Accidents Case Studies.pdf

7/26/2019 Accidents Case Studies.pdf

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ccidents Case Studies


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Collapse of crane

Crane Operator had hoisted up a bag

of sand (780 kg) over the roof .

While doing so, the Overload Radius

Indicator (ORI) alarm sounded and the

cut-off was activated.

However, he by-passed the cut-off

and continued to lower the boom of the

crane

The crane suddenly toppled when he

started to swing the boom to its left.


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Factors Contributing To collapse

Site constraints.

Front outriggers not fully extended.

By-passed of safety devices.

Operator at risk behaviors.

Safe working load exceeded.

Lifting supervisor, rigger and

signalman were not appointed

No lifting plan.

No risk assessment conducted. No Permit-to-work system

Implemented.


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Analysis Cause and Root Cause

Crane collapse

Root cause Analysis

5 Whys question askingmethod

Q Why the crane collapse?

ADue to the crane was

overload

QWhy the crane was

overload?

AThe outrigger was not fully

extended.

QWhy outrigger was not

fully extended?

ASite constraints. (Root

Cause)


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QWhy lifting supervisor, rigger and

signalman were not appointed?

A Because there is no lifting plan

Q Why no lifting plan?

A Company did not have a Safety andHealth Management System to

manage the lifting operation at site.

(Root Cause)

Analysis Cause and Root Cause

QWhy the operator by-passed safetydevices?

A If the operator had refused to carry outthe lifting work, even when the safety

requirements were not in place, he would

not be paid. (Root Cause)


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Corrective and Prevent Action

To eliminate the hazard by use of

chin wheel or chain block to hoist

up the sand in small quantity, since

there is a site constraints

Gin Wheel

Provide every root cause with control measures Use of Hierarchy of Control to initiate control

measures Elimination Substitution

Engineering controls Administrative controls

Personal protective

equipment

Leastpreferred

Mostpreferred

Chain block


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To establish Safety and Health ManagementSystem and implement to manage the lifting

operation issues at site, eg lifting plan, risk

assessment and Permit-to-work system




Personal protective

equipment

Leastpreferred

Most

preferred

Administrative controls


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The occupier shall implement control the cranesupplier to carry out the lifting operation safety or

else will not be paid in order to deter the at risk

behaviors of the operator




Personal protective

equipment

Leastpreferred

Mostpreferred


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Collapse of crane- Most of the crane collapse

over the side

Most of the crane topple over the side


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Safety awareness for crane

operation

The load carrying capacity of the crane variesaccording to the various quadrants

Over the side

Over the sideOver the

front

Quadrant ofoperation

Over the rear

The operation zone

Operating zone

called quadrants


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operation

The Stability of

crane over the side

is always weak ascompare to the

front or rear

Most of the crane collapse over the side

The capacity of thecrane may change

when rotating a load

from one quadrant

to another.


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operation

To obtain a safe

quadrant is the first

consideration for

crane operation

Instead of theconvenience of

parking the crane

or others


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Ensure safe operation

Stability of Crane

(Tipping Stability)

Structural Stability

Integrity of LiftingGear/ SafetyDevices

Adopted to basic principles of craneoperation


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Stability of Crane (Tipping Stability)- Obtain a safe quadrant

- Ensure crane operate on the good footing

- Outrigger use correctly

- Crane shall on the level footing

45

400t

hk

hard

core

compactedsubgrade

25mm thk steelplate (6mx3m)

outrigger base

plate25mm thk steelplate(2.4mx4m)

65 ton

45


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Structural Stability

- Do not overload crane

(refer to load chart for capacity)

- Ascertain the load weight

before lift


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Integrity of Lifting Gear/ Safety Devices - Wire ropes / Rigging equipment in service

condition

- eg. Over-hoist / over-loading limit switch in

good working order


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Have a success ful l i f t !

Documents

Accidents Case Studies.pdf