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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Government of Western AustraliaDepartment of Commerce
Published by WorkSafe,PO Box 294, WEST PERTH WA 6872.
Tel: Toll Free 1300 307 877.
Email: institute@worksafe.wa.gov.au
®
www.worksafe.wa.gov.au/institute
The SafetyLine Institute material has been preparedand published as part of Western Australia’scontribution to national OHS skills development.
© 2009 State of Western Australia. All rights reserved.
Details of copyright conditions are published at the SafetyLine Institute website.
Before using this publication note should be taken of the Disclaimer, which is published at the
SafetyLine Institute website.
mailto:institute@worksafe.wa.gov.aumailto:institute@worksafe.wa.gov.auhttp://www.worksafe.wa.gov.au/institutehttp://www.worksafe.wa.gov.au/institutehttp://www.worksafe.wa.gov.au/institutemailto:institute@worksafe.wa.gov.au
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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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READING – MOBILE CRANES – SAFE USE
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.
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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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READING – MOBILE CRANES – SAFE USE
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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READING – MOBILE CRANES – SAFE USE
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.
Your feedback
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