beyond work at height and there is potential for wider application to address other risk areas.

1.2 CONTEXT OF THE STUDY

In June 2000 the Deputy Prime Minister and the Health and Safety Commission (HSC) launched the Revitalising Health and Safety (RHS) Strategy Statement(1). Underpinning this were the new targets for health and safety in the UK given in Table 1. The HSC also invited Advisory Committees to set targets for their industries. The Construction Industry Advisory Committee(2) (CONIAC) responded by setting more stringent targets for the construction industry. These are shown in Table 1 alongside the RHS targets.

Table 1 Revitalising health and safety (RHS) and CONIAC targets for health and safety

Target By 2004/5 By 2009/10

RHS CONIAC RHS CONIAC

Reduction in incidence rate of fatalities and major injury accidents

-5% -40% -10% -66%

Reduction in incidence rate of cases of work-related ill-health

-10% -20% -20% -50%

Reduction in number of working days lost per 100,000 workers from work related injury and ill-health

-15% -20% -30% -50%

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In October 2000, the HSC agreed to establish eight ‘Priority Programmes’ within its Strategic Plan(3). Three of these priority programmes are ‘Construction’, ‘Falls from height’ and ‘Workplace transport’. This decision acknowledged that significant reductions in construction, falls from height and workplace transport accidents would go a long way towards achieving the Revitalising targets. Significant numbers of accidents involving either falls from height or workplace transport are reported in the construction industry.

1.3 AIMS

The overall aims of this project are to:

1. To raise understanding of global risks in construction.

2. To provide a practical basis for addressing all significant risks when selecting approaches to construction work.

1.4 OBJECTIVES AND SCOPE OF WORK

In order to achieve the aims outlined in Section 1.3, the following objectives were set and define the scope of work:

1. To set the context of this project in relation to the principles of risk management.

2. To obtain and present risk data on a representative range of construction occupations, activities and equipment.

3. To hold an HAZID workshop with staff from HSE’s Construction Division to address global risk scenarios.

4. To develop a Toolkit for addressing global risk issues in construction.

5. To apply the global risk methodology to a series of construction scenarios.

6. To develop material suitable for dissemination.

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1.5 SCOPE OF THIS REPORT

Section 2 introduces the regulatory framework within which the construction industry operates.

Section 3 contains an overview of the principles of risk management and introduces the concept of global risk. Section 4 contains an overview of the use of hazard identification (HAZID) techniques.

Section 5 contains analyses of the key risks in construction based on the accidents reported to HSE under the RIDDOR reporting system. A variety of techniques including risk ranking and pattern matching are used to indicate where the key risk areas are in construction.

The results of an HAZID workshop held with HSE Inspectors to investigate a series of global risk scenarios are presented in Section 6.

A global risk methodology is outlined in Section 7. Data for use with the proposed Toolkit are contained in Section 8.

Section 9 contains a series of scenarios illustrating the concepts of global risk within construction. These are developed from the scenarios discussed in the HAZID workshop.

The conclusions drawn from this work are presented in Section 10, followed by the recommendations in Section 11.

The references used in this work are given in Section 12, and the appendices contain the briefing note used for the HAZID workshop and a template for HAZID sessions.

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2. REGULATIONS ADDRESSING CONSTRUCTION RISKS

This section contains an overview of the requirements for risk assessment in the various regulations applicable to the construction industry. This section addresses both the current regulatory framework and the regulatory framework proposed in the forthcoming revisions to the Construction (Design and Management) Regulations . The Work at Height Regulations are of particular relevance to the construction industry due to the amount of work undertaken at height and the fact that the regulations replace elements of the Construction (Health, Safety and Welfare) Regulations. These regulations are discussed in detail.

2.1 OVERALL REGULATORY FRAMEWORK

This section is presented in order to provide an overview of the regulatory framework under which the regulations governing construction activities have been developed. In doing so, it provides an indication on what may be considered to be acceptable approaches to risk management, particularly in the case

The overall regulatory framework is described in HSE’s Reducing Risks, Protecting People(4). From which the following text has been adapted. This indicates that the most dramatic shift in value preferences of society has been the pressure on regulators for greater clarity and explanation of their approaches to the regulation of risk. This is reflected in the broadly stated principles of good regulation published by the Better Regulation Task Force which require:

• the targeting of action: focusing on the most serious risks or where the hazards need greater controls;

• consistency: adopting a similar approach in similar circumstances to achieve similar ends;

• proportionality: requiring action that is commensurate to the risks;

• transparency: being open on how decisions were arrived at and what their implications are; and

• accountability: making clear, for all to see, who are accountable when things go wrong.

The stages below characterise the system, governed by the principles set out above, that has evolved in HSE in the course of undertaking its own statutory responsibilities and in advising and assisting HSC, for example in implementing policies on modernising health and safety legislation. The stages are:

• Stage 1: Deciding whether the issue is primarily one for HSC/E.

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• Stage 2: Defining and characterising the issue.

• Stage 3: Examining the options available for addressing the issue, and their merits.

• Stage 4: Adopting a particular course of action for addressing the issue efficiently and in good time, informed by the findings of the second and third points above and in the expectation that as far as possible it will be supported by stakeholders.

• Stage 5: Implementing the decisions.

• Stage 6: Evaluating the effectiveness of actions taken and revisiting the decisions and their implementation if necessary.

Reference 4 suggests that HSE’s general thrust in applying the Tolerability of Risk framework is aimed at ensuring that its approach for addressing hazards is inherently precautionary and leads to control regimes that improve or at least maintain standards, while retaining the principles of proportionality, consistency, etc as mentioned above.

Thus when HSE apply the framework to policy formulation, regulatory development and enforcement activities, it:

• Takes into account that societal concerns are often absent for a wide range of hazards, for example, this is often the case for those hazards that are familiar or where the risks they give rise to are generally accepted as being well controlled. Hazards giving rise to societal concerns have a number of well known features and such concerns are often absent for many routinely encountered occupational hazards. This means that when determining where the hazard falls on the Tolerability of Risk triangle HSE can, as a general rule, for most occupational hazards, focus on the individual risks. HSE would weigh up the extent (if any) to which societal concerns are taken into account according to the degree that they are pertinent to the circumstances under consideration.

• Decide, from the information gathered in going through the decision-making process, how precautionary its approach will be when determining where the individual risk and societal concerns is on the Tolerability of Risk geometry;

• Concentrate on ensuring that duty holders must have in place suitable controls to address all significant hazards arising from their undertakings.

• Start with the expectation that those controls should, as a minimum, implement authoritative good practice precautions (or achieve similar standards of prevention/protection), irrespective of specific risk estimates.

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In this context HSE would:

• Regard a hazard as significant unless past experience, or going through the decision-making process described earlier, shows the risk from it to be extremely low or negligible when compared to the background level of risk to which people are exposed, and the hazard does not give rise to societal concerns.

• Consider as authoritative sources of relevant good practice those enshrined in prescriptive legislation, Approved Codes of Practice and guidance produced by Government. HSE would also consider including as other sources of good practice, standards produced by Standards-making organisations (e.g. BS, CEN, ISO) and guidance agreed by a body representing an industrial or occupational sector (e.g. trade federation, professional institution, sports governing body). Such considerations would take into account that HSE is a repository of information concerning good engineering, managerial and organisational practice, and would also include an assessment of the extent to which these sources had gained general acceptance within the safety movement.

The next stage is to distil from the information gathered at Stages 2 (characterising the problem) and 3 (examining options and their merits) on individual risks and societal concerns and, by applying the tests and the criteria in paragraphs 118-139 and Appendix 3 of Reference 4, decide whether adoption of authoritative good practice precautions is an adequate response to the hazards. HSE’s experience suggests that in most cases adopting good practice ensures that the risks are effectively controlled.

One consequence of linking the required control regime to relevant good practice (or measures affording similar levels of protection) is that the control measures so derived apply regardless of the length of exposure. In most circumstances, one would expect control measures to be in place at all times. For example, if good practice requires that accidental contact with the moving parts of a machine should be prevented through the fitting of a guard, the guard will need to be in place, however short the period the machine is being used.

There will be, however, cases where existing good practice:

• Was not identified as an option at Stage 3. This will be particularly true for hazards that are new or not well studied, or where the circumstances in which people interface with the hazard are untypical or exceptional.

• Is found to result in inadequate control of risks.

In these circumstances it is necessary to examine whether any of the other options identified at Stages 2 and 3 would reduce the risks to the degree HSE considers appropriate. If one is found HSE would advocate its adoption. However, as it go through this iterative process of examining options, there will be occasions when it may find that no option is available for reducing the risks to a tolerable level. This will be the case for risks from activities:

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• That are so high and their control inherently so difficult that it is not possible to find reasonable control measures that one could feel confident would work in practice.

• Where it is not possible to allay the societal concerns about the risk. For example, though experts may regard available control measures as adequate for controlling a particular risk, that view may not be shared by society as a whole, as established through existing democratic processes and regulatory mechanisms, either because the majority of people believe that the measures will not always be observed or that they have doubts that the risks should be entertained at all.

HSE would conclude in such circumstances that it is dealing with activities located in the upper, ‘unacceptable’ region of the framework. In its experience, activities or processes where the above conditions apply are relatively rare. There may be several reasons for this. First, as noted above, advances in technology mean that most risks can now be controlled. Secondly, HSE are aware that as regulators it can often allay societal concerns by giving reassurance that risks are being properly controlled through the introduction of progressively more stringent regulatory instruments, such as the use of guidance, ACOPs, or prescriptive legislation, culminating if necessary in the introduction of process regulations such as notification or licensing systems.

Nevertheless, in situations where intolerable risks are found to apply, HSE shall give consideration to banning these activities or processes. For existing risks where banning would be an incomplete solution because the hazard is already widespread, remedial action of some kind has to be undertaken – removal of asbestos prior to demolition of buildings is a case in point.

Reference 4 stresses that HSE uses the above criteria and framework flexibly and with commonsense. For example, addressing certain hazards from existing situations may require that certain activities be undertaken which would fall into the intolerable region for a short period of time, e.g. when the emergency services are engaged in saving life. The decision-making process provides the necessary flexibility. Thus in the above example of the emergency services, as we go through the iterative stages of the decision-making process, we should be able to gauge the best option overall for ensuring that measures are introduced so that health and safety standards are not compromised.

2.2 REGULATIONS RELEVANT TO CONSTRUCTION ACTIVITIES

)The basis of health and safety law in Great Britain is the Health and Safety at Work Act 1974(5

(HASAWA). This sets out the general duties that employers have towards employees and members of the public, and also the duties that employees have to themselves and to each other. This act applies to all work activities.

The role of regulations is described in Reference 6. Regulations are law and approved by Parliament. They may be based on EC Directives. Regulations are usually made under the HASAWA following proposals from the Health and Safety Commission (HSC).

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The HASAWA is essentially a goal-setting act. It sets out what must be achieved, but not how it must be done. HSE Guidance and Approved Codes of Practice give advice, but employers are free to take other measures providing that they do what is reasonably practicable. However, there are some risks that are so great, or the risk control measures are so costly, that it would not be appropriate to leave it to the employer’s discretion to decide what to do about them. In these situations, regulations identify these risks and set out specific action that must be taken.

)The Management of Health and Safety at Work Regulations 1992(7 provide more explicit information on what employers are required to do to manage health and safety under HASAWA. These regulations apply to all work activities.

In addition to these general regulations, regulations have been produced to address particular industries where hazards are particularly high (e.g. construction) or to address particular hazards (e.g. lifting operations and equipment).

The regulations governing health and safety in Great Britain with specific relevance to construction activities are summarised in Table 2.

Table 2 Regulations governing health and safety in relation to construction activities

Regulation

Health and Safety at Work etc Act 1974(5) (HASAWA)

Management of Health and Safety at )Work Regulations 1999(7 (MHSWR)

Provision and Use of Work Equipment )Regulations 1998(8 (PUWER 98)

Lifting Operations and Lifting )Equipment Regulations 1998(9

(LOLER)

Construction (Health, Safety and (Welfare) Regulations 1996 10) (CHSW)

Comments

This sets out the general duties that employers have towards employees and members of the public, and also the duties that employees have to themselves and to each other. This act applies to all work activities. These duties are qualified by the principle ‘so far as is reasonably practicable’.

The main requirement of relevance is for employers to carry out risk assessments.

PUWER 98 applies to all work equipment including lifting equipment. Under PUWER 98 there are requirements to select suitable work equipment in terms of: • Its construction and design. • Where it is to be used. • The purpose for which it is to be used.

LOLER applies to any equipment that lifts or lowers loads and includes its attachments used for anchoring, fixing or supporting it. For example: • Rope access equipment including anchor points. • Ropes, karabiners, harnesses and strops. • Rigging systems. • Mobile elevating work platforms. • Cranes. The term ‘load’ includes a person.

The majority of the CHSW is to be incorporated in the revised CDM Regulations. Regulations 6 and 7 have requirements in relation to work at height to: • Prevent falls from height by physical precautions or,

where this is not possible, provide equipment that will arrest falls.

• Ensure that there are physical precautions to prevent falls

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Regulation

Construction (Design and (11)Management) Regulations 1994

(CDM)

Comments

through fragile materials. • Erect scaffolding, access equipment, harnesses and nets

under the supervision of a competent person. • Ensure there are criteria for using ladders. These requirements have been superseded by the WAHR.

These regulations require that health and safety is taken into account and managed throughout the whole life cycle of a project i.e. from concept, design, planning, construction, maintenance and repair. The regulations apply to most building and civil engineering works. The CDM regulations require that: • Health and safety plans are prepared for use both before

and during the construction phase. • Designers consider foreseeable health and safety risks

during construction, cleaning and maintenance of a structure. Where possible hazards should be designed out. If they cannot be designed out then the risks should be minimised and information should be provided about the remaining risks.

• Designers should cooperate with Planning Supervisors in communicating any assumptions that they have made on the construction methodology.

• When planning the project the contractor identifies the hazards and assesses the risks risk associated with them.

The CDM Regulations are currently being revised, and will be implemented in 2006.

2.3 CONSTRUCTION (DESIGN AND MANAGEMENT) REGULATIONS

The overall outline of the CDM Regulations is described in Table 2. The proposed revisions summarised below are taken from Reference 12. These proposals are currently being consulted on.

The Health and Safety Commission’s (HSC) proposes a single set of Regulations, covering construction work in Great Britain. The proposed Regulations would consolidate and revise provisions in the Construction (Design and Management) (CDM) Regulations 1994 and the Construction (Health, Safety and Welfare) (CHSW) Regulations 1996, which implemented the Temporary or Mobile Construction Sites Directive (TMCS) (1992/57/EEC).

The proposals build on the general principles of CDM and experience of its implementation and take account of the responses to the 2002 Discussion Document (DD) Revitalising health and safety in construction and other feedback from industry. They reflect the HSC and Construction Industry Advisory Committee (CONIAC) commitment that the revision exercise should improve the management of risk, and therefore ensure responsibility is placed with those in the best position to influence or manage it.

They aim to simplify and clarify what duty holders need to do, so that they can easily identify and understand their own role (and those of other members of the project team). To make it easier to understand the various responsibilities, we have restructured the proposed Regulations, to group their requirements by duty holder. The proposals have also tried to make application

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of the Regulations and guidance simpler and more suitable, and the proposals more compatible with less-traditional procurement methodology.

As part of this process, what remains of the CHSW Regulations, after the amendments due to the new Work at Height Regulations, are now incorporated into the single set of revised CDM Regulations.

The proposals recognise the influence of clients on the whole process, and seek to encourage clients and all members of their project teams to communicate and work effectively together, from the start to the end of the project, to ensure health and safety issues are identified and addressed. To ensure services and adequate welfare facilities are provided from the start of construction work, and to help provide a level playing field for prospective Principal Contractors (PC) to price for such facilities, clients are required to state at the tender stage how much notice of mobilisation will be given.

To assist clients in discharging their duties, the proposals have replaced the Planning Supervisor (PS) with a new role “the co-ordinator” to provide advice and support. The co-ordinator’s role has evolved from that of the PS, but is re-enforced (in tandem with the client’s duties) to create an empowered and key advisor to the client, and pivotal figure in ensuring an effective and cohesive project team. The proposals have not lost sight of the fact that good health and safety has commercial benefits too: better quality, and more chance of the project being completed on time and coming in on budget because the site will be better managed. The proposals see the coordinator as being instrumental in ensuring this.

Designers have considerable potential to reduce the risks associated with construction work, as well as those associated with building use, maintenance, cleaning, and eventual demolition. The proposals reflect this. The principles are largely unchanged, but revised requirements clarify the factors they must take into account when exercising their professional judgement. The aim is to encourage designers to focus on what they can do, in the design, to eliminate hazards, where possible, and reduce the risks resulting from any that remain.

There are no substantial changes regarding the PC or contractors, except to make explicit, in the proposed Regulations, the PC’s key role in managing the construction phase; and the contractor’s duty to plan, manage and monitor their own work to ensure that it is carried out in accordance with the plan and, so far as is reasonably practicable, safely and without risk to health. The PC’s key role in promoting worker consultation and involvement is also emphasised.

Construction, design and management are inseparable links in the safe, healthy and effective construction project management chain. For this reason, CONIAC felt it was important to retain the current title of the CDM Regulations. The proposals focus on achieving effective planning and management, with the minimum of bureaucracy – concentrating on the provision of necessary and relevant information, rather than on generic documents adding to bureaucracy without adding value.

The proposals also recognise that competence is crucial, and that the person best placed to do something may not necessarily be the best suited. The Regulations therefore provide for necessary functions to be undertaken only by those who are competent; but also offer support –

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primarily in the role of the co-ordinator – for clients who may be unfamiliar with construction work.

The HSC understands that, although there is a clear desire for better Regulations, industry culture is the biggest hindrance to progress, and HSC cannot directly change this by the law.

2.4 WORK AT HEIGHT REGULATIONS

This section contains a summary of the proposed Work at Height Regulations based on the information presented on the HSE web site(13) and in HSE’s Brief guide to the Work at Height Regulations(14). This summary is followed by detailed information on some of the specific information contained in the regulations.

2.4.1 Overview

The Work at Height Regulations 2005 came into effect on 6 April 2005. The Regulations will apply to all work at height where there is a risk of a fall liable to cause personal injury.

The Regulations place duties on employers, the self-employed, and any person that controls the work of others (for example facilities managers or building owners who may contract others to work at height). The Regulations do not apply to the provision of paid instruction or leadership in caving or climbing by way of sport, recreation, team building or similar activities.

As part of the Regulations, duty holders must ensure:

• All work at height is properly planned and organised.

• Those involved in work at height are competent.

• The risks from work at height are assessed and appropriate work equipment is selected and used.

• The risks from fragile surfaces are properly controlled.

• Equipment for work at height is properly inspected and maintained.

The Regulations include schedules giving requirements for existing places of work and means of access for work at height, collective fall prevention (e.g. guardrails and working platforms), collective fall arrest (e.g. nets, airbags etc), personal fall protection (e. work restraints, fall arrest and rope access) and ladders.

There is a simple hierarchy for managing and selecting equipment for work at height. Duty holders must:

• Avoid work at height where they can.

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• Prevent falls where they cannot avoid working at height by the use of work equipment or other measures to.

• Minimise the distance and consequences of a fall should one occur by using work equipment or other measures where they cannot eliminate the risk of a fall.

HSE’s key messages to duty holders are:

• Those following good practice for work at height now should already be doing enough to comply with these Regulations;

• Follow the risk assessments you have carried out for work at height activities and make sure all work at height is planned, organised and carried out by competent persons;

• Follow the hierarchy for managing risks from work at height - take steps to avoid, prevent or reduce risks; and

• Choose the right work equipment and select collective measures to prevent falls (such as guardrails and working platforms) before other measures which may only mitigate the distance and consequences of a fall (such as nets or airbags) or which may only provide personal protection from a fall.

2.4.2 Risk assessments

It is suggested that each assessment should be proportionate to the risks involved, but some of the factors that will need to be considered will include:

• The environment and conditions of the site - this would include: its location; access and egress to and from the site; weather and ground conditions on the site; and the risks relating to other activities on the site or surrounding area.

• The task to be performed - this would include: the extent of the task; its complexity; its duration; and the frequency with which the task needs to be performed.

• The people involved - this would include: the numbers involved in the work; the degree of their exposure to the risk; the competence of the workers involved; and the levels of supervision required. Duty holders should also consider risks to or presented by those not directly involved in the work.

• The work equipment and/or other structures to be used - this would include: the suitability of existing structures for work at height (including the existence of fragile surfaces); the selection of work equipment to be used; and any risks arising from pre and post use of the work equipment (for example installing and dismantling scaffolding or using a mobile elevated platform or ladder on a busy road).

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The requirements of the WAHR are fairly comprehensive and imply that global risk issues should be addressed explicitly. This is illustrated by how global risk issues are considered in the following sections on the use of appropriate work equipment.

2.4.3 Use of appropriate work equipment

The WAHR recognise that work at height can be performed safely in a number of different ways, using a wide range of work equipment. The choice of equipment will depend on the risk assessment – different types of equipment will have advantages and disadvantages depending on the task and the environment in which the work is to be performed. Whatever equipment is selected it should be of sound construction in suitable material, be of adequate strength and be free from obvious defects. It must also meet any specific requirements set out in the WAHR Schedules.

The choice of equipment involves “reasonable practicability” and must comply with Regulation 6(3) to prevent a person falling or, to the extent that cannot be achieved, mitigate the distance and consequences of such falls. Choices should be thought through. A ladder may reach the workplace but if workers need to climb it for long durations or with heavy or bulky equipment, scaffolding is likely to be more appropriate. On the other hand, the risks of installing scaffolding should be considered, especially for work where a MEWP might be more appropriate.

Selecting equipment for access or egress will depend on the particular use envisaged. For frequent access, more permanent arrangements should be considered. For example, if a scaffold is to be in place for some time, the erection of a staircase with handrails would be more appropriate than a ladder tied in place, especially if bulky loads are being carried up a long flight. The use of hoists or other methods if this will reduce the risks of falls should be considered.

Systems of work or means of access should be designed so that workers do not have to climb over guardrails. If frequent access is required it may be appropriate to use gates, which will allow access when required and also protect those working on the scaffold by providing a barrier. For work on high-rise buildings, which may take considerable periods of time to complete, the use of mast climbing work platforms or suspended platforms may be appropriate. These should only be erected, altered, operated or dismantled by those with the necessary competence and in accordance with the manufacturer’s instructions.

Mobile elevating work platforms (MEWPs) should not generally be used as a means of access to or from another structure or surface – climbing out of MEWPs in these circumstances has injured several people. However, MEWPs may be used for this purpose if they have been specifically designed for it, or as part of a properly planned operation where, in exceptional circumstances, this is the safest way to gain access to a place of work at height. In such cases suitable fall protection should be worn and correctly anchored.

Ladders, including fixed ladders and stepladders, are commonplace and used in most employment sectors. However, people can often seriously underestimate the risks involved in using them.

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Ladders should only be used as work equipment, either for access and egress or as a place from which to work, where a risk assessment shows that the use of other work equipment is not justified because of the low risk and the short duration of the job or unalterable features of the work site. The risk assessment is essential and should consider not only those using the ladder but others who could be affected, such as passers-by. The safety of sole workers who use ladders, such as window cleaners, depends significantly on their correct use, and adequate training is essential. Safety should not be compromised by haste to complete the job. All ladders need to be used in accordance with the manufacturers’ instructions.

If ladders are to be used to work from, and not just for access or egress, it is important that:

• A secure handhold and secure support are available at all times.

• The work can be reached without stretching.

• The ladder can be secured to prevent slipping.

Whilst it is tempting to try and ensure that all the work is completed without having to go down the ladder and move it, overreaching while working from a ladder is a major cause of falls even for experienced workers.

The choice of equipment for work at height must comply with the relevant Schedules of the WAHR.

2.4.4 Fragile surfaces

Regulation 9 of the WAHR requires duty holders to manage the risks from fragile surfaces. By this we mean surfaces where there is a risk of a person or object falling through. These surfaces may be either close to or part of the structure on which work is to be done and will include vertical or inclined surfaces.

Any surface from which work at height is carried out must be strong and stable enough so that any foreseeable loads placed on it will not lead to its collapse. Duty holders should consider whether work on a fragile surface could be done in a way which does not expose workers to risk by having to stand on or near the surface, e.g. can the work be done from below? Duty holders should consider the whole installation, including the fixings of the surface material, and remember that while the surface may support a person’s weight, it may prove fragile once the weight of a load being carried is taken into account. It is also vital to consider the dynamic forces of the person falling from height onto the surface, and the effect of ageing on the surface material and the deterioration caused by weather, environment, impact and any structural alterations. Fragile roof lights in non-fragile roofs can be difficult to see - they may have been painted over and in bright sunshine they can blend in with the surrounding sheets. Fragile surfaces can also be vertical, or nearly so, as well as horizontal. For example some, mainly older, skylights may have large vertical glass sections which people can fall through.

If the work requires regular or occasional access where there is a fragile surface, permanent fencing, guards or other measures to prevent falls should be in place. Where a risk of falls remains, fall arrest equipment is required, so far as is reasonably practicable.

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2.5 RISK MANAGEMENT GUIDANCE

Beyond the information available in HSE Regulation, Guidance and Approved Codes of Practice, industry-specific guidance is available from sources such as Croner. These information sources contain outline risk assessments for a range of construction activities thus providing the person assessing the risks with a starting point for their own risk assessment.

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3. RISK MANAGEMENT

3.1 INTRODUCTION

This section provides an introduction to the concepts of risk management. It also introduces the concept of global risk, and how the approach to managing global risk may differ from traditional approaches to managing risk.

In particular, the following are addressed:

• Overview of generic and global risks.

• Risk assessment techniques.

• Establishing levels of risk.

• Risk controls.

• Cost-benefit analyses.

Hazard identification (HAZID) techniques are discussed in Section 4.

3.2 RISK MANAGEMENT OVERVIEW

3.2.1 Management of generic risks

The basis of risk management is generic and applicable to numerous scenarios across all industries. The approach is summarised in Figure 3, with further details on each of the steps given in Table 3.

Identify hazards

Analyse risks

Consequences




Risk controls

Likelihood

Identify hazards

Analyse risks

Consequences




Risk controls

Likelihood

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Figure 3 Generic approach to risk management

Table 3 Steps in the generic approach to risk management

Step


Identify hazards

Analyse risks

Assess and prioritise risks

Control risks

Comments

Identify the particular construction activity and the potential way that it is intended to undertake that activity.

Identify what sources of potential harm may result from the proposed activity.

Analyse the chances of these potential sources of harm occurring in terms of likelihood and consequences, i.e.

• how likely is an event to happen; and

• what are the potential consequences and their magnitude.

This establishes the level of risk.

Consider the issues including feasibility, costs and benefits associated with those risks and the means of controlling the risks.

Control those risks using the most appropriate method.

Risk is defined as:

Risk = likelihood × econsequenc

Where: likelihood = the probability or frequency of an injury occurring

consequence = the outcome of an event (e.g. severity of injury)

Where historical data on injury frequencies are not available, an estimate of likelihood can be made from exposure data, whereby:

Likelihood = expsosure × injury of y probabilit

Where: exposure = the amount of time that worker(s) are exposed to the activity.

probability = the ratio of an outcome being an injury to the total number of of injury possible outcomes (probability is expressed as a number

between 0 and 1, with 0 indicating an impossible outcome and 1 indicating an outcome is certain).

3.2.2 Management of global risks

Whilst the approach outlined in Figure 3 may give appropriate results in many instances, there are other instances where the wider (or global) implications of the risks need to be considered. In particular, issues may arise in terms of the unintentional transfer of risk to:

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• Other workers: doing assembly work at height to avoid the risks associated with lifting the finished component exposes one group of workers to the risks associated with working at height, whilst other groups of workers are exposed to the risks of being struck by objects falling from height. Using a scaffold system to provide a safe work platform at considerable height for one group of workers puts those erecting and dismantling the scaffold at risk, when the use of rope access may have been more appropriate.

• Other organisations: specifying offsite construction of large units avoids the risks associated with onsite construction, but in doing so transferring the risk to those involved in manufacturing, loading, transporting, unloading and erecting the units.

• Other activities: using a ladder as a working platform as there are less risks associated with erecting and dismantling ladders than scaffolds, but the risks associated with working from a ladder are potentially greater.

• Members of the public: using mobile elevated work platforms to provide a safe working platform for work on a property adjacent to a busy highway can potentially put members of public (pedestrians and drivers) at risk.

The examples given may be the appropriate choices in some instances when they reduce the overall risk levels. However, the decision to adopt a particular construction method needs to be made explicitly with due consideration to the global (or overall) risks and the potential for transferring risks.

An alternative approach to that shown in Figure 3 is shown in Figure 4. The key difference is that alternative methods of undertaking the construction activity are identified, and for each of those methods the potential risks are assessed at each stage of the construction activity. Each of the methods is then ranked in terms of its global (or overall) risk profile. The method with the lowest overall risk that is compatible with the feasibility, costs and benefits is selected. Such an approach focuses more explicitly on the global risks associated with the methods of undertaking an activity.

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Identify hazards

Analyse risks

Consequences


Likelihood

For each method ateach stage

ofconstruction


Rank overall risks




Identify hazards

Analyse risks

Consequences



Rank overall risks




Likelihood


of construction

Figure 4 Generic approach to risk management considering global risks

Whilst the approach outlined in Figure 4 may sound reasonable as a concept, determining the break point between, say, scaffold / platform access and abseiling options would be more challenging in the absence of specific risk (and cost) data. Indeed, considering time of exposure, risk level, impact on other contractors, cost and reasonable practicability is complex and presents significant challenges for all parties in maximising overall risk reduction and achieving clarity and consistency in assessments.

The present situation, therefore, is that those responsible for health and safety of others may make inappropriate decisions, creating greater risk on their sites than necessary. Even by raising awareness of the good sense in addressing global risks, they may, in the absence of guidance, be simply unable to weigh up the alternatives. Where the balance of risks may be apparent to HSE Inspectors, it would not be reasonable to expect the same level of knowledge within the industry as a whole. This report is aimed at providing both a framework for assessing global risks and data to support those assessments.

3.3 RISK ASSESSMENT TECHNIQUES

The principles of minimising the risks to health and safety of workers are readily understood. The ways in which risks can be weighed up in relation to frequency, potential consequences, exposure time, numbers of people involved, allowance for uncertainty (variability and the unknown), etc is far more complex, particularly when the decisions are to be made by people ‘on the ground’. The ways in which risks are assessed are dealt with in this section, addressing absolute risks where hard data are available and notional risks where relative measures can be used.

There are a series of formal techniques for identifying and managing risks. These range from the traditional approach to risk assessment to the more sophisticated techniques typically employed in the major hazard industries. These techniques can be categorised as follows:

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• Qualitative analysis: uses word form or descriptive scales to describe the likelihood and the severity of the hazard being assessed.

• Semi-quantitative analysis: here, the qualitative scales are given values. The number allocated to each description does not have to bear an accurate relationship to the actual magnitude of the severity or likelihood.

• Quantitative analysis: uses numerical values (rather than descriptive scales used in qualitative and semi-qualitative analysis) for both the severity and likelihood using data from a variety of sources.

There are numerous available risk assessment techniques, each of which may be useful in particular circumstances. While there is no single method which is the correct one for any particular situation, anyone assessing risks should consider the nature of the construction activities and select the most appropriate combination of techniques to ensure that a robust and comprehensive risk assessment is conducted. Both qualitative and quantitative methods are discussed in the following sections to provide the reader with an overview of their particular applicability.

3.3.1 Qualitative analyses

One of the most common approach to qualitative risk assessment is the use of a Risk Matrix, which assesses individual incidents in terms of categories (e.g. low, medium, high) of their expected likelihood and severity. Examples of the risk matrix approach are provided in the Australian Standard AS 4360 (Risk Management)(15) and the HSE document Reducing Risk, Protecting People(4). Risk matrices may need to be tailored to meet the requirements of the analyses, for instance those analyses presented in Section 5.3.3. Risk nomograms provide an alternative approach.

Such qualitative methods can provide a relatively rapid understanding of the risk profile of the construction activity, and can be based on judgement alone or can be refined using more detailed information. However, it is not easy to incorporate the effects of risk control measures within risk matrices. Risk matrices are difficult to use to assess global risks where a large number of hazards exist at different stages of construction. More detailed methods are likely to be required to assess such issues.

When using risk matrices or nomograms it is important to define individual incidents or scenarios on a consistent basis, so that compatible events are assessed. For example a risk matrix could be used to evaluate specific outcomes of incidents (e.g. fatalities from a major scaffold collapse) or a specific cause of an incident (failure of scaffold ties). The likelihood and severity would be defined very differently depending on which definition of the incident is used. Hence, the analyst should decide how incidents will be defined, and use the same approach for all incidents. A balance must be struck between defining events in sufficient detail and defining too many events to manage in the assessment.

An example risk matrix is shown in Figure 5, along with indicative definitions of the levels of risk index (Table 4), likelihood (Table 5) and consequence (Table 6)

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Figure 5 Qualitative risk matrix showing the levels of risk index

Likelihood rating

A Almost certain

B Likely

C Moderate

D Unlikely

E Rare

Insignificant

1

5

4

3

2

1

Consequence rating

Minor Moderate Major

2 3 4

10 15 20

8 12 16

6 9 12

4 6 8

2 3 4

Catastrophic

5

25

20

15

10

5

squares in index Risk = likelihood × severity (where a likelihood rating of A = 5 and E = 1)

Table 4

Low

Levels of risk corresponding to the risk index in Figure 5

Colour Description Definition

High Requires priority action

Moderate Must be reduced as low as reasonably possible

Acceptable if as low as reasonably possible

Table 5 Definitions of likelihood

Likelihood rating

Description Likelihood

A Almost certain The event is expected to occur in most circumstances

B Likely The event will probably occur in most circumstances

C Moderate The event should occur at some time

D Unlikely The event could occur at some time

E Rare The event may occur only in exceptional circumstances

Table 6 Definitions of consequence

Likelihood rating

Description Consequence

1 Insignificant No injuries, low financial loss

2 Minor First aid treatment, medium financial loss

3 Moderate Medical treatment required, high financial loss

4 Major Extensive injuries, loss of production, major financial loss

5 Catastrophic Death, substantial financial loss

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3.3.2 Quantitative analyses

Quantitative analyses are typically used in the major hazard industries where data on the performance and failure rates of equipment and processes are readily available. HSE(16) notes that a quantitative risk assessment (QRA) need not always be complex. It should be devised for the task in hand, and that will determine the necessary degree of detail. QRAs will therefore only be appropriate and cost effective for some situations, and will need to differ significantly in depth.

HSE(16) states that “predictions based on QRA are not hard and fast figures as in a balance sheet. They are useful guides to policy making, but their limitations must be made clear to the policy maker.” However, HSE recognises that despite potential misgivings, QRA cannot be ignored in the decision-making process since it is the only technique that allows numbers to be estimated for comparison and ranking purposes other than qualitative techniques. QRA can assist judgement. However, it needs to be balanced with consideration of other issues, such as human factors, that cannot easily be measured.

R2A(17) indicate that potential disadvantages of quantitative risk assessment include:

• Deviation from reality: Quantitative risk assessment (QRA) is all about finding out what things must conspire together to bring about a serious problem, assessing which of these has the greatest importance in the hazard, and suggesting that such items be the primary focus of risk management. It often deals with very small numbers and statistics, which can often lead observers to question the validity of the approach. One important factor in the outcome is the failure data used. Often an analyst is forced to use failure data for 30-year-old facilities simply because it is widely accepted in the field as being the most reliable, whereas more modern data is less certain. A possible answer is that whilst it is not an exact description of reality, it can be the best available to date so that until another better method is developed it should be used to demonstrate due diligence.

• Reproducibility: There are arguments that the results of quantitative risk assessment are best used to compare the relative safety of different systems and not look at the absolute magnitude of the risk in relation to risk criteria. Whilst relative risk may be useful for designers to choose an optimum design, it does not address the public and hence the regulator’s concern of the level of risk a facility presents beyond its site boundary. However, the use of alternative failure rate data and consequence models can also provide different results for analyses conducted on the same plant. Standardised failure data and methodologies would also address some of the differences between QRA results that can arise between studies carried out by different analysts on similar facilities.

• Applicability of data: A major limitation of quantitative risk assessment is that it relies on the application of generic data where no specific data is available. This does not take into consideration improvements in standards, or the possibility that local systems are superior.

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• Transparency: QRA is a methodology widely used in the process industry, where risk is localised, and can often be contained within the site boundaries. ‘Black box’ QRA approaches contain value judgements that are not made explicit and the wide range of parameters is beset by uncertainty. A more transparent approach seeks to exemplify the source, range and application of assumptions, so as to provide decision makers with the best possible information at the time the decision is made.

• Expense: The expense of QRA may be high.

In this study, quantitative data will be used to inform the investigation of global risk issues. Where possible, data relating to construction activities in Great Britain will be presented for use.

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3.4 ESTABLISHING LEVELS OF RISK

Levels of risk can be established as:

• Absolute risks: where absolute data are available.

• Notional risks: where relative data are used.

The calculation of absolute risks is feasible in the process industries where detailed information on the performance and failure rates of mechanical components (such as pipes and valves) are available. In the construction industry, where many of the incidents and accidents involve a broad and complex interaction of causation factors (see Reference18) it is not feasible to calculate absolute risks. However, there are sufficient hard data available to derive notional risks that are based on reported accident data for the construction industry as a whole.

Both qualitative and quantitative methods can be used to establish notional risks. Section 3.3.1 indicates how risk levels would be established using a qualitative risk matrix based on the levels of likelihood and consequence. In order to illustrate the use of quantitative methods, a worked example is proposed.

If we consider the risks involving workers tripping over on an untidy site, the steps involved in calculating a notional risk index and the information required are summarised in Table 7.

Table 7 Indicative risk level for workers tripping on a construction site

Risk element Data required Assumptions Data

Exposure Occasions per day Workers will walk across the site five times per day.

5

Days per year The site is active for more than a year, and 220 days / workers will be on site around 220 days per year year.

People per shift Around 10 workers will be working in this area. 10 workers

Shifts per day Only one shift per day. 1

Exposure per year Calculate this from the four rows above to give 11,000 an exposure of 11,000 occasions per year on which a worker is at risk of tripping.

Probability Probability of accident per use

There will be a trip involving a reportable injury about 1 in every 1,000 crossings of the site.

1 / 1,000

Likelihood Injury frequency per Exposure x probability indicates that around 11 11 year (likelihood) reportable trips will occur each year.

Consequence Severity rating Each injured worker will have to take, on 5 days (consequence) average, around five days off work as a result of

the accident.

Risk Risk index (per year) Likelihood x consequence gives a risk value of 55 (in this case, 55 days lost per year.)

55

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A risk index of 55 is obtained from Table 7. In this case, the index can be readily visualised as it is expressed in terms of days lost off work. Other risks on a particular site could also be assessed in a similar manner.

Whilst the process may look relatively straightforward in this example, there are a range of issues that need to be considered in making the assumptions. These are summarise in Table 8 under the primary risk headings.

Table 8 Issues to consider in calculating risk levels for construction activities

Risk element Issues Exposure • The exposure in Table 7 was calculated on a yearly basis. A more appropriate

measure may be to calculate the exposure on a project basis by making an assumption of the duration of the work activities under consideration.

• Experience of the particular work activity will be required in order to estimate the number of times per day that a worker is exposed to a particular activity.

• An alternative measure of occasions per day may be hours per day. Consistency is required. For instance, comparing uses of ladders with hours spent on roofs will not yield comparable results.

• Databases can be built up within individual organisations or industry wide similar to those used for cost estimating.

Probability

Likelihood

Consequence

Risk

• Estimating the probability of having an accident whilst undertaking an activity is probably the most difficult of these pieces of data to obtain. However, we are only considering notional risk levels, not absolute risk levels. As such, the key point is: is the probability of having an accident 1 in every 100 times the activity is undertaken or 1 in 1,000 or greater? Indicative probabilities can be estimated from a combination of RIDDOR accident data, experience and comparisons with other easy to visualise probabilities.

• The probability of obtaining a reported accident was used in the calculation in Table 7. However, not all incidents will lead to reportable accidents, particularly in the case of trips. Most of those incidents involving workers being struck by moving vehicles will result in a reportable accident. The ‘accident triangle’ could possibly be used to convert incidences into reportable accidents.

• The calculated likelihood gives an indication of how many accidents may happen on a project or in a year. These estimates should be compared with actual figures recorded on projects and future estimates adjusted accordingly.

• An alternative way of expressing the severity (and risk index) is in terms of the cost of an accident. This will be a more appropriate measure when comparing risks that can result in a range of severities such as a fall from height that can result in either an over 3-day, a major or a fatal injury accident. In such cases, an average accident costs can be calculated from the RIDDOR-reportable accidents.

• The risk index must be calculated in a comparable format (regardless of whether the risk index is a meaningful number or not) to be able to make comparisons between risks form different sources. This is particularly the case for assessing global risks.

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3.5 RISK CONTROLS

Risk controls are those policies, procedures, equipment that can eliminate, substitute, control or give protection from risks occurring during construction. In deciding on which risk controls to employ, there are two key questions that need to be addressed:

• How much will the risk control reduce the original risk by?

• How much will the risk control cost?

Data on the costs can be obtained from estimating databases (e.g. those produced by Spon or Wessex), suppliers data or experience.

Data on the effectiveness of risk controls can be obtained from:

• Detailed evaluations of equipment such as that for ladder stability devices(19).

• Considerations of hazard-specific risk controls based on workshop data such as that

heightfor construction transport(20), hand-arm vibration syndrome(21) and falls from

(22,23).

• Industry ‘rule of thumb’ values of risk control effectiveness.

An example of the latter category is given in Reference 17, and shown in Table 9 for four general categories of risk control. No information is given in Reference 17 as to the source of these values.

Table 9 Indicative effectiveness of risk controls by category(17)

Category of risk control Effectiveness

1 Removal or eliminations 100%

2 Design or physical (engineering) controls 90%

3 Administrative (procedural) controls 50%

4 Training (work methods or personnel) controls 30%

3.6 COST-BENEFIT ANALYSES

Cost benefit analysis (CBA) offers a framework for comparing the benefits of reducing risks against the costs incurred for a particular option for managing risks. This can be done by expressing all relevant costs and benefits in a common currency – usually money.

3.6.1 Costs

In Section 3.5, it was noted that costs of risk controls could be obtained from estimating databases (e.g. those produced by Spon or Wessex), suppliers data or experience. However, HSE(4) is relatively clear about what it constitutes as being costs, and adopts the following principles when it make judgements about costs in assessing possible regulatory options:

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• The costs to be considered are those which are incurred unavoidably by duty holders as a result of instituting a health and safety measure. In other words, the costs that should be considered are only those which are necessary and sufficient to implement the measures to reduce risk. Where duty holders incur additional costs for other reasons, these should not be counted. So, for example, extra costs incurred by the duty holders adopting ‘deluxe’ measures where ‘standard’ ones would serve just as well should be excluded. Also, if access is required for work at height, this is a construction cost that will always be incurred in undertaking that work.

• For any particular measure, it will be proper to include the cost of installation, operation, maintenance and the costs due to any consequent productivity losses resulting directly from the introduction of the measure. In general, these should be estimated on the basis of the value of the economic resources involved. This will usually be the same as the financial costs to the duty holder, but there may be cases where alternative estimation procedures are necessary.

• Monetary gains accrued from the introduction of a health and safety measure should be offset against the costs. This is because measures for managing risk can have the effect of reducing costs. Typical examples are the reduction of losses (e.g. damage to property, lost production) resulting from decreases in accidents or incidences of ill health, and savings made from any productivity gains resulting directly from the introduction of the measure. However, costs should be offset only against those productivity savings which can actually be realised, i.e. unit cost reductions. The following should not be offset:

¾ Potential savings / gains, which may depend upon the state of the market, such as the profits which would result from selling on the increased production made possible through improved productivity.

¾ Gains which would accrue from an improved commercial reputation. ¾ Indirect savings such as those resulting from reduced insurance premiums or

civil damages. ¾ The ability of the duty holder to afford a control measure is not a legitimate

factor in the assessment of costs. This ensures that duty holders are presented with a level playing field.

3.6.2 Benefits

Benefits arise from avoiding accidents. In terms of cost-benefit analyses, the derives from avoiding the cost of an accident.

In calculating the costs of accidents, the following assumptions are made:

1. The costs of accidents are taken as the ‘average’ values given by HSE for 1995/96(24).

2. The values of the costs of accidents to society are used to calculate the benefits.

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3. The costs for each year are up-rated by the nominal gross domestic product per capita.

The costs of accidents to society estimated in Reference 24 are shown in Table 10.

Table 10 Costs to society of accidents in 1995/96 and 2003/04

Accident severity Estimated cost to society 1996/96

Estimated cost to society 2003/04

Fatal injury £1,017,675 £1,192,368

Major injury £29,690 £34,787

Over 3- day injury £3,525 £4,130

The DfT(25) suggest that future accident values can be derived by increasing the estimates by the expected long-term GDP per capita, on the assumption that the real cost of each element of the accident costs will increase in line with output. Annex 6 of the Green Book(26) suggests that the growth per capita in the UK be taken as 2%. The uprated costs for 2003/04 are shown in the right column of Table 10.

3.6.3 Comparison of risk against costs

In comparing cost against risks HSE(4), when regulating, will be governed by the principles that:

• There should be a transparent bias on the side of health and safety. For duty holders, the test of ‘gross disproportion’ implies that, at least, there is a need to err on the side of safety in the computation of health and safety costs and benefits. HSE adopts the same approach when comparing costs and benefits and moreover, the extent of the bias (i.e. the relationship between action and risk) has to be argued in the light of all the circumstances applying to the case and the precautionary approach that these circumstances warrant.

• Whenever possible, standards, should be improved or at least maintained.

In practice, HSE when regulating will consider that normally risk reduction action can be taken using good practice as a baseline – the working assumption being that the appropriate balance between costs and risks was struck when the good practice was formally adopted and the good practice then adopted is not out of date. Examples of good practice are included in HSE guidance. However, there will be cases where some form of computation between costs and risks will form part of the decision-making process. Typical examples include major investments in safety measures where good practice is not established.

The concepts of comparing costs against risk are illustrated for four potential risk controls in relation to the base case in:

• Figure 6: where the residual risk levels are shown for each risk control along with the costs to implement those controls.

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-110

-60

-10

40

90

0

0.5

1

1.5

2

2.5

• Figure 7: where the ratios of benefits (i.e. risk reductions) to costs are shown for each risk control.

In this example, risk controls 3 and 4 would warrant implementation, whilst risk controls 1 and 2 would not unless there were special circumstances.

1 2 3 4Base

Risk

Cost

Figure 6 Indicative comparisons of costs and risks for four risk controls

Ben

efit

: Cos

t

Base 1 2 3 4

Figure 7 Indicative comparisons of costs and risks for four risk controls

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3.6.4 Estimating costs and benefits

Following on from the example of Section 3.4, Table 7 has been reproduced and extended into Table 11 to include the risk control evaluation. Such a method can be set up readily on a spreadsheet in order to compare a range of risk control options at various stages of construction. In Table 11 the measure for comparing risk controls has been taken as being risk reduction per £100. This has been taken for convenience only in order to avoid numbers with large numbers of decimal places which are difficult to visualise.

Table 11 Indicative risk level for workers tripping on a construction site

Risk element Data required Assumptions Data

Exposure Occasions per day Workers will walk across the site five times per day.

5

Days per year The site is active for more than a year, and 220 days / workers will be on site around 220 days per year year.

People per shift Around 10 workers will be working in this area. 10 workers

Shifts per day Only one shift per day. 1

Exposure per year Calculate this from the four rows above to give 11,000 an exposure of 11,000 occasions per year on which a worker is at risk of tripping.

Probability Probability of There will be a trip involving a reportable injury 1 / 1,000 accident per use about 1 in every 1,000 crossings of the site.

Likelihood Injury frequency per Exposure x probability indicates that around 11 11 year (likelihood) reportable trips will occur each year.

Consequence Severity rating Each injured worker will have to take, on 5 days (consequence) average, around five days off work as a result of

the accident.

Risk Risk index (per year) Likelihood x consequence gives a risk value of 55 (in this case, 55 days lost per year.)

55

Risk controls Risk control Training is provided to the worker and is 30% effectiveness effective in reducing risk (trips) by around 30%

Risk control cost Ten workers attend an in-house training course £1,000 for around two hours, say £100 cost per worker.

Risk reduction per 30% of the 55 days = 16.5 days. For a £1,000 1.65 £100 cost, this gives a risk reduction per £100 of 1.65

days lost.

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4. HAZARD IDENTIFICATION STUDIES (HAZID)

4.1 OVERVIEW

Conditions that exist or may arise in or around a site, and which could lead to undesirable incidents, are known as hazards. Hazard identification studies (HAZID) are the processes of evaluating construction activities to identify what activities, procedures, plant, processes, substances, situations or other circumstances pose a risk to health and safety. Identifying hazards is a key step in the risk management process outlined in Section 3.2.

The HAZID process (and specific techniques for HAZID) should be appropriate to the specific site or activity, and involves a range of participants who have knowledge of relevant aspects of that site or activity. In particular, the HAZID process should:

• Enable the duty holder to identify hazards and the potential incidents that may occur (continuously, intermittently or occasionally) as a result of the construction activity.

• Not rely solely on data that are reactive, it should also involve thinking ahead to what may happen.

• Enable the duty holder to identify new hazards and potential incidents that could be introduced as a result of the proposed construction activities (intended or unintended) i.e. the global risks.

Robust and comprehensive HAZID is essential to the objective of ensuring safe construction and is essential to the entire process of safety management. Inadequate hazard identification is one of the most significant threats to safe construction, because hazards cannot be properly assessed and controlled if they have not been identified. Duty holders must therefore identify all significant hazards on the construction site, and the incidents that could occur, and keep this information up to date in light of changes. The information should be used to determine the control measures that are necessary to reduce risks as low as reasonably practicable

One of the pitfalls of hazard identification is to discard some incidents because they are perceived to be extremely unlikely or of low consequence (usually because the existing controls are assumed to be highly effective), with the result that these hazards will not be fully evaluated. This should be avoided for two reasons:

• The judgement that an incident should be discarded may be incorrect.

• Incidents may be unlikely or of low consequence only as a result of the control measures in place, and a key purpose of the HAZID and safety assessment process is to identify these critical control measures and determine their effectiveness. It would therefore be self-defeating to disregard incidents on this basis, and the controls may not be adequately managed if their importance is not recognised.

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All potential incidents should be recorded, with screening, analysis and assessment of the hazards, their consequences or the effectiveness of the controls undertaken along with the other incidents.

Other potential pitfalls that should be avoided include:

• Being comprehensive and systematic with respect to some construction activities, which are easily identified, without being comprehensive and systematic with respect to other activities.

• Failing to record important information discussed during the HAZID, e.g. assumptions, uncertainties or debated issues, gaps in knowledge, details of hazards, incidents or control measures, etc.

• Allowing the hazard identification workshops to be dominated by individual persons, or groups within the organisation (excluding input from others).

• Where HAZIDs are conducted across several sessions, failing to review previous session findings, remind participants of the scope and objectives, introduce new participants to the process, etc.

A combination of different HAZID techniques may be needed, depending on the nature of the construction activities, and to ensure that the full range of factors (e.g. human and engineering) is properly considered. Different sources of information should be referred to, and opinions sought from different parties. It is also good practice to build an independent check into the hazard identification process.

By involving different groups (disciplines) and all levels of the organisation this will give the HAZID sufficient breadth and depth because each work group and level will tend to bring a different knowledge base and perspective, and will tend to identify different types of hazard usually related to their area of work. In addition, it is often found that certain hazards which are not evident to individual work groups, are identified as a result of combining the knowledge of specialists in different groups, because those hazards arise from the interactions (or breakdowns) between different groups.

4.2 HAZID TECHNIQUES

There are numerous hazard identification techniques available, each of which may be useful in particular circumstances. These techniques are used regularly in the major hazard industries. However, the techniques are applicable to construction activities. Many of the techniques are probably being applied already to construction risk assessments, whilst others could be applicable. Whilst there is not likely to be any single method that is the correct one for any particular situation there will be appropriate combinations of techniques to ensure that a robust and comprehensive list of hazards and incidents is identified.

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The Victoria Department of Primary Industries(27) provides a brief summary of the techniques available. The following sections have been adapted from that summary.

4.2.1 Checklists

There are many established checklists (e.g. Croner’s Construction Risk Assessment(28)), each of which (or a combination) can be used to guide the identification of hazards and associated risks. These offer straightforward and effective ways of ensuring the basic types of incidents are considered. However, it should be noted that checklists are rarely sufficient on their own, as they may not cover all types of hazards, and the potential for risks to be transferred, and they tend to suppress any lateral thinking.

4.2.2 Historical records of incidents

Databases of actual incidents and near misses that have occurred are a useful reference because they give a very clear indication of how incidents can actually arise. Such databases are available within HSE(29), and may be available formally within company records or be held informally as people’s experience. However, historical data alone cannot be relied on, as the range of events that has actually occurred may not be the entire range of possible events.

4.2.3 What-if techniques

This is typically a combination of the above techniques, often using a prepared set of ‘what-if’ questions on potential problems that may occur as part of the construction activity. This approach is broader but less detailed than a Hazard and Operability Study (HAZOP).

4.2.4 Brainstorming

This is typically an unstructured or partially structured group process, which can be effective at identifying obscure hazards of a type that may be overlooked by the more systematic methods.

4.2.5 Task analysis

Task analysis is a technique developed to address human factors, procedural errors and so-called ‘man-machine interface’ issues. This type of hazard identification is useful for unearthing potential problems relating to procedure failures, human resources, human errors, fault recognition, alarm response, etc. Task analysis can be applied to specific jobs such as lifting operations or to specific working environments such as control rooms. Task analysis is particularly useful for looking at areas where there is a low ‘fault-tolerance’, where human error can easily cause major incidents.

4.2.6 Fault and event tree analysis

The two techniques can be used in isolation or in combination, and describe scenarios as follows:

• Fault trees describe incidents (e.g. falls from a roof) in terms of the combinations of underlying failures that can cause them (such as ignoring method statements combined with ‘failure’ leading to a trip).

35

• Event trees describe the possible outcomes of a hazardous event, in terms of the failure or success of reduction and mitigation measures such as fall arrest equipment.

In terms of the two components of risk:

• Fault trees give an indication of the likelihood of an incident occurring.

• Event trees give an indication of the consequences of an incident.

Fault tree and event tree analysis is time-consuming, and it may not be practicable to use these methods for more than a small number of scenarios. However, the methods have the advantage that they provide a visual interpretation of the causes and consequences and can include control measures in a transparent way.

Whilst the typical application of these methods in the major hazard industries involves quantifying the likelihood and consequences, sketching the causes and consequences can provide a means of visualising how a construction activity may end in an incident.

4.2.7 Hazard and operability studies

Hazard and operability studies (HAZOP) involve highly structured and detailed techniques, developed primarily for application to chemical process systems. They generate a comprehensive understanding of the possible ‘deviations from design intent’ which may occur. However, HAZOP is less suitable for identification of hazards not related to process operations and, as such, may not be applicable to the majority of construction activity outside the engineering construction industry.

HAZOP also tends to identify hazards specific to the section being assessed, while hazards related to the interactions between different sections (i.e. those generating global risks) may not be identified. Hence, HAZOP may need to be combined with other hazard identification methods, or a modified form of HAZOP used, in order to overcome these limitations.

4.2.8 Failure modes, effects and criticality analysis

Failure modes, effects and criticality analysis (FMECA) is a highly structured technique, usually applied to a complex item of mechanical or electrical equipment. The overall system is described as a set of sub-systems, and each of these as a set of smaller subsystems, and so on down to component level. Individual system, sub-system and component failures are systematically analysed to identify their causes (which are failures at the next lower-level system), and to determine their possible outcomes (which are potential causes of failure in the next higher-level system).

FMECA is less suitable for identification of hazards not related to mechanical or electrical equipment and, as such, may not be applicable to the majority of construction activity outside the engineering construction industry or equipment manufacturers.

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5. KEY CONSTRUCTION RISKS

5.1 INTRODUCTION

This section provides an overview of the key risk areas in construction based on analyses of the RIDDOR accident data for 1996/97 to 2003/04.

A variety of information about accidents can be obtained from the RIDDOR data. For example, fields such as work process, agent involved in the accident, occupation and age of the injured person have been analysed to assess the basic circumstances of an accident.

Graphical analyses are presented of the areas with the largest number of reported accidents for industries, accident kinds, occupations, work processes, agents and age ranges. For each of these categories, the risks are ranked in terms of their relative likelihood and impact and presented in risk matrices. Recognising that, in addition to individual risk areas, information is required on which workers were doing which job using which agent when they had particular accidents, pattern-matching analyses are presented later in this section.

Where the accident data for 2001/02 to 2003/04 have been recorded using different coding systems (i.e. occupations, work processes and agents) this is noted, and the data are plotted in separate graphs from the 1996/97 to 2000/01 data. The total number of accidents are presented for the first five-year period. To make comparisons with the number of accidents reported between 2001/02 and 2003/04, the data would need to be averaged (i.e. divide the totals by five and three respectively). It should be noted that the population by category with the new coding is also likely to be different and, as such, care should be taken in making comparisons.

The figures in the following sections contain data on fatal, major and over three-day injury accidents. The following legend is used in the figures to denote the accident types:

• O – over three-day injury accident.

• M – major injury accident.

• F – fatal accident.

Where the year ends in ‘F’ this indicates that the accident data available for that year have been finalised by HSE. Where the year ends in ‘P’ this indicates that provisional data were available at the time that this project was undertaken.

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5.2 GLOBAL ANALYSIS

The accidents reported in construction are shown in Figure 8 on a year-by-year basis. The number of accidents reported has remained relatively constant (between 14,000 and 15,000 over the eight-year period. However, the number of accidents reported has reduced from a peak in 1999/2000 of around 15,000 to below 14,000 in 2003/04. The majority of the reduction appears to have been as a result of the reductions in the number of over 3-day injury accidents, with the major injury accidents remaining relatively constant.

18000

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0 199697F 199798F 199899F 199900F 200001F 200102F 200203F 200304P

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Figure 8 Fatal, major and over 3-day injury accidents in construction between 1996/97 and 2002/04 by HSE year

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The key industry sector where most of the accidents are reported is shown in Figure 9 to be ‘construction bld’. This is a general description that encompasses most building and civil engineering work. The largest of the specific sectors are installation of electric wiring, highway / road work, plumbing, roofing and painting / glazing. In recent years, construction activities have been recorded in their component parts: domestic, civil engineering and commercial construction. This potentially gives more detail as to the source industries of these accidents.

a) 1996/97 to 2001/02 70000

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Figure 9 Accidents in construction between 1996/97 and 2003/04 by industry

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Figure 10 shows that between 1996/97 and 2003/04, the primary accident kind for the overall number of accidents reported was handling and sprains. In terms of the number of fatal and major injury accidents, trips, struck by falling objects, low-level falls and high-level falls were the primary accident kinds. Each were involved in similar numbers of major injury accidents, with considerable variation in the number of over 3-day accidents reported due to the potential severity of the outcome of each accident kind. The largest number of fatal injury accidents resulted from high-level falls. When the accidents reported in 2001/02 to 2003/04 are considered separately, the detail of the trip and handling accidents become more evident. Of the handling accidents, handling sharp objects results in both the largest number of handling accidents, and the most severe accident profile. Of the identifiable sources of trips, obstacles and uneven ground were the most significant.

a) 1996/97 to 2003/04 35000

30000

25000

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0

500

O M F

2001/02 to 2003/04

1000

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Figure 10 Accidents in construction between 1996/97 and 2003/04 by accident kind

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The occupations of the workers involved in the reported accidents in the construction industry are shown in Figure 11. Carpenters / joiners were involved in the largest number of accidents, followed by two categories of general construction workers (‘oth construction’ and ‘other building’). Bricklayers, electric fitters and plumbers also featured highly. In 2002/03 to 2003/04, two of the generic categories of construction workers (other labourers and construction workers not elsewhere classified) were involved in the first and third largest numbers of reportable accidents. Carpenters, masons, electric fitters and plumbers still featured in significant umbers.

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Figure 11 Accidents in construction between 1996/97 and 2003/04 by occupation

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The work processes being undertaken at the time of the reported accidents are shown in Figure 12. On-site transfer dominates the figure between 1996/97 and 2000/01, followed by handling processes. Of the specific work processes, loading and unloading, maintenance, joinery / carpentry and finishing processes were involved in significant numbers of accidents. In 2001/02 to 2003/04, handling activities are the most significant. These are followed by surface treatments (i.e. painting), walking / running (similar to on-site transfer), climbing / descending (stairs, equipment or vehicles), and labouring.

a) 1996/97 to 2000/01

16000

14000

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10000 O M F

b)

0

O M F

2001/02 to 2003/04

1000

2000

3000

4000

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6000

7000

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Figure 12 Accidents in construction between 1996/97 and 2003/04 by work process

42

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The agents involved in the accidents are shown in Figure 13. The number of over 3-day injuries involving handling leads to agents such as heavy objects, sharp objects, awkward objects and handling sprains being the most significant in terms of the overall number of accidents. When fatal and major injury accident are considered, falls from moveable ladders and scaffolding, and trips are significant. When aggregated, the being struck by a falling agent constitutes the third largest number of accidents overall after handling and trip accidents. The list of agents used in 2001/02 to 2003/04 identifies the individual agent, but does not differentiate on the basis of accident kind. Floors, building (and other materials) and moveable ladders are the most significant in terms of both the overall number of accidents and the number of fatal and major accidents.

a) 1996/97 to 2000/01 6000

5000

4000

b)

0

500

O M F

2001/02 to 2003/04

1000

1500

2000

2500

3000

3500

4000

4500

5000

Figure 13 Accidents in construction between 1996/97 and 2003/04 by agent

43

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The age profile of the workers involved in the construction accidents is shown in Figure 14. This indicates a distribution skewed towards younger workers, and with a peak at around 25 to 39. The largest variation is in the number of over 3-day injury accidents, with the major injury accidents numbering around 3,000 to 4,000 for the age groups between 20 and 60.

0

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NO

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Figure 14 Accidents in construction between 1996/97 and 2003/04 by age

44

Figure 15 shows the number of accidents in construction by employment status, with employees outnumbering the self-employed by around ten to one. The proportion of over 3-day injuries affecting the self-employed is smaller than that for employees. This may reflect differences in reporting between the two groups. There were few accidents involving trainees, perhaps reflecting the small number of trainees in the construction industry.

120000

100000

80000

60000

40000

20000

0 EMPLOYED BY EMPLOYEE SELF EMPLOYED TRAINEE WORK

OTHER EXPERIENCE

O M F

Figure 15 Accidents in construction between 1996/97 and 2003/04 by employment status

45

5.3 KEY RISK AREAS

5.3.1 Introduction

In the previous section, the accident statistics were presented for a range of fields including the occupations, work processes and agents involved in those accidents. In this section, the accident data are used to identify the most significant risks affecting the construction industry. Two techniques have been used to identify the key risks:

• Risk ranking matrices

• Pattern matching analyses

These techniques are described in the following sections.

5.3.2 Risk ranking methodology

Analyses are undertaken to rank each of the occupations, work processes and agents etc. involved in the accidents in terms of their relative number of occurrences (‘likelihood’) and impact. Each of these items can then be inserted into a risk matrix in the form shown in Figure 16 and broadly categorised as being of relatively low risk (green), relatively high risk (red) or somewhere in between (amber). This categorisation acts as a guide to the relative significance of an item. Where there are a large number of items in the risk matrices, only those items with medium-high and high likelihoods are shown in the figures.

Figure 16 Risk matrix combining likelihood and impact

Impact

L ML MH H

Like

lihoo

d

H

MH

ML

L

The impact is calculated as a function of the cost of the accidents associated with a field (e.g. occupation, agent etc.), both to society as a whole and to an individual worker. The two impacts are combined to give an overall impact ranging between low (‘L’) and high (‘H’). The monetary value of impact is calculated from the cost of accidents estimated by HSE(30). The overall cost to society is estimated by summing the costs to society of all of the fatal, major and over 3-day injury accidents reported in relation to a particular item. The cost to individuals is estimated by summing the costs to individuals of all of the fatal, major and over 3-day injury accidents and dividing the total cost of an item by the total number of accidents relating to that item.

46

Each item of data is assigned to a quartile on the basis of its cost. The quartile positions are obtained from the minimum, maximum and average cost values along with cost values mid-way between the minimum and average, and average and maximum. The highest cost items whose values fall between the maximum and the first quartile point are assigned to the first quartile. Similarly, the remaining items are assigned to the second, third and fourth quartiles. The first quartile corresponds to high (H) impact, with the fourth quartile corresponding to low (L) impact.

The ‘likelihood’ is estimated from the overall number of accidents reported under a particular item. If population and exposure data were available, for each item within a field, it would be possible to calculate a ‘true’ likelihood. However, such population and exposure data are not available for the type of global data being analysed here. Overall accident numbers are thus used as a surrogate measure of likelihood. The underlying assumption is that those accidents that occur in the largest numbers are the accidents that have the greatest likelihood of occurring. Whether or not this assumption is valid, it is logical for attention to focus on accidents which occur in large numbers with significant impact (i.e. fall in the red ‘zone’ of the risk matrices as formulated here). The likelihood is determined by assigning each item within a field to a quartile on the same basis as the accident costs.

47

5.3.3 Risk ranking matrices

Figure 17 highlights construction building as a key risk area, along with work on highways and other specialist construction. However, construction building is a generic industry classification used for most civil engineering and building construction.

Since 2002/03, the SIC industry field has been recorded in more detail. In particular, this provides more information on the distribution of accidents between the different sectors of construction building. Figure 18 indicates that domestic construction, civil engineering and electrical works present the most significant risks.

Impact L ML MH H

Like

lihoo

d

H 45210 CONSTRUCTION BLD

MH 45310 INST ELEC WIRING 45250 OTH CONST (SPEC)

ML 45330 PLUMBING 45230 HIGHWAY/ROAD ETC

L

45320 INSULATION WORK 45410 PLASTERING 45430 FLOOR/WALL COVER 45211 CONST COMMERCE 45212 CONST DOMESTIC

45450 OTH BUILD COMPL 45420 JOINERY INSTALL 45340 OTH BUILD INSTAL 45500 RENTING CONST/DE 45240 WATER PROJECT

45220 ROOF COVER/FRAME 45440 PAINTING/GLAZING 45110 DEMOLITION

45213 CONST CIVIL ENG 45120 DRILLING/BORING

Figure 17 Accidents in construction 1996/97 to 2001/02 - Risk matrix for SIC industry

Impact L ML MH H

H 45250 OTH CONST (SPEC) 45210 CONSTRUCTION BLD 45212 CONST DOMESTIC

MH 45213 CONST CIVIL ENG 45310 INST ELEC WIRING

45230 HIGHWAY/ROAD ETC 45450 OTH BUILD COMPL 45330 PLUMBING

45211 CONST COMMERCE 45440 PAINTING/GLAZING

Like

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ML 45420 JOINERY INSTALL 45340 OTH BUILD INSTAL

45320 INSULATION WORK 45410 PLASTERING 45220 ROOF COVER/FRAME 45430 FLOOR/WALL COVER 45500 RENTING CONST/DE 45110 DEMOLITION

L 45240 WATER PROJECT 45120 DRILLING/BORING

Figure 18 Accidents in construction 2002/03 to 2003/04 - Risk matrix for SIC industry

48

Figure 19 shows the risk matrix for the accident kinds over the eight-year period with the 2001/02 to 2003/04 accident kinds mapped onto the pre-ICC kinds. Figure 19 indicates that trips, being struck by falling materials and high falls are the three key risk areas. Figure 20 shows the risk matrix for the detailed accident kind criteria used in 2001/02 to 2003/04. The extra detail provides a slightly different picture as the struck by falling object and trip accidents are split into a number of individual categories. With the high fall category remaining the same, the significance of these accident kinds is boosted.

Impact L ML MH H

05 - HANDLING/SPRAINS 06 - TRIP

Like

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H 02 - STRUCK BY

MH 07L - LOW FALL 07H - HIGH FALL

ML 04 - STRIKE / STEP ON 01 - MACHINERY

15 - OTHER KIND 07X - FALL 03 - TRANSPORT

L 10 - EXPOSURE/HOT SUB 17 - ASSAULT/VIOLENCE 14 - ANIMAL

11 - FIRE XX - NOT KNOWN 12 - EXPLOSION

13 - VOLT 08 - COLLAPSE/OVERTURN 09 - DROWNING/ASPHYX

Figure 19 Accidents in construction between 1996/97 and 2003/04 - Risk matrix for accident kind

Impact L ML MH H

OTHER-TRIP OTHER-HIT OBJECT

HIGH FALL

H LOW FALL SHARP LIFT PUTDOWN

OTHER-HANDLING FALL UNSPEC TRIP OBSTRUCT BODYMOVE TRIP UNEVEN MACHINERY

MH OTHER STRUCTURE SLIP WET HAND TOOL UNKNOWN-TRIP

CARRYING FALL STRUCT

ML PUSH PULL SLIP DRY

FALL EQUIP ELECTRICITY

Like

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FORWARD

EJECTED NO INFO COLLAPSE HOT COLD REVERSE ASPH ENGULF OTHER-HIT FIXED HARM FAILURE UNKNOWN-OBJECT PRESSURE NORM UNKNOWN-HANDLING UNKNOWN-VEHICLE HARM HANDLING EXPLOSION OTHER-EXPOSED TO OVERTURN STEP ON UNKNOWN-EXPOSED PHYS ASSAULT RUNAWAY VEHICLE ASPH CONFINED

L FIRE ANIMAL MANHAND PERS PERSON HARM NORM OP UNKNOWN-HIT FIX HANDPERS EQUI FRM EXPLOSION INFECSUB PATH HIGH LOW TEMP

Figure 20 Accidents in construction 2001/02 to 2003/04 - Risk matrix for accident kind

49

The risk matrix for occupations in the first six years is shown in Figure 21. This shows that carpenters / joiners, bricklayers / masons, roofers, builders and a variety of (other non-specified) construction and building workers are the occupations facing the most significant risks. The risk matrix for occupations in 2002/03 and 2003/04 is shown in Figure 22. This indicates that carpentry and a generic occupation (other labourer) are the two key areas. Electrical fitters, masons, road workers, scaffolders and roof workers are also significant.

L H

H

MH (bl )

/

/

ML /

ML MH CARPENTER/JOINER BRICKLAYER/MASON

OTH CONSTRUCTION OTHER BUILDING

REFUSE CARE ASSIST

FORK LIFT DRIVER ELECTRIC FITTER PLUMBER/HEATING CONSTRUCTION OTHER MISC SCAFFOLD/STEEPLE OTHER MANUAL BUILDING LABOUR PAINTER/DECORATE MAINTAIN FITTER GOODS DRIVER ROAD CONSTRUCT PLASTERER

ankOTH LABOUR ENGINEER/TECHNOL RAIL CONSTRUCT ENGINE/ELEC OTH MACH PLANT STEEL ERECTOR PLANT DRIVERS GLAZIER OTH ROUTINE OP SERVICE/PIPES WELDERS PRODUCT MANAGERS GENERAL MANAGERS

ROOFER BUILDER

GARDENER OTH ELECTRICAL FLOORER CLEANERS OTH/TRANS/MACH BARBENDER FIXER CRANE DRIVERS

Impact

Like

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Figure 21 Accidents in construction 1996/97 to 2001/02 - Risk matrix for occupation

L H

H

MH

ML

/

ML MH LABOURER OTH CARPENTER

PLUMBER HEATING PROCESS OPS GROUNDSMEN METAL PRODUCTION ENG TECH MOBILE MACHINE

ELECTRIC FITTER CONSTRCT OPS NEC MASON ROAD CONSTRUCT SCAFFOLDER ROOF TILER PAINTER DECORATE LABOURER BUILD ENG PROS NEC PLASTERERS GLAZIER CONSTRUCT MGR STEEL ERECTOR TRANSPORTOPSNEC HGV DRIVER OTH STORAGE HAND ELECTRICAL ENG PLANT OPS NEC WELDING TRADES PIPE FITTERS FORK-LIFT TRUCK FLOOR WALL TILER ELEC ENG NEC

CONSTRUCTION NEC

CLEANER DOMESTIC TELECOM ENGINEER VAN DRIVER

OTH SERVICE MGR ELEC TECHNICIANS CRANE DRIVERS GEN OFFICE CLERK

MECH ENG CIVIL ENGINEERS PROCES PLANT LAB

Impact

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Figure 22 Accidents in construction 2002/03 to 2003/04 - Risk matrix for occupation

50

Figure 23 shows the risk matrix for the work processes undertaken in the first five years, whilst Figure 24 shows the corresponding data for 2001/02 to 2003/04. On-site transfer is the most significant work process. With the change to the ICC system, the accidents that would have been coded as involving on-site transfer have been distributed amongst a number of the replacement work processes. In particular, climbing / descending equipment, stairs and vehicles are the key risk areas. In addition, surface treatment ranks as the most significant individual work process.

L H

H

MH

/

( ) ROOFING

ML

/

ML MH GNRL HANDLING ON-SITE TRANSF

REFUSE COLLECTN LA BUILDINGS TRAVEL/DELIVER PLASTERING LA ROAD WORKS

GNRL LABOURING LOAD/UNLOADING GNRL OTH GENERAL JOBBING GNRL MAINTN JOIN CARPENTRY SCAFFOLDING FINISHING PROCS GROUND WORKS blank

ELECTRICAL BRICKLAYING GNRL INSTALL ETC PLUMBING STRUCTURAL ERECT INADEQUATE DATA SURFACE TREATMNT FOUND GRND WKS SURFACING GLAZING ROAD REPAIRS DEMOLITION DIST NETWORKS HOUSE BUILD SEWER GRND WKS

WOOD SAWING FABRICATION MIX MORTAR CONCR MACHINING SOCIAL SERV TILING GNRL AMENITIES CONCR CUTTING

STONE CUTTING TUNNELLING GNRL SERV FLOOR COVERING SITE MANAGEMENT

HEAT/VENTILATION MOBILE WITH OP SITE PREPARATION COMMERCIAL BUILD BUILDING MAINTN JOBBING ROOFER HIGHWAY MAINTN SITE PLANT HIRE INSULATION CRANE WITH OP PILING WATER GRND WKS ROOF SHEETING

Impact

Like

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Figure 23 Accidents in construction 1996/97 to 2000/01 - Risk matrix for work process

L H

H LABOURING NEC

MH

LOAD/UNLOAD

ROOFING

ML

LAY/REPAIR

ML MH OTH HANDLING CLIMB/DESCEND EQ

SURFACE TREAT

STORING MAINTN MACHINES

ROAD BUILD/REP ELECTRICAL BRICKLAYING SCAFFOLDING

STRUCTURAL ERECT FOUNDATION/EXCAV PROD MANUFACTURE

ENTER/LEAVE TRAV IN VEHICLE DEMOLITION

Impact

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Figure 24 Accidents in construction 2001/02 to 2003/04 - Risk matrix for work process

51

Figure 25 shows the risk matrix for the agents in the first five years, whilst Figure 26 shows the corresponding data for 2001/02 to 2003/04. In the first five years, falls from movable ladders are the most significant agent. Other significant agents include falls from various parts of the construction site, trips / falls, and being struck by various falling objects. Whilst accidents involving workers being struck by moving vehicles are typically of medium-high impact, they occur less frequently than those accidents involving falls or being struck by falling objects.

In 2001/02 to 2003/04, it is less obvious how the agents were involved in accidents as the link with the accident kind is no longer present. However, the most significant agents appear to be building and other materials vehicles (presumably being struck by), floors (presumably tripping on) and moveable ladders. Other significant agents include scaffolding.

52

Impact L ML MH H

H HS WEIGHT HS SHARP

FALL LADDER-MOVE

HS WEIGHTL STRUCK BY FALL SCAFFOLD TRIP UNEVEN SB ARTICLE

TRIPS/FALLS SB FREE FALL OBJ

TRIP SLIPPERY FALL ACCESS SB HANDTOOL FIXED

(blank) SB BUILDING

FALL STAIRS FALL VEHICLE SB FLYING OBJECT SB LIFTED SB CHIPS FALL WORKAREA MOVEABLE FALL WORKPLAT

MH SB STAGING SB HANDTOOLS

SB VEHICLE FALL LADDER-OTH

SMALL FALL ROOFEDGE WALK FALL STRUCT OTHER FALL TOWER MACHINERY FALL OTHER FALL TRENCH FALL FRAGILE SPLASH CONSTR RELEASE6 FALL LADDER-FIX TRIP WET-OUTDOOR UGCABLES SB DRILLS NOT

HS PATIENT EXPOSURE VEH FLT HOT BODY

FALL TRESTLE SCAFFOLD

VEH TRANS/CONSTR VOLT

SB PNEUMATIC SB HOISTS PLANT DRILLS VEH EXCAVATOR

ML BUILDING VEH DUMPER VEH PRIVATE CAR FALL PLANT

Like

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FIRE/EXPLOSION VEH TRAN/GENERAL

CIRCULAR GRINDING VEH DUMP TRUCK OHLINES OBJECT FALL LIFTING VEHICLE-OVERTURN WOODWORK RELEASE3 EXPOSE/EXPLODE TRIP WET-INDOOR

SB PRESSURE VEH ROAD MAKE EQ VEH GOODS LGV STACKS

COLLAPSE/OVERTRN VEH GOODS HGV DOMESTIC FALL MANLIFT

SB ASSAULT EXCAVATOR EARTH VEH TRANSPORT PILERS FALL STEEL DOG INERT FLT-MACH SB JET MIXING ASPHYXIATION ASSAULT/VIOLENCE SB ELECTRIC

HANDTOOL FALL SUSPENDED

OXYGEN ROLLS

RELEASE1 CYLINDER NETWORK CONVEYOR SAWING VEH TRACTOR

L SB GRINDING FALL STACKS

FALL CRADLE LIFTS

SB CIRCULAR VEH BULLDOZER SB CUTTERS VEH PSV EJECTION VEH GULLEY SAW TEST MACH FLASH

WIRE/ROPE/CABLE VEH ROUGH

FALL SHEETING TRACTOR-WHE-MACH RELEASE4 WATER MIXERS VEH LOADER CONCRETE BLEVE CEMENT VEH TANKER VEH TRAILER CLAY HOIST TRACTOR-LOA-MACH CLOTHING CLOUD SB PETROL VEH TRANSP/AGRI

Figure 25 Accidents in construction 1996/97 to 2000/01 - Risk matrix for agent

53

L H

H

FLOORS

MH

ROOFS

FLT

ML

DUMPER

CAR

ML MH

BUILDING MATS OTHER MATS&MACH MOVEABLE LADD

INJD PERSON STAIRS STEPS DOORS WALLS MISC PORT CON NAILING VEH COMPTS OTHER MACH&EQU CUTTING DRILLING SAWING PIPE LINE WRK MACH COMPTS PARTICLES WINDOWS OTHER HAND TOOL WATER STRETCH WATER JOIN DEVICES FURNITURE OTHER SUBSTANCES STORAGE ACCESS STORED SHEET HAND TRUCKS SCRAPING SUB NO RISK EXPOSED SURF OTHER SAWS MACHINED PRTS

MOB SCAFFOLD FIXD SCAFFOLD OTHER SURF&STRUC

OTH ELEC CAB NO INFO

EXCAVATOR FIXD LADDERS OTHER VEHICLE STEELWORK OTHER HGV LIGHT VAN

WORK GROUND ROLLS COILS TAPS VALVES DOMESTIC EQUI HOSES NOT K MAT&MACH TREE PLANT WASHING FACIL

LOOSE PRODUCT OTH HARM TOXI MOTORS OTHER CONVEY EQU LORRY LOADER STORAGE CONTA MIX BLEND UGROUND CABLE

CEILINGS

ELEVATORS TRAILER FRAGILE ROOF OTH LIFT EQUI

TRENCH

Impact

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Figure 26 Accidents in construction 2001/02 to 2003/04 - Risk matrix for agent

The risk matrix for age (Figure 27) shows that the majority of workers face significant risks except the ‘young’ (under 20), in particular, those aged 25 to 40.

Impact L ML MH H

30 - 34

H 35 - 39 25 - 29

NOT KNOWN 40 - 44

Like

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MH 20 - 24 45 - 49

50 - 54

55 - 59 ML 16 - 19

01 - 15 60 - 64 L 65+

Figure 27 Accidents in construction 1996/97 to 2003/04 - Risk matrix for age

54

5.3.4 Pattern matching analyses

The analyses described in Sections 5.2 and 5.3.3 provide an insight into the relative significance of single factors. Pattern matching analyses permit combinations of accident kinds, occupations, work processes and agents to be compared in order to identify which categories occur most frequently. These analyses are carried out by comparing each accident record with every other accident record in order to see how many matches each one has. Those combinations that appear most frequently give an indication as to what may be considered priority areas.

The pattern matching analyses can also be used in conjunction with the risk ranking matrices described in Section 5.3.2 to prioritise the combinations in terms of their potential likelihood and impact.

The pattern matching analyses are carried out for the first five years (1996/97 to 2000/01), followed by the last three years (2001/02 to 2003/04). The change to the ICC coding system in 2001/02 means that it is not possible to match accidents reported in the first five years with those reported in the subsequent three years. The matches including the occupations for 2001/02 and 2002/03 to 2003/04 have been undertaken separately, as the occupation coding system changed in 2002/03 with the introduction of the SOC 2000 system. It will be possible to repeat the pattern matching exercise for the recent accident data once the new coding systems have been established over several years, thus providing greater insight. The blank cells in the following tables result from those accidents reported via the local authority enforced sectors during the period 1996/97 to 2000/01 where the HSE coding system was not used for occupations, work processes or agents. If data were available they would likely split the row into several subsidiary elements. The more meaningful figures, where the frequency of combination is clear, are from cases where all cells are filled in.

Microsoft Excel is limited to 65,536 rows in a worksheet. As such, only 65,536 accidents can be compared with one another. As 72,707 accidents were reported between 1996/97 and 2000/01, only the fatal and major injury accidents have been compared for the first five years.

55

The most frequently occurring combinations of accident kinds and agents are shown in Table 12 for fatal and major injury accidents reported in the first five years. Low and high falls from ladders represent the most significant combinations overall as a result of the near 2,500 major injury accidents combined with 36 fatalities. Being struck by falling objects has resulted in a similar number of fatalities overall; but being struck by falling objects during lifting operations is the most significant of these ‘struck by’ combinations. Various trips are significant in terms of major injury accidents, whilst high falls from scaffolding and roofs are significant in terms of fatalities.

Table 13 shows the matches for all accident severities in the period 2001/02 to 2003/04, whilst Table 14 shows the matches for the fatal and major injury accidents over that period.

In terms of the overall accident numbers, trip accidents involving ‘floors’ stand out with over 3,000 reported accidents. Of the handling/sprain accidents, those involving awkward body movements are reported in the largest number of incidents, although the majority of these resulted in over 3-day injury accidents. Falls from moveable ladders were reported in over 2,600 accidents.

In terms of the combination of fatal and major injury accidents, a similar picture emerged to that for the first five years with (low and high) falls from moveable ladders being the most significant combination. Fixed and mobile scaffolding are now differentiated, with high falls being more significant for fixed scaffolding. Building materials are the most common agent involved in striking workers.

56

Table 12 Accidents in construction between 1996/97 and 2000/01 - Most frequently occurring matches of fatal and major injury accidents for accident kind and agent

Accident kind Agent F M F+M

LOW FALL FALL LADDER-MOVE 5 1282 1287

TRIP TRIP OBSTRUCT 0 1257 1257

HIGH FALL FALL LADDER-MOVE 31 1178 1209

TRIP TRIP 0 1073 1073

HANDLING/SPRAINS HS SHARP 0 724 724

STRUCK BY SB ARTICLE 0 701 701

STRUCK BY STRUCK BY 3 674 677

TRIP TRIP UNEVEN 0 667 667

HIGH FALL FALL SCAFFOLD 19 594 613

TRIP TRIP SLIPPERY 0 543 543

STRUCK BY SB FREE FALL OBJ 9 487 496

STRUCK BY SB LIFTED 20 382 402

TRIP TRIPS/FALLS 0 377 377

LOW FALL FALL SCAFFOLD 0 374 374

STRUCK BY SB BUILDING 10 340 350

HANDLING/SPRAINS HANDLING/SPRAINS 0 344 344

HANDLING/SPRAINS HS WEIGHT 0 339 339

LOW FALL FALL VEHICLE_OTH 0 296 296

HIGH FALL FALL ROOFEDGE 30 259 289

STRIKE / STEP ON WI FIXED 0 280 280

57

Table 13 Accidents in construction between 2001/02 and 2003/04 - Most frequently occurring matches of fatal, major and over 3-day injury accidents for accident kind and

agent

Accident kind Agent F M O Match

OTHER-TRIP FLOORS 0 638 1136 1774

BODYMOVE INJD PERSON 0 78 1310 1388

LOW FALL MOVEABLE LADD 3 794 533 1330

TRIP UNEVEN FLOORS 0 411 846 1257

OTHER-TRIP STAIRS STEPS 0 442 755 1197

OTHER-HIT OBJECT BUILDING MATS 2 344 628 974

HIGH FALL MOVEABLE LADD 9 592 238 839

OTHER-HIT OBJECT OTHER MATS&MACH 2 293 493 788

LIFT PUTDOWN BUILDING MATS 0 63 691 754

TRIP OBSTRUCT BUILDING MATS 0 262 379 641

UNKNOWN-TRIP FLOORS 0 249 337 586

SHARP BUILDING MATS 0 101 433 534

SHARP OTHER MATS&MACH 0 97 428 525

FALL UNSPEC MOVEABLE LADD 5 294 169 468

LIFT PUTDOWN OTHER MATS&MACH 0 26 416 442

TRIP OBSTRUCT OTHER MATS&MACH 0 180 239 419

OTHER-HANDLING BUILDING MATS 0 61 324 385

LOW FALL MOB SCAFFOLD 2 182 171 355

SHARP CUTTING 0 34 321 355

SLIP WET STRETCH WATER 0 123 191 314

58

Table 14 Accidents in construction between 2001/02 and 2003/04 - Most frequently occurring matches of fatal and major injury accidents for accident kind and agent

Accident kind Agent F M O F+M

LOW FALL MOVEABLE LADD 3 794 533 797

OTHER-TRIP FLOORS 0 638 1136 638

HIGH FALL MOVEABLE LADD 9 592 238 601

OTHER-TRIP STAIRS STEPS 0 442 755 442

TRIP UNEVEN FLOORS 0 411 846 411

OTHER-HIT OBJECT BUILDING MATS 2 344 628 346

FALL UNSPEC MOVEABLE LADD 5 294 169 299

OTHER-HIT OBJECT OTHER MATS&MACH 2 293 493 295

TRIP OBSTRUCT BUILDING MATS 0 262 379 262

UNKNOWN-TRIP FLOORS 0 249 337 249

HIGH FALL FIXD SCAFFOLD 12 188 74 200

LOW FALL MOB SCAFFOLD 2 182 171 184

HIGH FALL ROOFS 14 168 47 182

TRIP OBSTRUCT OTHER MATS&MACH 0 180 239 180

HIGH FALL MOB SCAFFOLD 5 159 85 164

LOW FALL FIXD SCAFFOLD 2 127 104 129

SLIP WET STRETCH WATER 0 123 191 123

HIGH FALL FLOORS 8 99 53 107

HIGH FALL OTHER SURF&STRUC 5 98 40 103

SHARP BUILDING MATS 0 101 433 101

59

Additional information can be obtained by considering the most frequently occurring combinations of work processes in combination with the accident kinds and agent. These combinations are shown in Table 15 for fatal and major injury accidents reported in the first five years.

On-site transfer is the dominant work process associated with the various combinations, with trips during on-site transfer resulting in the four largest combinations. Moveable ladders and stairs represent the most significant fall risks, whilst handling of sharp object is the most significant handling combination.

Table 16 shows the matches for all accident severities in the period 2001/02 to 2003/04, whilst Table 17 shows the matches for the fatal and major injury accidents over that period.

In terms of the overall accident numbers, trips involving ‘floors’ are the most significant combination. Trips when climbing / descending stairs and steps represent the single largest combination. Low falls from moveable ladders whilst painting (surface treatment) or climbing / descending are highly significant.

In terms of the fatal and major injury accidents, falls (high and low) from moveable ladders whilst undertaking paining, climbing descending, electrical and maintenance work dominate the data. Trips on stairs and steps and ‘floors’ are also significant. High falls from roofs are the largest single source of fatalities.

60

Table 15 Accidents in construction between 1996/97 and 2000/01 - Most frequently occurring matches of fatal and major injury accidents for accident kind, work process

and agent

Accident Kind Work Process Agent F M F+M

TRIP ON-SITE TRANSF TRIP OBSTRUCT 0 743 743

TRIP ON-SITE TRANSF TRIP 0 533 533

TRIP ON-SITE TRANSF TRIP UNEVEN 0 395 395

TRIP ON-SITE TRANSF TRIP SLIPPERY 0 314 314

HANDLING / SPRAINS GNRL HANDLING HS SHARP 0 220 220

LOW FALL ON-SITE TRANSF FALL LADDER-MOVE 1 204 205

HIGH FALL ON-SITE TRANSF FALL LADDER-MOVE 1 177 178

LOW FALL ON-SITE TRANSF FALL STAIRS 1 151 152

TRIP ON-SITE TRANSF TRIPS/FALLS 0 152 152

STRUCK BY GNRL HANDLING SB ARTICLE 0 149 149

HIGH FALL ROOFING FALL ROOFEDGE 12 109 121

LOW FALL ELECTRICAL FALL LADDER-MOVE 0 118 118

LOW FALL GNRL LABOURING FALL LADDER-MOVE 1 117 118

STRUCK BY GNRL HANDLING STRUCK BY 0 110 110

LOW FALL FINISHING PROCS FALL LADDER-MOVE 0 103 103

STRUCK BY LOAD / UNLOADING SB ARTICLE 0 103 103

HIGH FALL SCAFFOLDING_MSC FALL SCAFFOLD 4 97 101

HANDLING/SPRAINS GNRL HANDLING HS WEIGHT 0 99 99

HANDLING/SPRAINS GNRL HANDLING HANDLING/SPRAINS 0 98 98

LOW FALL LOAD / UNLOADING FALL VEHICLE_OTH 0 93 93

61

Table 16 Accidents in construction between 2001/02 and 2003/04 - Most frequently occurring matches of fatal, major and over 3-day injury accidents for accident kind,

work process and agent

Accident Kind Work Process Agent F M O Match

OTHER-TRIP CLIMB / DESCEND EQ

STAIRS STEPS 0 266 510 776

TRIP UNEVEN WALK / RUN ELSE FLOORS 0 183 359 542

OTHER-TRIP WALK / RUN ELSE FLOORS 0 194 324 518

LOW FALL SURFACE TREAT MOVEABLE LADD 1 257 135 393

LOW FALL CLIMB / DESCEND EQ

MOVEABLE LADD 1 216 173 390

BODYMOVE OTH HANDLING INJD PERSON 0 9 282 291

HIGH FALL CLIMB / DESCEND EQ


SHARP OTH HANDLING OTHER MATS&MACH

0 43 192 235

OTHER-HIT OBJECT OTH HANDLING OTHER MATS&MACH

1 79 154 234

HIGH FALL SURFACE TREAT MOVEABLE LADD 2 166 56 224

TRIP OBSTRUCT WALK / RUN ELSE BUILDING MATS 0 83 128 211


FLOORS 0 82 127 209

LIFT PUTDOWN OTH HANDLING BUILDING MATS 0 8 199 207

LIFT PUTDOWN OTH HANDLING OTHER MATS&MACH

0 17 182 199

OTHER-HIT OBJECT OTH HANDLING BUILDING MATS 0 72 118 190

UNKNOWN-TRIP WALK / RUN ELSE FLOORS 0 78 109 187

BODYMOVE SURFACE TREAT INJD PERSON 0 7 170 177

LOW FALL ELECTRICAL MOVEABLE LADD 0 106 60 166

OTHER-TRIP LABOURING NEC FLOORS 0 48 108 156

TRIP OBSTRUCT WALK / RUN ELSE OTHER MATS&MACH

0 67 88 155

62

Table 17 Accidents in construction between 2001/02 and 2003/04 - Most frequently occurring matches of fatal and major injury accidents for accident kind, work process

and agent

Accident Kind Work Process Agent F M O F+M



LOW FALL SURFACE TREAT MOVEABLE LADD 1 257 135 258

LOW FALL CLIMB / DESCEND EQ


OTHER-TRIP WALK / RUN ELSE FLOORS 0 194 324 194

HIGH FALL CLIMB / DESCEND EQ


TRIP UNEVEN WALK / RUN ELSE FLOORS 0 183 359 183

HIGH FALL SURFACE TREAT MOVEABLE LADD 2 166 56 168

LOW FALL ELECTRICAL MOVEABLE LADD 0 106 60 106

HIGH FALL ROOFING ROOFS 1 0

91 23 101

FALL UNSPEC CLIMB / DESCEND EQ


FALL UNSPEC SURFACE TREAT MOVEABLE LADD 1 84 42 85

TRIP OBSTRUCT WALK / RUN ELSE BUILDING MATS 0 83 128 83


FLOORS 0 82 127 82

OTHER-HIT OBJECT OTH HANDLING OTHER MATS&MACH

1 79 154 80

UNKNOWN-TRIP WALK / RUN ELSE FLOORS 0 78 109 78

HIGH FALL SCAFFOLDING FIXD SCAFFOLD 3 73 18 76

OTHER-HIT OBJECT OTH HANDLING BUILDING MATS 0 72 118 72

TRIP OBSTRUCT WALK / RUN ELSE OTHER MATS&MACH

0 67 88 67

OTHER-HIT OBJECT LABOURING NEC OTHER MATS&MACH

0 62 80 62

LOW FALL MAINTN MACHINES MOVEABLE LADD 0 58 44 58

63

The fourth field of information to be considered in the accident combinations is the occupation of the injured worker. The most frequently occurring combinations of accident kind, occupation, work process and agent are shown in Table 18 for fatal and major injury accidents in the last five years.

Of the readily identifiable occupations, the most significant combinations involve painters / decorators in both low and high falls from moveable ladders during painting (surface treatment) work. Electric fitters and carpenters / joiners were both involved in significant numbers of low falls from moveable ladders whilst undertaking their respective trades.

In 2001/02 the ICC accident recording system was introduced, but the occupation coding system remained the same as that used for the previous five years. Table 19 shows the matches for all accident severities in 2001/02, whilst Table 20 shows the matches for the fatal and major injury accidents over that period.

As with the previous five years, painters / decorators being involved in low and high falls from moveable ladders are the primary combinations. Electric fitters are involved in significant numbers of trips on stairs and steps and low falls from moveable ladders whilst climbing / descending or undertaking electrical work.

The patterns for the fatal and major injury accidents are the same as those for all accident severities.

In 2002/03, the SOC2000 coding system was introduced for occupations. Table 21 shows the matches for all accident severities in the period 2002/03 to 2003/04, whilst Table 22 shows the matches for the fatal and major injury accidents over that period.

In terms of the overall accident numbers, the primary matches correspond with those identified in the first five years. Painters / decorators involved in low and high falls from moveable ladders during painting (surface treatment) work. Electric fitters again feature predominantly in terms of low falls from moveable ladders, trips on stairs and steps and high falls from moveable ladders.

The previous trends are repeated for the fatal and major injury accidents. However, high falls from roofs and scaffolding (fixed and mobile), involving roof tillers and scaffolders respectively, feature as significant combinations.

64

Table 18 Accidents in construction between 1996/97 and 2000/01 - Most frequently occurring matches of fatal and major injury accidents for accident kind, occupation,


Accident Kind

Occupation Work Process Agent F M F+M

TRIP 0 86 86 LOW FALL ELECTRIC FITTER ELECTRICAL FALL LADDER

MOVE 0 81 81

TRIP OTH CONSTRUCTION

ON-SITE TRANSF TRIP OBSTRUCT

0 78 78

FALL 0 69 69 TRIP OTHER BUILDING ON-SITE TRANSF TRIP

OBSTRUCT 0 68 68

HIGH FALL PAINTER/DECORA TE

SURFACE TREATMNT

FALL LADDERMOVE

2 64 66

LOW FALL PAINTER / DECORATE

SURFACE TREATMNT

FALL LADDERMOVE

1 62 63

LOW FALL CARPENTER / JOINER

JOIN/CARPENTR Y

FALL LADDERMOVE

0 61 61

TRIP CARPENTER / JOINER

ON-SITE TRANSF TRIP OBSTRUCT

0 60 60

HIGH FALL ROOFER ROOFING FALL ROOFEDGE

6 53 59

HIGH FALL SCAFFOLD / STEEPLE

SCAFFOLDING_ MSC

FALL SCAFFOLD

0 57 57


ON-SITE TRANSF TRIP 0 57 57


SCAFFOLDING_S TR

FALL SCAFFOLD

2 54 56

HIGH FALL ELECTRIC FITTER ELECTRICAL FALL LADDERMOVE

1 52 53

HIGH FALL 3 50 53 TRIP ELECTRIC FITTER ON-SITE TRANSF TRIP

OBSTRUCT 0 52 52


ON-SITE TRANSF TRIP UNEVEN 0 49 49

HIGH FALL PAINTER / DECORATE

FINISHING PROCS

FALL LADDERMOVE

0 48 48

TRIP OTHER BUILDING ON-SITE TRANSF TRIP UNEVEN 0 48 48 STRUCK BY

0 47 47

65

Table 19 Accidents in construction in 2001/02 - Most frequently occurring matches of fatal, major and over 3-day injury accidents for accident kind, occupation, work process

and agent

Accident Kind Occupation Work Process Agent F M O Match


SURFACE TREAT

MOVEABLE LADD

0 23 10 33

LOW FALL ELECTRIC FITTER

CLIMB / DESCEND EQ

MOVEABLE LADD

0 19 12 31

OTHER-TRIP ELECTRIC FITTER

CLIMB / DESCEND EQ

STAIRS STEPS

0 17 13 30


SURFACE TREAT

MOVEABLE LADD

0 19 7 26

OTHER-HIT OBJECT

BRICKLAYER / MASON

BRICKLAYING BUILDING MATS

0 7 19 26

BODYMOVE CARPENTER / JOINER

OTH HANDLING

INJD PERSON

0 0 25 25


ELECTRICAL MOVEABLE LADD

0 15 6 21

OTHER-TRIP CARPENTER / JOINER

CLIMB / DESCEND EQ

STAIRS STEPS

0 8 13 21

HIGH FALL ROOFER ROOFING ROOFS 0 14 5 19

LOW FALL PLUMBER / HEATING

CLIMB / DESCEND EQ

MOVEABLE LADD

0 9 9 18


CLIMB / DESCEND EQ

MOVEABLE LADD

0 11 6 17

TRIP UNEVEN ELECTRIC FITTER

WALK/RUN ELSE

FLOORS 0 5 12 17

BODYMOVE ELECTRIC FITTER

OTH HANDLING

INJD PERSON

0 0 16 16

HIGH FALL ELECTRIC FITTER

CLIMB / DESCEND EQ

MOVEABLE LADD

0 12 4 16

OTHER-TRIP PLUMBER / HEATING

CLIMB / DESCEND EQ

STAIRS STEPS

0 3 13 16

SHARP CARPENTER / JOINER

OTH HANDLING

SAWING 0 4 12 16

FALL UNSPEC PAINTER / DECORATE

SURFACE TREAT

MOVEABLE LADD

0 10 5 15

HAND TOOL CARPENTER / JOINER

SURFACE TREAT

SAWING 0 2 13 15


SCAFFOLDING FIXD SCAFFOLD

0 13 2 15

LIFT ROAD ROAD BUILDING 0 1 14 15 PUTDOWN CONSTRUCT BUILD/REP MATS

66

Table 20 Accidents in construction in 2001/02 - Most frequently occurring matches of fatal and major injury accidents for accident kind, occupation, work process and agent

Accident Kind Occupation Work Process Agent F M O F+M


SURFACE TREAT

MOVEABLE LADD

0 23 10 23


CLIMB / DESCEND EQ

MOVEABLE LADD

0 19 12 19


SURFACE TREAT

MOVEABLE LADD

0 19 7 19


CLIMB / DESCEND EQ




0 15 6 15

HIGH FALL ROOFER ROOFING ROOFS 0 14 5 14


SCAFFOLDING FIXD SCAFFOLD

0 13 2 13


CLIMB / DESCEND EQ

MOVEABLE LADD

0 12 4 12


CLIMB / DESCEND EQ

MOVEABLE LADD

0 11 6 11

FALL UNSPEC PAINTER / DECORATE

SURFACE TREAT

MOVEABLE LADD

0 10 5 10


CLIMB / DESCEND EQ

MOVEABLE LADD

0 10 0 10


CLIMB / DESCEND EQ

MOVEABLE LADD

0 9 9 9

FALL UNSPEC ELECTRIC FITTER


1 8 4 9

OTHER-TRIP CARPENTER / JOINER

CLIMB / DESCEND EQ


LOW FALL BRICKLAYER / MASON

BRICKLAYING FIXD SCAFFOLD

1 7 6 8


SURFACE TREAT

MOVEABLE LADD

0 8 4 8

HIGH FALL ROOFER CLIMB / DESCEND EQ

MOVEABLE LADD

0 8 3 8

HIGH FALL ROOFER ROOFING FIXD SCAFFOLD

1 7 0 8

OTHER-HIT OBJECT

BRICKLAYER / MASON

BRICKLAYING BUILDING MATS

0 7 19 7


CLIMB / DESCEND EQ

MOVEABLE LADD

0 7 4 7

67

Table 21 Accidents in construction between 2002/03 and 2003/04 - Most frequently occurring matches of fatal, major and over 3-day injury accidents for accident kind,

occupation, work process and agent

Accident Kind Occupation Work Process Agent F M O Match



0 65 38 103

LOW FALL PAINTER DECORATE

SURFACE TREAT

MOVEABLE LADD

0 62 26 88

HIGH FALL PAINTER DECORATE

SURFACE TREAT

MOVEABLE LADD

1 52 19 72

OTHER-TRIP LABOURER OTH CLIMB / DESCEND EQ


LOW FALL CARPENTER SURFACE TREAT

MOVEABLE LADD

0 28 28 56

OTHER-TRIP LABOURER OTH WALK / RUN ELSE

FLOORS 0 18 38 56

OTHER-TRIP PLUMBER HEATING

CLIMB / DESCEND EQ



CLIMB / DESCEND EQ


HIGH FALL ROOF TILER ROOFING ROOFS 5 35 8 48 BODYMOVE CARPENTER SURFACE

TREAT INJD PERSON 0 2 44 46

HIGH FALL SCAFFOLDER SCAFFOLDING FIXD SCAFFOLD

2 38 6 46

LIFT ROAD ROAD BUILD / BUILDING 0 2 44 46 PUTDOWN CONSTRUCT REP MATS

LIFT PUTDOWN

MASON BRICKLAYING BUILDING MATS

0 5 39 44

SHARP CARPENTER SURFACE TREAT

SAWING 0 3 41 44

TRIP UNEVEN LABOURER OTH WALK / RUN ELSE

FLOORS 0 15 28 43

LOW FALL PLUMBER HEATING

SURFACE TREAT

MOVEABLE LADD

0 28 14 42



1 26 14 41

OTHER-HIT OBJECT

MASON BRICKLAYING BUILDING MATS

0 16 24 40

OTHER-TRIP CARPENTER CLIMB / DESCEND EQ


OTHER-HIT OBJECT

CARPENTER SURFACE TREAT

BUILDING MATS

0 12 25 37

68

Table 22 Accidents in construction between 2002/03 and 2003/04 - Most frequently occurring matches of fatal and major injury accidents for accident kind, occupation,


Accident Kind Occupation Work Process Agent F M O F+M



0 65 38 65

LOW FALL PAINTER DECORATE

SURFACE TREAT

MOVEABLE LADD

0 62 26 62

HIGH FALL PAINTER DECORATE

SURFACE TREAT

MOVEABLE LADD

1 52 19 53

HIGH FALL ROOF TILER ROOFING ROOFS 5 35 8 40

HIGH FALL SCAFFOLDER SCAFFOLDING FIXD SCAFFOLD

2 38 6 40

LOW FALL CARPENTER SURFACE TREAT

MOVEABLE LADD

0 28 28 28

LOW FALL PLUMBER HEATING

SURFACE TREAT

MOVEABLE LADD

0 28 14 28



1 26 14 27

HIGH FALL CARPENTER SURFACE TREAT

MOVEABLE LADD

1 23 5 24

FALL UNSPEC PAINTER DECORATE

SURFACE TREAT

MOVEABLE LADD

0 23 7 23

OTHER-TRIP LABOURER OTH

CLIMB / DESCEND EQ


HIGH FALL SCAFFOLDER SCAFFOLDING MOB SCAFFOLD

2 19 7 21

LOW FALL CARPENTER CLIMB / DESCEND EQ

MOVEABLE LADD

0 21 6 21

HIGH FALL ROOF TILER ROOFING MOVEABLE LADD

1 19 10 20

OTHER-TRIP LABOURER OTH

WALK / RUN ELSE

FLOORS 0 18 38 18

ELECTRICITY ELECTRIC FITTER

ELECTRICAL OTH ELEC CAB

2 16 12 18


CLIMB / DESCEND EQ


LOW FALL MASON BRICKLAYING MOB SCAFFOLD

0 17 13 17

OTHER-TRIP PAINTER DECORATE

SURFACE TREAT


OTHER-TRIP PLUMBER HEATING

CLIMB / DESCEND EQ


69

70

6. HAZID WORKSHOP

6.1 INTRODUCTION

The objective of the HAZID workshop was:

To identify and characterise the primary risks associated with a range of construction hazards in such a way as to provide guidance on selecting the appropriate risk control / working method.

The methodology described in this section was aimed at:

• Identifying the typical hazards occurring in a range of construction activities.

• Characterising the risks associated with those hazards.

• Characterising the risks associated with alternative work methods and risk controls for addressing those hazards.

6.2 WORKSHOP ATTENDEES

The attendees at the HAZID workshop were:

Attendee Organisation Comments

Andrew East HSE Principal Inspector responsible for construction safety.

Russell Calderwood HSE Specialist Inspector.

Emma Davies HSE Inspector responsible for CDM operational issues.

Mark Hatfield HSE Inspector responsible for construction workplace transport issues

Phil Bernard- Carter BOMEL Humans factors consultant

Mike Webster BOMEL Chartered civil and structural engineer and project director

6.3 METHODOLOGY

BOMEL provided an overall context for the workshop by reviewing the project and highlighting the issues relating to global risks in construction. This review was intended to inform HSE attendees about the requirements for a global approach to risk in the construction industry, the thought process behind such an approach and the indicative scenarios to be considered.

The original intention was to address scenarios for:

• Work at height

71

• Workplace transport

• Lifting operations

• Working with electricity

• Slips and trips

However, as the workshop progressed, it was decided that the most useful information would be obtained if the delegates were to concentrate on the key areas of:

• Work at height (including access to roofs)

• Movement of materials / workplace transport (including lifting operations).

For these two areas, each stage was considered in turn and recorded. The following approach was taken:

• Step 1: The potential construction methods were identified, and one was selected as the baseline method.

• Step 2: The potential stages of the construction process were identified.

For each of the construction methods at each stage of the construction process:

• Step 3: Hazardous scenarios were listed together with an indication of the causal influences and potential effects.

• Step 4: Estimates were made of the most likely frequency and consequences associated with the risks in relation to the baseline method.

• Step 5: Estimates were made of the risk level in relation to the baseline method by combining the frequency and consequence ratings.

Estimates of the most likely frequency and consequences associated with the risks proved to be difficult to rate in absolute terms. The typical grading systems were proving to be too coarse and not differentiating significantly between individual risks. As such, the most common work method was selected as a baseline, and the other methods assigned a rating indicating that their frequencies or consequences were either lower or higher than those of the base case. In the recording form this was signified by the use of either a ‘+’ or a ‘-’. Where a particular risk was considered to be significantly lower or higher than the base case two or more plus or minus signs were assigned.

The frequency ended up being treated as a composite value of exposure time and frequency of exposure to the hazards during that time.

72

6.4 WORKSHOP FINDINGS

The results from the workshop are summarised in Table 23 for work at height and Table 24 for material movements / workplace transport. These summaries have been developed from the raw data collected at the workshop and organised to present the qualitative data more clearly in terms of:

• Phase / method – what work method is being used at each phase of construction.

• Hazard – what are the primary hazards associated with that work method at that phase of construction.

• Risks / comments – what are the risks and what contributes to either reducing (positive factors) or increasing (negative factors) the risk.

73

Table 23 Scenario 1: Work at height (including work on a fragile roof)

Ref. No. Method Hazard Risks / Comments

Freq

Relative

Con Risk Freq

Ratings

Con Risk

1 Transportation

1.1 Ladder • Loading / unloading Positive: Base Base Base 5 5 25

Negative: • Manual handling of large

particularly from transit vans ladders

1.2 Scaffold tower • Loading / unloading Positive: • Aluminium rather than steel Negative: • Stored in vehicle and

loading/unloading requires

= - - 5 4 20

1.3 Fixed scaffold •

•

MSD Moving vehicles

Positive: • Bring in separate workforce Negative: • Transported in larger vehicles with poor

visibility • More workers exposed • Significant amounts of loading Considerations: • Independent or system scaffolds

+ + ++ 6 6 36

1.4 MEWP • Vehicle issues similar to fixed scaffolds

Positive: • Less likely Negative: • More serious injury potential (but less

likely)

- + = 4 6 24

74

- -


Freq

Relative

Con Risk Freq

Ratings

Con Risk

2 Erection

2.1 Ladder •

•

MSD Ladders toppling

falling / Positive:

Negative: • Risk associated with tying in the ladder

Base Base Base 5 5 25

2.2 Scaffold tower •

•

•

Falls from poor technique Overturn Struck by dropped objects

Positive:

Negative: • Competence issues – anyone can tackle this

activity

- + = 4 6 24


•

•

MSD Falls Struckobjects

by dropped

Positive:

Negative: • Competence issues – more competence

required than mobile scaffolding • Also need to use harnesses • More people exposed • Increase in duration of exposure • Also requires ladders (until stairways take

over)*

+* +* ++ 6 6 36

2.4 MEWP •

•

•

•

Ground conditions & toppling Misuse Overhead obstructions Crushing

Positive: • Will not go up if the conditions are outside

operating parameters Negative:

+ - 3 6 18

75


Freq

Relative

Con Risk Freq

Ratings

Con Risk

3 Integrity & reliability

3.1 Ladder Positive: • Less people exposed Negative: • Inspection & maintenance needed • Some ladders are designed for construction,

but domestic ladders may get used


3.2 Scaffold tower Positive: - + = 4 6 24

Negative: • Mixing of components • Misuse • Not using all components

3.3 Fixed scaffold Positive: - ++ + 4 7 28

Negative:

Considerations: • Scaffold boards (tube & fitting wood versus

system)

76

- -

- - ---


Freq

Relative

Con Risk Freq

Ratings

Con Risk

3.4 MEWP Positive: • Inspection & maintenance needed – LOLER • Looked after by hire companies • Fail to safe • Very few failures • Goes wrong less often than ladders Negative: • Faults are not spotted so easily

+ - 3 6 18

4 Access to roof

4.1 Ladder •

•

•

•

•

FFH Slip in getting onto roof Collapse if not tied / Base slip Overloading Rotation

Positive:

Negative: • Can fall further on ladders • Have to move ladders, so the risk is more

frequent • Difficult to get materials up there (i.e.

window frames)


4.2 Scaffold tower •

•

FFH Falls between levels

Positive: • OK if erected properly • Safe & stable for material access Negative: • Misuse by external climbing • Workers need to have something to hold on

to

- 3 4 12

77

- - --

-- - - -


Freq

Relative

Con Risk Freq

Ratings

Con Risk


•

FFH Fall between levels (if properly done)

Positive: • Much less frequent • Safe & stable for material access Negative: • Need for and adequacy of ties • Best for accessing roof when tied in

= (if

ladder)

3 5 15

4.4 MEWP • See erection Positive: = 2 5 10

Negative: • Should not be used for access as getting out

of the platform is potentially unsafe • If the MEWP is moving then overturning is

a risk Considerations: • Assumed that it is sited

5 Access on roof

5.1 Ladder • FFH Positive: Base Base Base 5 5 25

Negative: • Over-reaching • Lack of contact

78

- -

--

- - --

- - -


Freq

Relative

Con Risk Freq

Ratings

Con Risk

5.2 Scaffold tower • Destabilisation Positive: + - 3 6 18

Negative: • May have edge protection missing or boards

may break • Is possible to de-stabilise tower if force is

used or heavy object strikes tubes • Hauling materials up can destabilise


•

Not issue if properly tied in Potential overload with materials

Positive: • Tolerant of impact damage – considerable

redundancy Negative: • Can move around uninhibited • Several trades

+ 2 6 12

5.4 MEWP •

•

•

Standing on handrail Can go into traffic routes on occasions Overload potential

Positive: • Working from a MEWP is reasonable Negative: • Limited number of positions (i.e. above

handrail) • Will need to use other measures such as

harnesses • Work area is localised

= 3 5 15

5.5 Crawling boards • ok for short term

5.6 Valley gutters •

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Freq

Relative

Con Risk Freq

Ratings

Con Risk

5.7 Nets / harnesses / airbags

•

6 Removal

6.1 Ladder Positive: • Slightly less than erection • Taken down form ground level Negative: • Needs to be untied


6.2 Scaffold tower Positive: + ++ +++ 6 7 42

Negative: • Higher than erection


•

•

Ties taken out too early Struck by removed components Taking out bracing

Positive:

Negative: • Higher than erection • Exposing others (larger

components) number of

+++ ++ +++++ 8 7 56

6.4 MEWP Positive: • Virtually nil Negative:

= = = 5 5 25

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Table 24 Scenario 2: Material movements and workplace transport


Freq

Relative

Con Risk Freq

Ratings

Con Risk

1 Transportation

1.1 Large telehandlers • Traffic congestion Positive: Base Base Base 5 5 25

Negative: • Unlikely to close road

1.2 Small telehandlers • Traffic congestion Positive: = = = 5 5 25

Negative: • Unlikely to close road

1.3 Tower crane • Vehicle movements Positive: + = + 6 5 30 • Road blocked? • Spare space early on

Negative: • Large number of vehicles • Will close road

2 Driver access

2.1 Large telehandlers • Falls from cab / steps • Base Base Base 5 5 25

2.2 Small telehandlers • Falls from cab / steps • = - - 5 4 20

2.3 Tower crane • Falls from height Positive: - +++ ++ 4 8 32 • Occupational health • Operators tend to stay up there for whole

day Negative: • Operators tend to stay up there for whole

day • Difficult to rescue

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Freq

Relative

Con Risk Freq

Ratings

Con Risk

3 Erection / Dismantling

3.1 Large telehandlers • Adding lifting accessories

Positive: • Pre-use check Negative:


3.2 Small telehandlers • Adding lifting accessories

Positive: • Pre-use check Negative:

= = = 5 5 25

3.3 Tower crane • Collapse • FFH • Material falls • Foundation

construction

Positive: • Reliant on highly skilled workforce • Highly controlled to match high risk Negative: • Weather • Slinging • Ground conditions • Due to loading / unloading / slinging

+++ ++ +++++ 8 7 56

4 Material movements (including load integrity)

4.1 Large telehandlers (dumpers and loaders)

• Struck by moving vehicles (people and structure)

• Unstable materials • Forks not adjusted for

load • Overturning • Reversing

unavoidable

Positive:

Negative: • Need close access to communicate with

driver, but may involve standing in driver’s blind spot

• Unauthorised use


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- - - ----


Freq

Relative

Con Risk Freq

Ratings

Con Risk

4.2 Small telehandlers •

•

•

•

•

Struck by moving vehicles (people and structure) Unstable materials Forks not adjusted for load Overturning Reversing unavoidable

Positive: • Better visibility than larger ones & more

manoeuvrable Negative: • Need close access to communicate with

driver, but may involve standing in driver’s blind spot

• Unauthorised use

- = - 4 5 20

4.3 Tower crane • Traversingmaterials

/ falling Positive: • Reduces subsequent material movements as

put exactly where required rather than extra handling of telehandlers (i.e. transfer from drop off to point of use)

• Reduces tripping risks Negative: • Weather

- 2 4 8

• Poor loading • Communication is remote, but work would

stop if communication failed • Reduces vehicle movements • More of a hazard of being struck by a load • Can be working ‘blind’

5 Loading / unloading

5.1 Large telehandlers • Base Base Base 5 5 25

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Freq

Relative

Con Risk Freq

Ratings

Con Risk

5.2 Small telehandlers • Dependent on stable load

• = = = 5 5 25

5.3 Tower crane •

•

•

Falls from height for slinger Safe positioning Line of sight

•

•

•

Time of day Communication quality Dependent on vehicle (i.e. cannot unload curtain sided vehicles – would need telehandlers / mobile cranes to unload before tower crane can be used)

+ + ++ 6 6 36

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6.5 WORKSHOP ANALYSES

Estimates have been made of the risk level by combining the frequency and consequence ratings after the workshop. Several approaches to combining the frequency and consequence ratings were considered.

The approach adopted has been to take the baseline frequencies and consequences as having a rating of five. Five has been selected as a base value in order to avoid either the frequency or consequence ratings having a value of zero. From this, we either added or subtracted one for each ‘+’ or ‘-’ recorded against the alternative methods of working. The resulting ratings of frequency and consequence were then multiplied together to give a risk level index. The risk indices are shown in Table 25 for the work at height scenarios and Table 26 for the workplace transport and materials movement scenarios.

Table 25 Overall risk levels for each construction method – Work at height

Construction phase Construction method

Ladder Scaffold tower Fixed scaffold MEWP

1 Transportation 25 20 36 24

2 Erection 25 24 36 18

3 Integrity & reliability 25 24 28 18

4 Access to roof 25 12 15 10

5 Access on roof 25 18 12 15

6 Removal 25 42 56 25

Overall risk 150 140 183 110

Proportion of base 100% 93% 122% 73%

Table 25 shows the risk levels for fixed scaffolding to increase in relation to those for ladders during transportation, erection and removal. However, for access to and on the roof, the risk levels for fixed scaffolding decrease in relation to those for ladders. When summed, this gives fixed scaffolding a risk level of around 122% of that for ladders. This difference is primarily due to the extra risks incurred during transportation, erection and removal even though each of these activities may only last a relatively short time in comparison to the time spent accessing the work area via the scaffolding.

MEWPs rank as lower risks overall than ladders in all but the transportation and removal phases, where they are considered to be of similar risk levels. These reductions in risk between transportation and removal give MEWPS the lowest overall risk level, around 73% of the risk of ladders.

Scaffold towers are judged to have a risk level just lower (around 93%) than that of ladders. Whilst scaffold towers are considered to have lower risk levels than ladders in transportation and provision of access, they were considered to impose somewhat higher risk levels at the removal stage.

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Intuitively this raises questions in relation to the trade off between increased risk during transportation, erection and removal of the scaffolding in relation to the reduced risk level for the operatives working off the scaffolding.

The initial tendency is to consider applying:

• Weightings to the various construction phases.

• Seeking separate relative ratings on exposure time and probability.

However, there is no objective rationale for the former, whilst the latter may improve rankings between construction methods but not between construction phases. Both approaches also serve to complicate the a relatively simple and transparent approach and convey a level of sophistication that is not justified or open to validation. As such, it is considered best to treat the HAZID as a means of identifying key hazards and highlighting where significant risks lie and why. This may provide sufficient information to make a decision on the appropriate construction method. However, comparison and ranking are probably best undertaken as a separate exercise where other factors can also be considered.

Table 26 Overall risk levels for each construction method – Material movements / workplace transport


Large telehandlers

Small telehandlers

Tower crane

1 Transportation 25 25 30

2 Driver access 25 20 32

3 Erection 25 25 56

4 Material movements (inc load integrity) 25 20 8

5 Loading / unloading 25 25 36

6 Dismantling 25 25 56

Overall risk 150 140 218

Proportion of base 100% 93% 145%

Table 26 shows the risk levels for the two sizes of telehandlers are similar for all but driver access and material movements. There are likely to be less steps on smaller telehandlers making access easier. Smaller telehandlers are also likely to have better visibility than larger ones and be more manoeuvrable, making accidents less likely during vehicle movements.

The risk levels for tower cranes raise similar issues to those for fixed scaffolding. Whilst the tower crane is considered to have lower risks for the primary material movement phases, it is considered to present higher risks as a result of transportation, erection, driver access and dismantling. Tower cranes are also considered to present higher risks during the loading / unloading phases due to the slinger operations.

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However, wider issues also have to be considered as telehandlers are unable to provide the access to upper storeys that tower cranes can. The key point is that the HAZID does raise issues to be addressed in terms of the key risk areas. These issues have to be addressed in terms of what is reasonably practicable.

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88

Identify hazards

Analyse risks

Consequences


Likelihood

For eachmethod ateach stage

of construction

7. GLOBAL RISK TOOLKIT

7.1 INTRODUCTION

This section contains an overview of the Global Risk Toolkit. The Toolkit essentially consists of a series of simple techniques supported by a comprehensive source of information to allow the user to estimate likelihoods and consequences.

Where possible assessments of global risk should be based on the experience, knowledge and judgement of those carrying out the assessments. However, it is recognised that on some occasions this knowledge may need to be supplemented by hard data giving relative values of factors such as likelihood and consequences. Such data are provided in the Toolkit.

7.2 SCOPE OF THE TOOLKIT

The scope of the Toolkit is summarised in Figure 28, with sources of supporting information for each of the activities provided in the following sections.


Rank overall risks




Identify hazards

Analyse risks

Consequences



Rank overall risks




Likelihood


of construction

Figure 28 Scope of the Global Risks Toolkit

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2

3

4

5

6

7

8

9

7.3 KEY QUESTIONS

There are a number of key questions that potential users may have before using the Toolkit. A selection of these are addressed in

Table 27 Key questions and answers regarding the Toolkit

Questions Answers

1 When should the Toolkit be applied? When to apply the Toolkit should be self-evident, as the hazard identification and risk assessment process should indicate when a particular construction activity requires a series of choices to be made that may result in risk being transferred as a result of that decision.

What are the hazards and risks to consider for a particular activity?

What alternative methods of construction should be considered?

What are the means of ranking alternative scenarios?

What is reasonably practicable within the regulations?

How can I demonstrate that I have taken the right approach?

What are the areas of greatest risk?

Where is global risk an issue?

What questions need to be addressed as part of the risk assessment in order to identify and address global risk issues?

This should come out of the HAZID process whereby the skills and experience of the participants are used to identify and prioritise key hazards and risks.

Only those that are reasonably practicable to undertake, and enable the construction work to be completed efficiently.

Initially, by qualitative methods during the HAZID. Subsequently, if required, by quantitative methods.

Guidance is provided in Section 2. For further detail, reference will need to be made to the Regulations and their associated Guidance and ACOPs.

As with any risk assessment, it should be based on best practice and documented. In this case, the HAZID and any subsequent calculations and decisions will need to be documented.

This should be determined by the HAZID and any subsequent quantitative assessments.

In most construction activities. However, the extent of the global risk assessment needs to be proportionate.

These issues are described in the Toolkit.

7.4 IDENTIFYING THE HAZARDS AND ASSOCIATED RISKS

7.4.1 Identification

Potential hazards and the risks associated with them should be identified as part of a hazard identification (HAZID) exercise. Guidance on the use of HAZID is contained in Section 4.2. A template is provided in Table 24, and an example of the application of the template is given in Section 6.4.

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A selection of personnel with relevant experience should be used for the HAZID, and the overall objectives should be to:

1. Identify the key hazards for each construction method at each stage of construction.

2. Identify and rank the risks associated with each of these hazards to obtain an indication of where the key risks are and why they are key risks.

The suggested steps are:

Step 1: Identify the potential construction methods, and one select one as the baseline method.

Step 2: Identify the potential stages of the construction process.

For each of the construction methods at each stage of the construction process:

Step 3: List hazardous scenarios together with an indication of the causal influences and potential effects.

Step 4: Make estimates of the most likely frequencies and consequences associated with the risks in relation to the baseline method by assigning one or more ‘+’ or ‘-’ symbols to indicate if the frequencies and consequences are (significantly) greater or less than the base method.

Step 5: Make estimates of the risk level in relation to the baseline method by combining the frequency and consequence ratings.

Step 6: Assess whether there is enough information to make a decision on the appropriate construction method.

Step 7: If there is not sufficient information, collect information from the participants to undertake a quantitative analysis.

7.4.2 Analysis

A qualitative analysis can be undertaken within the HAZID by assigning values to the frequencies and consequences in relation to the baseline construction method. This will need to be done for each construction method for each stage of construction. The risk levels are calculated by multiplying the frequencies and consequences to give a risk level index.

Each risk index should be entered into a summary table. A template is provided in Table 30, and an example of the application of the template is given in Section 6.4.

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Table 28 HAZID template for summarising overall risk indices


1 2 3

1 25

2 25

3 25

4 25

5 25

6 25

Overall risk 150

Proportion of base 100% % %

These risk indices give a preliminary assessment of where the key risk areas are and how each construction method compares with the alternatives. This enables the subsequent discussions to be focussed on the key risk areas and deciding on what can be done to manage those risks. The discussion should also focus on the key issues of practicability, considering (but not limiting to) issues such as:

• Feasibility

• Costs

• What extra benefits are offered by each method?

• What competencies and experiences are likely to be available?

• What plant is available?

• Is the plant required for use elsewhere on site?

• What are the relative efficiencies of each method?

If there is sufficient information to select an appropriate construction method or combination of methods, this should be documented, and the process is complete. If, however, there is insufficient information and a quantitative risk assessment is considered necessary, the approach outlined in Section 7.5 should be followed.

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Table 29 HAZID Template


Freq

Relative

Con Risk Freq

Ratings

Con Risk

1 Construction Phase 1

1.1 Method 1 • Positive: Negative:





2.1 • Positive: Negative:





3.1 Large telehandlers • Positive: Negative:


3.2 Small telehandlers • Positive: Negative:

3.3 Tower crane • Positive: Negative:

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7.5 QUANTITATIVE RISK ASSESSMENT

7.5.1 Assessing and ranking the risks

A quantitative risk assessment may not be considered necessary in all circumstances, or it may be that a small number of quantitative risk assessments are undertaken to validate or calibrate qualitative risk assessments. Where a quantitative risk assessment is considered appropriate, it is recommended that a computerised spreadsheet be set up based on the example provided in Sections 9.2.2 and 9.3.2.

The titles in the spreadsheet correspond to those used in the HAZID, whilst the data should be derived from a combination of experience and the data sources outlined in Section 8. If the decision is taken to undertake a quantitative risk assessment in the HAZID session, then the same participants can be used to provide some of the required data.

By setting up the analysis in a spreadsheet, sensitivity analyses can be undertaken to see how the results vary with issues such as:

• Lengthening or shortening of the construction stages.

• Variations in the size of workforce available.

• Differences in accident probabilities.

This would provide information on how much the risks varied and whether the subsequent rankings changed significantly.

7.5.2 Addressing risk controls

The calculation approach adopted calculates the effectiveness of each alternative construction method in controlling the risks in relation to the baseline method as follows:

essEffectiven = Riskbaseline − Risk ealternativ ×100

Riskbaseline

This effectiveness is converted into a cost-benefit ratio by expressing it as a risk reduction per pound spent as follows:

essEffectiven × Riskbaselinereduction Risk = Cost e alternativ − Costbaseline

This gives an indication of what extra benefit in risk reduction is gained for expenditure over and above that spent on the base construction method.

The approach proposed by HSE(4) (see Section 3.6) is to only compare the costs of the health and safety components. It is not always possible to separate out the health and safety costs as the work is construction process is required anyway, e.g. access to height or material movements are required to get the job done. There are also other benefits that may arise as a result of the chosen method of construction. For instance:

94

• If the plant can also be used elsewhere on site.

• Skills and competencies already exist on site.

• Efficiency gains can be made.

It should be borne in mind that the calculated values and rankings are merely a guide to aid the decision-making process.

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8. DATA SOURCES

8.1 INTRODUCTION

This section contains data and information on data sources on the following quantitative and qualitative components of risk:

Quantitative Qualitative

Exposure Risk registers • Work at height Likelihood

Probabilities • Workplace transport

• MEWPs

• Telehandlers

Consequences Risk modifiers

It is suggested that this section is used in conjunction with Section 5 and, most importantly, experienced and skills gained from working in the construction industry.

8.2 EXPOSURE

Exposure is probably the most straightforward of the three components of risk, as it uses information and knowledge that will already be available within construction organisations for estimating purposes. Exposure is simply how many workers are exposed to the hazard and for how long. Essentially, this is the number of workers that are required to undertake a task. Such information should be readily available from organisations’ past experience and estimating guides such as those produced by Spon and Wessex.

8.3 PROBABILITIES

8.3.1 Construction accidents

Table 30 shows the accidents reported in the construction industry in 2003/04 along with the accident rates and number of workers / employees. From these figures, the annual risk of a death expressed as a probability of around 1 in 28,600 is calculated. For reported major injury accidents, the annual probability is around 1 in 300, whilst that for reported over 3-day injury accidents is around 1 in 150. HSE(31) estimates from the Labour Force Survey that around half of the non-fatal injury accidents are reported in construction. Taking this into account, the annual probabilities halve to around 1 in 150 for major injury accidents and 1 in 75 for over 3day injury accidents.

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Table 30 Probability of having a reportable accident in construction in 2003/04

Severity Population Accidents

Number Rate Probability 1 in

Fatal 2m workers 70 3.5 0.000035 28,571

Major 1.19m employees 3,982 335.1 0.003351 298

Over 3-day 1.19m employees 8,144 683.6 0.006836 146

8.3.2 Other causes of death

In order to put the probabilities given in Table 30 into context, Table 31(4) gives the figures for annual risk of death for the population as a whole expressed in the form of 1 in. Table 31 shows that the probability of a death in construction is similar to that of dying due to lung cancer caused by radon in dwellings.

Table 31 Annual risk of death for various causes averaged over the entire population

Cause of death

Cancer

Injury and poisoning

All types of accidents and all other external causes

All forms of road accident

Lung cancer caused by radon in dwellings

Gas incident (fire, explosion or carbon monoxide poisoning)

Lightning

Annual risk

1 in 387

1 in 3,137

1 in 4,064

1 in 16,800

1 in 29,000

1 in 1,510,000

1 in 18,700,000

Few data are available on the likelihoods or probabilities of having accidents. In may instances, reliance will have to be made on judgment and experience. The RIDDOR accident data can only be expressed in terms of the overall number of workers (or employees) in the construction industry as global data are not readily available for how many workers undertake particular activities or use particular items of plant. Within individual organisations, staff will be able to make more appropriate estimates of exposure using their knowledge of working practices within that organisation.

8.3.3 Ladders and scaffolding in construction

The following tables are presented to give an indication of the accident rates for ladders and scaffolding in the construction industry as a whole. However, it should be borne in mind that it is likely that more workers will be exposed to ladders than scaffolding.

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Table 32 Accidents involving ladders in the construction industry in 2003/04

Accident severity Number Employment Rate 1 in

Fatal 7 2,000,000 0.000004 285,714 Workers

Major 471 1,190,000 0.000396 2,527 Employees

Over 3-day 371 1,190,000 0.000312 3,208 Employees

Total non-fatal 842 1,190,000 0.000708 1,413 Employees

Table 33 Accidents involving mobile scaffolding in the construction industry in 2003/04


Fatal 3 2,000,000 0.000002 666,667 Workers

Major 156 1,190,000 0.000131 7,628 Employees



Table 34 Accidents involving fixed scaffolding in the construction industry in 2003/04


Fatal 4 2,000,000 0.000002 500,000 Workers

Major 131 1,190,000 0.000110 9,084 Employees



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8.4 CONSEQUENCES

This section provides an indication of what the consequences of accidents are for various accident kinds, occupations, work processes and agents. The consequences are expressed as costs to society for the accidents reported in the construction industry in 2003/04. The cost data for the fatal, major and over 3-day injury accidents have been taken from Table 10 based on the costs of accidents in Great Britain derived by HSE in Reference 24.

Ratios are given for the consequences expressed as a ratio of the factor with the lowest consequences. This shows that the consequences vary more for accident kind than occupation, work process or agent. Occupation is the field with least variation.

Table 35 Consequences associated with accident kinds (global categories)

Accident Kind - Map Accident numbers - Total Costs

Ratio Fatal Major Over 3

day Total Total (£m) Average

13 - VOLT 7 61 75 143 £10.778 £75,373 12.7

03 - TRANSPORT 10 95 105 210 £15.662 £74,581 12.6

08 -COLLAPSE/OVERTURN

3 40 26 69 £5.076 £73,565 12.4

07H - HIGH FALL 31 507 223 761 £55.521 £72,958 12.3

XX - NOT KNOWN 1 13 18 32 £1.719 £53,717 9.1

07X - FALL 5 250 163 418 £15.332 £36,679 6.2

07L - LOW FALL 2 633 515 1,150 £26.532 £23,071 3.9

12 - EXPLOSION 9 8 17 £0.346 £20,360 3.4

02 - STRUCK BY 7 741 1,360 2,108 £39.740 £18,852 3.2

01 - MACHINERY 1 180 300 481 £8.693 £18,073 3.0

15 - OTHER KIND 1 97 216 314 £5.459 £17,385 2.9

17 -ASSAULT/VIOLENCE

16 25 41 £0.660 £16,094 2.7

04 - STRIKE / STEP ON 2 121 391 514 £8.209 £15,970 2.7

06 - TRIP 1,246 1,982 3,228 £51.530 £15,963 2.7

10 - EXPOSURE/HOT SUB

88 205 293 £3.908 £13,338 2.2

11 - FIRE 6 29 35 £0.328 £9,385 1.6

05 -HANDLING/SPRAINS

627 3,224 3,851 £35.127 £9,121 1.5

14 - ANIMAL 1 16 17 £0.101 £5,933 1.0

Grand Total 70 4,731 8,881 13,682 £284.720 £20,810 3.5

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Table 36 Consequences associated with accident kinds (detailed categories)

Accident Kind - Detailed Accident numbers - Total Costs

Ratio Fatal Major Over

3-day Total Total (£m) Average

RUNAWAY 1 3 6 10 £1.322 £132,151 22.3

UNKNOWN-VEHICLE 1 4 6 11 £1.356 £123,300 20.8

REVERSE 2 16 20 38 £3.024 £79,577 13.4

ELECTRICITY 7 61 75 143 £10.778 £75,373 12.7

COLLAPSE 3 40 26 69 £5.076 £73,565 12.4

HIGH FALL 31 507 223 761 £55.521 £72,958 12.3

FORWARD 6 67 69 142 £9.770 £68,802 11.6

NO INFO 1 13 18 32 £1.719 £53,717 9.1

FALL STRUCT 4 69 114 187 £7.641 £40,859 6.9

FALL UNSPEC 5 250 163 418 £15.332 £36,679 6.2

OTHER-HIT FIXED 1 13 40 54 £1.810 £33,515 5.6

UNKNOWN-EXPOSED 5 1 6 £0.178 £29,677 5.0

FALL EQUIP 2 90 112 204 £5.978 £29,304 4.9

FRM EXPLOSION 2 1 3 £0.074 £24,568 4.1

LOW FALL 2 633 515 1,150 £26.532 £23,071 3.9

OVERTURN 5 4 9 £0.190 £21,161 3.6

EXPLOSION 9 8 17 £0.346 £20,360 3.4

UNKNOWN-TRIP 91 99 190 £3.574 £18,813 3.2

TRIP OBSTRUCT 327 365 692 £12.883 £18,617 3.1

MACHINERY 1 180 300 481 £8.693 £18,073 3.0

HARM FAILURE 20 24 44 £0.795 £18,065 3.0

HARM HANDLING 24 31 55 £0.963 £17,507 3.0

OTHER 1 97 216 314 £5.459 £17,385 2.9

EJECTED 58 83 141 £2.360 £16,741 2.8

OTHER-HIT OBJECT 1 436 741 1,178 £19.420 £16,485 2.8

HARM NORM OP 2 3 5 £0.082 £16,393 2.8

PHYS ASSAULT 16 25 41 £0.660 £16,094 2.7

SLIP WET 100 165 265 £4.160 £15,699 2.6

SLIP DRY 54 90 144 £2.250 £15,626 2.6

PRESSURE NORM 6 10 16 £0.250 £15,626 2.6

OTHER-EXPOSED TO 26 44 70 £1.086 £15,517 2.6

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Accident Kind - Detailed Accident numbers - Total Costs

Ratio Fatal Major Over

3-day Total Total (£m) Average

OTHER-TRIP 496 903 1,399 £20.984 £14,999 2.5

STRUCTURE 1 78 255 334 £4.959 £14,847 2.5

UNKNOWN-OBJECT 5 10 15 £0.215 £14,349 2.4

TRIP UNEVEN 178 360 538 £7.679 £14,273 2.4

VEHICLE 14 42 56 £0.660 £11,794 2.0

STEP ON 16 52 68 £0.771 £11,343 1.9

OTHER-HANDLING 142 484 626 £6.939 £11,084 1.9

PERSON 2 7 9 £0.098 £10,943 1.8

SHARP 230 887 1,117 £11.664 £10,443 1.8

HAND TOOL 73 282 355 £3.704 £10,434 1.8

PUSH PULL 58 233 291 £2.980 £10,240 1.7

CARRYING 55 221 276 £2.826 £10,239 1.7

FIRE 6 29 35 £0.328 £9,385 1.6

UNKNOWNHANDLING

7 42 49 £0.417 £8,510 1.4

HOT COLD 11 97 108 £0.783 £7,253 1.2

BODYMOVE 43 420 463 £3.230 £6,977 1.2

LIFT PUTDOWN 92 935 1,027 £7.062 £6,876 1.2

ANIMAL 1 16 17 £0.101 £5,933 1.0

Grand Total 70 4,731 8,872 13,673 £284.683 £20,821 3.5

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Table 37 Consequences associated with occupations

Occupation Accident numbers - Total Costs



PAINTER DECORATE 7 199 205 411 £16.116 £39,211 3.7

ROOF TILER 6 176 253 435 £14.322 £32,923 3.1

ELECTRIC FITTER 9 319 503 831 £23.906 £28,767 2.7

LABOURER BUILD 4 107 217 328 £9.388 £28,622 2.7

HGV DRIVER 1 44 72 117 £3.020 £25,815 2.4

CONSTRUCT MGR 1 91 106 198 £4.796 £24,221 2.3

ELECTRICAL ENG 1 41 81 123 £2.953 £24,009 2.2

CONSTRUCTION NEC 6 316 534 856 £20.352 £23,776 2.2

STEEL ERECTOR 1 50 92 143 £3.312 £23,159 2.2

SCAFFOLDER 3 201 309 513 £11.845 £23,090 2.2

LABOURER OTH 11 647 1,145 1,803 £40.352 £22,380 2.1

OTH STORAGE HAND 1 25 94 120 £2.450 £20,419 1.9

CARPENTER 7 501 953 1,461 £29.711 £20,336 1.9

GLAZIER 1 69 153 223 £4.225 £18,944 1.8

CONSTRCT OPS NEC 2 344 598 944 £16.821 £17,819 1.7

PIPE FITTERS 48 63 111 £1.930 £17,387 1.6

ROAD CONSTRUCT 3 99 453 555 £8.892 £16,021 1.5

PLANT OPS NEC 51 91 142 £2.150 £15,141 1.4

PLASTERERS 102 190 292 £4.333 £14,839 1.4

MASON 239 460 699 £10.214 £14,612 1.4

FLOOR WALL TILER 31 61 92 £1.330 £14,460 1.4

WELDING TRADES 41 81 122 £1.761 £14,433 1.4

ENG PROS NEC 113 233 346 £4.893 £14,142 1.3

PROCESS OPS 63 137 200 £2.757 £13,787 1.3

GROUNDSMEN 59 129 188 £2.585 £13,751 1.3

METAL PRODUCTION 52 115 167 £2.284 £13,676 1.3

FORK-LIFT TRUCK 38 91 129 £1.698 £13,161 1.2

TRANSPORTOPSNEC 47 122 169 £2.139 £12,656 1.2

PLUMBER HEATING 198 530 728 £9.077 £12,468 1.2

ENG TECH 19 70 89 £0.950 £10,675 1.0

Grand Total 64 4,330 8,141 12,535 £260.561 £20,787 1.9

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Table 38 Consequences associated with work processes

Work process Accident numbers - Total Costs



DEMOLITION 5 50 40 95 £7.866 £82,804 9.2

ROOFING 9 187 261 457 £18.314 £40,075 4.5

ELECTRICAL 9 263 403 675 £21.545 £31,918 3.6

TRAV IN VEHICLE 1 62 56 119 £3.580 £30,088 3.4

SCAFFOLDING 5 255 354 614 £16.294 £26,538 3.0

FOUNDATION/EXCAV 2 96 160 258 £6.385 £24,748 2.8

LAY/REPAIR 1 40 77 118 £2.902 £24,592 2.7

STRUCTURAL ERECT 2 99 177 278 £6.560 £23,596 2.6

SURFACE TREAT 15 902 1,602 2,519 £55.879 £22,183 2.5

WALK/RUN CARPARK 22 16 38 £0.831 £21,879 2.4

ROAD BUILD/REP 4 154 464 622 £12.043 £19,362 2.2

SUPPORT TO TRAV 18 19 37 £0.705 £19,044 2.1

LABOURING NEC 5 467 920 1,392 £26.007 £18,683 2.1

MAINTN MACHINES 2 223 448 673 £11.992 £17,819 2.0

CLIMB/DESCEND EQ 1 489 707 1,197 £21.123 £17,647 2.0

ASBESTOS 31 41 72 £1.248 £17,329 1.9

BRICKLAYING 1 187 351 539 £9.147 £16,971 1.9

WALK/RUN ELSE 1 389 633 1,023 £17.339 £16,949 1.9

CONC FORMWORK 14 21 35 £0.574 £16,393 1.8

PROD MANUFACTURE

1 47 171 219 £3.534 £16,135 1.8

OTH HANDLING 3 316 865 1,184 £18.142 £15,323 1.7

WOOD PROCESSING 17 32 49 £0.724 £14,766 1.6

LOAD/UNLOAD 1 190 498 689 £9.859 £14,309 1.6

ENTER/LEAVE 36 73 109 £1.554 £14,255 1.6

AMENITIES 9 25 34 £0.416 £12,245 1.4

STORING 71 207 278 £3.325 £11,960 1.3

ADMIN WORK 8 25 33 £0.382 £11,562 1.3

TRAV ON HIGHWAY 8 32 40 £0.410 £10,261 1.1

LAND MAINTENANCE 8 35 43 £0.423 £9,834 1.1

CLEAN INTERNAL 6 32 38 £0.341 £8,971 1.0

Grand Total 68 4,664 8,745 13,477 £279.443 £20,735 2.3

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Table 39 Consequences associated with agents

Agent Accident numbers - Total Costs



ROOFS 6 99 62 167 £10.854 £64,995 7.6

FLT 2 49 74 125 £4.395 £35,159 4.1

FIXD SCAFFOLD 4 173 190 367 £11.572 £31,532 3.7

MOVEABLE LADD 7 588 400 995 £30.453 £30,606 3.6

OTH ELEC CAB 2 67 115 184 £5.190 £28,209 3.3

MOB SCAFFOLD 3 214 240 457 £12.013 £26,286 3.1

OTHER SURF&STRUC 2 81 138 221 £5.772 £26,119 3.1

WINDOWS 1 18 86 105 £2.174 £20,702 2.4

FLOORS 4 560 956 1,520 £28.198 £18,552 2.2

STRETCH WATER 57 70 127 £2.272 £17,889 2.1

BUILDING MATS 4 462 1,107 1,573 £25.413 £16,156 1.9

STAIRS STEPS 205 325 530 £8.474 £15,988 1.9

DOORS WALLS 1 93 254 348 £5.477 £15,737 1.8

OTHER MACH&EQU 77 136 213 £3.240 £15,212 1.8

PIPE LINE WRK 49 94 143 £2.093 £14,635 1.7

PARTICLES 37 80 117 £1.618 £13,825 1.6

OTHER MATS&MACH 1 250 695 946 £12.759 £13,488 1.6

JOIN DEVICES 31 71 102 £1.372 £13,447 1.6

VEH COMPTS 48 119 167 £2.161 £12,942 1.5

DRILLING 56 141 197 £2.530 £12,845 1.5

INJD PERSON 2 73 467 542 £6.853 £12,644 1.5

MISC PORT CON 82 214 296 £3.736 £12,623 1.5

LOOSE PRODUCT 25 66 91 £1.142 £12,552 1.5

WATER 26 69 95 £1.189 £12,520 1.5

MACH COMPTS 32 86 118 £1.468 £12,444 1.5

NAILING 67 181 248 £3.078 £12,412 1.5

OTHER HAND TOOL 24 86 110 £1.190 £10,819 1.3

FURNITURE 20 76 96 £1.010 £10,517 1.2

SAWING 30 135 165 £1.601 £9,704 1.1

CUTTING 29 173 202 £1.723 £8,531 1.0

Grand Total 39 3,622 6,906 10,567 £201.022 £19,024 2.2

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8.5 RISK REGISTERS

This section contains a series of risk registers for:

• Low-level work at height

• High-level work at height

• Workplace transport

• Mobile elevating work platforms (MEWPs)

• Telehandlers

These risk registers are intended, primarily, to inform the HAZID as they provide indications of what the key risk areas are and what the typical factors involved in those risks are.

8.5.1 Work at height

The risk registers for work at height have been categorised in terms of the key agents involved, i.e. ladders, scaffolding, roofs and steps. Information is provided for the key occupations and activities frequently involved in falls from height.

Table 40 Low-level falls risk register for construction

Involving Activity Typical factors

Moveable Ladders

Electrical Fitter • Electrical Work • Main cause: Many cases involve electricians • Climbing /

descending stairs, vehicles or

slipping from ladders due to a lapse in concentration whilst undertaking electrical work resulting in a loss of balance or footing –

equipment (on-site transfer)

appears that step ladders are not a suitable platform to work from

• Maintenance of • Pulling cable / wire which snapped causing machines electrician to fall backwards and of ladder

• Electric shock caused by incorrect work undertaken by apprentice which was consequently not checked by supervisor, causing worker to lose balance

• Foot caught in cable while working causing electrician to lose balance

• Working or ascending / descending ladder in poor lighting

Painter / Decorator • Surface Treatment • Climbing /

descending stairs, vehicles or

All the points raised below also apply to electrical fitters undertaking electrical work, climbing / descending stairs, vehicles or equipment or

equipment (on-site performing the maintenance of machines transfer)

• Ladder not tied or otherwise secured at all or Carpenter / Joiner • Surface Treatment

106


• Climbing / descending stairs,

inadequately, possibly because nowhere to tie or no-one to foot it joint primary cause

vehicles or • Foot slipped or misplaced footing primarily equipment (on-site whilst descending ladder - joint primary cause transfer) • Injured person overstretching / over reaching -

joint secondary cause • Ladder not suitable for work undertaken, e.g.

too short, not of industrial quality, tower scaffold or other more secure work platform required; attempting to climb ladder whilst carrying tools, materials or heavy objects - joint secondary cause

• Ladder positioned on slippery or uneven surface (e.g. dust sheets, wet waste wallpaper, chippings, polished floor)

Plumber / Expert

Heating • Plumbing • Surface Treatment • Climbing /

descending stairs, vehicles or equipment (on-site transfer)

Plasterer • Plastering • Surface Treatment

• Poor planning or communication leading to the use of ladders where a tower scaffold or secure work platform would be appropriate

• Wet or muddy working conditions contributing to slippage when climbing / descending ladder

• Ladder not erected properly, e.g. locking catch hadn’t clicked in place

• Ladder faulty, e.g. broken rungs, missing rubber feet, not erected properly, lack of a formal system for ladder examination / maintenance

• Injured person blown off by gust of wind • Lack of training in the safe use of a ladder, e.g.

user not aware of safe working gradient on a ladder

Scaffolding

Scaffold / Steeple Worker

• Scaffolding • Boards breaking or snapping e.g. transom spacing too wide, or boards contain a series of knots

• Falling through incomplete work platforms, e.g. unboarded / unguarded trap doors, unattended gaps in flooring

• Loss of balance e.g. due to standing on flooring such as pipes or tubes as a substitute for floor boards, harness caught on a fitting

Bricklayer / Mason • Bricklaying • Board broke / gave way • Foot slipped through / between two scaffold

boards causing loss of balance • Working on incomplete or poorly structured

work platform, e.g. boards not secured, unguarded ends, no toe boards, standards over spanned

• Use of unofficial access routes with inadequate safety precautions in place as shortcuts

Carpenter / Joiner • Surface Treatment (mobile scaffolding)

• Lost footing or balance and slipped from scaffold platform (most often the trestle Painter / Decorator

107


Plasterer scaffold) or fell through gap in work platform • Floor trestles over-spaced due to restrictions in

floor space causing floor boards to snap

Stair steps (including step ladders)

Electric Fitters • Electrical work • Climbing /


(e.g. painter / • Climbing / decorator, carpenter / descending stairs, joiner) vehicles or

equipment (on-site transfer)

• Surface treatment

Step ladder involved in all cases of electrical fitter falling from ‘steps’ whilst completing electrical work. In this case falls from the steps of a ladder are classified as fall from ‘stairs steps’ • Fell when stepping from work platform onto

step ladder / steps • Lost balance and slipped from steps • Walking on incomplete or poorly constructed

staircase

• Slipped of stairs – lost balance or footing • Footwear wet / muddy / slippery causing fall

(recommendation: use a boot scraper) • Walking on incomplete or poorly constructed

staircase • Fell through open stairwell • No handrail in place • Fell when stepping from work platform onto

steps

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Table 41 High-level falls risk register for construction


Moveable Ladders

Painter / Decorator • Surface Treatment • Ladder not tied or otherwise secured at all or • Climbing / inadequately - joint primary cause

descending stairs, vehicles or equipment (on-site

Injured person overstretching / over reaching mainly during surface treatment work - joint primary cause

transfer) • Foot slipped, misplaced footing or foot caught • General

Maintenance in rungs primarily whilst descending the ladder - secondary cause

• General Labouring • Ladder positioned on slippery or uneven surface

• Ladder faulty, e.g. broken rungs, missing rubber feet, not erected properly

• Ladder not suitable for work undertaken, e.g. too short, tower scaffold or other more secure work platform required, attempting to climb ladder whilst carrying tools or materials

• Fall from top of ladder when transferring from ladder to work platform or vice versa

• Lack of training in the safe use of a ladder, e.g. user not aware of safe working gradient on a ladder

• Wet or muddy conditions contributing to slippage when climbing / descending ladder

• No system for examining or maintaining ladders

Electrical Fitter • Electrical Work • Climbing /


• General Installation

• Maintenance of machines

Carpenter / Joiner • Joinery / Carpentry

• Climbing / descending stairs, vehicles or equipment (on-site transfer)

• General Jobbing

• Injured person blown of by gust of wind • Lack of monitoring by contractor of workers

who undertake work remotely • General Labouring • Loss of grip due to wearing of gloves • Surface treatment • Ladder unhooked itself e.g. from gutter,

window sill • Bonus payment scheme, i.e. salary affected by

not working in adverse weather conditions. This is a problem for workers installing satellite dishes

Electrical fitters were also affected by the following: • Pulling cable / wire which snapped causing

electrician to fall backwards and of the ladder

Roofer Roof Tiler

• Roofing • Climbing /


• Roof Sheeting

• Electric shock caused by incorrect work undertaken by apprentice which was consequently not checked by supervisor, causing worker to lose balance

Scaffolding

Scaffold / Steeple Many of these accidents could have been avoided • Scaffolding Worker if adequate edge protection, guard rails and toe • Climbing /

boards existed or those present were secure. Indescending stairs, addition, by wearing and clipping a harness to the vehicles or available safety lines would have reduced the equipment (on-site

109


transfer) number of falls. • Boards breaking or snapping e.g. transom

spacing too wide, boards contain a series of Bricklayer / Mason • Bricklaying

Carpenter / Joiner • Carpentry / Joinery

• Surface Treatment

knots or overloading • Batons or hop-ups failed • Guard rails gave way • No edge protection or toe boards • Not wearing harness or harness unclipped • Working on incomplete or poorly structured

work platform, e.g. boards not secured, unguarded ends, standards over spanned, inferior welding, scaffolding not adequately tied to gable

Roofer Roof Tiler

• Roofing

• Loss of balance e.g. due to standing on flooring such as pipes or tubes as a substitute for floor boards, staging not tied together, harness caught on a fitting or foot slipped through / on edge of gap between scaffold boards causing loss of balance

• Use of unofficial access routes with inadequate safety precautions in place as shortcuts

• Floor trestles over-spaced due to restrictions in floor space causing floor boards to snap

• Wet or frosty weather conditions made boards slippery

• Open-wrist gloves catching on scaffolding • Unsafe system of work, e.g. holes prepared for

stairwell to be installed left unguarded or unidentified as a hazard

Roof Edge / Roofs

Roofer Roof Tiler

• Roofing • Roofer not wearing harness or clipping it to available safety line

• Inadequate protection from potential hazards, e.g. from roof lights, no edge protection, no staging to support weight, no guard rails, no safety nets

• Foot slipped from roof e.g. slippery tiles because wet, frosty or overgrown with moss

• Slipped when stepping from roof onto ladder – gap between roof and first rail bigger than CHSWR requirements

• Unsafe system of work.

Fragile Roof

Roofer • Roofing • Fell through fragile roof lights which were not Roof Tiler boarded nor identified as a hazard • Roof Sheeting

• Not wearing or clipping harness to available safety line

• Unsafe system of work e.g. no edge protection around or covering over fragile roof lights, no guard rails, inadequate access across the roof, no leading edge protection, no safety nets

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8.5.2 Workplace transport

The primary workplace transport risks in construction are shown in Table 42. These can be categorised into the two key activities of loading / unloading and on-site transfer.

On site transfer has two distinct components, the movement of people and the movement of construction vehicles leading to workers being struck by the vehicles. Given the nature of construction work, the number of movements of both people and vehicles can be extensive. Low falls from vehicles whilst moving also present significant risks.

Table 42 Workplace transport risk register for construction

Risk from Involving Typical factors

Loading and unloading

Low falls From vehicles Most falls involve workers falling from the back of (flat bed) vehicles. The falls resulted from stumbling / tripping, pushing / pulling loads or loads falling.

Struck by Objects falling from a Few details are available in the investigation vehicle reports or notifier comments.

Struck by Objects, being lifted or Typically unloading heavy building components free-falling using lifting equipment.

On-site transfer

Low falls From vehicles Little detailed information, but where information was available accidents typically involved workers slipping whilst getting out of vehicles, or falling from overturning vehicles.

Struck by Moving construction Being hit by reversing forklift trucks is common. vehicles especially forklift trucks, A large number of factors were involved in the dumpers, excavators, accidents including: dump trucks, HGVs • Inadequate separation and road construction • Restricted visibility due to loads or raised plant forks

• Reversing with boom raised • Lurching forward • Driver error • Being in the wrong gear • Driver’s foot slipping off the clutch whilst in

gear • Driver forgetting that the vehicle was not in

automatic braking mode • Driver knocking vehicle into gear • Driver not seeing the victim • Driving too close to an excavation • Inadequate segregation • Excessive length of reverse required • Use of vehicle on unsuitable terrain • Poor maintenance. • Failure to jump clear when jumping off of a

moving vehicle

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Risk from Involving Typical factors

• Running into the back of another vehicle • Being struck by excavator buckets or

counterweights • Freeing dumper by excessive ‘rocking’ • Reversing in a blind spot without a banksman • Standing behind digger to keep warm • Driving too fast • Not wearing a seatbelt • Being hit by vehicles at roadworks.

8.5.3 Mobile elevating work platforms

There have been around 80 reportable accidents involving mobile elevating work platforms (MEWPs) in the period 2001/02 to 2003/04. The typical factors involved in these accidents are shown in Table 43.

Table 43 MEWP risk register for construction

Risk from

Working from a MEWP

Setting up and manoeuvring MEWP

Dismounting MEWP

Typical factors

Primary issues: • Trapped against structure (Primary cause) • Worker not wearing a harness falling from a bucket due to:

sudden movement in lowering MEWP bucket; elbow of boom hitting obstruction; losing balance; over-reaching; and handling items.

• Handling / cut injuries from handling materials in MEWP bucket Other issues • Cutting spark from steel erector set light to blanket • MEWP struck by a car causing worker to be thrown from bucket. • Left MEWP to work on steelwork and fell. • Wall collapsed causing MEWP to overturn • Hammer fell from MEWP onto worker below • Electric shock from overhead cable. • Mechanical failure causing workers to be thrown from bucket.

• MEWP ran away when lowered from jack legs • MEWP ran away whilst being set up • Concrete footing gave way leading to bucket sliding down wall. • Overhead crane hit MEWP • MEWP too high and hit obstruction • MEWP toppled into excavation • Hand crushed when lowering scissor lift • Foot trapped under jack legs • Driver thrown out of reversing MEWP when it hit a mound of

waste.

• Injured dismounting from MEWP

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8.5.4 Telehandlers

There have been around 50 reportable accidents involving telehandlers in the period 2001/02 to 2003/04. The typical factors involved in these accidents are shown in Table 44.

Table 44 Telehandler risk register for construction

Risk from

Struck by telehandler

Struck by load

Loading / unloading

Training

Other factors

Typical factors

• Struck by moving telehandler despite good visibility. • Telehandler forks dislodged scaffolding boards. • Driver’s visibility impaired by height of forks, causing him to

strike other worker. • Driver (not wearing seatbelt) shot forward when telehandler

struck gulley grid. • Accidentally knocked controls from outside causing telehandler

to move. • Telehandler rolled and trapped driver. • Crushed by telescopic arm of telehandler. • Struck by ‘parked’ telehandler.

• Trusses slid off of telehandlers forks. • Worker on blind side of telehandler struck by moving load. • Telehandler wheel hit divot causing sheeting load to hit

scaffolding. • Adjustment to telehandler boom caused roof trusses to rock and

strike worker. • Telehandler boom dislodged lintel causing it to fall. • Mortar tub not lifted by lifting points and fell from forks. • Operator error resulted in concrete skip falling form forks. • Forks became trapped in loading bay – dislodging them caused

load to ‘jump’. • Telehandler forks caught scaffold putlog when brick under

outrigger failed.

• Worker lost footing and fell when loading washer unit from roof to telehandler bucket.

• Worker failed to release grip on truss lifted from telehandler and fell.

• Nylon webbing sling failed causing load to fall. • Injured whilst adjusting forks. • Overreached to take load from pallet on telehandler forks and

strained himself. • Finger trapped in freeing telehandler sling. • Telehandler jolted back after lifting excessive load causing back

injuries to operator. • Tripped whilst loading telehandler from uneven ground.

• Untrained driver overturned telehandler by turning with boom raised.

• Telehandler slid down bank - untrained driver . • Telehandler overturned as a result of manoeuvring load to side

without stabilisers – operator unqualified. • Telehandler reversed over worker – driver not trained.

• Fell from bucket fitted to telehandler whilst adjusting bolts. • Stepped off telehandler supported cage onto fragile roof and fell

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Risk from Typical factors

through. • Hand trapped by telehandlers fork. • Worker destabilised wooden box used as a work platform on

telehandlers forks. • Tripped and fell under wheels of telehandler. • Slipped when climbing onto / from telehandler.

8.6 RISK MODIFIERS

Table 45 is presented in order to provide an indication as to the type of issues that may act as risk modifiers, either in a positive or negative sense in reducing or increasing the risk. These are issues that should be considered and discussed as part of the HAZID.

Table 45 Issues to consider in ranking the risks

Issues Detailed issue Decrease risk Increase risk

Work required

Nature of work Less hazardous More hazardous

Duration of work Shorter term Longer term

Frequency of work Several times a day One off

Height of work Low High

Site Weather conditions Good Poor

Ground conditions Good Poor

Adjacent activities No effect Interfere with

Work equipment

No. of people exposed Few Many

Access / egress Good Poor

Mitigation measures Available None

Escape measures Available None

Inspection & maintenance

Undertaken None

Worker Supervision In place None required

Health requirements Not applicable Good health required

Competence No specific requirements High competence required

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9. GLOBAL RISK SCENARIOS

9.1 INTRODUCTION

In order to illustrate the concepts described in the earlier sections of this report and the application of the Global Risk Toolkit, a range of scenarios are presented in this section. These scenarios have been grouped into the two primary areas used in the HAZID workshop described in Section 6, namely:

• Work at height (including access to a roof).

• Workplace transport and material movements.

These two areas involve many of the most hazardous scenarios that occur in construction, with each scenario corresponding to a different stage of the construction process. They also indicate how the techniques may be applied to other construction activities.

9.2 WORK AT HEIGHT

The scenario to be considered for work at height is access to the roof of a two-storey industrial unit. The four potential means of access and work platforms to be considered are:

• Moveable ladders (of construction, not domestic, quality).

• Moveable tower scaffolding.

• Fixed tubular scaffolding.

• Mobile elevating work platforms (MEWPs).

Moveable ladders were considered as the baseline against which the other means of work at height were considered.

In line with the requirements of the Work at Height Regulations, the assessment of global risks addresses all phases of the construction process from delivery of the equipment to site, through erection and use to the removal of that equipment.

9.2.1 Hazard identification

The hazard identification (HAZID) exercise was carried out as part of a workshop held with HSE inspectors. The results are given in Table 23. Further information on the factors underlying accidents can be used as a source of information to inform the HAZID. This is contained in:

• Table 40: low falls in construction.

115

• Table 41: high falls in construction.

• Table 43: the use of MEWPs in construction.

The HAZID identified the following stages at which hazards needed to be identified and risks assessed:

• Transportation

• Erection

• Integrity & reliability

• Access to roof

• Access on roof

• Removal

Each of these scenarios is considered separately.

9.2.2 Global risk assessment

The global risk assessment has been undertaken by spreadsheet using the methods described in Section 94 and the data provided in Section 8. Table 49 contains the results from the risk assessment. Each of the construction stages has been considered for each of the four access methods, and individual risks have been estimated.

Whilst the calculation process is relatively straightforward, a number of assumptions have to be made in order to estimate the numbers in each of the cells. Details on these assumptions are contained in the tables as follows:

• Table 46: Assumptions underlying estimates of exposure

• Table 47: Assumptions underlying estimates of accident probability

• Table 48: Assumptions underlying estimates of cost of each means of access

Every Single application will have its own assumptions and criteria. Those presented here are for illustrative purposes only. In particular, due consideration would need to be given to the extent of labour cost required for the workers associated with each access method as some will allow work to be completed faster than others.

116

Table 46 Assumptions underlying estimates of exposure

Access method Uses per day Days per project People per shift No. shifts per day

• Moved 10 • Negligible for • 2 workers • 1 shift per day

Ladder times per day transportation

• 15 days for throughout

construction

Scaffold tower

• Moved twice per day

• 0.25 day for transportation

• 0.5 day for erection and

• 2 workers for erection and removal

• 3 workers for

• 1 shift per day

removal construction • 10 days for

construction

• Not moved • 2 days for erection

• 3 workers for erection and

• 1 shift per day

Fixed scaffold • 5 days for construction

removal • 6 workers for

construction

MEWPs • Moved 5 times

per day • 15 days for

construction • 2 workers

throughout • 1 shift per day

Table 47 Assumptions underlying estimates of accident probability

Access method

Ladder

Scaffold tower

Fixed scaffold

MEWP

Probability of accident

• 1 in 1,400 from Table 32. Assume that this applies to ladder activities at all stages of construction.

• 1 in 3,400 from Table 33. Assume that this applies to scaffold tower activities at all stages of construction.

• 1 in 4,200 from Table 34. Assume that this applies to fixed scaffold activities at all stages of construction.

• 21 accidents involving MEWPs reported in 2003/04. Assuming 1,190,000 employees, this gives a probability of 1 in 56,700.

Table 48 Assumptions underlying estimates of cost of each means of access

Access method

Ladder

Scaffold tower

Fixed scaffold

MEWP

Cost estimates

• Aluminium, £30 per week.

• Aluminium, £75 per week.

• Tubular, £90 per week.

• Self-propelled, use own site staff to operate, £320 per week.

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Table 49 Global risk assessment – Work at height

No. Method Uses per Days per People No. shifts Exposure Probability Probability of Injury Severity Risk per Rank Risk control Risk control day project per shift per day per of accident accident per use frequency rating project effectiveness cost £

project per use per project % (1 in)

1 Transportation 1.1 Ladder 1 0.1 2 1 0.2 1,400 7.14E-04 1.43E-04 9,121 1.3 2 0.0 204 1.2 Scaffold tower 1 0.25 2 1 0.5 3,400 2.94E-04 1.47E-04 9,121 1.3 3 -2.9 300 1.3 Fixed scaffold 1 2 2 1 4 4,200 2.38E-04 9.52E-04 45,640 43.5 4 -3,235.9 180 1.4 MEWP 1 0.25 2 1 0.5 56,700 1.76E-05 8.82E-06 45,640 0.4 1 69.1 960 2 Erection

2.1 Ladder 10 15 2 1 300 1,400 7.14E-04 2.14E-01 18,852 4039.7 4 0.0 204 2.2 Scaffold tower 2 1 2 1 4 3,400 2.94E-04 1.18E-03 73,958 87.0 1 97.8 300 2.3 Fixed scaffold 1 2 3 1 6 4,200 2.38E-04 1.43E-03 73,958 105.7 2 97.4 180 2.4 MEWP 5 15 2 1 150 56,700 1.76E-05 2.65E-03 73,958 195.7 3 95.2 960 3 Integrity & reliability

3.1 Ladder 10 15 2 1 300 1,400 7.14E-04 2.14E-01 73,958 15848.1 4 0.0 204 3.2 Scaffold tower 2 10 2 1 40 3,400 2.94E-04 1.18E-02 73,958 870.1 3 94.5 300 3.3 Fixed scaffold 1 5 3 1 15 4,200 2.38E-04 3.57E-03 73,958 264.1 2 98.3 180 3.4 MEWP 5 15 2 1 150 56,700 1.76E-05 2.65E-03 73,958 195.7 1 98.8 960 4 Access to roof

4.1 Ladder 10 15 2 1 300 1,400 7.14E-04 2.14E-01 73,958 15848.1 4 0.0 204 4.2 Scaffold tower 2 10 4 1 80 3,400 2.94E-04 2.35E-02 73,958 1740.2 3 89.0 300 4.3 Fixed scaffold 1 5 4 1 20 4,200 2.38E-04 4.76E-03 73,958 352.2 2 97.8 180 4.4 MEWP 5 15 2 1 150 56,700 1.76E-05 2.65E-03 73,958 195.7 1 98.8 960 5 Access on roof

5.1 Ladder 10 15 2 1 300 1,400 7.14E-04 2.14E-01 73,958 15848.1 4 0.0 204 5.2 Scaffold tower 2 10 2 1 40 3,400 2.94E-04 1.18E-02 73,958 870.1 3 94.5 300 5.3 Fixed scaffold 1 5 3 1 15 4,200 2.38E-04 3.57E-03 73,958 264.1 2 98.3 180 5.4 MEWP 5 15 2 1 150 56,700 1.76E-05 2.65E-03 73,958 195.7 1 98.8 960 6 Removal

6.1 Ladder 1 1 2 1 2 1,400 7.14E-04 1.43E-03 18,852 26.9 2 0.0 204 6.2 Scaffold tower 1 1 2 1 2 3,400 2.94E-04 5.88E-04 73,958 43.5 3 -61.5 300 6.3 Fixed scaffold 1 2 3 1 6 4,200 2.38E-04 1.43E-03 73,958 105.7 4 -292.3 180 6.4 MEWP 1 1 2 1 2 56,700 1.76E-05 3.53E-05 73,958 2.6 1 90.3 960

C1117\04\001r Rev O September 2005 118

Table 50 provides a summary of the ranking of the overall risks from the quantitative risk assessments undertaken in Table 49, whilst Table 51 provides a summary or the ranking of the risk reductions per pound spent. Table 52 provides a summary of the risk indices calculated in Table 49

Table 52 shows that the key difference from the qualitative results obtained from the HAZID presented in Section 6.5 is that fixed scaffolding is assessed to have a lower overall risk than ladders and tower scaffolding (although it ties with tower scaffolding in Table 50 in terms of ranks). Table 51 shows that fixed scaffolding ranks the highest in terms of risk reductions per pound spent. This perhaps gives a better representation of the benefits to be gained in reducing the construction time (and exposure) over that for ladders than obtained in the qualitative analyses, although this would vary with different scenarios of varying construction times.

MEWPs are seen to have the lowest overall risk index in Table 52. This ties in with the qualitative findings shown in Table 25. It is interesting to note that the risk index for ladders is significantly greater than that for the other three construction methods.

Table 50 Ranking of the overall risks associated with each construction method at each stage of construction – Work at height


Ladder Scaffold tower

Fixed scaffold

MEWP


2 Erection 4 1 2 3




6 Removal 2 3 4 1

Overall risk 20 16 16 8

Table 51 Ranking of the risk reductions per £ associated with each construction method at each stage of construction – Work at height


Ladder Scaffold tower

Fixed scaffold

MEWP


2 Erection 4 2 1 3




6 Removal 2 3 4 1

Overall risk 20 14 12 14

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Table 52 Risks associated with each construction method at each stage of construction and overall global risks – Work at height

Construction method Construction phase Ladder Scaffold

tower Fixed

scaffold MEWP


2 Erection 4,040 87 106 196

3 Integrity & reliability 15,848 870 264 196

4 Access to roof 15,848 1,740 352 196

5 Access on roof 15,848 870 264 196

6 Removal 27 44 106 3

Overall risk 51,612 3,612 1,135 786

Effectiveness - % 0 93 98 98

Cost - £ 204 300 180 960

Risk reduction per £ 0 500 2,103 67

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9.3 WORKPLACE TRANSPORT AND MATERIAL MOVEMENTS

The scenario to be considered for workplace transport is that of moving materials on a town centre commercial development with relatively limited space. The three potential means of moving material to be considered are:

• Large telehandlers

• Small telehandlers

• Tower cranes

The assessment of global risks addresses all phases of the construction process from delivery of the equipment to site, through erection and use to the removal of that equipment.

9.3.1 Hazard identification

The hazard identification (HAZID) exercise was carried out as part of a workshop held with HSE inspectors. The results are given in Table 24. Further information on the factors underlying accidents can be used as a source of information to inform the HAZID. This is contained in:

• Table 42: workplace transport in construction.

• Table 44: the use of telehandlers in construction.

The HAZID identified the following stages at which hazards needed to be identified and risks assessed:

• Transportation

• Driver access

• Erection

• Material movements (including load integrity)

• Loading / Unloading

• Dismantling (see Erection)

Each of these scenarios is considered separately.

9.3.2 Global risk assessment

The global risk assessment has been undertaken by spreadsheet using the methods described in Section 7.5 and the data provided in Section 8.

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Table 56 contains the results from the risk assessment. Each of the construction stages has been considered for each of the four access methods, and individual risks have been estimated.

Whilst the calculation process is relatively straightforward, a number of assumptions have to be made in order to estimate the numbers in each of the cells. Details on these assumptions are contained in

• Table 53: Assumptions underlying estimates of exposure

• Table 54: Assumptions underlying estimates of accident probability

• Table 55: Assumptions underlying estimates of cost of each means of access

Table 53 Assumptions underlying estimates of exposure

Plant Uses per day Days per project People per shift No. shifts per day

Large telehandler • 1 per day during transportation and erection

• Driver access 5 per day

• Material movements and loading/unload ing 20 times per day

• 0.25 days during transportation

• 0.5 days during erection

• 100 days during construction activities

• Two people for transportation

• One driver • 20 workers on

site exposed during material movements

• 3 exposed during loading / unloading

• 1 per day

Small telehandler • Ditto large telehandler

• Ditto large telehandler



Tower crane • 1 per day during transportation and erection

• Driver access once per day

• Material movements and loading/unload ing 20 times per day

• 1 day during transportation

• 5 days during erection

• 100 days during construction activities

• Four people for transportation

• One operator • Three people

for erection • 20 workers on

site exposed during material movements

• 3 exposed during loading / unloading

• 1 per day

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Table 54 Assumptions underlying estimates of accident probability

Plant

Large telehandler

Small telehandler

Tower crane

Probability of accident

• 23 accidents involving telehandlers reported in 2003/04. Assuming 1,190,000 employees, this gives a probability of 1 in 52,000. No differentiation is made in accident records between small and large telehandlers.

• HAZID indicated that larger telehandlers were more risky for material movements, therefore assume 1 in 47,000 for this stage of construction..

• 23 accidents involving telehandlers reported in 2003/04. Assuming 1,190,000 employees, this gives a probability of 1 in 52,000. No differentiation is made in accident records between small and large telehandlers.

• HAZID indicated that smaller telehandlers were less risky for material movements, therefore assume 1 in 52,000 for this stage of construction.

• 20 accidents involving telehandlers reported in 2003/04. Assuming 1,190,000 employees, this gives a probability of 1 in 59,500.

Table 55 Assumptions underlying estimates of cost of each means of access

Plant

Large telehandler

Small telehandler

Tower crane

Cost estimates

• 7m reach, £275 per week.

• 5m reach, £300 per week (smaller telehandlers are more expensive than larger ones)

• 3 tonne, 40m reach, 30m under the hook. • £6,000 for erection. • £5,500 for removal. • £1,900 per week for hire. • £100 per week for hook items.

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Table 56 Global risk assessment – Workplace transport and material movements

No. Method Uses per Days per People No. shifts Exposure Probability of accident Probability Injury Severity Risk per Rank Risk control Risk day project per shift per day per per use of accident frequency rating project effectiveness control

project (1 in) per use per project % cost £

1 Transportation 1.1 Large telehandler 1 0.25 2 1 1 52,000 1.92E-05 9.62E-06 74,581 1 1 0.0 5,500 1.2 Small telehandler 1 0.25 2 1 1 52,000 1.92E-05 9.62E-06 74,581 1 1 0.0 6,000 1.3 Tower crane 1 1 4 1 4 59,500 1.68E-05 6.72E-05 74,581 5 3 -599.2 53,500 2 Driver access

2.1 Large telehandler 5 100 1 1 500 52,000 1.92E-05 9.62E-03 23,071 222 2 0.0 5,500 2.2 Small telehandler 5 100 1 1 500 52,000 1.92E-05 9.62E-03 23,071 222 2 0.0 6,000 2.3 Tower crane 1 100 1 1 100 59,500 1.68E-05 1.68E-03 73,958 124 1 44.0 53,500 3 Erection

3.1 Large telehandler 1 0.5 1 1 1 52,000 1.92E-05 9.62E-06 23,071 0 1 0.0 5,500 3.2 Small telehandler 1 0.5 1 1 1 52,000 1.92E-05 9.62E-06 23,071 0 1 0.0 6,000 3.3 Tower crane 1 5 3 1 15 59,500 1.68E-05 2.52E-04 73,958 19 3 -8,304.8 53,500 4 Material movements (including load integrity)

4.1 Large telehandler 20 100 20 1 40,000 47,000 2.13E-05 8.51E-01 74,581 63,473 3 0.0 5,500 4.2 Small telehandler 20 100 20 1 40,000 57,000 1.75E-05 7.02E-01 74,581 52,338 2 17.5 6,000 4.3 Tower crane 20 100 20 1 40,000 59,500 1.68E-05 6.72E-01 18,852 12,674 1 80.0 53,500 5 Loading / Unloading

5.1 Large telehandler 20 100 3 1 6,000 52,000 1.92E-05 1.15E-01 18,852 2,175 1 0.0 5,500 5.2 Small telehandler 20 100 3 1 6,000 52,000 1.92E-05 1.15E-01 18,852 2,175 1 0.0 6,000 5.3 Tower crane 20 100 3 1 6,000 59,500 1.68E-05 1.01E-01 73,958 7,458 3 -242.9 53,500

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Table 57 provides a summary of the ranking of the overall risks from the quantitative risk assessments undertaken in Table 56, whilst Table 58 provides a summary or the ranking of the risk reductions per pound spent. Table 59 provides a summary of the risk indices calculated in Table 56

Table 52 shows that the key difference from the qualitative results obtained from the HAZID presented in Section 6.5 is that the tower crane is assessed to have a lower overall risk than telehandlers despite having the largest risk in most of the individual construction phases. This result is largely due to the risks presented by workers being struck by moving telehandlers over a relatively long construction phase. This risk outweighs the other higher risks imposed by tower cranes over shorter periods such as erection and removal. This result would be expected to vary with different scenarios of varying construction times. Table 58 shows that tower cranes rank the highest in terms of risk reductions per pound spent.

Table 57 Ranking of the risks associated with each construction method at each stage of construction – Workplace transport and material movements


Large telehandler

Small telehandler

Tower crane



3 Erection 1 1 3

4 Material movements (including load integrity) 3 2 1

5 Loading / Unloading 1 1 3

6 Dismantling (see Erection) 1 1 3

Overall risk 9 8 14

Table 58 Ranking of the risk reduction per £ associated with each construction method at each stage of construction – Workplace transport and material movements


Large telehandler

Small telehandler

Tower crane



3 Erection 1 1 3

4 Material movements (including load integrity) 3 1 2

5 Loading / Unloading 1 1 3


Overall risk 9 7 15

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Table 59 Risks associated with each construction method at each stage of construction and overall global risks – Workplace transport and material movements


Large telehandler

Small telehandler

Tower crane



3 Erection 0 0 19

4 Material movements (including load integrity) 63,473 52,338 12,674

5 Loading / Unloading 2,175 2,175 7,458


Overall risk 65,871 54,736 20,298

Effectiveness - % 0 17 69

Cost - £ 5,500 6,000 53,500

Risk reduction per £ 0.0 22.3 0.9

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10. CONCLUSIONS

In relation to the initial objectives, the following conclusions can be drawn from the work undertaken in this project:

Objective 1: To set the context of this project in relation to the principles of risk management.

1. The framework for the consideration of global risks only requires a small change from the generic framework for risk assessment. This change involves assessing the risks of all alternative construction methods at each stage of construction.

2. Whilst risk assessment is addressed in a range of regulations applicable to the construction industry, it is only the Work at Height Regulations that raise global risk issues, although the term global risk is not used explicitly. No methodology is presented.

3. The key barriers to undertaking global risk assessment are the lack of a methodology and the supporting data.

Objective 2: To obtain and present risk data on a representative range of construction occupations, activities and equipment.

The following conclusions can be drawn from the analyses of the RIDDOR accident data:

4. The overall number of accidents reduced between 1999/2000 and 2003/04. This reduction resulted primarily from a reduction in the number of over 3-day injury accidents over that period.

5. In terms of the readily identifiable industries, domestic construction, civil engineering construction and electrical installation work report the largest number of accidents. However, there has been a tendency to classify organisations under a catch-all industry description of construction building.

6. The largest number of accidents overall involved handling / sprain injuries. The majority of these involved over 3-day injury accidents. Trips, struck by falling objects, low falls and high falls were involved in the largest numbers of major injury accidents. High falls are the most significant accident kind in terms of severity as they are involved in the largest number of fatalities.

7. Of the readily identifiable occupations, carpenters / joiners are involved in the largest number of accidents overall and the largest number of major injury accidents.

8. Handling and painting (surface treatment) activities are the work processes involved in the largest numbers of accidents.

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9. ‘Floors’ and building materials are the agents involved in the largest number of accidents overall. Moveable ladders are involved in the largest number of major injury accidents.

10. The age profile of the workers indicates a distribution skewed towards younger workers, and with a peak at around 25 to 39. The largest variation is in the number of over 3-day injury accidents, with the major injury accidents numbering around 3,000 to 4,000 for the age groups between 20 and 60.

11. Employees outnumber the self-employed by around ten to one in terms of overall accident numbers. The proportion of over 3-day injuries affecting the self-employed is smaller than that for employees. This may reflect differences in reporting between the two groups. There were few accidents involving trainees.

12. The most significant combination involves painters / decorators having low and high falls from moveable ladders whilst undertaking painting (surface treatment) work. Electric fitters also feature prominently in terms of low and high falls from moveable ladders and trips on stairs and steps.

Objective 3: To hold an HAZID workshop with a staff from HSE’s Construction Division to address global risk scenarios.

A HAZID workshop was held with representatives of HSE’s Construction Division to address a variety of scenarios relating to work at height and workplace transport (including material movements).

13. As a result of this workshop, a qualitative method for addressing global risks was developed. One construction method is selected as the baseline measure, and judgements are made as to whether the frequency and consequences associated with the other construction methods are greater or less than those for the base method at each construction stage.

14. Based on the experience of the HAZID participants, judgements can be made as to whether risks are slightly, somewhat or significantly greater or less than those of the base method.

15. The relative frequencies and consequences can be combined by multiplying them together to give a risk index. By summing these risk indices over all stages of construction, an indication can be obtained of the global (or overall) risk level for each construction method.

16. The global risk indices can give an indication as to where the key risks lie for each construction method and stage of construction such that effort can be focussed on potential risk controls for those methods and / or stages of construction.

17. The global risk indices will need to be considered in the light of other key information including cost, practicalities, environmental issues and available resources.

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18. Whilst the global risk indices can give an indication of the global risks, they may not provide a sufficiently clear-cut answer and may need to be supplemented by quantitative analyses.

Objective 4: To develop a Toolkit for addressing global risk issues in construction.

A Global Risk Toolkit has been developed to permit the assessment of global risks in construction.

19. A staged approach is considered appropriate in order to ensure that the global risk assessment is proportionate. The first stage is a HAZID with qualitative analyses of the results. If this generates sufficient information to allow a decision to be made on the appropriate construction method, then the task is complete. If further information or clarification is required, a methodology is presented for quantitative assessment of the global risks.

20. Whilst a methodology is useful, it needs to be supported by guidance on the data to be used in both qualitative and quantitative risk assessments. Such data are readily available within the expertise contained in construction organisations as the exposure of workers is a function of how long they spend working on an activity. Such information is readily used for estimating purposes.

21. Data on the probability of accidents are presented in order to provide indications of how often construction accidents occur in relation to other accidents or causes of death. However, construction workers may well have a feel from their own experiences as to how frequently different forms of accidents occur in relation to one another. This data can be used for the quantitative risk assessments.

22. Data on the consequences of accidents are presented in terms of the costs to society. This shows that the variation in consequences are much greater for accident kind than they are for occupation, work process or agent. The consequences vary least for occupations.

23. Potential risk reductions can be compared to the base method in terms of risk reduction per pound spent. This enables comparisons to be made in terms of costs and benefits.

Objective 5: To apply the global risk methodology to a series of construction scenarios.

The Global Risk Toolkit has been applied to the range of scenarios addressed in the HAZID workshop in order to provide comparisons of the qualitative and quantitative methods and to provide full worked examples throughout the various phases of the Global Risk Toolkit.

24. The quantitative risk assessments for the work at height scenarios enabled some of the questions relating to length of exposure to be addressed. This showed consistent results for the construction method with the lowest global risk (MEWPs in this example). However, these analyses showed positive effect of scaffolding reducing the construction period and thus exposure to risk compared with ladder access. These risk

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reductions outweighed the increases in risk incurred in erecting and removing the scaffolding.

25. The key difference from the qualitative results obtained from the HAZID presented in is that the tower crane is assessed to have a lower overall risk than telehandlers despite having the largest risk in most of the individual construction phases. This result is largely due to the risks presented by workers being struck by moving telehandlers over a relatively long construction phase. This risk outweighs the other higher risks imposed by tower cranes over shorter periods such as erection and removal.

26. The results presented are indicative and representative of the scenarios presented. They do indicate the ability to consider risk trade-off and transfer between different construction methods and stages of construction. Sensitivity analyses are recommended in order to see if the results remain similar with variations in construction time and manning levels.

27. The results of the quantitative risk assessments need to be combined with other relevant information including practicalities, environmental issues and available resources.

Objective 6: To develop material suitable for dissemination.

28. This report contains the Global Risk Toolkit, a methodology for undertaking global risk assessments in construction. It is supported by significant data on construction risks not available before. When disseminated, this report should provide sufficient guidance to allow the construction industry to address global risk issues.

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11. RECOMMENDATIONS

Based on the work undertaken, the following recommendations are presented:

1. The Global Risk Toolkit should be considered by both HSE and industry as a means of highlighting and addressing global risk issues in construction.

2. The Global Risk Toolkit should not be viewed as a prescriptive guide to assessing global risks, but as an aid to decision making based on experience gained in the construction industry and combined with other relevant information including practicalities, environmental issues and available resources. The Global Risk Toolkit will indicate where questions need to be asked and addressed.

3. A phased approach should be taken to global risk assessment, starting with a qualitative risk assessment. Only if the qualitative approach does not generate sufficient information should a quantitative risk assessment be undertaken.

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12. REFERENCES

1 Department of the Environment, Transport and the Regions: Revitalising Health and Safety – strategy statement – June 2000, DETR, July 2000.

2 Working Well Together Campaign: CONIAC targets for improvement, wwt.uk.com.

3 Health and Safety Commission: Strategic Plan 2001-2004, www.hse.gov.uk.

4 Health and Safety Executive: Reducing risks, protecting people, ISBN 0-7176-2151-0, 2001.

5 Health and Safety at Work etc Act, 1974, HMSO, 1974.

6 Health and Safety Executive: Health and Safety Regulation – A short guide. http://www.hse.gov.uk/pubns/hsc13.htm.

7 Management of Health and Safety at Work Regulations, 1999.

8 Safe use of work equipment. Provision and Use of Work Equipment Regulations 1998, Approved Code of Practice and Guidance L22, HSE Books, 1998, ISBN 0 7176 1626 6.

9 Safe use of lifting equipment. Lifting Operation? and Lifting Equipment Regulations 1988, Approved Code of Practice and Guidance L113, HSE Books, 1998, ISBN 0 7176 1628 2.

10 Construction (Health, Safety and Welfare) Regulations, 1996.

11 Construction (Design and Management) Regulations, 1994.

12 Health and Safety Commission: Revision of the Construction (Design and Management) Regulations (CDM) 1994, Construction (Health, Safety and Welfare) (CHSW) Regulations 1996, Approved Code of Practice (ACoP) and Guidance, CD 200, April 2005.

13 Health and Safety Executive: The Work at Height Regulations 2005, http://www.hse.gov.uk/falls/wahr.htm.

14 Health and Safety Executive: The Work at Height Regulations: A brief guide, http://www.hse.gov.uk/pubns/indg401.pdf.

15 Australian/New Zealand Standard: Risk management, AS/NZS 4360:1995.

16 Health and Safety Executive: Quantified risk assessment: Its input to decision making, Publication C20, 1184.

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17 R2A: Risk and Reliability – An introductory text, 4th Edition.

18 BOMEL Limited. Improving Health and Safety in Construction Phase 2 – Volume 1: Summary report, HSE Research Report 231, June 2004.

19 Loughborough University: Evaluating the performance and effectiveness of ladder stability devices, HSE Research Report 205, 2004.

20 BOMEL Limited: Improving health and safety in construction: Phase 2 – Depth and breadth. Volume 3: Construction transport accidents - Underlying causes and risk control, HSE Research Report 233, June 2004

21 BOMEL Limited: Improving health and safety in construction: Phase 2 – Depth and breadth. Volume 4: Hand Arm Vibration Syndrome - Underlying causes and risk control, HSE Research Report 114, June 2003

22 BOMEL Limited: Falls from height – Prevention and risk control effectiveness, HSE, Research Report 116, June 2003.

23 BOMEL Limited: Improving health and safety in construction: Phase 2 – Depth and breadth. Volume 5: Falls from height - Underlying causes and risk control, HSE Research Report 234, June 2004

24 Health and Safety Executive: The costs to Britain of workplace accidents and workplace ill-health in 1995/96, Second edition, HSE Books, 1999, ISBN 0 7176 1709 2.

25 Department for Transport: Highways Economics Note No. 1, 2002.

26 HM Treasury: The Green Book – Appraisal and Evaluation in Central Government, 2003.

27 State of Victoria, Department of Primary Industries: Hazard Identification, Mines Regulation Guidance Note, MPV-GN-02, 2002.

28 CRONER: Construction Risk Assessment,

29 BOMEL Limited. Improving Health and Safety in Construction Phase 2 – Volume 2: RIDDOR Accident Data Analysis Tool, HSE Research Report 232, June 2004.

30 Health and Safety Executive: The costs to Britain of workplace accidents and workplace ill-health in 1995/96, Second edition, HSE Books, 1999, ISBN 0 7176 1709 2.

31 Health and Safety Executive: Health and Safety Statistics Highlights 2003/04, www.hse.gov.uk/statistics/hss04.pdf, 2004

Published by the Health and Safety Executive 06/06

RR 458

Documents

RESEARCH REPORT 458 - Health and Safety Executivedismantling the scaffold at risk, when the use of rope access may have been more appropriate. • Other organisations: specifying offsite