Hazard & Operability Studies (HAZOP) - Part 1

7/24/2019 Hazard & Operability Studies (HAZOP) - Part 1

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Hazard & Operability Studies

(HAZOP)

Hazard & Operability Studies (HAZOP)

Prepared for ADGAS

by

Environmental Centre for Consultancy (ECC)

December 2009

Environmental Centre For Consultancy (ECC)Tel : +(971) (2) 6741333 Fax : +(971) (2) 6741322

P.O. Box : 43870, Abu Dhabi, U.A.E, Email: [email protected]

Part 1
mailto:[email protected]:[email protected]


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HAZOP Course Objectives

Safety Management System

HAZOPS What?

Benefits of HAZOPS

Methods For Identifying and Assessing Plant Hazards

HAZOPS Overview

HAZOPS Methodology

HAZOPS When?

Contents

Course Instructor: Prof. Ossama Aboul Dahab (ECC General Manager)


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Examples of Administrative Safeguards

Planning & Preparation for HAZOPS

HAZOPS Study Deviation Checklists

Study Wrap up, Reporting and Follow up

LPG Storage Facilities Checklist (API 2510)

Gasoline Transfer

Oil & Gas Separator

HAZOPS Exercises

Contents (Contd)


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HAZOP Course Objectives

After completing this course, each participant should:

Understand the relationship between HAZOPS and the other elements of

an HSEMS

Understand HAZOPS methodology

Have a clear grasp of the benefits of HAZOPS

Understand the steps that must be taken to

Prepare and Select team

Lead and conduct

Report and Follow-up on HAZOPS


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Be familiar with some common errors committed by inexperienced

HAZOPS leaders,

Understand the critical importance of good facilitating skills to the

success of HAZOPS

Begin developing HAZOPS leadership/facilitating skills

Contd


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Risks:

Liability

Health damage, accidents

Loss of markets

Increase costs

Opportunities:

Improved productivity

Cost-savings

Good reputation

Good relations with controlling authorities

Business And Safety


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Better control and recovery measures

Fundamental elements of Loss Prevention

Foundation to the prevention of incidents

Safety Management Systems


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Components of HSEMS


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HSEMS Elements 119 Expectations


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Hazard Analysis Tools and Techniques :

HAZARD Analysis Tools and Techniques Summary

Hazard/Risk

Analysis

Method

What Where in

ADGAS Why

HAZARD

Identification

(HAZID)

The HAZID technique is a broad, initial

study that focuses on (1) identifying

apparent hazards, (2) assessing the

severity of potential problems that could

occur involving the hazards, and (3)

identifying means (safeguard) for

reducing the risks associated with the

hazards. This technique focuses on

identifying weaknesses early in the life of

a system, thus saving time and money

which might be required for major

redesign if the hazards are discovered at

a later-date.

New Projects,

Plant

Modification

Request

Drilling

Work over

assessment

apart from

Most often conducted early in

the development of an activity

or system where there is little

detailed information or

operating procedures, and is

often a precursor to furtherhazard/risk analyses.

Primarily used for hazard

identifications and ranking in

any type system/process


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Hazard/Risk

Analysis

Method

What Where in

ADGAS Why

What-if checklist

analysis

What-if analysis is a brainstorming

approach that uses loosely

structured questioning to (1)

postulate potential upsets that may

result in mishaps or system

performance problems and (2)

ensure that appropriate safeguards

against those problems are in place.

Checklist analysis is a systematic

evaluation against pre-established

criteria in the form of one or more

checklists.

During Technical

HSE Audits.

Generally applicable to any type

of system, process or activity

(especially when pertinent

checklists of loss prevention

requirements or best practices

exist).

Most often used when the use ofother more systematic methods

(e.g. FMEA and HAZOP analysis)

is not practical.

Contd


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Hazard/Risk

Analysis

Method

What Where in

ADGAS Why

Failure modes

and effects

analysis(FMEA)

FMEA is an inductive reasoning

approach that is best suited to reviews

of mechanical and electrical hardware

systems. The FMEA technique (1)

considers how the failure modes of

each system component can result in

system performance problems and (2)

ensures that appropriate safeguards

against such problems are in place. A

quantitative version of FMEA is

known as failure modes, effects and

criticality analysis (FMECA).

Applicable

in SIL

reviews &

HSE

Critical

Equipment

assessment

As an input to establish SIL failure

rates of the particular component.

Primarily used for reviews of

mechanical and electrical systems

(e.g., fire suppression systems,

vessel

Often used to develop and optimizeplanned maintenance and

equipment inspection plans.

Sometimes used to gather

information for troubleshooting

systems.

Contd


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Contd


Hazard/

Risk

Analysis

Method

What Where in

ADGAS Why

Hazard

and

operability

(HAZOP)

analysis

The HAZOP analysis technique is an

inductive approach that uses a

systematic process (using special guide

words) for (1) postulating deviations

from design intents for sections of

systems and (2) ensuring that

appropriate safeguards are in place to

help prevent system performance

problems.

All Plant

Modification

resulting in

change of

process systems

Drilling work-

overs of well

testing and

Ties-ins

Primarily used for identifying safety

hazards and operability problems of

continuous process systems ( especially

fluid and thermal systems),

Also used to review procedures and other

Sequential operations.


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Element 4. Risk evaluation & management

Sub-element 4.1 Identification

No. Summarized ExpectationsScore

(0-4)

1

There are procedures for systematic identification of HSE hazards, effects and

aspects that affect, or arise from, the company activities or products.

2

HSE hazards, effects and aspects are identified by experienced personnel who use

established procedures; scope includes activities under company control (or which it

can be expected to influence) and covers the whole lifetime of projects.

3 There is a register of HSE hazards, effects and aspects for all company units.

Subtotal


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Sub-element 4.2 Evaluation & Assessment

No. Summarized ExpectationsScore(0-4)

1There are procedures for systematic assessment of HSE risks and evaluation of

significance of hazard, effects and aspects for all operations and assets.

2

The assessment and evaluation methodology takes into account legal and

regulatory requirements, applicable policies/standards and costs/benefits of risk

reduction measures.

3 All identified hazards, effects and aspects are ranked in terms of risk.

4

There is a process to determine, on the basis of risk, those hazards, effects and

aspects which are deemed significant, require controls and the nature of these

controls.

Subtotal


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Sub-element 4.3 Controls, Ownership and Performance in

Maintaining Controls


(0-4)

1HSE risks are made ALARP during design stage, with emphasis on incident

prevention through removal or reduction of hazards.

2

The HSEMS provides a demonstrable link between significant risks and

commensurate controls or reduction measures; defined controls are

documented/assigned and implementation responsibilities are understood.

3

Performance indicators exist for all HSE-critical activities and performance is

measured / monitored routinely. Employee performance appraisal includes

reference to HSE performance indicators and good performance is rewarded.

Subtotal


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Sub-element 4.4 Recovery

No. Summarized ExpectationsScore(0-4)

1

There are procedures which ensure appropriate recovery action when HSE controls

fail; the procedures are recorded and responsible persons defined who understand

their responsibilities.

2

Procedures for high risk recovery scenarios are regularly tested, reviewed and updated

in light of actual incidents, analysis of drills and industry best practice

Subtotal


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Sub-element 4.5 Recording and HSE Case


(0-4)

1

Records of hazard and effects management process are complete, up-to-date, and

accessible to and understood by the operations supervisors. Records provide detail of

activities that must be discontinued or restricted and the recovery action to be taken

when a control fails.

2All recommendations and actions arising from hazard / aspects analyses and reviews

are systematically recorded and closed-out.

3

Critical operations and installations are identified and fully documented with

demonstration of risk reduction to ALARP level. HSE Cases or equivalent

documentation are available for all operations and installations defined as critical.

4Contractors managing HSE critical activities have HSE Cases or equivalent

documentation of risk management demonstration.

Subtotal


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What Needs to be Recorded for each Hazard & Effects Sheet?

Hazard and Effects RegisterH-0

Rev.: No of Pages: 1

1. Hazard group: 2. Hazard:

Prepared by: Custodian: Authorized by: Rev. information:

3. Applicable to:

4. Assessment of hazard:

5. Top event:

6. Location and acceptance criteria:

6.1 Location 6.2 Acceptance criteria


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7. Threats and threat controls:

7.1 Threats: 7.2 Controls:

8. Consequences and risk assessment:

8.1 Consequences:

--------------------------------------------------------------

8.2 Risk potential:

P A E R

9. Exposure:

10. Recovery and preparedness measures:

11. Escalation factors and controls:

11.1 Escalation factors 11.2 Controls

12. Reference documents:

13. Deficiencies:

Contd


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Methods of Handling Risks

Identification of RisksExposures/Liabilities

DecideMethods of

handlingRisks

AvoidanceRisk ReductionLoss Financing

RiskTransfer

Engineeringcontrol

measures

Managementcontrol

Monitoring and Review

RiskRetention


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Risk Management Process

What can gowrong?

How Likely isit?

What are theImpacts?

Understanding Risk

Managing Risk


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Presence of hazardous materials

- Physical, chemical, and toxic properties

- Quantities and type of containment

Physical and chemical conditions present

Initiating events

- Process deviations and upsets

- Equipment failure

- Loss of utilities

- Management control failure

- Human error

- External events

Sequence of Hazardous


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Propagating factors

- Chain of events

- Ignition source

- Management control failure

- Human error

- Weather conditions

Risk management failure

- Safety system

- Mitigation system

Contd


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- Emergency plan

- Human error

- Training

Occurrence

- Discharge, leak, release

- Fire, explosion, toxic chemical exposure

Consequences

- Employee and public health, injuries, and death

- Property damage

- Environment damage

Contd

H d & O bili S di


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Potential consequences

Human

consequences

Environmentalconsequences

Economicconsequences

Employee injury

and death Air pollution Property damage

Public injury and

death Water pollution Loss of employment

Loss of employment Land pollution Lost production and

inventories

Psychological effects Ecological damage Reduction in sales

Personnel and

public relations Wildlife injury and death Legal liability

H d & O bili S di


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Risk Concepts

How Big? How Often?

Consequences Frequencies

Acceptability Criteria

H d & O bilit St di


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Risks classified according to estimated likelihood and potential

severity of harm

Numbers may be used to describe risk levels, i.e., quantify the risk

Decide if Risk is Tolerable

H d & O bilit St di


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Risk Matrix

A B C D E

Sever ity People As s ets Environ-

ment

Reputa-

tion

Has occurred in

world-wide

industry but not in

ADNOC

Has occurred in

other ADNOC

Group Company

Has occurred in

specific ADNOC

Group Company

Happens several

times per year in

specific ADNOC

Group Company

Happens several

times per year in

same location or

operation5.

Catastrop

hic

Multiple fatalities

or permanent total

disabilities

Extensive damage Massive effectInternational

impact

4. Severesingle fatality or

permanent total

disability

Major damage Major effect National impact

3. Cri ticalMajor injury or

health effectsLocal damage Localized effect

Considerable

impact

2. Marg inalMinor injury or

health effectsM inor damage Minor effect M inor impact

1.

Negligible

slight injury or

health effectsSl ight damage Slight effect Sli ght impact Low

Probability

High

Medium (ALARP)

H d & O bilit St di


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Risk Acceptability

A L A R P

NEGLIGIBLERISK

COMPARE RISKWITH BENEFITS

I n t o l e r a n c e L e v e l

CCH d & O bilit St di


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Risk Control Plan

Those Actions which

Eliminate the

Hazard

Those Actions which Reduce theLikelihood to a Tolerable or

Negligible Level

Those Actions which

Eliminate or Reduce

the Consequence

Categories of Actions

ECCHa ard & Operabilit St dies


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Example Inherent Safety Approaches

Eliminate

Remove the hazard altogether; e.g.., permanently shutdown an

operation or discontinue using a particular material

Substitute

Replace with less hazardous material; e.g., use sodium

hypochlorite instead of chlorine

Abate

Reduce the quantity stored, used or generated; e.g., reduce

inventory

Contd

ECCHazard & Operability Studies


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Means of eliminating or minimising adverse effects from happening.

Control methods can be:

Engineering control method elimination of chemical or process,

substitution, ventilation, segregation, protective barriers

Engineering control method- safe operating procedures, employee

rotation, run hazardous operation when there are less employees

around

Personal protective equipment- use as last resort. Examples are

respirators, hearing protection

Contd



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Example Risk control Actions

An alteration to the physical design or control system

A change of operating method

A change in process (pressure, temperature)

A change in the process materials

A change in the test and inspection/ calibration of key safety items

A reduction in the likely number of people and/or value of

property exposed

Contd



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Review Adequacy of Risk Control Action Plan

Contd

New controls: tolerable risk levels

New hazards created?

Most cost-effective solution?

Peoples views: need for and practicality of controls

Used in practice, not ignored in face of work pressures?

Continual review and advise if necessary.



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Benefits

Commonly understood

Often contain legal requirements

Apply to all

Limitations

Based on experience (no prediction)

Consensus standards

Site details may or may not apply

Engineering Codes for Hazard Control



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HAZOPS What?

Systematic and thorough

Creative approach to identifying hazards

Provides a means to reveal potential hazards and operability

problems at design stage

Minimizes cost to implement appropriate safeguards in new or

modified facilities

Participants gain a thorough understanding of the facility



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Overall Pattern of HAZOP Study

Intention

Deviation

Cause

Sequence

Safeguards

Action



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Benefits of HAZOPS

A Systematic and through review

Evaluates consequences of operator error

Predictive evaluation of events

Improved plant efficiency

Better understanding by all concerned parties



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A good study will:

Identify hazard and operability problems not found by other

methods

Identify them when improvements are easy and cheap

Give the team an excellent understanding of how the plant or process

will actually work

Contd



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Allow better operating instructions and control sequences to be

written

Lead to quicker and smoother start-up of new plant

Provide team members with a useful general tool which can be used

in other aspects of work

Contd



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Methods for Identifying and Assessing Plant Hazards

zz

HAZARDS

Methods of assessing hazards

Methods of identifying hazards

Hazard

Analysis

(HAZAN)

Code

Of

practice

Experience(Obvious)

(Obvious)See what

happensCheck

list

Hazard and operability

Study (HAZOP)



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HAZOPS Overview (Summary)

HAZOPS, or HAZARD and Operability Study, is a method of

reviewing the design and operation of processing units in refineries,

chemical plants, and other hydrocarbon handling facilities.

HAZOPS differ in several ways from the more traditional types of

reviews, such as P&ID reviews, and design or specialist reviews.



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Overview of HAZOP Process

Identify

Assess

Evaluate

Selec t NODE, State INTENT, Select PARAMETER + GUIDE

WORD

Deviation

CausePossible?

Likely?

ConsequenceCan barrier fail?

Does it matter?

Recommendation

Audi t/ Review

Yes

No

Brainstorm

No

Yes

Close-out/

Approval



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HAZOP TechniqueSelect a section of the plant (Node)

Select a HAZOP Parameter not previously considered

e.g. Pressure

Select a relevant Deviation not previously considered

e.g. More

Are there any Causes for this Deviation not previously discussed and recorded?

Record the new Cause

Are associated consequences of any significance?

Record the Consequences

Have all relevant HAZOP Parameters for this plant section been considered?

Record the Safeguards

Any Action necessary?

Record the agreed Action

Yes

No

Yes

No

Yes

No

Have all the Deviations for the HAZOP Parameter been considered?

Yes

No

Yes

No



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p y

(HAZOP)

HAZOP Technique

No

Yes

Select a section of the plant (Node)

Have all relevant HAZOP Parameters for this plant section

been considered?

Select a HAZOP Parameter not previously considerede.g. Pressure

Have all the Deviations for the HAZOP Parameter been

considered?

Select a relevant Deviation not previously considered

e.g. More

Are there any Causes for this Deviation not previously

discussed and recorded?

Yes

Yes

No

No



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p y

(HAZOP)

HAZOP Technique

Record the new Cause

Are associated consequences of any significance?

Record the Consequences

Record the Safeguards

Any Action necessary?

Record the agreed Action

Yes

Yes



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p y

(HAZOP)

It is systematic.

A HAZOPS begins by partitioning the unit into small sections.

The design envelope for each section is then defined.

This represents the pressures, temperatures, flow rates, stream

compositions, and other process, parameters within which that

section is assumed to operate without a hazard.

This is defined as normal operation.

Contd



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p y

(HAZOP)

Contd

It is thorough.

Each Section is then examined for every imaginable deviation from

normal operation.

For example, if a section is determined to have a certain normal flow

rate, then a series of questions are asked, starting with,

What can cause No Flow in this line section and what are the

consequences if that happens?

What can cause More Flow



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p y

(HAZOP)

What can cause Reverse Now?

Similar questions are asked for pressure, temperature, level,

composition, contaminants, and other process and operating

parameters.

Contd



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p y

(HAZOP)

It identifies potentially hazardous failure scenarios.

This is the primary purpose of the HAZOPS review, name!y to

uncover those sequences of events that can lead to toxic Or flammable

releases.

It identities operability problems.

Between 4O% and 80% of the recommendations emerging from a

HAZOPS review tend to improve operability, e.g. upsets Leading to

off- spec product shutdowns, or equipment damage.

Contd



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It evaluates key, safety-related operating procedures, or, where those

are unavailable, identifies crucial operation requirements.

HAZOPS reviews generally lead to modifications in operating

procedures or, for new facilities HAZOPS reviews have been used to

help write the operating procedures.

Contd



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Problems normally arise from deviations outside of the intended

operating envelope.

The data used by the team are complete and accurate, no changes

will be made without consideration of the implications for the

HAZOP study.

The design work is competent.

Construction, commissioning, operation and maintenance will be

done to good professional standards.

Assumptions in HAZOP



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Contd

It is documented.

The HAZOPS review leaves a record that can be used for developing

procedures for training, or, most importantly, that can be used to help

evaluate future changes to the plant design or procedures.



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Terminology

Sequence of HAZOP

study through the

project fife cycle

Fundamental

assumption HAZOPS

HAZOPS clarification

Deviation matrix

HAZOPS how?

HAZOPS Methodology

HAZOPS flowchart

HAZOPS team

Review team: who?

Team function: leader

Team functions : scribe

Team functions : members

Team rules

HAZOPS when?



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HAZOPS worksheet

Additional deviations

Brainstorming causes

Develop consequences

without safeguards

Identifying safeguards

Priority of safeguards

Administrative safeguards

Contd

SLR

Risk ranking matrix

Expansion of deviations and guide works

HAZOPS for procedures

Batch unit characteristics

Batch unit database

Additional deviations for batch processes



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HAZOPS methodology

Cause-by-cause (CBC) method

Hazop team selection

When to conduct HAZOPS

Sections/Node selection

HAZOP study deviation guidewords

Contd



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Is there a realistic cause of the deviation?

Are the consequences of the deviation significant?

These two questions cannot be completely separated.

Other points:

Think out the consequences from first principles, working in

small steps.

Consider the time development.

Causes and Consequences



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Be careful of grouping causes are the consequences truly identical?

Sometimes a significant consequence will be found within the design

operating envelope.

Cover all consequences, including those outside the section under study.

Rely on teams experience. Make a qualitative judgment

Contd...



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HAZOPS Terminology

Intentions How the process sections are expected to operate

Parameters Process and operation variables such as flow, pressure,

and temperature

Guidewords No, more, as well as, part of , reverse, and other than



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Contd

Deviations Departures from the design intentions (guideword +

parameter)

Causes Reasons why deviations might occur (possible causes)

Consequences Results of the unique cause an event causing

damage, injury, or other loss (potential consequences)



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Contd

Safeguards Design and operating features that reduce thefrequency of mitigate the consequences (existing

systems and procedures).

The team should evaluate the existing safeguards for

each non-trivial consequence for which there is arealistic cause.

Some leaders prefer to ignore the safeguards when

evaluating the sequence of consequences, this gives the

worst case.

Decide if they are sufficient to control the risk or if

improvement is needed.

A qualitative estimate of frequency or reliability may

help the team to decide.



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Contd

Recommendations Recommendations for design or operating changes,

or further study

Decide on the approach at outset of the study.

Two main approaches

Immediately refer all actions and reviews outside

the study.

Allow a few minutes to discuss possible changes,

record any agreed solution and continue the study

with that change in place.Otherwise record the

ideas and refer outside.



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Contd

Section/Node Study reference : used to organize study into

manageable segments

All recommendations should be reviewed by the

team before the report is completed.

Must ensure that recommendations satisfy the

problems identified by the team.

Also confirm that the changes do not introduce

new problems



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At the end of the a stage:

The team can suggest no more deviations,

All causes of each deviation have been considered,

Actions have been recorded for every consequence where the

residual risk was unacceptable,

Completing a Stage



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The guideword OTHER has been fully explored,

All members of the team are satisfied with the exploration of

potential problems.

The team can then move on to the next section, starting again with a

review of the design, the operating conditions and the design

intention.

Contd



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HAZOPS Fundamental Assumption

When a process is operating within its design envelope, the

potential for hazard and operability problems does not exist


(HAZOP)


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HAZOP study is a critical analysis of a planned or existing operation.

It is done by a small team working in a structured and systematic way.

The team develops a conceptual model of the process or operation and

examines this line by line or step by step.

Overall Pattern of HAZOP Study


(HAZOP)


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A design intention is developed for the stage under examination,

including wherever possible a statement of the intended operating

envelope.

The process or design is systematically searched for possible deviations

from the design intention.

The team seeks possible deviations using a set of guidewords, coupled

with system parameters, as an aid to imagination.

Contd


(HAZOP)


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For each physically meaningful deviation the team seeks possible

causes and then considers if there are significant consequences.

The associated risk is then evaluated, into account all existing

safeguards.

An action is generated whenever the residual risk is non-trivial.

Contd


(HAZOP)


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HAZOPS Clarifications

A HAZOPS is a systematic evaluation of deviations outside the design

envelope

The purpose of a deviation is to guide the study team into identifying

unique causes

The potential for hazard or operability problems exists only when the

process deviates outsides its design envelope


(HAZOP)


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(HAZOP)

Matrix of Parameters

GUIDE WORDS

No More Less As Well As Part Of ReverseOtherThan

PA

RA

ME

TE

R

FLOW *

PRESSUR

E*

TEMPERA

TURE*

LECEL

PHASE

COMPOSITION

(SPECIFIC

COMPONENT)

OPERATION

NOT USED

USUAL

POSSIBLE

NORMAL PARAMETERS


(HAZOP)


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Page No.73

(HAZOP)

Deviation Matrix

Guidewords

Design

Parameters No Less More Reverse Part of As Well As

Other

Than

Flow No Flow Less

Flow

More

Flow

Reverse

Flow

Wrong

concentrationContamination

Miss-

directed

Temperature - Less

Temp.

More

Temp. - - - -

Pressure - Less

Pressure

More

Pressure - - - -

Level - Less

Level

More

Level - - - -

Miscellaneous Startup/

shutdown

Leak/

Rupture

Human

Factors - - - -

GUIDEWORD + Parameter = Deviation


(HAZOP)


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Page No.74

(HAZOP)

Guideword + Parameter = Deviation

A guideword is an action word or phrase

Examples are no or more of.

A parameter is a variable, a component or an activity relevant to

the system under study.

Examples are flow, pressure or mix

A standard set of guidewords can be used

Parameters will vary according to the system

Generating Deviations

Combine a Guideword with a Parameter


(HAZOP)


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Page No.75

(HAZOP)

Standard Guidewords

Guideword MeaningNo (not, none) None of the design intent is achieved

More (more of, higher) Quantitative increase in a parameter

Less (less of, lower) Quantitative decrease in a parameter

As well as (more than) An additional activity occurs

Part of Only some of the design intention is achievedReverse Logical opposite of the design intention occurs

Other than (other) Complete substitution or another activity takes place.

Other useful guidewords include

Where else Applicable for flows, transfers, sources and destinations

Before/after The step (or some part of it) is effected out of sequence

Early/late The timing is different from from the intention

Faster/slower The step is done/not done with the right t iming


(HAZOP)


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Page No.76

(HAZOP)

Some possible parameters

Flow Pressure Temperature

Mixing Stirring Transfer

Level Viscosity Reaction

Composition Addition Separation

Time Phase Speed

Particle size Measure Control

pH Sequence Signal

Start/Stop Operate Maintain

Services Communication


(HAZOP)


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Page No.77

(HAZOP)

Many will be suggested during a good study.

Helped by imaginative and lateral thinking by the team

members.

Some will not be physically meaningful so do not need further

examination.

Generating Deviations


(HAZOP)


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Page No.78

(HAZOP)

Some will be meaningful but the team will see no likely causes or

significant consequences.

For all meaningful deviations which have likely causes the team

should evaluate the consequences and decide whether the risk is

acceptable; if not an action must be generated.

Contd


(HAZOP)


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Page No.79

(HAZOP)

Alternative Ways of Working

Guideword + Parameter = Deviation

HAZOP study developed using this approach.

Encourages systematic working by the team.

Perhaps best suited to batch processes.

Parameter + Guideword = Deviation

Commonly used now.

Good for continuous operations.

Requires more care by the team leader.

Both Approaches Can Give Excellent Results.


(HAZOP)


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Page No.80

(HAZOP)

Be thorough but imaginative

Think through all guidewords for each parameter

Refer to the design intention to identify parameters

Encourage lateral thinking

All team members should think about possible deviations

Important Features


(HAZOP)


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Page No.81

(HAZOP)

Review progress

Run through the guidewords before leaving a stage

Use check lists with care

Dont just use a predetermined list of deviations- think them out

for each problem

Use checklists as a back-up, not as a primary source

Contd


(HAZOP)


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Page No.82

(HAZOP)

HAZOPS How ??

Select a node/selection

Apply a deviation

Brainstorm all potential causes (stay within the section)

Develop ultimate potential consequence(s) (look inside and outside the

section)

List existing safeguards (for each cause and consequence scenario)

Develop risk ranking (optional but recommended)

Propose recommendations (weigh consequences against safeguards)

Repeat for each deviation

Repeat for each section


(HAZOP)


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Page No.83

(HAZOP)

HAZOPS Flowchart


(HAZOP)


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Page No.84

(HAZOP)

Contd

Specify the section or stage to be examined

Describe and discuss the step and the operation.

Determine the design envelope.

Develop and record the design intention.

Select a guideword

Using the description and design intention, combine the

guideword with a parameter to get a meaningful deviation

Seek a possible cause for the deviation and identify the

consequences


(HAZOP)


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Page No.85

(HAZOP)

Contd

Yes

Evaluate the safeguards. Decide if they are adequate or

if a change or further study is needed. Record

Have all the causes for this deviation been considered?

Yes

Dose another parameter give a meaningful deviation

with this guideword?

No

Are there further guidewords to consider?

No

Examination of this section / stage is complete

Yes

No


(HAZOP)


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Page No.86

(HAZOP)

HAZOPS Flowchart (Contd)

Cause-by-Cause Method

Agree on actions to remove or reducecause likelihood or mitigate

consequence(s) or consider further study

Are likelihood and severity of ultimate

consequences for this cause too great forexisting safeguards? Utilize Risk Ranking

Matrix for guidance

A

B


(HAZOP)


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Page No.87

(HAZOP)

Hazards Study Team

Leader

Scribe

Team Members

Design Engineer(s)

Process Engineer(s)

Operations

Safety/environmental specialist

Rotating equipment specialist

Maintenance/inspection/metallurgy

Instrument engineer

Electrical engineer

Other specialists


(HAZOP)


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Page No.88

( )

Review Team : Who?

Each process hazards review team should be composed

of individuals from different facility functions and/or

backgrounds

Each discipline/function on a multi-discipline review

team brings a different perspective and different

assigned responsibilities

Promote synergistic interaction

Field Operations representative a must


(HAZOP)


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Page No.89

( )

Team Functions: Leader

Has responsibility for ensuring that all asks are carried out:

Planning

Running

Recording

Reporting

Ensures that the team works together toward a common goal

Limits opinion

Ensures expertise of all team members utilized


(HAZOP)


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Page No.90

( )

Team Functions: Scribe

Records the HAZOP study in sufficient detail for the proceedings to

be easily understood

Does not take part in the discussions unless requested by Leader


(HAZOP)


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Page No.91

( )

Team Functions: Members

Use their experience, training and judgment to identify any issues

that should be discussed by the whole team

Assist the team in resolving issues by suggesting changes that may

overcome the problem

Assist the team in arriving at a consensus


(HAZOP)


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Page No.92

( )

HAZOPS When ?

Full study when mechanical design is firm

Mini-study of design changes, anytime

Follow-up studies at regular intervals during the life cycle of the facility

Existing facilities


(HAZOP)


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Page No.93

( )

Additional Deviations

Mechanical Seal Damage

Exchanger Tube Leak

Sampling

Maintenance

Wrong Material

Corrosion/Erosion

Pipe Specification Break

No reaction

More reaction

Less reaction

As-well-As Reaction

Wrong Reaction

No Mixing

More Mixing

Less Mixing

Service Failure

Instrumentation

Testing

Relief

Ignition

Abnormal Operation

External Events

Safety


(HAZOP)


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Page No.94

Examples of deviations and their associated guidewords

Deviation

type

Guide

word

Example interpretation for

process industry

Example interpretation for aProgrammable Electronic System,

PES

NegativeNO No part of the intention is

achieved, e.g. no flowNo data or control signal passed

Quantitative

modification

MORE

LESS A quantitative increase, e.g.

higher temperature A

quantitative decrease e.g.

lower temperature

Data is passed at a higher rate than

intended Data is passed at a lower

rate than intended

Qualitative

modification

AS WELL

AS PARTOF

Impurities presentSimultaneous execution of

another operation/step Only

some of the intention is

achieved, i.e. only part of an

intended fluid transfer takes

place

Some additional or spurious signal

is present The data or control signals

are incomplete


(HAZOP)


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Page No.95

Contd

Deviationtype

Guideword

Example interpretation forprocess industry

Example interpretation for aProgrammable Electronic System,

PES

Substitution

REVERSE

OTHER

THAN

Covers reverse flow in pipes

and reverse chemical reactions

A result other than the original

intention is achieved, i.e.transfer of wrong material

Normally not relevant

The data or control signals are

incorrect

TimeEARLY

LATE

Something happens early

relative to clock time, e.g.

cooling or filtration

Something happens late

relative to clock time, e.g.

cooling or filtration

The signals arrive too early with

reference to clock time The signals

arrive too late with reference to

clock time

Order or

sequence

BEFORE

AFTER

Something happens too early

in a sequence, e.g. mixing or

heating Something happens

too late in a sequence, e.g.

mixing or heating

The signals arrive earlier than

intended within a sequence The

signals arrive later than intended

within a sequence


(HAZOP)


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Page No.96

Conducing a HAZOPS Brainstroming Causes

Stay in the section when identifying causes

For feed sections (from off-plot) it is appropriate to identify

causes outside the node

Do not criticize causes during brainstorming

Use a flip chart or document in the computer


(HAZOP)


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Page No.97

Conducting a HAZOPS Develop Consequences without

Safeguards

Common error by hazards analysis teams is to take credit for

safeguards when developing consequences

When developing consequences consider the following:

Operator is not available or is not paying attention

Control valves are in manual

Alarms and Safety interlocks don not function

Procedures are not followed or are not understood


(HAZOP)


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Page No.98

Contd

Do not take credit for soft alarms associated with control loop if

controller failure may be underlying reason for valve action

failure (wide open or closed); consider the control loop as

blank box with all functionality lost.

Evaluate global consequences (inside and outside section)

Upstream

Downstream

Off-plot, if appropriate


(HAZOP)


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Page No.99

Developing Consequences Develop Events Chronologically

Upstream

Event 1

Upstream

Event 2

Final

Upstream

consequence

Downstream

Event 1

Downstream

Event 2

Final

DownstreamConsequence

Initiating

Cause

Time


(HAZOP)


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Page No.100

Evaluate global safeguards (inside and outside the section)

Challenge effectiveness of safeguards

Visualize the accident sequence

Consider time effects

Urgency may reduce effectiveness of human reactions (stress)

Conducting A HAZOPS Identifying Safeguards


(HAZOP)


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Page No.101

Cause elimination first, consequence mitigation second

Inherent design cushion (better than minimum consensus standards)

Written procedures for

Operations

Maintenance

Inspection

Testing

Training

Priority For Safeguards


(HAZOP)


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Page No.102

History

Previous incidents (lack of)

Equipment inspection (I.e., clean or non-corrosive service

Equipment

PSVs

Redundant /voting instruments

Independent alarms/shutdowns

Control instruments

Contd


(HAZOP)


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Page No.103

Operating procedures are written, up-to-date, understood, and

followed

Alarms and shutdowns are tested as necessary to ensure reliability

Operators are trained in the duties of their area, both initial and

refresher training

Vehicular traffic Is limited through plant. Lines are routed and

equipment located such that potential for vehicle impact to piping and

equipment is minimized.

Examples of Administrative Safeguards


(HAZOP)


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Page No.104

Equipment is fit for its intended use (verify relief and drainage

systems for existing plants).

Emergency response plans are written and communicated to all

employees, including contractors. Evacuation signals are known and

evacuation routes established. Hypothetical drills are held as

appropriate.

Contd


(HAZOP)


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Page No.105

Piping and Instrument diagrams reflect actual field conditions.

Fire protection and mitigation equipment Is installed, adequately

sized, functional, and tested on suitable frequency.

Fire department or brigade Is trained with sufficient equipment

available. Fire monitors, pumps, etc. are located appropriately.

Electrical area classification is understood and followed.

Contd


(HAZOP)


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Page No.106

Maintenance procedures are written, up-to-date, understood and

followed. Work permit system is in place and followed, Hot work,

vessel entry, and other work permit procedures are In place and

followed.

Inspection procedures and training are appropriate for the

equipment under review.

Contd


(HAZOP)


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Page No.107

S = The severity of the ultimate consequences predicted

L = The likelihood of the ultimate consequences developing given

the safeguards that are currently In place

R = The risk (per Risk Ranking Matrix) is a combination of the

likelihood and severity of the predicted or ultimate

consequences

SLR


(HAZOP)


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Page No.108

Risk Ranking Matrix

A B C D E

Sever ity People As s et s Environ-

ment

Reputa-

tion

Has occurred in

world-wide

industry but not in

ADNOC

Has occurred in

other ADNOC

Group Company

Has occurred in

specific ADNOC

Group Company

Happens several

times per year in

specific ADNOC

Group Company

Happens several

times per year in

same location or

operation

5.Catastrop

hic

Multiple fatalitiesor permanent total

disabilities

Extensive damage Massi ve effectInternational

impact

4. Severesingle fatality or

permanent total

disability

Major damage Major effect National impact

3. Crit ical

Major injury or

health effectsLocal damage Localized effect

Considerable

impact

2. Marg inalMinor injury or

health effectsMinor damag e Minor effect M inor impact

1.

Negligible

slight injury or

health effectsSl ig ht damag e Sli ght effect Sli ght impact Low

Probability

High

Medium (ALARP)

ECC Hazard & Operability Studies(HAZOP)


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Page No.109

Primary Keywords

Flow Temperature

Pressure Level

Separate (settle, filter,

centrifuge) Composition

React Mix

Reduce (grind, crush, etc.) Absorb

Corrode Erode

Isolate Drain

Vent Purge

Inspect Maintain

Start-up Shutdown



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Page No.110

As mentioned above, when applied in conjunction with a

Primary Keyword, these suggest potential deviations or

problems. They tend to be a standard set as listed below:

Secondary Keywords



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Page No.111

Word Meaning

No The design intent does not occur (e.g. Flow/No),

or the operational aspect is not achievable

(Isolate/No)

Less A quanti tative decrease in the design intent

occurs (e.g. Pressure/Less)

More A quanti tat ive increase in the design intent

occurs (e.g. Temperature/More)

Reverse The opposite of the design intent occurs (e.g.

Flow/Reverse)

Contd



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Page No.112

Also The design intent is completely ful f il led, but in

addition some other related activit y occurs (e.g.

Flow/Also indicating contamination in a product

stream, or Level/Also meaning material in a tank

or vessel which should not be there)

Other The activity occurs, but not in the way intended

(e.g. Flow/Other could indicate a leak or product

flowing where it should not, or

Composition/Other might suggest unexpected

proportions in a feedstock)

Contd



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Page No.113

Fluctuation The design intent ion is achieved only

part of the time (e.g. an air-lock in a

pipeline might result in Flow/Fluctuation)

Early Usually used when studying sequential

operations, this would indicate that a

step is started at the wrong time or done

out of sequence

Late As for Early

Contd



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Page No.114

The Process/ Activity Based HAZOP Guide WordsGUIDE

WORD MEANING EXAMPLE

NoThe activity/stage in theprocess is not carried out orceases

No reactant charged to the process

More Quantitative increase in stageor activity

Longer batch time

Less

Quantitative decrease in stage

or activity Shorter batch time

As Well AsA further stage or activityoccurs in addition to theoriginal intention

Additional, unplanned processoperation

Part of The incomplete performance ofa stage or activity

Missing component

Reverse Inversion of the stage oractivity

Heat rather than cool

Other ThanA stage or activity occurring atthe wrong time relative toothers

Batch discharged before reactioncompleted

NoSomething else happens Wrong material charged


P d l HAZOP G id W d


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Page No.115

Procedural HAZOP Guide Word

GUIDEWORD

MEANING

No The step in the procedure is not done

MoreMore is done than intended (e.g. valve fully instead of partially opened)

Less Less is done than intended (e.g. purging time is reduced)

As Well AsOther activities are carried out as well (e.g. several valves areopened instead of one)

Part of

The procedure is not fully performed (e.g. only single block is

used instead of double block)

ReverseThe opposite of the intent (e.g. opening instead of closing avalve)

Other ThanSomething completely different (e.g. opening the wrongvalve)



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Page No.116

No Flow Wrong routing - blockage - incorrect slip blind - incorrectly installed

check valve - ruptured pipe - large leak - equipment failure (control

valve, isolation valve, pump, vessel) etc.) - incorrect pressure

differential - isolation in error, etc.

More Flow

Increased pumping capacity - increased suction pressure - reduced

delivery head - greater fluid density - exchanger tube leaks -

restriction orifice plates removed - cross connection of systems -

control faults- control valve trim changed - open bypass - more

quantity (incorrect timer)

Expansion of Deviation and Guidewords



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Page No.117

Less Flow

Line restriction - filter blockage-defective pumps - fouling of vessels,

valves, orifice plates - density or viscosity changes - less quantity

(incorrect timer) - small leak (flange, valve), etc.

Reverse Flow

Defective check valve - siphon effect - incorrect differential pressure

- two- way-flow - emergency venting - incorrect operation - in-line

spare equipment - minimum flow bypass - etc.

Misdirected Flow

Wrong routing - isolation in error - etc.

Contd



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Page No.118

More Level

Outlet isolated or blocked - inflow greater than outflow - multiple

inlets - control failure - faulty level measurement - etc.

Less Level

Inlet flow stops - leak - outflow greater than inflow - control

failure - faulty level measurement etc.

More Temperature

Ambient conditions - fouled or failed exchanger tubes - lire

situation - cooling water failure - detective control -header control

failure - internal fires - reaction control failures - heating medium

leak into process - etc.

Contd


C d


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Page No.119

Less Temperature

Ambient conditions - reducing pressure-fouled or failed exchange

tubes - loss of heating -depressurization of liquefied gas (auto

refrigeration) -Joule/Thompson effect - etc.

More Viscosity

Incorrect material specification - incorrect temperature - high solids

concentration - emulsification. etc.

Less Viscosity

Incorrect material specification - incorrect temperature - solvent

flushing rate.

Contd



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Page No.120

More Pressure

Surge pressure (water hammer) problems - leakage from

interconnected HP system - gas breakthrough (inadequate

venting) - isolation procedures for relief valves defective -

thermal overpressure - positive displacement pumps - failed open

PCVs - design pressures - specification of pipes vessels - fittings,

instruments- etc.

Contd



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Page No.121

Less Pressure

Generation of vacuum condition (reduced/pressure) - condensation

gas dissolving in liquid - restricted pump/compressor suction line

undetected leakage - vessel drainage - blockage d blanket gas

reducing valve, etc.

Contd



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Page No.122

Instrumentation

Control philosophy - location of instrumentation - response time -

set points of alarms and trips - time available for operator

intervention . alarm and trip testing - fire protection - trip/control

amplifier - panel arrangement and location - auto/manual facility

and human error - tail-safe philosophy - etc.

Contd



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Page No.123

Sampling Sampling procedure - frequency - time for analysis result - calibration of

automatic samplers - reliability/accuracy of representative sample -

diagnosis of result etc.

Corrosion/Erosion

Cathodic protection arrangements - internal/external corrosion

protection

engineering specification - embrittlement - stress corrosion cracking

- fluid velocities (vibration) - etc.

Contd



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Page No.124

Service Failure

Failure of instrument air/steam/nitrogen/cooling water/hydraulic

power/electric power/water or other - contamination of instrument

air, nitrogen, etc. -telecommunications - heating and venting systems -

computers - etc.

Contd


C d


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Page No.125

Composition Change

Wrong material or concentration - leaking isolation valves leaking

exchanger tubes - phase change (condensation, boiling or freezing) -

incorrect feedstock/ specification - inadequate quality control

process control upset reaction intermediates/ byproducts

polymerization- setting of slurries (lack of mixing) - missing

component - etc.

Contd


C td


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Page No.126

Ignition

Grounding arrangements - insulated vessels/equipment insulating

flanges (stray current) - low conductance fluids - splash filling of

vessels - static gyration - insulated strainers and valve components

dust degenerating and handling - hot surfaces (auto ignition) etc.

Spare Equipment

Installed/non-installed spare equipment -availability of spares

modified specification - storage of spares - catalog of spares- test

running of spare equipment - etc.

Contd


C td


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Page No.127

Safety Toxic properties of process materials - lire and gas detection

system/alarms - emergency shutdown arrangements - fire fighting

response time - emergency and major emergency

training - contingency plans - TLVs of process materials and

methods of detection - first aid/medical resources - effluent

disposal - hazards created by others (adjacent storage

plant, etc.) - testing of emergency equipment

- compliance with local/national regulations

Contd



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Page No.128

Contamination

Leaking exchanger tubes or isolation - incorrect operation of system -

interconnected systems (especially services, blanket systems) - effect

at corrosion - wrong additives - ingress of air shutdown and startup

conditions- H2S - liquid carryover - etc.

Contd


C td


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Page No.129

Relief

Relief philosophy (process/fire, etc.) -type of relief device and

reliability - relief valve discharge location- pollution implications -

two-phase flow - effect of debottlenecking on relief capacity -

cascaded thermal relief valves - etc..

Contd



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Page No.130

Abnormal Operation (Startup/shutdown)

Purging - flushing - startup - normal shutdown - emergency

shutdown - emergency operations - etc.

Maintenance (resting)

Frequency - sequence of steps - substitution of steps isolation

philosophy - drainage - purging - cleaning - drying - blinding -

access - rescue plan - training - pressure testing (hydrostatic) -

work permit system - condition monitoring, etc.

Contd


HAZOP M th d l


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Page No.131

HAZOP Methodology


C


132/154

Page No.132

Contd


C d


133/154

Page No.133

Contd


HAZOPS M th d l (S )


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Page No.134

Select a Section

The partitioning or sectioning of the process plant is done prior to

the HAZOPS.

This is described more fully in section 4, Planning and

Preparation.

Typically, sectioning begins at the point wh8re the feed enters the

plant and follows the process through to the product leaving the

plant. Normally, sections are selected that include lines and

equipment between major vessels or equipment.

HAZOPS Methodology (Summary)


C td


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Page No.135

In many instances the HAZOPS team will have to go back and

study auxiliary systems that tie into the main process sections.

Describe Intention of Section.

The Process Engineer or study member most familiar with how

the process unit s intended to operate describes the purpose or

intention of the section to be studied.

The entire team participates in the discussion to ensure

understanding.

This description is documented in the HAZOPS worksheet.

Contd


HAZOP Study Methodology


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Page No.136

In considering the information to be recorded in each of

these columns, it may be helpful to take as an example the

simple schematic below.

HAZOP Study Methodology

DEVIATION CAUSE CONSEQUENCE SAFEGUARDS ACTION


Contd


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Page No.137

Apply a Deviation

A deviation is a guideword (no, more, less, as well as, etc.) coupled with

a process, design, or operating parameter (flow, pressure, temperature,

Typically, the team starts with the standard deviations listed on the

HAZOPS worksheet and works through them in order.

There are additional deviations that have been developed for

continuous and batch processes as well as for procedures.

After discussing each of the standard deviations listed on the

worksheet, depending on the section that is being analyzed, additional

deviations may also be discussed.

Contd


Contd


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Page No.138

Brainstorm Possible Causes.

The team brainstorms possible causes of each deviation for each

section.

The rules of brainstorming apply; no such thing as a bad idea; do not

discuss or edit others ideas while brainstorming; keep the discussion

moving.

Remember to stay in the study section when looking for causes.

Contd


Contd


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Page No.139

After the team has run of causes, review the list that has been created

and verify that they are plausible causes within the section of that

deviation. At this point, causes may be challenged to determine their

credibility.

If a standard deviation from the worksheet has a cause or causes

that have previously been discussed (for example, a cause for no

flow may be valve PV-1 closed while a cause for more pressure

may also be valve PV-1 closed), the discussion does not need to be

documented again.

Contd


Contd


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Page No.140

However, to provide verification that all standard deviation on the

worksheet are discussed for each section, the phrase No new ad I

causes should be entered in the Possible Cause column of the

worksheet for that standard deviation.

Develop Potential Consequences for Each Cause

For each unique cause, develop the consequences with no existing

systems/practices (safeguards) present or in place.

Contd


Contd


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Page No.141

At this point in the discussion, no credit is given for operator

action, control or alarms (assume the unit is in manual control), or

procedures being followed.

With no safeguards, develop the consequences to their plausible

conclusion, specifically looking outside the study section for

potential effects both upstream and downstream of the initiating

cause.

This is considered analyzing the global consequences the unique

cause.

Contd


Contd


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Page No.142

Determine the Existing Systems/Procedures (Safeguards)

Document the existing practices, procedures, and/or systems (alarms,

operator surveillance of process indicators, shutdown safety systems,

etc.) that prevent the cause from occurring, or mitigate the effects of

the potential consequences.

Contd


Contd


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Page No.143

The safeguards need not be confined to the study section.

Consider:

safeguards that prevent the unique cause from occurring ,

safeguards that alert the operator that potential consequences

{abnormal condition} are developing; and

safeguards that prevent or mitigate the effects or consequences of

the unique cause.

Contd


Contd


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Page No.144

Determine the Risk Ranking

Based upon the potential consequences developed and the existing

systems/procedures identified, determine a risk ranking of the

unique cause/consequence scenario.

This risk ranking will help guide the team in determining if a

recommendation may be appropriate, to reduce the risk of the

scenario.

Contd


Contd


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Page No.145

The risk ranking matrix is used as follows:

The cause/consequence scenario is - qualitatively evaluated to determine

how likely the scenario will fully develop to the global or complete

consequences predicted for that unique cause,

given the safeguards that are in place (likelihood) and how severe those

consequences may be should they occur (seventy).

Contd


Contd


146/154

Page No.146

The likelihood ranking (1 to 4) and the severity ranking (1 to 4) are

combined using the matrix to provide a qualitative risk ranking (1 to 7).

Each developed cause/consequence scenario is ranked with an SLR,

where

S presents severity,

L represent , represents likelihood, and

Rrepresents risk

Propose Recommendations

If the risk is considered high, a recommendation (also known as proposed

action) is made by the study team.


Contd


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Page No.147

For scenarios with risk rankings of 1, 2, or 3, the HAZOPS team is

encouraged to propose recommendations that

Prevent the unique cause from occurring,

Reduce the likelihood that the scenario will fully develop to the

global or complete consequences predicted, or M

Mitigate the predicted consequences. For risk rankings of 4 or

higher, the risk is considered to be insignificant - or negligible and

therefore recommendations are made at the discretion of the

HAZOPS team.

Contd


Contd


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Page No.148

The HAZOPS team is encouraged to reach consensus with each

recommendation.

If full agreement from the team cannot be reached in a reasonable

time nod the ca consequence scenario concerns should be tabled for

further discussion or studied outside the HAZOPS.

Contd


Contd


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Page No.149

HAZOPS teams should also be trained to ovoid designing solutions to

hazard or operability problems that have been identified.

Allowing the study team to discuss detailed design issues will slow the

study team down, increasing the cost of the stud and reducing the

effectiveness of the team.

Contd


Contd


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Page No.150

A rule for the study leader to follow is:

if the team is searching for a problem Jet the discussion continue:

if the team is searching for a solution ask them to propose one or

more ideas, recap these ideas, end discussion and then co with the

study.

Contd


Contd


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Page No.151

Assign SOE.

To support follow-up of recommendations, the study team may wish

to assign categories to the cause/consequence scenarios developed.

The HAZOP study worksheet includes a column tiled SOE where

S represents safety,

O represents operability, and

E represents environmental.

Contd


Contd


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Page No.152

Each recommendation may be associated with one or more of these

categories.

By associating each developed recommendation, the study leader

may produce reports that are sorted by the type of use/consequence

scenario.

Alternatively, each cause/consequence scenario may be assigned one

or more of these categories to allow future analysis of the scenarios

that were developed for each study.

Contd


Draft Report


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Page No.153

Locations Unit Study date

P&ID No P&ID Tit

Documents

Hazard & Operability Studies (HAZOP) - Part 1