Safe Use of Mobile Cranes, 20 Pages

8/13/2019 Safe Use of Mobile Cranes, 20 Pages

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Occupational Health & Safety

Practitioner

Reading

MOBILE CRANES – SAFE USE

January 2009

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Contents

OVERVIEW.....................................................................................................................1 SECTION 1: INTRODUCTION.......................................................................................2 SECTION 2: CRANE OWNERS AND MANAGEMENT RESPONSIBILITIES ...............3 SECTION 3: PLANNING................................................................................................6 SECTION 4: PERSONNEL ............................................................................................7 SECTION 5: OPERATION .............................................................................................9 SECTION 6: ATTACHMENTS .....................................................................................13 SECTION 7: ROPES, SLINGS AND TAGLINES .........................................................14 SECTION 8: RECORDS TO BE KEPT ........................................................................16 SUMMARY ....................................................................................................................16


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READING – MOBILE CRANES – SAFE USE

OVERVIEW

This reading outlines the safe systems of work necessary for the

safe operation of mobile cranes.

Objectives

After reading this information you should be able to:

understand the basic risk assessment process;

apply knowledge in relation to licensing and operator

competency requirements for specialised operations; and

recall significant details of operational requirements.

Author

John McCamey Dip. Mechanical Engineering

JANUARY 2009 SAFETYLINE INSTITUTE PAGE 1


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Section 1: INTRODUCTION

Glossary of termsWhen they are first used, glossary terms are indicated with an

asterisk (*). Make sure that you are familiar with the Glossary of

terms before going any further.

Mobile crane Crane capable of travelling over asupporting surface without the need forfixed runways (including railway tracks)and relying only on gravity for stability,i.e. with no vertical restraining connection

between itself and the supporting surfaceand no horizontal restraining connection(other than frictional forces at supporting-surface level) which may act as an aid tostability.

Lattice boom Structure consisting of chord membersthat are held in place by bracing.

Workbox Personnel-carrying device, designed tobe suspended from a crane, whichprovides a working area for persons

elevated by and working from the box.

Spreader beam Strut for spreading double leg slings.

Lifting beam Beam attached to a hook.

Tagline Rope which may be fastened to asuspended load to restrain spinning orswing of the load.

PAGE 2 SAFETYLINE INSTITUTE JANUARY 2009


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1.1 Most mobile crane accidents are

due to operational error

From statistical information, most incidents and accidents involvingmobile cranes* are normally related to operational error. This

reading provides useful information to persons

who own, supervise or operate mobile cranes,

including the dogman who slings loads.

The reading should increase the knowledge level

of any participant in regards to mobile crane safe

use. By incorporating the contents of this reading

into work practices, it should help to reduce

crane accidents and damage to plant.

KEY POINT

This reading forms only apart of the knowledge thata person would need toknow to safely operate amobile crane.

Section 2: CRANE OWNERS AND MANAGEMENT

RESPONSIBILITIES

2.1 Responsibilities are in four keyareas

A crane hire company which owns cranes of various lifting

capacities would have to consider the following before a crane is

sent out on hire:

Planning

Selection

Control

Operators.



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2.2 Planning – gaining sufficient

information to make a proper crane

selection

Management planning, as against operator planning, is all about

getting sufficient information from the client. Management needs to

obtain a clear description of the job to be done, site conditions,

restrictions and hazards. This would include the mass, size of load,

distance from set up to load and any other relevant details. The

use of forms to record this information should be considered to

maintain a consistent approach.

2.3 Selection – sending a crane with

sufficient capacity

The correct selection of a crane can only be made if sufficient

information has been obtained from the client, or a crane company

representative has been to the site to ascertain the load and

conditions. The selection of the right crane for the job cannot be

stressed too strongly. The use of an inappropriate crane may

result in damage to that crane, damage to adjacent equipment or,

more significantly, personal injury or death.



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2.4 Control – adequate control for

specific crane operations

Control or supervision is all about management having sufficientexpertise to understand when certain types of crane lifts require

supervision. This would apply to any high hazard type lifts; for

example, multiple crane lifts or loads that have a large surface

area. This may be as simple as lifting a large sheet of flat steel.

Management should instruct all crane operators that if the load is

outside the crane's capabilities, the operator must not attempt to lift

the load.

2.5 Operators

The operator must have an appropriate licence issued under Safe

Work Australia’s National Standard for Licensing Persons

Performing High Risk Work, for a particular crane type.

Management must provide and

maintain the following items for crane operators: KEY POINT

Crane operators must havean appropriate licence.

Crane manufacturer's operator's manual.

Cranes that do not have a computerisedradius display should have a 20-30 metre

measuring tape, so that the correct working

radius of the crane may be measured.

Personnel protective equipment, such as gloves, safety

helmets and substantial enclosed footwear.

A crane logbook is required in the crane cab, so that the

operator can record any unintended crane stoppages, or faults

found with the crane.



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Section 3: PLANNING

3.1 Risk management processThere are three specific steps in the risk management process:

1. identify each hazard;

2. assess the risk of injury or harm to a person resulting from

each hazard; and

3. consider the means by which the risk may be reduced.

3.2 Site planning

One mobile crane may be used in three or more different

workplaces in a day and it is most

important that the operator

completes the risk management

process before setting up at each

new workplace. Site planning may

include job requirements, priorities

and site hazards such as working inclose proximity to power lines.

Prior to setting up the crane for use,

consideration must be given to:

underground services;

recently filled trenches;

surrounding structures;

obstructions; overhead service lines; KEY POINT

Crane operators must havean appropriate licence.

other equipment; and

on-site facilities.



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Section 4: PERSONNEL

4.1 Licensing requirements – craneoperators

In order to ensure an understanding of the different types of mobile

crane operators' licences, reference must be made to the National

Standard for Licensing Persons Performing High Risk Work.

The Licensing Standard has replaced the Certification Standard for

Users and Operators of Industrial Equipment

[NOHSC:1006(2001)], following the standard's adoption into stateand territory occupational health and safety regulations.

Those currently working within the law may continue to do so

before being required to convert to a national licence. Those who

do not have a valid licence must not perform high risk work.

Those who wish to work in an occupation defined as high-risk will

need to be trained to carry out such work by a Registered Training

Organisation and assessed by a Registered Assessor.



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The standard has implications for workers involved in the following

activities:

• scaffolding work, rigging work, dogging work;

• crane and hoist operation:

- tower cranes;

- self-erecting tower cranes;

- derrick cranes; portal boom cranes;

- bridge and gantry cranes;

- vehicle loading cranes;

- non-slewing mobile cranes;

- slewing mobile cranes;

- material hoists;

- personnel and materials hoists;

- boom-type elevating work platforms;and

- vehicle-mounted concrete placing

booms.

• forklift operation (forklifts and order-

picking forklift trucks);

• concrete placing boom operation;

and

• pressure equipment operation:

- boiler operation;

- turbine operation; and

- reciprocating steam engine operation.



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Section 5: OPERATION

5.1 DocumentationThe documents you would expect to find in a crane cab are:

crane manufacturer's operators manual;

record logbook; and

copy of current plant registration (for mobile cranes greater

than 10 tonne capacity).

5.2 Load chart

One of the most important items in the crane is the load chart,

which sets out the safe working loads in various configurations.

This allows the crane driver to operate safely, within the

parameters of the manufacturer's load chart.

5.3 General operation

The ability of the crane operator is a very important factor in the

safe performance of the crane during lifting operations. Most

hazards can be avoided by exercising care and a common sense

approach to crane operation.

Pre-Operational checks

Before commencing operations, the crane operator is required to

carry out pre-operational checks in accordance with the

instructions provided in the manufacturer's operator's manual.



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5.4 Setting up the crane

Extending Outriggers

Crane operators should never attempt to extend the boom unless

all outriggers, where required, are extended and down on a hard

surface, with the crane level. Operators should read and fully

understand the crane load chart, including all notes, and have read

the operator's manual before attempting to use the crane. Cranes

have lost stability and tipped over, with no load on the hook,

because the operator had not extended the outriggers as per the

manufacturer's instructions.

Axle Lockouts

Operators, when operating a mobile crane fitted with axle lockouts,

should regularly check that they are functioning correctly. If the

axle lockouts are not used as per the manufacturer's requirements,

then the stability of the crane is greatly reduced.

Ground Conditions

Crane operators should always make enquiries about site

conditions from a person at the site who has a good working

knowledge of all underground hazards. For example, the position

of drainage pipes or soak wells at the site.

5.5 Only freely suspended loads to be

lifted

There have been a number of incidents over the years where

operators have attempted to remove a tree that had been partly

dug out. A number of cranes have sustained structural damage

from lifting a load that was not completely free, its weight beingunderestimated by personnel on site. Personnel involved in

removing a tree should spend time and actually measure the root

ball and surrounding soil, to obtain an accurate weight before

having the crane operator attempt to lift the load.



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5.6 Keep clear of power lines during

operation

Power line contact is the largest single cause of fatalitiesassociated with crane users. The crane operator, before setting up

a crane, must check for the proximity of power lines and exercise

extreme care during lifting operations. Crane operators are

required to maintain a clear distance, from any part of the crane or

load, of three metres for distribution lines on poles and six metres

from transmission lines on towers.

5.7 Leaving a mobile craneunattended

Crane operators should always check that the crane is correctly

stowed before leaving the site. In particular, in adverse weather

conditions a hydraulic crane boom should be completely retracted,

and lattice boom* cranes should have the boom lowered onto

trestles with the slew brake and slew lock applied.

NOTE: Operators are not to leave the crane cab while a load is

suspended from the crane hook.

5.8 Access to cranes

Extreme care should be taken by the crane operator when entering

or leaving the crane cabin. Crane operators should take particular

care in wet and slippery conditions.

5.9 Multiple crane lifts

Multi-crane hoisting should not take place unless in accordance

with the following; and appropriate reductions, in accordance with

load charts, achieved.



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Do the physical dimensions and mass of the load prevent it

from being handled by any single crane?

Load chart reduction for multiple lifting -

Two cranes: The crane operator is to reduce the SWLload by 16 2/3%. This allows the operator to lift a load up

to 83 1/3% of the crane's load chart in any particular

configuration.

Three Cranes: The crane operator is to reduce the SWL

load by 25%. This allows the operator to lift a load up to

75% of the crane's load chart in any particular

configuration.

Four Cranes: The crane operator is to reduce the SWL by

331/3%; This allows the operator to lift a load up to 66

2/3%.of the cranes load chart in any particular

configuration.

Hoisting must be supervised by a competent person

(intermediate rigger or advanced rigger) who is not otherwise

involved in the operation.

Cranes must be fitted with a winch to be considered acceptable

for multi-crane lifting.

NOTE: For additional information, refer to AS2550.1, section 6.27

Multiple Crane Operation.

5.10 Operational requirements when

lifting personnel in a workbox

a) Crane must have drive-up and drive-down controls on both the

hoisting and luffing motions.

(b) Crane operator must remain at the controls of the crane.

(c) Crane operator must ensure that the crane has a minimum safe

working load of one tonne in the configuration that the workbox* is

to be lifted.

(d) Further to (c) above, when the crane is in a configuration to lift

a workbox, personnel and equipment (which includes the

headache ball), then the crane is to maintain twice the safe

working load capacity of all the combined deductions.

(e) The crane operator must not travel the crane with personnel in

the workbox.



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Section 6: ATTACHMENTS

6.1 Workboxes

Workboxes attached to a crane are used for conveying personnel

with tools and work materials to an elevated work location or to a

work location below the level at which the crane is located.

Workboxes are normally of steel construction and have side infills

and overhead steel mesh infill protection. Harness anchors, within

the workbox, must be provided for the personnel who use the

workbox. Workboxes are normally designed by an engineer and

are required to have registration of the design through an

appropriate statutory authority.

The workbox, once manufactured, is required to be test loaded to

not less than 2.2 times its safe working load, to prove its structural

integrity.

The following data should be provided on the workbox:

tare weight in kilograms;

safe working load in kilograms;

minimum rated crane capacity;

maximum personnel capacity; and the

design registration number.

6.2 Spreader beams

Spreader beams* are used to support long loads, for example,

packs of roof sheeting, and may be designed to extend in length.Spreader beams are normally designed by engineers to meet a

particular standard and are test loaded to 10% overload. Spreader

beams used in offshore applications would be tested to a far

higher overload, due to the inherent higher dynamic forces

resulting from snatching loads in rough sea conditions. Spreader

beams are required to have the safe working load (SWL) stencilled

on the beam and also their tare weight. The design calculations, if

required for perusal, should be made available through the owner

of the equipment.



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6.3 Lifting beams

The majority of lifting beams* are purpose built for applications

such as lifting engines out of locomotives or other types of plant.

Lifting beams, as with spreader beams, would normally be

designed by an engineer and would require the safe working load

and the tare weight of the beam to be stencilled on the beam. The

lift chains or wire rope slings are usually captive to the beam and

the beam may be stored on a purpose built rack when out of use.

The lifting beams are normally tested to 10% overload.

Section 7: ROPES, SLINGS AND TAGLINES

7.1 Wire ropes

Running Ropes

The term "running ropes" refers to wire ropes used on auxiliary

and main hoists on cranes. Running ropes are required to have a

rated load (SWL) of only one quarter of the minimum breaking

load, a 4 to 1 safety factor.

Standing Ropes (Pendant Ropes)

Standing ropes are ropes that do not run over any sheeve system.

A typical example would be pendant ropes on a pinjib type crane.

Standing ropes are required to have a rated load (SWL) of only

1:3.5 of the minimum breaking load, a 3.5 to 1 safety factor.

7.2 Slings

Chain Slings

The majority of chain slings used in industry are made up using

grade 80 chain (grade T). The chains and associated fittings can

be used in reasonably arduous conditions, however, they require

inspection on a regular basis by a competent person to check for

wear and damage to chain links, hammerlocks, hooks and fittings.



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Wire Rope Slings

There is limited use of wire rope slings on mobile cranes, as most

loads are slung using chain slings. Wire rope slings are required to

have a working load limit (WLL) of only one fifth of the minimum

breaking load, a 5 to 1 safety factor. Wire rope slings normally

have swagged ferrules at the eyes and the WLL is usually

stamped into the ferrule. Otherwise there is a tag attached to the

wire rope sling with the WLL stamped on the tag.

Synthetic Slings

Sausage Slings - The name sausage sling is given to this

particular synthetic sling because it is made from one

continuous filament with one joiner and is encased in a canvas

type cover. The sausage sling has a tag sewn onto the cover

giving the working load limit of the sling. These slings are used

where damage to the load may occur if chain slings are used.

Flat Webbing Slings - These slings were banned on

construction sites a few years ago by some statutory

authorities after a sling failure caused a fatality. The new flat

webbing slings are approximately 50% stronger than similar

slings manufactured at the time of the accident. The new

standard has called for a safety factor of up to 9 to 1 in relation

to the minimum breaking load and the working load limit. When

these slings are used in accordance with manufacturer'srecommendations they are quite safe for use on a construction

site. A competent person should inspect this type of sling at

regular intervals, depending on usage, to ensure that the sling

is only used while it is in a sound condition. Damaged slings

should be destroyed to prevent any further use.

Taglines*

The primary function of a tagline is to steady and control the load.

Taglines must be made from non-conductive materials and have a

minimum rope diameter of 16mm.



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Section 8: RECORDS TO BE KEPT

8.1 Crane logbook A crane logbook is required in the crane cab, so that the operator

can record any unintended stoppages or other faults found with the

crane. The competent person, when carrying out a major

inspection, is also required to record any comments in the crane

logbook. This is also the case for maintenance type inspections

recorded in the logbook.

8.2 Operator’s manual An Operator's Manual must be kept in the crane cab, so the crane

driver can access the manual at all times.

SUMMARY

You have now completed the reading and should have a good

basic understanding of the risk assessment process, licensing and

operator competency requirements for specialised operations, and

the significant details of operational requirements.

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Safe Use of Mobile Cranes, 20 Pages