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C A S E S T U D I E S

O F

C O N S T R U C T I O N A C C I D E N T S

I N

H O N G K O N G

CITA CONSTRUCTION INDUSTRY TRAINING AUTHORITYSSKS5SS . . ' ' ' ' ' ' .' " ,

in collaboration with

LABOUR DEPARTMENT, H O N G K O N G G O V E R N M E N T

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Copyright © by Construction Industry Training Authority 1997

First edition, April 1997

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Published by Construction Industry Training Authority

This publication is available from :

Construction Industry Training Authority

95 Yue Kwong Road

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C o n t e n t s

Page

Foreword by Chai rman of CITA

Foreword by Deputy Commiss ioner for Labour, Labour D e p a r t m e n t

Classif icat ion of Accidents by Cause

Case 1.1

Case 1.2

Case 1.3

Tragedy ar is ing out of lifting operat ion

A worke r w a s s t ruck t o death by a slipping roll-over skip

Collapse of a c rawler c rane boom while lifting

re in fo rcement bars caused leg injury

Sec t i on 2 : Fall o f p e r s o n f r o m he igh t

Case 2 . 1 Fatal acc ident due to the col lapse of a wooden p la t fo rm

erec ted inside a lift shaf t

Case 2 . 2 Death caused by falling into an unpro tec ted caisson

Case 2 . 3 Unsuitable and insuff icient safe means of access and

egress can cause ser ious injury

Case 2 . 4 Fatality resul ted f r o m falling t h r o u g h an unpro tec ted lift

shaf t opening

Case 2 . 5 Substandard working p la t fo rm can cause fatal acc ident

Case 2 . 6 A worke r fell f r o m an unfenced work ing p la t fo rm resu l ted in

head injury

Case 2 . 7 W o o d e n p la t form col lapsed dur ing d ismant l ing and resu l ted

in fatality

Case 2 . 8 Unsuitable and insufficient safe means of access and

egress can kill

Sec t i on 3 : C o n t a c t w i t h e lec t r i c i t y o r e lec t r i c d i s c h a r g e

Case 3 . 1 Electrocut ion caused by crane-j ib coming into con tac t

wi th an over-head cable

Case 3 . 2 Electrocut ion caused by poor insulat ion of e lectr ic w i re

and unear thed meta l casing

1

5

9

13

17

21

25

29

33

37

41

45

49

Page

Case 3 . 3 E lec t rocut ion resu l ted f r o m an e lec t r ic a rc weld ing p r o c e s s

Case 3 . 4 A w o r k e r w a s e lec t rocu ted by an 1 1 kilo-volt over-head cable

Case 4 . 1 Col lapse of a t e m p o r a r y debr is -chute killed a w o r k e r a t s i te

Case 4 . 2 Unsuppo r ted t r e n c h can kill

Case 4 . 3 A w o r k e r w a s bur ied to dea th inside a t r e n c h

Case 5.1

Case 5.2

Case 5.3

Case 5.4

Section 1 1 ; Fall of passenger hoist or appliance carrying persons

Case 1 1 . 1 W o r k e r s w e r e killed in a passenge r ho is t acc iden t

Case 1 1 . 2 A w o r k e r w a s killed a f te r fal l ing t o g e t h e r w i t h a work ing

p la t fo rm suspended by a w inch

53

57

•

61

65

69

Ser ious injur ies ar is ing out of d ismant l ing of a col lapsed c r a n e 73

Tragedy due to fall ing ob ject and fal l ing f r o m height 77

Fatal acc ident caused by fal l ing ob jec t (meta l bar ] 81

Acc identa l sho t by a ca r t r i dge-opera ted fixing too l 85

Case 6 . 1 A w o r k e r w a s s t r uck t o death in aspha l t laying 89

Section 7 : C o n t a c t wi th moving machinery or object being machined

Case 7 . 1 Fatal acc ident resu l ted f r o m burs t ing abrasive whee l 93

Section 8 : Drowning

Case 8 . 1 Fall of a t r u c k into t he sea resu l ted in t h e d rown ing of 97

the t r u c k dr iver

Section 9 : Exposure t o fire

Case 9 . 1 Tragedy a t t r i bu ted t o t he neg lec t of genera l , f i re , 101

chemica l and cons t ruc t i on safety

Section 1 0 : Confined space

Case 1 0 . 1 Gassing in a conf ined space 105

Case 1 0 . 2 D rowned in a deep ca isson 109

113

119

C a s e 1 . 1

T R A G E D Y A R I S I N G O U T O F L I F T I N G

O P E R A T I O N

C a s e 1 . 1

The following construction personnel should pay special attention to this accident

case:

• Steel benders

• Workers

• Plant operators

• Slingers

• Concretors

SummaryA worker was killed when he fell into the gap between the shaft of a bored-pile and a reinforcement-

steel cage while the said cage detached from the pair of suspending hangers and fell into the shaft of the

bored-pile.

Circumstances

A contractor was responsible for the design and construction of a piled foundation which consisted of

90 bored-piles. The accident happened inside a bored-pile with a diameter of 2.5 metres. The pile had

been drilled and reached the bed rock at about 34 metres below ground.

A metal platform of about 4 metres by 4 metres was constructed at the top of the bored-pile. The

outside edges of the platform were provided with metal guard-rails. The inside opening facing the

shaft of the bored-pile was unprotected and not covered.

At the time of the accident, a crawler crane with a safe working load of 55 tonnes was used to lower a

itietal-bar reinforcement-steel cage into the shaft of the bored-pile.

The deceased and a team of workers were standing on the metal platform at the top of the bored-pile.

They were responsible for the assembling of the reinforcement-steel cage sections and lowering the cage

into the shaft of the bored-pile. Only two of the workers wore safety belts with the lanyards anchored

to the metal guard-rails of the platform but the deceased did not wear any safety belt.

After the third section of the reinforcement-steel cage was joined to the cage section in the shaft of the

bored-pile, the whole cage was lowered further down the shaft of the bored-pile. The deceased was

giving signals to the crane operator while the other workers were guiding the cage down into the shaft

of the bored-pile.

When the whole reinforcement-steel cage was being lowered into the shaft by the crawler crane and

there was about 9 metres of cage section still protruding above the bored-pile opening, the pair of

hangers attached to the shackles of the lifting gear suddenly detached from the cage. As a result, the

whole cage fell under gravity to the bottom of the shaft.

The deceased, without wearing safety belt, lost his balance and fell together with the cage to the bottom

of the shaft. He was found lying between the cage and the shaft wall below ground water level and was

dead.

Observation

The reinforcement-steel cage which consisted of 3 sections had a total weight of about 7 tonnes. Whilst

it was being lowered into the shaft of the bored-pile by the mobile crane, the two U-shaped metal

hangers which were fixed to the top part of the cage by means of U-shaped metal clips, clip-plates and

nuts had to bear the 7-tonne weight.

Apparently the metal hangers and the clip assemblies were unable to withstand the heavy weight. The

clips gave way and the hangers thus detached from the cage. As a result, the cage fell under gravity to

the bottom of the shaft.

It was believed that the failure of the hangers and the clips was attributed to the poor design of the U-

shaped hangers, the unreliable (clipping) method by which the hangers were fixed onto the cage and

the poor workmanship of the fixing work.

When the reinforcement-steel cage was falling down the shaft of the bored-pile, the deceased who was

working on the metal platform near the shaft opening lost his balance and fell together with the falling

cage into the shaft.

Legal Implication

The contractor responsible for this site could be found in breach of the following provisions of the

Construction Sites (Safety) Regulations:

1. Regulation 38(l)(b) - The contractor responsible for a lifting appliance shall, before it is used,

ensure that every part of any load to be raised or lowered by the appliance

is adequately secured so as to prevent danger arising to persons or property

as a result of the slipping or displacement of any part of the load.

2. Regulation 38Q(5) ~ The contractor shall take all reasonable steps to ensure that no worker

remains on any dangerous place on the construction site without wearing

a safety belt provided to the worker.

RecommendationThe accident might have been prevented if the following precautionary measures were adopted :-

1. The reinforcement-steel cage should be adequately secured before lifting so as to prevent danger

arising to persons or property as a result of the slipping or displacement of any part of the cage.

2. Every side of a working platform from which a person is liable to fall a distance of more than 2

metres should be provided with suitable guard-rails of adequate strength to a height between

900mm and 1150mm.

3. Safety harness and suitable anchorage for the secure attachment of the lanyard should be provided

for every worker working at height of more than 2 metres.

4. Steps should be taken to ensure that for those workers who wear safety harness, the lanyards

should be securely attached to the anchorages.

Reminder1. Workers should not be allowed to stay in the area under suspended loads.

2. All slings, ties and hooks etc. should be properly secured and have sufficientstrength for lifting load and should comply with regulations.

3. All chains, slings, ropes of lifting gear should not be used unless they havebeen thoroughly examined and certified by a competent examiner within theproceeding 6 months.

C a s e 1 . 2

A W O R K E R W A S S T R U C K T O D E A T H B Y

A S L I P P I N G R O L L - O V E R S K I P

The following construction personnelcase:

• Tower crane

• Tower crane

• Bar benders

• Bar fixers

operators

signallers

should pay special attention to this accident

• Concretors

• Wire rope sling inspectors

• Riggers

Strnimary

A worker was struck to death by an empty roll-over skip which slipped out from the hook of a wire rope

sling when the skip was lowered from the rooftop to the ground level by a tower crane.

Circumstances

The accident occurred on a construction site where blocks of multi-storey Y-shape residential building

were under construction.

On the day of the accident, concreting work was in progress at the twenty-third floor with the assistance

of a tower crane erected at the central core of the building. Two roll-over skips were used for carrying

concrete alternatively. A wire rope sling which consisted of an eye at one end and a hook at the other

was hung from the hook block of the tower crane. The hook of the sling was used to hook the skip

handle during lifting operation by the tower crane.

Prior to the accident, the deceased was assigned to stay on the ground and filled the skip with concrete.

When the skip had been filled with concrete, he was required to secure the sling to the skip handle and

to give hand signals to the crane operator for hoisting of the skip.

At the time of the mishap, the crane operator was turning the main jib of the crane anti-clockwise and

driving the trolley of the jib outwards so that the skip would not hit the building. When the skip was

being lowered to about the sixteenth floor level, it suddenly slipped out from the hook of the sling and

fell to the ground. It hit the deceased on his head and he was killed.

Observation

Investigation revealed that the weight of the empty skip was about 200 kilograms and the hook of the

sling was not fitted with a safety catch. When the skip was being lowered to ground level by the tower

crane, the skip handle was displaced and caused the skip to slip out from the hook of the sling. The

higher the lowering speed of the skip, the greater would be the chance of skip handle displacement.

The chance of skip handle displacement would be even greater if the skip was lowered as soon as the

anti-clockwise rotation of the jib and/or the outward movement of the trolley of the jib were stopped

abruptly.

Legal Implication

The contractor responsible for this site could be found in breach of the following provision of the


Regulation 38(1) - The contractor responsible for a lifting appliance shall, before it is used, ensure that

every part of any load to be raised or lowered by the appliance is securely suspended

or supported when being raised or lowered; and adequately secured so as to prevent

danger arising to persons or property as a result of the slipping or displacement of

any part of the load.

Recommendation

This accident might have been prevented if the following precautionary measures were adopted :-

1. The provision of a safety catch at the hook of the wire rope sling would prevent the slipping out

of the handle of the skip and the subsequent fall of the skip.

2. Workers should not be allowed to stay in the area under suspended loads.

Reminder

1. Safety check of the lifting appliances and gears should be done by competentpersons before lifting operation.

2. Workers should not be allowed to stay in the area under suspended loads.

C a s e 1 . 3

C O L L A P S E O F A C R A W L E R C R A N E B O O M

W H I L E L I F T I N G R E I N F O R C E M E N T B A R S

C A U S E D L E G I N J U R Y

C a s e 1 . 3

C O L L A P S E O F A C R A W L E R C R A N E

C A U S E D L E G I N J U R Y


case:

• Crane operators

• Crane signallers

• Bar benders

• Bar fixers

• Riggers

Simunary

While lifting bundles of reinforcement bars, the boom of a crawler crane collapsed and crushed the legs

of a bystander. The cause of the boom failure was believed to be crane overloading.

Circumstances

The accident happened in a godown where a lorry delivered 19 bundles of reinforcement bars for

stacking in the open yard of the godown.

Each bundle consisted of about 100 reinforcement bars and each of them was 16mm in diameter and

12 metres in length. The weight of each bundle was approximately 2,000 kilograms.

The reinforcement bars were lifted in a batch of 5 bundles by a crawler crane with a boom length 70

feet (or 21.34 metres). In fact, the crane had been examined by a competent examiner prior to the

accident. The safe working load, as shown on the Certificate of Test and Thorough Examination of

Crane, was 11.2 tons (11.4 tonnes) at a working radius of 24 feet (732 metres). No boom angle

indicator nor safe working load chart indicating the safe working load at respective boom angles was

provided on the crawler crane.

When lifting the third batch of the reinforcement bars, the crane slightly tipped and the load swung.

The crane operator then lowered the bundles back on the lorry immediately and asked his co-workers,

five of them altogether, to check the number of bundles being lifted When the co-workers confirmed

that the load consisted of five bundles only, the crane operator tried again to lift the load. However,

when it was being raised, the load swung to the right and the boom of the crane collapsed and fell to the

right of the crawler crane onto the ground. All workers immediately ran away except a senior godown

assistant, who was watching the operation, could not escape in time and had his legs crushed by the

falling boom. As a result, his left lower limb was amputated and his right lower limb was severely

crushed.

10

It was reported that the working radius of the crawler crane at the time of the accident was found to be

32 feet (i.e.9.76 metres).

Observation

The lifting capacity of a crane is significantly affected by its working radius - the larger the radius, the

smaller would be the safe working load. At the time of the accident, the working radius of the crawler

crane was 32 feet (i.e.9.76 metres), which exceeded the certified radius of 24 feet (7.32 metres) by

33%. As such, lifting capacity of the crane was correspondingly reduced. The weight of the reinforcement

bars being lifted was approximately 10,000 kilograms (5 x 2,000 kilograms), or roughly 10 tonnes.

As no boom angle indicator nor safe working load chart indicating the safe working load at respective

boom angles was provided on the crane, it would be difficult for the crane operator to be readily aware

of an overload situation, especially when the crane was being operated beyond its maximum working

radius specified in the certificate.

It is believed that the collapse of the boom was attributed to the overloading of the crane at the time of

the accident.

Legal Implication


Factories and Industrial Undertakings (Lifting Appliances and Lifting Gear) Regulations:

1. Regulation 15(2) requires the owner of a crane to ensure not to use the crane with the jib

extended at a radius which exceeds the maximum radius specified for the jib in the current

Certificate of Test and Thorough Examination relating to that crane;

2. Regulation 11 (2) (a) requires the owner of a crane which has a variable operating radius to

ensure that the crane is not used unless it has clearly and legibly marked on it the safe working

load at various radii of the jib and the maximum radius at which the jib may be worked; and

3. Regulation 11(2) (b) requires the owner of a crane which has a variable operating radius to

ensure that the crane is not used unless it is fitted with an accurate indicator, clearly visible to

the driver, which shows the radius of the jib, at any particular time and the safe working load

applicable to that radius.

Recommendation

Overloading had been and is still the main cause of crane accidents. The consequences were often

catastrophic.

To prevent this type of accidents, the following safety precautions should be adhered to :

n

1. Automatic safe load indicator, radius load indicator and motion limit switch together with

respective audio-visual warning systems, which are essential to the safe operation of the crane,

should be fitted.

2. The jib of the derrick crane should not extend to a radius which exceeds the maximum radius

specified for the jib in the current Certificate of Test and Thorough Examination relating to the

crane for lifting.

3. In no circumstances should the load exceed the Safe Working Load.

Reminder1. Suitable and properly maintained automatic safe load indicator, radius load

indicator and motion limit switch together with audio-visual warning systemsshould be fitted with the crane.

2. The crane operator should be properly trained and certified to use liftingappliances.

3. The Safe Working Load should be clearly indicated on the crane and not beexceeded under any circumstances.

4. Workers should not be allowed to stay in the area under suspended load.

12

C a s e 2 . 1

F A T A L A C C I D E N T D U E T O T H E C O L L A P S E

O F A W O O D E N P L A T F O R M E R E C T E D

I N S I D E A L I F T S H A F T

C a s e 2 . 1

F A T A L A C C I D E N T D U E T O *

L I F T S H A F T


case :

• Debris removal workers

• Lift installers

• Scaffoiders

Working platform installers

Formworkers

Summary

Two workers fell from the third floor to the ground inside a lift shaft of an industrial building under

construction. Their bodies were found buried under timbers and boards inside the pit of the lift shaft.

They were rushed to the hospital but were certified dead before arrival.

Circtunstances

A sub-contractor had a contract with the main contractor to undertake site clearing in a construction

site. The lift shaft involved in the accident was about 5 metres in length and 3.5 metres in width. A

wooden platform was erected inside the lift shaft on the third floor and its height was about 18,3

metres. The platform served no specific purpose and was merely left there to catch debris, concrete

fragments and timber pieces. As a matter of fact, it was planned to be removed soon.

At the time of the mishap, two workers of the sub-contractor were clearing the debris on the platform.

Suddenly part of the platform structure failed and one worker lost his foothold and fell to the bottom

of the lift shaft. The other worker, though managed to escape the fall in the first collapse, fell subsequently

when the entire platform collapsed at the end. As a result, the two workers sustained fatal injuries in

the fall.

The two deceased who had come from the Mainland China were employed as labourers in the site for

about 3 months. They had little experience in construction work and their main duties were to perform

casual and cleaning work as assigned by their direct employers.

The contributory factor leading to the collapse of the platform was believed to be one or a combination

of the following : deterioration of the individual components of the platform, displacement of the

platform from its support due to severe vibration and additional burden of debris and rubbish tipped

on the platform.

14

Legal Implication


Factories & Industrial Undertakings Ordinance:

"It shall be the duty of eveiy proprietor of an industrial undertaking to ensure, as far as is reasonably

practicable, the health and safety at work of all persons employed by him at the industrial undertaking;

the duty in this case should include in particular -

Section 6A(2)(a) - The provision and maintenance of plant and systems of work that are, so far as is

reasonably practicable, safe and without risks to health;

Section 6A(2)(c) - The provision of such information, instruction, training and supervision as is

necessary to ensure, so far as is reasonably practicable, the health and safety at

work of all persons employed by him at the industrial undertakings."

Recommendation

A safe system of work should be established and maintained to ensure the safety of every worker engaged

in the cleaning of wooden platforms erected inside the lift shafts. This includes :-

1. The wooden platform should be properly designed, constructed, inspected and regularly

maintained to ensure its structural stability before any person is allowed to work on it and to

carry out cleaning operation.

2. Activities that may affect the stability of the wooden platform should be avoided whenever

practicable.

3. Suitable safety harness with fall arresting system attached to an independent life-line should be

provided for every worker engaged in the cleaning work inside the lift shafts.

4. Training should be provided to all workers to ensure that they are aware of the danger associated

with the work at height and they can properly use personal protective equipment.

5. A monitoring system should be devised to ensure that all workers who work at height will

follow the site safety procedure.

6. When work is being carried out inside a lift shaft, it should be made known to every personnel

working in the site by way of warning notices so as to prevent any object from falling into the

lift shaft.

15

Reminder

1. Suitable safety harness with fall arresting system attached to an independentlife-line must be provided for every worker engaged in work at height.

2. When work is being carried out inside a lift shaft, it should be made known toevery personnel working in the site so as to prevent any object from fallinginto the lift shaft.

16

C a s e 2 . 2

D E A T H C A U S E D B Y F A L L I N G I N T O A N

U N P R O T E C T E D C A I S S O N

C a s e 2 . 2

D E A T H C A U S E D B Y F A L L I N G I N T O A N

U N P R O T E C T E D C A I S S O N


case:

• Excavation workers

• Caisson workers

• Roadwork construction workers

Summary

A caisson worker fell into a caisson of three metres in depth while he was working on a sloping ground

near the opening of the caisson and the caisson was situated at the foot of a slope. His body struck

against a metal formwork which was under fabrication at the bottom of the caisson. He sustained

serious injury and subsequently passed away in hospital after several days.

Ctrctunstances

On the day of the accident, caissons were being constructed for a footbridge foundation in a construction

site and a team of four workers including the deceased were working at the job site at the time of the

mishap. Two of these workers were assigned to fabricate metal caisson formwork (caisson ring) at the

bottom of a caisson while the others worked on the ground level near the caisson opening.

The caisson in question was located at the foot of a small slope. A lot of loose rocks of different shapes

and sizes lay around the caisson opening. The depth of the caisson was about 3 metres and its diameter

measured at the ground level was about 2 metres. Neither barriers were erected around the caisson

opening nor the opening was covered at the time of accident.

The deceased was working on the ground level near the caisson opening. It was a sloping ground and

because he was standing on the loose rocks> he suddenly lost his balance and fell into the caisson. A

rock with a diameter of about 20cm also fell into the caisson together with the deceased. His body

struck against the metal formwork that was under fabrication at the bottom of the caisson. He sustained

serious injury and was dead after several days.

18

Legal Implication



Regulation 40(1) - The contractor responsible for any construction site where there is an excavation,

shaft, pit, or opening in the ground into or down the side of which a workman or

other person lawfully on the site is liable to fall a distance of more than 2 metres

shall, for purpose of preventing any such fall, so far as practicable ensure that a

suitable barrier is erected as close as is reasonably practicable to the edge of the

excavation, shaft, pit, or opening.

Recommendation

1. Suitable barrier, e.g. guard rails with adequate strength, should be provided at the edge of the

caisson opening so as to prevent persons from falling down.

2. As far as practicable, loose rocks on the slope near the caisson opening should be cleared away;

or alternatively, persons should not be allowed to work near the caisson opening unless suitable

barrier is provided around the opening.

Reminder

Opening from which a person is liable to fall a distance of more than 2 metresshould be securely covered or properly fenced around the opening.

19

C a s e 2 . 3

U N S U I T A B L E A N D I N S U F F I C I E N T S A F E

M E A N S O F A C C E S S A N D E G R E S S C A N

C A U S E S E R I O U S I N J U R Y

C a s e 2 . 3


M E A N S O F A C C E S S A N D E G R E S S C A N C A U S E

S E R I O U S I N J U R Y

The followingcase:

• Demolition

construction

workers

personnel should pay special attention to this accident

Summary

A worker was walking on a pitched roof of corrugated asbestos sheets of a village house. Suddenly,

some asbestos sheets on which he was stepping broke up. He then fell through the broken roof,

dropped onto the floor and was injured.

Circumstances

A contractor had to demolish some dilapidated village houses which had been vacated by villagers.

Some of these houses were built with asbestos building materials and these materials had to be removed

first before the houses were to be demolished. Prior to the day of the accident, some flimsy single row

bamboo scaffolds with nylon sheets had been erected to surround the houses in order to confine the

asbestos removal work.

On the day of the accident, it was discovered that some nylon sheets were not hanging properly at their

positions. One worker was assigned to hang the sheets back to their designated positions. The pitched

roof had the shape of an inverted V. One face of the roof was not covered while the other face was

covered by corrugated asbestos sheets. He used a wooden ladder to climb up the roof and in order to

reach the opposite end and put the nylon sheets back to their designated positions at that end, he was

required to walk on the roof. When he was walking near the middle of the roof, some asbestos roof

sheets on which he was stepping on broke up. He fell through the broken roof, dropped from a height

of 4.3 meters onto the ground and suffered injuries.

Legal Implication



Regulation 38A(a) - There is, so far as is reasonably practicable, suitable and sufficient safe access to

and egress from every place on the site at which any person at any time works,

which access and egress shall be properly maintained.

22

Recommendation

Every place on the site at which any person at any time works should be provided with suitable and

sufficient safe access.

Reminder

1. Demolition workers must receive proper training in safety before they areallowed to perform demolition works.

2. Workers must not take short-cut by using unsafe access and egress.

3. Employers must provide suitable and safe means of access and egress forworkmen working at site.

4. Adequate steps must be taken to prevent workers from using unsuitableaccess and egress.

23

C a s e 2 . 4

F A T A L I T Y R E S U L T E D F R O M F A L L I N G

T H R O U G H A N U N P R O T E C T E D L I F T S H A F T

O P E N I N G

O P E N I N G


case:

• All construction site workers

Summary

The accident took place on a job site on the twelfth floor of a building under construction. While

walking along the lift lobby on the twelfth floor, a construction worker inadvertently stepped into an

unfenced lift shaft opening because of inadequate lighting. He fell a distance of more than 30 metres

and sustained fatal injury.

Circttmstances

The deceased was a plasterer. On the day of the accident, a group of workers including the deceased

were assigned to perform the external plastering work at a building construction site.

At the time of the mishap, the deceased was working at the external wall of the building. Later he went

inside the building in order to wash his hands and to fetch a piece of rigid plastic foam sheet for his

work.

However, he had to pass through a dark lift lobby and a drum of water for cleaning purpose was placed

near the lift shaft opening. The lift shaft opening was neither properly fenced nor suitably lit.

Inadvertently, he stepped into the lift shaft opening and fell from the twelfth floor to the ground. He

was certified dead on arrival at the hospital.

During the investigation of the accident, simulation tests on the lighting condition at the accident

scene were performed and the results indicated that there was an unacceptable level of illumination and

insufficient artificial lighting at the lift lobby location.

Legal ImpHcation



1. Regulation 38P(1) states that the contractor responsible for a construction site shall ensure that

every opening, corner, break, edge or other dangerous place through or from which any person

on the site is liable to fall a distance of more than 2 metres is provided with either:

(a) a suitable guard-rail or guard-rails of adequate strength to a height of between 900mm and

1150mm above the surface across which persons are liable to pass so erected as to prevent

as far as possible the fall of persons; or

(b) a covering so constructed as to prevent the fall of persons, materials or articles; any such

covering shall be clearly and boldly marked to show its purpose or be securely fixed in

position.

2. Regulation 50(d) states that, at a construction site where any workman is required or authorized

to be in the vicinity of any dangerous opening (whether in the ground or in a structure), the

contractor responsible for the site shall ensure that the place, approach, part or opening is

adequately and suitably lit to the extent necessary to secure that workman's safety.

Court Judgement

The defendant was found guilty and fined.

Recommendation

1. Every lift shaft opening from which any person on the site is liable to fall a distance of more

than 2 metres shall be provided with a suitable guard-rail or guard-rails of adequate strength to

a height of between 900mm and 1150mm above the surface to prevent the fall of persons.

2. Suitable and adequate lighting to secure workers' safety should be provided on site.

3. Safe means of access and egress should be provided and properly maintained.

R e m i n d e r

1. Whilst working on the upper floors of a building

should pay attention to

shaft openings.

2. Adequate lighting and

provided at all lift shaft

under construction

the locations and conditions of the fencing

suitable guard-rails of

openings.

sufficient strength

, workers

of the

must

lift

be

17

C a s e 2 . 5

S U B S T A N D A R D W O R K I N G P L A T F O R M

C A N C A U S E F A T A L A C C I D E N T

C a s e 2 . 5

S U B S T A N D A R D W O R K I N G P L A T F O R M C A N

C A U S E F A T A L A C C I D E N T


case:

• Plasterers

• Painters

• Scaffolders

Summary

A worker fell from a substandard working platform at the exterior of the fourteenth floor of a building

under construction while he was doing cement splashing and plastering work. He fell to the second

floor and sustained fatal injury.

Circumstances

A contractor was responsible for constructing a 19-storey office building. On the day of the accident,

construction of the building up to the level of the sixteenth floor was in progress.

The deceased was employed by the contractor to do minor works at the site.

Prior to the accident, the deceased and a co-worker were engaged in cement splashing and plastering at

the fourteenth floor. The deceased was doing plastering work to the external face of a parapet wall at

one side of the building whereas the co-worker at the opposite side of the building was doing similar

work Both of them performed their work on temporary working platforms made of bamboo scaffolding

and wooden planks erected outside the building. However, they did not wear any safety belt.

While work was progressing, workers at the site heard a loud noise and found the deceased lying

unconsciously on the second floor of the building. He was then rushed to the hospital where he was

certified dead.

Observation

Single row bamboo scaffolding was erected outside the building. The temporary working platform

where the deceased stood consisted of loosely placed planks. The planks were supported by the scaffolding

at one md and by the walings of the external wall of the building at the other end. The width of the

planks was between 100mm to 150mm and the thickness was 25mm. Void spaces ranging from about

300mm to 1300mm were found between the planks. It was believed that when the deceased was

30

performing his work on the temporary working platform, he tried to walk from one plank to another

across the void space. However, he lost balance and fell through the void space and resulted in fatal

injury.

Legal Implication



1. Regulation 38L :

every working platform from which a person is liable to fall a distance of more than 2

metres shall be either closely boarded, planked or plated, or is a platform consisting of

open metal work having interstices none of which exceeds 3800 square mm in area;

every board or plank forming part of a working platform shall be not less than 200mm in

width and not less than 25mm in thickness, or, not less than 150mm in width when the

plank exceeds 50mm in thickness.

2. Regulation 38N :

- every side of a working platform from which a person is liable to fall a distance of more

than 2 metres shall be provided with a suitable guard-rail or guard-rails of adequate strength

to a height between 900mm and 1150mm.

Court Judgement


Recommendation

1. Suitable and sufficient working platforms that are properly designed, constructed and maintained

should be available and used by workers.

2. Working platforms must be closely planked to prevent workers from falling.

3. Every plank forming part of a working platform should have sufficient strength.

4. If provision of suitable working platform is not feasible, the contractor should erect and keep in

such positions as to be effective to protect persons carrying on the work suitable safety nets or

safety belts or other suitable and sufficient equipment of such a design and so constructed and

installed as to prevent so far as practicable injury to persons.

31

Reminder

1. Adequate safety training especially on "safe practices on working at height"must be provided for those workers who are engaged in work at height.

2. Double row scaffolds with suitable working platforms must be provided forworkers performing external plastering work.

32

C a s e 2 . 6

A W O R K E R F E L L F R O M A N U N F E N C E D

W O R K I N G P L A T F O R M R E S U L T E D I N

H E A D I N J U R Y

UNFENCED WORKINGPLATFORM

(INJURED WORKER)

33

C a s e 2 . 6

A W O R K E R F E L L F R O M A I M U N F E N C E D

W O R K I N G P L A T F O R M R E S U L T E D I N H E A D

I N J U R Y


case:

Painters

Plumbers

Plasterers

• Formworkers

• Electricians

StmunaryA worker lost his balance and fell from the working platform of a movable tubular scaffold while he was

painting a waterpipe on the external wall of a carpark of a private housing estate. The worker sustained

head injury as a result of the accident.

Circumstances

This accident took place in a carpark of a large private housing estate. On the day of the accident, two

workers were assigned to paint the exwternal walls of the carpark and a movable tubular scaffold was

required to facilitate the painting work.

The working platform of the movable tubular scaffold measured one metre wide, 1.2 metres long and

the height was about 2.3 metres. There was no guard-rail provided on the working platform.

There was a waterpipe located at high level of the external wall and before the painting work could be

carried out, the waterpipe had to be cleaned first.

At the material time, a worker was standing on the working platform of the movable tubular scaffold,

holding a piece of cloth by hand and tried to clean the waterpipe by leaning out of the working platform.

Suddenly, he lost his balance and fell from the working platform to the ground. As a result, he sustained

head injury.

34

Legal Implication



Regulation 38N(1) - The contractor responsible for a construction site shall ensure that every side of

a working platform, working place, gangway, run or stair being a side from which

a person is liable to fall a distance of more than 2 metres is provided with a

suitable guard-rail or guard-rails of adequate strength to a height between 900mm

and 1150mm.

Court Judgement


Recommendation

L Suitable and sufficient scaffolds should be provided, placed and kept in position for use.

2. Every part of the scaffold should be of good construction, made of strong and sound materials,

and free from patent defects. The scaffold should also be fixed, secured or placed in position so

as to prevent accidental displacement.

3. Movable tubular scaffold should be placed as close as possible to the working area in order to

avoid the leaning out of the workers from the working platform.

4. Suitable and safe access to and egress from the working platform of the movable tubular scaffold

should be provided to the workers.

5. The working platform of the movable tubular scaffold should be closely boarded, planked,

plated, and provided with out-riggers. Every board or plank forming part of the working platform

should be of sound construction, adequate strength and free from patent defects.

6. Suitable guard-rail or guard-rails of adequate strength to a height between 900mm and 1150mm

should be provided to every side of the working platform from which a person is liable to fall a

distance of more than 2 metres.

35

Reminder1. Before carrying out any work at height, workers should check that suitable

guard-rails of adequate strength to a height between 900mm & 1150 mmmust be provided to all sides of the working platform.

2. Workers should be trained and refrain from leaning out of a working platform.

3. Erection of tubular scaffold should be constructed in accordance with themanufacturer's instruction and provided with out-riggers.

36

C a s e 2 . 7

W O O D E N P L A T F O R M C O L L A P S E D

D U R I N G D I S M A N T L I N G A N D R E S U L T E D

I N F A T A L I T Y

C a s e 2 . 7

W O O D E N P L A T F O R M C O L L A P S E D D U R I N G

D I S M A N T L I N G A N D R E S U L T E D I N F A T A L I T Y


case:

• Working platform dismantlers

• Formworkers

• Scaffolders

Stunmary

This accident took place when a worker was dismantling a wooden platform erected inside a lightwell

of a high-rise building which was under construction in a construction site. At the material time, the

platform suddenly collapsed because the platform had been displaced laterally from its support and

caused the worker to fall together with the platform to the bottom of the lightwell. This resulted in his

fatality.

Circtunstances

On the day of the accident, a construction site worker was assigned to remove all the wood pieces

accumulated on a wooden platform and to dismantle the platform. The platform was basically a

wooden lattice framework horizontally erected inside the lightwell on the twenty-first floor of the

building.

Having cleared away all the wood pieces, the worker had to dismantle the wooden platform with a

crowbar. He started to dismantle the platform by removing one of the fixing battens of the platform.

While dismantling the platform, the worker was standing with his right foot on a concrete beam in the

lightwell and with his left foot on the wooden platform.

The platform was erected in such a way that the ends on one side of the lattice framework were rested

on shallow grooves of the concrete beam in the lightwell whilst the other ends of the framework rested

on some battens which were supported by bolts.

No sooner had the worker lifted up one of the fixing battens at the centre of the wooden platform than

the wooden platform collapsed. The worker fell together with the wooden platform to the bottom of

the lightwell.

The main contributory factor leading to the collapse of the platform was that the ends of the wooden

lattice framework resting on the grooves of the concrete beam were displaced laterally when the deceased

38

was trying to remove the fixing batten with the crowbar. These ends of the platform slipped out from

the grooves of the concrete beam and without the support of the concrete beam, the platform collapsed

immediately.

As the worker was standing with his left foot on the platform at that moment, he lost his balance and

fell from the twenty-first floor to the bottom of the lightwelL He died in the fall.

Legal Implication



Regulation 38Q(1) - " the contractor responsible for a construction site shall erect and keep in

such positions as to be effective to protect persons carrying on that part of the

work in the site suitable safety nets or safety belts or other suitable and sufficient

equipment of such a design and so constructed and installed as to prevent so far

as practicable injury to persons."

Court Judgement


Recommendation

1. A safe system of work should be provided and properly maintained for dismantling platforms in

a lightwelL Proper supervision of the dismantling work is necessary.

2. Adequate training on safety should be given to all workers especially when there is a risk of fall

of persons.

3. Safety harness, safety nets and other safety means should be provided to protect workers from

falling when they are required to work in the lightwelL

Reminder

Suitable safety harness with fall arresting system attached to an independentlife-line should be provided and used by workers when workers are required towork at height.

39

C a s e 2 . 8


M E A N S O F A C C E S S A N D E G R E S S C A N

K I L L

C a s e 2 . 8

M E A N S O F A C C E S S A N D E G R E S S C A N K I L L


case:

• Scaffolders

• Form workers

• Bar fixers

Stunmary

No suitable and sufficient safe means of access and egress provided to the workers on work sites have

been an important and main contributory factor leading to many serious accidents at construction

sites. In this typical accident, a formwork ganger, while climbing up and down a formwork, lost his

foothold and fell onto the podium of a building under construction, thus sustained fatal head injury.

Circumstances

This accident took place on a building site in the New Territories. The building under construction

was a residential estate with a commercial complex. At the time of the accident, formwork of the

commercial complex was in progress.

On the day of the accident, the deceased was assigned to transport dismantled tubular scaffolds from

one location to another location. In order to accomplish the work, the deceased requested a tower

crane operator to assist him in lifting and transporting the scaffolds to the designated area.

Because of the site condition, the worker had to climb, up the scaffolding to a higher level in order to

communicate with the tower crane operator by means of a walkie-talkie (wireless telecom set). Having

given the lifting instruction to the crane operator, the deceased then started to climb down from the

upper level of the scaffolding to the podium. Just at that moment, he lost his balance and fell from the

upper level of the scaffolding to the podium, thus sustained fatal head injury.

Legal Implication



Regulation 38A(a) - The contractor responsible for any construction site shall ensure that, so far as is

reasonably practicable, suitable and sufficient safe access to and egress from every

42

place on the site at which any person at anytime works, which access and egress

shall be properly maintained.

Recommendation

1. Suitable and sufficient safe access to and egress from every place on the site should be provided

at which any person at anytime works.

2. Safety training should be provided for workers working at height and steps should be taken to

ensure that workers will not use unsuitable access and egress on the site.

Reminder

1. Climbing up and down the formwork and scaffold are common dangerouspractices of workers especially for scaffolders, formwork workers and barfixing workers. These dangerous practices must be avoided.

2. Safety training must be provided for workers working at height.

3. Adequate steps must be taken to ensure that workers will not use unsuitableand insufficient access and egress.

43

Case 3.1

ELECTROCUTION CAUSED BY CRANE-JIBCOMING INTO CONTACT WITH AN OVER-HEAD CABLE

C a s e 3 . 1

E L E C T R O C U T I O N C A U S E D B Y C R A N E - J I B

C O M I N G I N T O C O N T A C T W I T H A N O V E R - H E A D

C A B L E


case:

• Crane operators

• Signallers

Summary

A lorry crane driver was electrocuted by an 11 kilo-volt (KV) overhead cable on a construction site

while he was unloading sand from the lorry when the crane jib came into contact with the cable.

Circumstances

In response to an order for the sand at a construction site, the deceased, who was a lorry crane driver,

made use of a lorry crane to deliver the sand to the construction site.

When the deceased arrived at the site, he parked the lorry crane at the unloading point. It happened

that the lorry was parked underneath an 11KV overhead cable. When the deceased started to unload

the sand by tipping the loading platform of the lorry crane, he noticed that the lorry jib was not in a

vertical position and it obstructed the unloading operation. In order to raise the jib to a vertical

position, he stood on the ground beside the lorry crane and controlled the movement of the jib. When

the jib was raised to its vertical position, it was 7.04 metres above the ground. It then came into contact

with the lowest point of the 11 KV overhead cable which was found to be 7.02 metres above the

ground. The rubber tyres of the lorry crane could not withstand the high voltage. The large magnitude

of the short-circuiting current that passed from the overhead cable through the lorry to earth caused the

lorry on fire. As the deceased was touching the metal part of the lorry and he was standing on the

ground, a complete earthing path was formed. The deceased was electrocuted by the electric current

coming from the overhead cable.

46

Legal Implication



Regulation 47(2) - A contractor responsible for a construction site where there is any electrically charged

overhead cable or apparatus shall take such precautions, by the provision of adequate

and suitably placed barriers or other means, as will prevent the cable or apparatus

from becoming a source of danger to workman employed on the site (whether as a

result of a lifting appliance coming into contact with the cable or apparatus or

otherwise).

Court Judgement


Recommendation

1. If there is a risk that a lorry crane jib can come into contact with a high voltage overhead cable,

the overhead cable should be diverted to a safe place, or rendered dead. If the overhead cable

cannot be diverted or rendered dead, a jib crane should not be operated underneath the overhead

cable.

2. A Signaller is needed to guide the lifting operation of a lorry crane in order to prevent the jib

from coming too close to the overhead cable.

3. Warning notice should be posted in close proximity of the overhead cable to warn people about

the danger of the overhead cable.

4. The operator of a lorry crane should be informed about the danger of the overhead cables. He

should be instructed and supervised to avoid such danger.

47

Reminder1. Crane operators must undergo approved crane operator training course and

be certified to ensure the safe operation of the crane.

2. Hazard identification (especially for over-head cables) has to be carried outby construction management prior to any construction operations, andcorresponding safety measures have to be taken to ensure that the operationis safe.

3. No lorry crane is allowed to operate in close proximity of high voltage overheadcables, especially during bad weather, if there is a risk that the crane jib cancome into contact with the ovehead cables.

48

C a s e 3 . 2

E L E C T R O C U T I O N C A U S E D B Y P O O R

I N S U L A T I O N O F E L E C T R I C W I R E A N D

U N E A R T H E D M E T A L C A S I N G

U N E A R T H E D M E T A L C A S I N G


case:

• Maintenance workers

• Electricians

Summary

A worker was electrocuted when he was carrying out the repairing work of a vehicle chassis at a

maintenance depot in the New Territories. The cause of this electrocution was mainly due to the poor

insulation of electric wire and the unearthed metal casing of an electric ventilation fan.

Circtunstances

On the day of the accident, a worker was assigned to carry out the maintenance work of a vehicle

chassis at a depot. A movable electric fan was used to improve the ventilation inside the vehicle chassis.

At the time of the accident, the upper part of the deceased's body was naked. A leakage current from

the accidentally energized metal casing of the electric fan passed through his body to the vehicle chassis

and eventually to the earth. He received a serious electric shock.

The deceased was unconscious when he was discovered. Artificial respiration and external heart

compression were given to the deceased by his co-workers who had been trained in first-aid. Ambulance

was later called and he was certified dead on arrival at the hospital.

During the investigation, it was found that the movable electric fan used at the time of the accident had

been electrically faulty and the metal casing of the electric fan had not been effectively earthed.

The earth resistance of the metal parts of the vehicle chassis was found to be about 900 ohms and this

indicated that the tyres of the vehicle were also not insulated.

50

Legal Implication

The owner of this maintenance depot could be found in breach of the following provisions of the

Factories and Industrial Undertakings (Electricity) Regulations:

1. Regulation 6 - All live conductors including those forming part of an apparatus, shall be so

insulated and further effectively protected where necessary so as to prevent

electrical hazard.

2. Regulation 18 - Where necessary to prevent electrical hazard adequate precautions shall be

taken either by earthing or other suitable means to prevent any metalwork,

other than the current-carrying conductors, enclosing or supporting any such

conductors, from becoming live.

Recommendation

1. A safe system of work including effective and regular maintenance of all electrical equipment

should be adopted at the workplace so as to prevent electrical hazard.

2. The socket outlets should be protected by residual current circuit breaker (RCCB) or current-

operated earth leakage circuit breaker (ELCB) with rating not exceeding 30mA.

3. The electric wire of a movable fan should be properly connected and tightly gripped onto the

plug so that the metal casing of the fan is effectively earthed.

4. Grommet should be provided at the cable entrance, of the terminal box of the fan.

5. Proper clothing and suitable personal protective equipment should be worn by workers when

carrying out electrical maintenance work.

Reminder

1. Electrical installation and equipment should be properly inspected andregularly maintained by a competent electrician to prevent electrical hazard.

2. Improper connection of electrical equipment to power supply outlet shouldnot be allowed.

51

C a s e 3 . 3

E L E C T R O C U T I O N R E S U L T E D F R O M A N

E L E C T R I C A R C W E L D I N G P R O C E S S

Case 3.3ELECTROCUTION RESULTED FROM ANELECTRIC ARC WELDING PROCESS

The following construction personnel should pay special attention to this accidentcase:• Electric arc welding workers

Summary

An electric arc welding worker was found lying unconsciously in a pool of water. He was then sent to

a hospital and he was certified dead before arrival at the hospital. Prior to the accident, the deceased

and his co-workers were engaged in welding metal girders above a pool of water.

Circumstances

The accident occurred on a construction site near a sea front. The construction work was to erect a

vertical structure supported by metal H-beam girders. A few days before the accident, some sea water

had penetrated through the sea wall and accumulated at the bottom of the structure and formed a pool

of water of about 0.3 metres in depth.

On the day of the accident, the deceased and his co-workers were assigned to weld some stiffener plates

to the underneath side of the lowest H-beam. Under this working environment, the workers sat in the

pool of water to do the welding work.

After the electric arc welding work had started for a short while, the co-workers heard a loud yelling

voice from the deceased. They rushed to the scene and saw the deceased lying in the water with the

electrode holder. They pulled him out of the water immediately. When the electrode holder was

removed from the deceased's body, some sparks were seen.

Observation

The electrical equipment used by the deceased was examined after the accident and they included the

arc welding transformer, the distribution board and the electrode holder. The following findings were

observed.:

1. The welding transformer was rated 415 volts input with an output of 75 volts. It was fitted

with a protective device against electric shock on the electric holder. When welding was not in

progress, this protective device would automatically reduce its output voltage to about 20 volts

which would be safe for a person under normal operation environment. However, when welding

was in progress or the electrode came into contact with water (accumulated on the ground to

„ _ _ _ •/ • ' . • • ; ' ' ' • • . ' .,' ' ' 54 ' • ' • . . , ' ' . . • ' •

form a complete low resistance path across the transformer output), a voltage of 75 volts was

maintained between the electrode holder and the girder structure or earth.

2. The distribution board with 30mA residual current device (RCD) from which the welding

tranformer took supply was found to be in good order. This RCD would provide adequate

protection against leakage of current to earth from the transformer primary windings or from

the electric cables connecting to the transformer primary windings. However, this RCD would

not provide protection against leakage of current to earth from the transformer secondary

windings or from the electrode holder.

3. There was no insulation cover on the live part of the electrode holder.

The above findings suggested that when the deceased was welding the stiffener plate underneath the

lowest H-beam, he might have slipped and fallen into the pool of water together with the electrode

holder. This caused the output voltage of the welding transformer to rise from 20 volts to 75 volts

which was high enough to give an electric shock to the deceased when his body came into contact with

the exposed live part of the electrode holder inadvertently.

Legal ImpHeatioji


Factories and Industrial Undertakings (Electricity) Regulations:

Regulation 6 - All live conductors including those forming part of apparatus, shall be so insulated and

further effectively protected where necessary so as to prevent electrical hazard.

Recommendation

1. Workers should not be allowed to perform welding work when they stand in water or in contact

with water. As far as practicable, all welding operations should be done in a dry working

environment.

2. The live part of the electrode holder should be insulated and effectively protected where necessary

so as to prevent electrical hazard.

Reminder

1. Home-made or non-approved arc welding set (especially the transformer)should not be used for welding work so as to avoid electrical hazard.

2. Do not allow workers to stand in water or in close contact with water to performwelding work.

55

C a s e 3 . 4

A W O R K E R W A S E L E C T R O C U T E D B Y A N

1 1 K I L O - V O L T O V E R H E A D C A B L E

C a s e 3 . 4

A W O R K E R W A S

1 1 K I L O - V O L T O V E R H E A D C A B L E

The following construction personel should pay special attention to this accident

case:

• Truck-mounted crane operators

• Lamp-post installers

• Signallers

Stimmary

A contractor had a contract with the Highways Department for the installation, maintenance and

operation of the public lighting system. A group of three workers were engaged in unloading a new

lamp-post from a truck-mounted crane. During the unloading operation, the lamp-post accidentally

came into contact with, or in close proximity of, an 11KV live' overhead power line. As a result, one of

them was electrocuted and one received an electric shock.

Circtunstances

On the day of the accident, hole digging work for installation of lamp-posts at the site concerned was

completed. The lamp-posts were transported to the site by a truck-mounted crane. When the truck

arrived at the site it was parked under some live' overhead power lines. These power lines were supported

on wooden H-poles and were about 8m above ground. There were no barriers, warning notices nor any

means to prevent any object from coming into contact with the power lines. The deceased (D/P), the

injured person (I/P) and a co-worker were assigned to unload and install the lamp-posts.

At the time of the accident, the I/P was operating the crane to unload the lamp-posts using the control

panel at the left side of the truck crane. He raised a lamp-post of about 11.7 metres in length from the

truck by means of the crane jib and tried to slew it to the rear side of the truck where the D/P was

standing on the ground to assist the unloading work. The lamp-post was suspended near its mid-point

by a nylon belt webbing sling and the co-worker was responsible for slinging and guiding the lifting

operation of the lamp-post. When one end of the lamp-post was lifted and came close to the D/P, he

tried to unload the lamp-post by pushing down one end of the lamp-post to the ground. This action

made the other end of the lamp-post tilt up and as a result the high end of the lamp-post came into

contact or got very close to the overhead power lines. Electricity was discharged from the overhead

power lines through the lamp-post to the D/P then to the earth. The I/P also received an electric shock

58

at the same time probably because the control panel that he was operating carried some electric charge

that was conducted through the crane jib and the lamp-post.

Legal Implication



Regulation 47(2) - A contractor responsible for a construction site where there is any electrically charged

overhead cable or apparatus shall take such precautions, by the provision of adequate

and suitably placed barriers or other means, as will prevent the cable or apparatus

from being a source of danger to workmen employed on the site (whether as a

result of a lifting appliance coming into contact with the cable or apparatus or

otherwise).

Recommendation

1. The site for unloading lamp-posts should be well away from the overhead power lines.

2. When the unloading operation has to be done underneath or in the vicinity of the overhead

power lines, application should be made to the power company for:

(a) rendering the overhead power lines electrically dead; or

(b) re-routing the overhead power lines.

3. If (1) and (2) above are not feasible, safety precautions should be taken to prevent the overhead

power lines from becoming a source of danger to the workmen by:

(a) providing adequate and suitably placed barriers or other means;

(b) displaying warning notices to highlight the presence of electrically charged overhead power

lines and to indicate the safe clearance from such lines; and

(c) providing a well trained signaller to supervise the unloading work so as to ensure that the

safe clearance between the lamp-post and the overhead power lines is maintained.

59

Reminder

1. Crane operators must be properly trained and certified to ensure that theyhave the skill and knowledge in operating the appliances.

2. Warning notices and barriers should be placed in suitable locations to preventthe overhead cables from being a source of danger to workmen employedon the site.

3. All overhead cables and metal parts should be treated with special care andshould be considered electrically live1 unless suitably clarified.

60

C a s e 4 . 1

C O L L A P S E O F A T E M P O R A R Y D E B R I S

C H U T E K I L L E D A W O R K E R A T S I T E

Case 4.1

KILLED A WORKER AT SITEThe following construction personnel should pay special attention to this accidentcase:• Debris removal workers• Temporary refuse chute fabricators• AH other construction site personnel

Summary

A hoist operator was struck and buried to death by the collapse of a temporary refuse chute made of

44-gallon metal drums in a building construction site.

Circumstances

A temporary dumping refuse chute was erected outside the external wall of a building under construction

to facilitate the transportation of debris from upper floors to the ground level.

The refuse chute was constructed by joining up a number of empty 44-gallon petroleum drums with 3

to 4 welding joins at the rims. A pair of iron brackets was employed to fix the chute onto the wall on

every floor. A wooden slide was attached to the lower end of the chute, i.e. the chute outlet at ground

level, to guide the flow of debris to the collection point on the ground floor.

On the day of the accident, dumping of debris through the chute was conducted at various floors and

cement was being transported from the ground floor to upper floors using a material hoist. The hoist

operator was sitting inside a wooden shed operating the hoist which was about one metre away from

the refuse chute.

Suddenly, a section of the temporary refuse chute slumped down to the wooden shed. The hoist

operator was buried by the refuse chute, rubbish and concrete waste. He was later rescued and rushed

to a hospital where he was certified dead.

Observation

The temporary refuse chute was found detached at the twelfth floor level. The section of the chute

below the twelfth floor, including those fixing brackets, had collapsed while the section above the

twelfth floor remained intact.

62

Examination of the section which was still hanging on the twelfth floor revealed that there were only

two welding points on the rim of the drum.

Some drums of the broken refuse chute on the ground floor were found to be full of concrete waste. In

the huge volume of debris that had buried the deceased, numerous battens and paper bags were also

found.

The temporary refuse chute was constructed by a sub-contractor and no structural drawings were

available.

Judging from the findings and the information available, it is believed that initially some large battens

had been dumped through the chute and they were stopped by the wooden slide at the chute outlet.

Subsequent large pieces of debris were blocked at the chute outlet and the waste accumulated inside the

chute. When the loading of the debris inside the chute together with the self weight of the chute

exceeded the strength of the welding joint, the chute started to collapse and caused the death of the

hoist operator.

Legal Implication


Factories and Industrial Undertakings Ordinance Chapter 59:

Section 6A(2) - It shall be the duty of the proprietor/contractor to ensure, so far as is reasonably

practicable, the health and safety at work of all persons employed by him. The matters

to which that duty extends include:

1. the provision and maintenance of the temporary refuse chute and systems of work

in the use of the refuse chute, so far as is reasonably practicable, safe and without

risks to health; and

2. any part of the construction site under the proprietor's/contractor's control, the

maintenance of it in a condition that is safe and without risks to health.

Recommendation

1. The contractor should never allow any worker to work in the vicinity of any temporary structure

which has a risk of collapse.

2. If a temporary refuse chute has to be constructed for waste disposal, it should be constructed

with adequate strength, securely fixed and maintained regularly.

63

3- The contractor should take all measures to prevent workers from gaining access to or working

close to the refuse chute when waste disposal is in progress.

Reminder1. Temporary refuse chute should be maintained regularly such that material

waste will not block the outlet.2. Temporary structures at site should have adequate strength and meet the

design standards. They should be maintained regularly and properly.

3. No workers should be allowed to work near the refuse chute outlet whenwaste disposal is in progress.

64

C a s e 4 . 2

U N S U P P O R T E D T R E N C H C A N K I L L

C a s e 4 . 2

U N S U P P O R T E D T R E N C H C A N K I L L


case:

• Backhoe operators


• Plumbers and pipe-fitters

Summary

Whilst two workers were working inside an unsupported trench, a section of the trench suddenly

collapsed. One of the workers could not escape in time and was buried.

Circumstances

An operator was assigned to excavate a trench of approximately 15.5 metres long, 1 metre wide and 1.7

metres to 2 metres deep with a backhoe for laying a 300mm drainage pipe. During excavation, the

excavated soil were placed along one side of the trench.

Two days later, when the trench had been excavated to 2.5 metres deep with almost vertical trench

sides, two workers went down to the trench bottom and started to level the trench bed with a plate

compactor and a shovel. They used the plate compactor and shovel to level the trench bed until it was

roughly levelled. Whilst they were working inside the trench, a few lumps of soil slid down from the

ground above. However, they did not aware the danger and continued to level the trench by the plate

compactor. A few minutes later, a section of the trench side with excavated soil on top suddenly

collapsed. One of the workers could not escape in time and was buried.

Observation

The causes of the collapse of the trench side might be a combination of the following factors :~

L Mechanical failure of the soil which cannot support its own weight.

2. Failure due to the weight of surcharge material on that particular trench side.

3. Breakdown of soil strength by moisture or water which had seeped into the trench.

4. Failure caused by the vibration from the plate compactor inside the trench.

5. Absence of any suitable and adequate shoring arrangement to support the trench sides.

66

Legal Implication



Regulation 39(1) - The regulation provides that the contractor responsible for any construction site at

which excavating or earthworking operations are being carried on shall cause a

structure made of suitable timber or other suitable material to be erected in

connection with the operations as soon as may be necessary after their

commencement so as to prevent workmen employed on the site from being

endangered by a fall or displacement of earth, rock, or other material (including

waste material and debris) adjacent to or forming the side of the excavation or

earthwork.

Recommendation

1. The contractor should incorporate safety precautions and emergency plans into the work

programme, and the excavation work should be supervised by a competent person.

2. The trench sides should be cut at such an angle that enables work be carried out safely inside the

excavation.

3. The sides of the trench should be properly shored and adequately supported so as to avoid

dangers arising from dislodgement of earth or other materials.

4. No material, plant or other load should be placed or stacked close to the edge of the trench.

5. All workers involved should be fully informed and instructed as to the details of the excavation

work, the associated dangers, the safety precautions and the emergency procedures.

6. Adequate and effective steps should be taken to prohibit worker from entering the unsafe trench.

Reminder

1. All earth excavation operations should comply with the safety standards andfrequent inspection and supervision of the excavation operations bycompetent persons are necessary.

2. Excavated trench should be properly supported to prevent any damage arisingout of the collapse of the trench.

67

C a s e 4 . 3

A W O R K E R W A S B U R I E D T O D E A T H

I N S I D E A T R E N C H

C a s e 4 . 3

A W O R K E R W A S B U R I E D T O D E A T H I N S I D E A

T R E N C H

The following construction workers should pay special attention to this accidentcase:


• Construction plant operators and truck drivers involved in excavation work

Summary

A team of workers were engaged in the levelling of blinding concrete with shovels in an unsupported

trench. A section of the vertical side of the trench suddenly collapsed and one of the workers was

buried to death by the collapsed earth materials.

Circtunstances

The accident took place on a roadwork site where several sections of an existing road were required to

be widened and re-constructed.

On the day of the accident, an excavator was used to excavate the trench. The required trench size was

at least 1.6 metres deep and 1.2 to 1.3 metres wide for laying a section of a 675mm~diameter drainage

pipe. However, the trench was found to be 1.6 to 2.1 metres deep and 1.8 metres wide after the

accident occurred.

With part of the trench being excavated, a worker 'A' joined in by manual trimming on the sides and

bottom of the trench. At about 3:30 p.m., worker 'A' and another worker £BJ were assigned to mark for

the blinding layer in the trench. At about 3:45 p.m., the excavator operator was asked to stop working

as a truck-mounted concrete mixer arrived on site and was ready for laying the blinding concrete. Due

to the excessive amount of concrete ordered for the trench, timbering work was not carried out to give

time for making a longer trench. The concrete mixer was driven away from the trench upon completion

of laying the blinding concrete and the deceased worker 'BJ, worker 'A' and another worker ' C each

used a shovel to level the blinding concrete to the pre-marked level of the blinding layer. At about 4:15

p.m., the blinding concrete layer had been levelled off and all the 3 workers were down in the middle

of the trench. Suddenly one side of the trench collapsed. Both workers 'A' and f C managed to escape

from the trench but the deceased worker CB' was trapped and buried by the collapsed earth materials.

70

The cause of this accident was believed to be a combination of the following factors:

1. vibration caused by the movement and operation of the truck-mounted concrete mixer had

loosened the hold on the side of the trench, and

2. absence of any suitable and adequate timbering arrangement for supporting the trench sides.

Legal Implication



Regulation 39(1) - The contractor responsible for any construction site at which excavating or

earthworking operations are being carried on shall cause a structure made of suitable

timber or other suitable material to be erected in connexion with the operation as

soon as may be necessary after their commencement so as to prevent workmen

employed on the site from being endangered by a fall or displacement of earth,

rock, or other material (including waste material and debris) adjacent to or forming

the side of the excavation or earthwork.

Court Judgement


Recommendation

1. Excavated trench should be properly shored and supported by a structure made of suitable

timber or other suitable material to prevent the workmen from being endangered by a collapse

or displacement of earth, rock or other material adjacent to or forming the side of the excavation.

2. No heavy vehicle, load or plant should be moved or placed near the edge of the trench being

excavated if it is likely to cause the side of the trench to collapse and thereby endanger any

person.

3. All workers required to work in an excavation should be fully instructed and informed of the

associated dangers arising from working inside an excavation. Necessary precautions should be

taken by the workers before performing excavation work.

4. Emergency escape should be provided for the excavation workers in case of emergency.

5. Excavation work should be supervised by competent persons.

71

Reminder

1. Safe system of work should be established to ensure that no heavy vehicle,load or plant are to be placed near excavation trench if it is likely to causetrench collapse thereby endanger any workman.

2. Every part of the trench being excavated should be properly supported toprevent any danger arising out of the collapse of the trench.

3. Workers should be given proper training on excavation safety.

4. Emergency escape should be provided for workers who are engaged inexcavation work.

5. Excavation work should be supervised by competent persons.

72

C a s e 5 . 1

S E R I O U S I N J U R I E S A R I S I N G O U T O F

D I S M A N T L I N G O F A C O L L A P S E D C R A N E

C a s e 5 . 1

D I S M A N T L I N G O F A C O L L A P S E D C R A N E


case:

• Tower crane operators

• Crane operators

• Welders

• Demolit ion workers

Siimmary

A tower crane collapsed after a fire and three workers were assigned to cut and dismantle the crane part

by part. However, while they were working, the crane mast sprang up suddenly. The three workers

were thrown into the air and fell either onto the crane mast or down to the ground. All of them were

injured.

Circumstances

Two 25-storey residential buildings were under construction on the site. One day, a fire broke out

which subsequently resulted in a tower crane installed at that site collapsed with its mast bent down

onto the first floor and its jib stretched out of the street beyond the site boundary.

After the fire, three workers were assigned to cut and dismantle the mast members of the collapsed

crane. The jib as well as the mast section above the slewing ring were removed first. The next step was

to dismantle the slewing ring. It was then temporarily kept in position by a mobile crane at the time of

the accident.

The workers squatted on the mast members of the crane and began to cut the mast members with oxy-

acetylene gas torches. Suddenly, the slewing ring detached from the crane structure and the crane mast

sprang up subsequently. Both workers were thrown into air and fell either onto the mast or down to

the first floor slab. They were all injured. One of them who struck the reinforcement bars protruding

up from the floor was found seriously injured.

74

Legal Implication



Regulation 38B - Where work cannot safely be done on or from the ground or from part of a building

or other permanent structure, the contractor responsible for the construction site

concerned shall provide, place and keep in position for use and properly maintain

either scaffold or, where appropriate, ladders or other means of support, all of which

shall be sufficient, strong and suitable for the purpose.

Court Judgement


Recommendation

1. A safe system of work should be adopted and a proper working procedure should be followed

for dismantling of the collapsed tower crane.

2. No workers should be allowed to work at height simply by riding on the mast of the crane.

Where work could not be done safely on ground, a suitable scaffold such as a mobile scaffold or

step ladders should be provided and kept in position for use by the workers.

Reminder

1. Safe system of work should be adopted for dismantling work.

2. Procedure in a dismantling work should be properly planned, implementedand supervised by competent persons.

75

C a s e 5 . 2

T R A G E D Y D U E T O F A L L I N G O B J E C T A N D

F A L L I N G F R O M H E I G H T

C a s e 5 . 2

F A L L I N G F R O M H E I G H T

The following construction personnel should pay special attention to this accidentcase:

• Scaffolders

• Plasterers

• Plumbers

• Painters

• Debris removal workers

Summary

A number of bamboo scaffolders were riding on a single row bamboo scaffold outside an existing

building which required external repair and renovation. Bamboos were being passed to the roof of the

building. Suddenly, a piece of broken concrete fell off from the building and hit one of the scaffolders.

The scaffolder fell from the third floor level onto the first floor canopy and died.

Circumstances

An existing building required external repair and renovation. Single row bamboo scaffolds were erected

outside the whole building for repair works to be carried out.

On the day of the accident, scaffolds were already erected outside the building except water tanks on

the roof. Scaffolders then made use of the erected scaffolds to convey bamboos to the top of the

building so that they could erect the remaining scaffolds for water tanks. Five workers - one on the

roof, one on the ground, and three riding on the scaffold at different levels - were responsible to convey

the material.

They passed the bamboo members from the ground to the roof by hand. In the course of transporting

the material, the worker on the roof inadvertently had one end of a bamboo struck on the external wall

at the eighth floor level of the building. Immediately, a piece of concrete suddenly fell off from the

external wall. The worker on the roof then shouted down to alert other scaffolders. Unfortunately, the

scaffolder on the third floor level was hit by the object and fell onto the first floor canopy. The victim

was rushed to hospital where he was certified dead on arrival.

78

Observation

It was observed that at the corner of the building at about the eighth floor level, there was a large crack

with a missing concrete fragment. The fragment that struck the deceased was about 9 kilograms in

weight and it matched with the crack.

The crack on the external wall seemed to have been existed for quite some time and part of the concrete

nearby might have been loosened before the accident as there were old marks along the crack.

It was also possible that during the scaffold erection the crack was disturbed and later when it was

struck by the bamboo the fragment fell off and caused the mishap.

Legal ImpMcation

A) The contractor responsible for this site could be found in breach of the following provisions of the


1. Regulation 49(1) - Where workmen are employed at any place on a construction site, the

contractor responsible for the site shall take such precautions as are

necessary to prevent any workman working at that place from being struck

by any falling material or object.

2. Regulation 38A (b) - The contractor responsible for any construction site shall ensure that every

place on the site at which any person at any time works shall, so far as is

reasonably practicable, be made and kept safe for any person working

there.

3. Regulation 38B - Where work cannot safely be done on or from the ground or from part of

a building or other permanent structure, the contractor responsible for

the construction site concerned shall provide, place and keep in position

for use and properly maintain either scaffolds or, where appropriate, ladders

or other means of support, all of which shall be sufficient, strong and

suitable for the purpose.

B) The contractor responsible for this site could also be found in breach of the following provisions of

the Factories and Industrial Undertakings Ordinance, Chapter 59:

1. Section 6A(1) - It shall be the duty of every proprietor of an industrial undertaking to ensure,

so far as is reasonably practicable, the health and safety at work of all persons

employed by him at the industrial undertaking.

79

2. Section 6A(2)(b) - It is the duty of a proprietor to carry out arrangements for ensuring, so far as

is reasonably practicable, safety and absence of risks to health in connection

with the use, handling, storage and transport of articles and substances.

Court Judgement


Recommendation1. Suitable precautions should be taken to prevent workers engaged in construction work from

being struck by any falling object.

2. Suitable scaffolds or other means of support should be provided so as to enable workers on the

site to carry out their work safely.

3. Suitable methods or system of work should be adopted for the transportation of bamboo members

from low level to high level or vice versa of a building so as to prevent falling off of materials.

Reminder

1. Suitable scaffold or other means of support should be provided to enableworkers to carry out their work safely when they work at height.

2. Workers should check the conditions of external building wall before carryingout any work and suitable methods should be adopted for the transportationof bamboo members to prevent the fall of materials.

3. External walls of a building should be properly maintained such that no fallingmaterial would be resulted from the deterioration of the building.

4. When the provision of suitable scaffold or other means of support isimpracticable, safety harness with secure attachment should be provided forworkers working at height.

80

C a s e 5 . 3

F A T A L A C C I D E N T C A U S E D B Y F A L L I N G

O B J E C T ( M E T A L B A R )

C a s e 5 , 3 ; ' : : ' :

O B J E C T ( M E T A L B A R )


case:

• All construction site workers

Summary

A worker was seriously injured when hit by a long metal bar on his head. He passed away in the

hospital five days after the accident. The metal bar (about 5 feet long, 3/8 inch in diameter) fell from

height and hit on other objects, subsequently sprang out and hit on the deceased's head, thus causing

the fatality. Nevertheless, the accident could have been avoided if the worker had worn a suitable safety

helmet.

Circumstances

This accident occurred on a construction site where an industrial building was under construction.

The structure of the building was built up to the top floor and most of the external bamboo scaffold

had been dismantled.

The deceased was an electrician. On the day of the accident, the deceased and two co-workers were

assigned to repair a flush water pump installed on the flat roof of the industrial building. When they

reached the flat roof, there was no other persons working at the external wall of the building at the

material time. Having spent about 10 minutes on repairing the pump, they succeeded in fixing the

pump and putting it back to good working order. They then went into the premises of the building

and chatted for a while.

Just at this moment, the two workers heard the deceased cry out loudly. They found that a long metal

bar (about 5 feet long and 3/8 inch in diameter) had pierced into the electrician's head. The deceased

then fell unconscious and was sent to hospital immediately.

At the material time, the deceased was injured not on the flat roof but inside the building in close

proximity to the flat roof. Under normal circumstances, he should not have been injured by any falling

object. However, he was fatally struck by a falling long metal bar. This accident was probably caused

by the following contributory factors:-

82

1. the metal bar had previously been placed on window frame at an upper floor. Someone worked

thereon and caused the metal bar to fall down accidentally; or

2. the metal bar was disturbed and caused to fall by strong wind or other unknown reasons; or

3. someone had deliberately or accidentally thrown it out from upper level.

Before reaching the ground , the metal bar might have hit other object, subsequently sprang out and hit

the deceased on his head, thus causing the fatality.

Legal Implication



Regulation 48(l)(b) - A contractor responsible for a construction site shall take all reasonable steps to

ensure that no workman remains on the site unless he is wearing a suitable safety

helmet.

Court Judgement


Recommendation

1. Suitable measures including proper work procedures and regular checks should be conducted

to guard against loose materials that are left at external walls or other places which may cause

injury to any person on the site.

2. Adequate steps should be taken to ensure that all workers on the construction site should not

throw materials from height.

3. Every person entering the site should be provided with a suitable safety helmet, and adequate

supervision should be carried out to ensure the wearing of the helmet so provided.

83

Reminder1. All workers entering the site must wear suitable safety helmets.

2. All workers on construction site must be warned of the danger of throwingmaterials from height.

3. Suitable measures including proper work procedures and regular checksshould be conducted to guard against loose materials that are left at placeswhich may cause injury to any person on the site.

4. Toe boards or similar devices should be provided around perimeter ofopenings or other places to prevent falling of objects.

84

C a s e 5 . 4

A C C I D E N T A L S H O T B Y A C A R T R I D G E

O P E R A T E D F I X I N G T O O L

C a s e 5 . 4

A C C I D E N T A L S H O T B Y A C A R T R I D G E -

O P E R A T E D F I X I N G T O O L


case:

• Cartridge-operated fixing tool operators

• E & M/Building services installation workers


• Plasterers

• Decorators

SummaryIn this accident, a construction worker who did not hold a certificate of competency used a cartridge-

operated fixing tool for driving pins into structural materials. When the tool was fired, a fixing pin

coming out from the tool caused the death of another worker who was passing by and in close proximity

to the firing tool.

Circumstances

The accident scene was a building construction site where the construction of several blocks of residential

buildings was in progress. On the day of the accident, an air-conditioning installation sub-contractor

was employed by the main contractor to carry out air-conditioning works.

In that morning, a worker of the sub-contractor went into the headquarters on the site. The headquarters

was basically a metal container lined with wood. He took out the fixing tool from its box but did not

check whether it had a cartridge in it. Instead, he pressed it against the wall and pulled the trigger

which caused the tool fired suddenly and resulted in an explosion that was out of his expectation.

The fixing pin went out through the wall of the container, hit the metal door jamb of another container

and ricocheted at an angle and eventually hit the head of another worker on the site. The injured was

then sent to a hospital immediately and passed away several hours later.

Legal Implication

The owner and operator of the tool could be found in breach of the following provisions of the Factories

and Industrial Undertakings (Cartridge-operated Fixing Tools) Regulations:

86

1. Regulation 11 (i) states that a tool shall not be used other than by a person who holds a certificate

of competency.

2. Regulation 17(a) states that no person shall misuse or, without reasonable excuse, interfere with

any tool, pin or cartridge.

Court Judgement


Recommendation

1. All cartridge-operated fixing tools, cartridges, pins and ancillary equipment should be stored in

a lockable strong tool box or container.

2. A loaded tool shall never be stored in the tool box or similar container or left unattended.

3. Only holders of certificate of competency are allowed to use cartridge-operated fixing tools.

4. No person shall misuse or, without reasonable excuse, interfere with any tool, pin or cartridge.

Reminder

1. A cartridge-operated fixing tool should never be used in a careless mannerand can only be operated by competent persons.

2. A cartridge-operated fixing tool should be thoroughly examined and checkedto ensure that the cartridge is unloaded before storage or after each shift.

3. While a tool is not required for use it should be kept in a tool box or a containerwhich should be locked and stored in a secure place.

4. Personal protective equipment such as helmet, eye protector and ear protectorshould be worn when operating cartridge-operated fixing tool.

87

C a s e 6 . 1

A W O R K E R W A S S T R U C K T O D E A T H I N

A S P H A L T L A Y I N G


case:

• Roadwork maintenance workers

• Roadwork signallers

• Vehicle-drivers working at roadwork sites

Stmimary

The main contractor was responsible for a container port terminal development project. A batching

plant was set up for this project at the development area and aggregates were delivered thereto by

lorries. Maintenance of a road leading to the development site was part of the project.

On the day of the accident, a foreman, the deceased and a co-worker were engaged in re-asphalting a

section of the said road. The job involved breaking up of the existing concrete surface and re-asphalting

3 layers afterwards. At the time of the accident, the deceased was carrying a steel barrier to fence off a

trench across the road. Unfortunately, a lorry passed by and hit the steel barrier. The deceased was

severely struck by the steel barrier being carried by him. He was certified dead on arrival at the hospital.

Circumstances

A section of the road was to be asphalted. A watchman was assigned to control entry of vehicles. There

were four lanes with a central divider in the middle. The lane next to the pavement (the first lane) was

for vehicles going into the site while the adjacent one (the second lane) was for those leaving. The other

2 lanes were not yet open to traffic.

On the day of accident, the foreman led the deceased and the co-worker to the working area to start the

second layer of asphalting. The first lane was asphalted first. As such, the second lane was left for traffic

in both directions. The trench across the second lane was covered by three metal plates.

After the first lane had been asphalted, a driver operated the grab mounted on a lorry CA' to relocate the

three metal plates over the trench, i.e. from second lane to first lane. Afterwards he drove his lorry 'A'

away. Meanwhile, the foreman led his team to fence off the second lane by steel barrier. All of them did

not wear any retroflective clothing designed for road works.

Lorry 'A' was followed by a lorry CB' moving at 4 to 5 km/hr. It was previously on the second lane. In

order to bypass the trench, it turned right to ride on the metal plates on the first lane and then turned

90

left to move back to the second lane.

Whilst lorry CB' was so moving, its left rear wheel hit the steel barrier being carried by the deceased. The

deceased was struck by the steel barrier and lost his balance. As a result, he sustained the fatal injury -

fracture of skull with intracranial haemorrhage and injury to brain. He was certified dead on arrival at

the hospital.

Legal Implication

The contractor responsible for this site could be found in breach of the following general duties provisions

under the Factories and Industrial Undertakings Ordinance:

"6A. 1. It shall be the duty of every proprietor of an industrial undertaking to ensure, so far

as is reasonably practicable, the health and safety at work of all persons employed by

him at the industrial undertaking.

2. Without prejudice to the generality of proprietor's duty under subsection (1), the

matters to which that duty extends include in particular-

(a) the provision and maintenance of plant and system of work that are, so far as

is reasonably practicable, safe and without risks to health;"

Recommendation

A system of work with the following particulars should be provided and maintained for the workers

carrying out road works:

1. Traffic should be regulated when road work is in progress;

2. All workers engaged in road work should wear high visibility jacket or belts, incorporating

orange retroflective stripes or patches; and

3. Smaller and lighter barrier such as traffic cones or traffic cylinders should be used.

4. Lorry drivers should pay special attention to the condition of construction sites and workers

nearby.

Reminder

1. Traffic should be regulated when road work is in progress.

2. Roadworkers should wear high visibility jacket or belts, incorporating orangeretroflective stripes or patches in order to avoid traffic accidents.

91

C a s e 7 . 1

F A T A L A C C I D E N T R E S U L T E D F R O M

B U R S T I N G A B R A S I V E W H E E L


case:

• Metal workers


• Workers operating grinders

Summary

A worker was fatally injured while the high-speed revolving abrasive wheel of a pneumatic grinder

being operated by him suddenly burst into pieces. A flying fragment of the wheel seriously wounded

the worker in his head, resulting in his death.

Circumstances

On the day of the accident, the worker was preparing to grind a drill-bit with the use of a pneumatic

grinder. The grinder, being installed on a wooden stand, was connected to an air-compressor for the

supply of air-pressure via an air hose.

The working air-pressure of the air-compressor at the time of accident was affixed at about 5kg/cm2;

the maximum working speed of the spindle of the grinder was about 6300 RPM.

An abrasive wheel was mounted on the spindle. The diameter of the abrasive wheel was about 20cm

with a maximum permissible speed of 3100 revolutions per minute (RPM). The abrasive wheel involved

was totally exposed with no guard provided.

At the time of mishap, the worker switched on the pneumatic grinder and stood in front of the grinder.

Suddenly, the revolving abrasive wheel of the grinder burst into pieces with a loud sound. The right

temple of the worker was severely hit by a flying fragment of the abrasive wheel, causing him to be

seriously wounded.

During investigation, simulation test with the use of a tachometer for assessing the spindle speed of the

pneumatic grinder was conducted on site. The average spindle speed was found to be greater than its

maximum permissible speed, i.e. the abrasive wheel must have been overspeeding beyond its permissible

limit at the time of the accident.

94

Laboratory examination revealed that the governor which was designed to control the spindle speed of

the pneumatic grinder was defective.

In conclusion, the main contributory factors leading to the cause of the accident were considered to be

overspeeding of the spindle and the abrasive wheel, the malfunction of the governor and the lack of a

protective guard.

Legal Implication

The owner of the pneumatic grinder could be found in breach of the following provisions of the

Factories and Industrial Undertakings (Abrasive Wheels) Regulations:

1. Regulation 5(3) - No abrasive wheel shall be operated at a speed in excess of the maximum

permissible speed in revolutions per minute;

2. Regulation 6(5) - Every governor and other device used for controlling the speed of an air

driven spindle on which an abrasive wheel is mounted shall be properly

maintained;

3. Regulation 7(2)A - An abrasive wheel shall not be mounted except by a person who has been

appointed in writing for that purpose by the proprietor of an industrial

undertakings;

4. Regulation 8(1) - A guard shall be provided and kept in position at every abrasive wheel in

motion.

Court Judgement


Recommendation

1. The abrasive wheel should never be operated at a speed in excess of its maximum permissible

speed as specified by the manufacturer;

2. The spindle of the pneumatic grinder should never be operated at a speed in excess of its maximum

working speed as specified for that spindle;

3. The spindle speed of a pneumatic grinder should be controlled by a properly maintained governor

(or other device) so that the spindle speed does not at any time exceed its maximum permissible

working speed;

4. The abrasive wheel should be properly mounted by a competent person who is appointed in

writing for that purpose by the proprietor;

95

5. The abrasive wheel should be provided with a protective guard of suitable design and construction;

and the protective guide should be kept in proper position whilst the abrasive wheel is in motion.

6. All practicable steps should be taken to ensure that the abrasive wheel used is suitable for the

work it is intended so as to reduce the risk of injury to workers.

7. Warning notice in using abrasive wheel should be posted in a noticeable location.

Reminder1. A strong and rigidly fixed (hood type with removable side plate) guard should

be provided and maintained for the pneumatic grinder.

2. Suitable personal protective equipment such as helmet, goggle and/or faceshield should be worn by the operative of a pneumatic grinder.

3. Grinding machines should be properly maintained and operated within thespeed limits of its spindles and abrasive wheels.

4. Competent person should be appointed to mount the abrasive wheel.

96

C a s e 8 . 1

F A L L O F A T R U C K I N T O T H E S E A

R E S U L T E D I N T H E D R O W N I N G O F T H E

T R U C K D R I V E R

TRUCK OVERRAN THEEDGE OF A BUND ANDFELL INTO THE SEA.

97

F A L L O F A T P R U G K

I N T H i D R O \ / V N H S I G O F *

The following construction personnelcase:

• Dump truck

• Landfill site

• Landfill site

drivers

supervisors

plant operators

should pay special attention to this accident

Summary

A truck driver was engaged in transporting earth materials from a formation site to a landfill site.

Tipping of earth materials from the truck to a designated point of the landfill site was the responsibility

of the truck driver. While driving to the tipping point of the landfill site, the truck overran the edge of

a bund and fell into the sea. The driver was drowned and later certified dead in the hospital on the

same day.

Circumstances

The accident occurred on a landfill site where new seawalls and a sanitary landfill were under construction.

In order to facilitate the landfilling works within the site, a number of lagoons were formed by the

formation of several inter-connected bunds.

On the day of the accident, the formation and extension of a bund CP' by tipping of earth materials was

in progress. The deceased was assigned to transport earth materials to the tipping point by the use of a

truck. In that morning, a foreman was posted at the bund to control traffic. A bulldozer operated by

a worker was resided at bund CP' to assist the tipping work. Later, the foreman left the bund CP' and

went to the site entrance to direct the trucks to the designated location after the trucks had been

weighed at the entrance. At 4:00 p.m., the truck driven by the deceased arrived at the entrance. After

weighing of the truck, the foreman directed the deceased's truck to bund CP' by hand signal. The

deceased's truck was followed by another truck £B\ At 4:15 p.m., both trucks reached bund *P\ The

deceased's truck was 10 metres ahead of truck £B\ After passing the first extension of the bund, the

deceased's truck went off the centre of the bund and moved towards the left edge of the bund. However,

it ran over the edge and fell into the sea. As a result, the deceased was drowned.

Investigation revealed that neither barrier / guard rail nor traffic warning notice was provided on the

bund to alert the truck drivers of the risk of overrunning the edge. Moreover, no rescue equipment was

98

provided in the site and no emergency arrangement was made to rescue persons who might fall into th<

sea. There was also no precautionary measure to ensure the truck drivers to follow the safe traffic rules

Legal Implication

The contractor responsible for this site could be found in breach of the following provision of tht


Regulation 52A(l)(a) -Where a construction site is situated on, or adjacent to, water into which s

workman is liable to fall with risk of drowning, the contractor responsible foi

the site shall provide suitable rescue equipment and keep it in an efficient state,

Court Judgement


Recommendation

1. Fencing, railing, warning signs or conspicuous obstacles such as coloured or reflective barriers

should be provided along the edges of the bund in order to warn the truck drivers to keep clear

of the edge and to avoid overrunning.

2. Clear instruction should be given to the truck drivers and supervision should be provided at site

so that safety precautions within the site can be followed by the truck drivers. Truck drivers

should not perform landfill operation if supervision is not provided.

3. Rescue equipment in good working condition should be provided in suitable locations and

workers should be trained to use the equipment in case of emergency.

4. Emergency procedures should be arranged to rescue persons who might fall into the sea.

R e m i n d e r

1.

2.

3.

Supervision should be provided at all times at landfill

drivers in the landfilling operation.

Rescue equipment in good working condition should

locations and personnel shall be trained to use the

emergency.

Barriers and warning signs should be provided along

prevent the falling of trucks into the sea.

site to direct the truck

be provided in

equipment in

the edges of a

suitable

case of

bund to

99

C a s e 9 . 1

T R A G E D Y A T T R I B U T E D T O T H E N E G L E C T

O F G E N E R A L , F I R E , C H E M I C A L A N D

C O N S T R U C T I O N S A F E T Y


case:

• Workers perform oxy-acetylene gas cutting operation

• Welders

• Painters

Stuiunary

Two workers engaged in gas cutting of the protruding ends of reinforcement bars accidentally ignited

the foam plastic blocks nearby. One of them attempted to extinguish the fire by throwing a container

of clear liquid that appeared to be water onto the fire. Unexpectedly, this caused a flash of fire and set

the other worker on fire. The latter ran in panic and fell into an unprotected lift shaft and was seriously

injured and died later.

Circtumstaiices

The accident took place at a site where a multi-storey residential block was being constructed. Two

riggers including the deceased were engaged in the erection of metal mould around the erected steel

reinforcement bars for concreting on the second floor. As some of the bars were too long and affected

their erection work, they decided to cut off the excessive length with an oxy-acetylene set. During the

cutting operation, a plastic foam inside an indented wall channel was accidentally ignited.

When they saw the fire they immediately retreated from the spot and tried to extinguish the fire. They

found a plastic container partially filled with a few litres of clear liquid that appeared to be water. There

was no label or writing on the container to indicate that the liquid inside was in fact gasoline. Believed

that the liquid was water, the workers threw it onto the burnt plastic foam in an attempt to extinguish

the fire. The result was detrimental. The flame flared up and one of the workers was set on fire.

Both workers were panic-stricken and they started to run away from the spot. As the worker on fire ran

past an unprotected lift shaft opening which measured 2.3 metres x 2.4 metres, he accidentally lost his

balance and fell into the opening. He fell a distance of about 3 metres and landed on a wooden

platform below. He sustained serious burn and multiple injuries and died later.

102

Legal Implication

The contractor responsible for this site could be found in breach of the following provisions of the law:

1. Regulation 38P of the Construction Sites (Safety) Regulations requires that every opening through

or from which any person is liable to fall a distance of more than 2 metres shall be provided with

guard-rail of adequate strength to prevent as far as possible the fall of persons.

2. Regulation 54 of the Construction Sites (Safety) Regulations requires all fire fighting appliances

provided in the site shall be maintained in good condition.

3. Regulation 5(1) of the Factories & Industrial Undertaking (Dangerous Substances) Regulations

which requires that gasoline, a listed substance to which these regulations apply shall be labelled

with the required particulars including the risks involved and the safety precautions to be taken.

Court Judgement


Recommendation

The incident revealed some typical unsafe conditions and practices that prevailed on sites. The tragedy

could be prevented if the following safety precautions had been taken :

1. Before using oxy-acetylene gas cutting, suitable steps should be taken to ensure that all combustible

materials are kept a safe distance away from the source of ignition.

2. Suitable fire fighting appliances should be provided within easily accessible distance when naked

flame process is conducted.

3. Container holding flammable substance should be properly labelled with the following

particulars:-

- the chemical name or common name of the substance;

- the classification of the substance such as flammable, toxic, etc;

- the symbol in respect of that classification;

- the indication of risk inherent in the substance; and

- the indication of the safety precaution required.

103

4. All lift shaft openings should be provided with suitable guard rails of adequate strength with a

height between 900mm and 1150mm.

5. Flammable substances should be properly labelled and stored.

Reminder1. Before using oxy-acetylene gas cutting, all combustible materials should be

kept a safe distance away from the source of ignition and fire fightingappliances should be provided within easily accessible distance.

2. AH lift shaft openings should be provided with suitable guard rails of adequatestrength.

3. Container holding flammable substance should be properly labelled.

4. Non-flammable or less flammable clothing and suitable personal protectiveequipment such as leather gloves, goggles should be worn by welders.

5. Welding work area should be isolated by non-flammable screens / curtains.

104

Case 10 .1

GASSING IN A CONFINED SPACE

C a s e 1 0 . 1

G A S S I N G I N A C O N F I N E D S P A C E


case:

• Welders

• Metal workers

• Workers working in confined space

Stimmary

A worker was found collapsed inside a long pipeline (about 2.2 metres diameter and 120 metres long)

located at a jobsite in the New Territories while he was carrying out grinding work inside the pipeline.

The accumulation of Carbon Monoxide generated from a petrol-fuelled portable generator inside the

pipeline poisoned the worker. He was certified dead on arrival at the hospital.

Circumstances

On the day of the accident, the deceased was assigned to grind a pipe-joint inside a long pipeline. He

fetched a portable electric generator, a portable hand-grinder, a light bulb and other handtools from

the workshop for his grinding work. The generator was petrol-fuelled and it was used to generate and

supply electricity to the grinder and to the light bulb inside the pipeline.

The deceased entered the long pipeline and started his work inside the pipeline at about 10 a.m. in that

morning. Having switched on the electric generator, he began to grind the pipe-joint alone. He

worked for a long time and was eventually found collapsed inside the pipeline at about 2:30 p.m.

Simulation Test

A simulation test was conducted after the accident by the Inspectorate with the assistance of the

Government Laboratory and the Occupational Hygienists. The purpose of the test was to find out the

concentration of the Carbon Monoxide generated from the portable petrol-fuelled generator after running

a certain period of time. The result of the test indicated that the IDLH (Immediately Dangerous to Life

or Health) concentration of the Carbon Monoxide would be exceeded in less than one hour of continuous

operation of that generator. The post mortem report also indicated that the cause of death for the

deceased was mainly due to Carbon Monoxide poisoning.

In conclusion, the work environment so set up inside the long pipeline was a confined space. Carbon

Monoxide was generated from the petrol-fuelled generator and accumulated in the long pipeline. The

106

high concentration of Carbon Monoxide inside the pipeline caused health hazards to persons working

in that confined environment.

Legal ImpHcation


Factories and Industrial Undertakings (Confined Spaces) Regulations:

1. Under Regulation 6, no person shall enter or remain in a confined space for any purpose unless

he is wearing an approved breathing apparatus and has been authorised to enter by the proprietor,

and where practicable, he is wearing a belt with a rope securely attached thereto and the free end

of the rope is held by a person who is outside the confined space and who is capable of pulling

him out of the confined space.

2. Under Regulation 9(1), a proprietor shall provide and keep readily available in a satisfactory

condition a sufficient supply of approved breathing apparatus, suitable reviving apparatus, vessels

containing oxygen, belts and ropes.

Court Judgement


Recommendation

In order to obviate the accident, the following preventive measures should be adopted:-

1. No person should be permitted to work in a confined environment where there is a risk of high

concentration of Carbon Monoxide or poisonous gases unless that person is wearing an approved

breathing apparatus.

2. Petrol-fuelled generator should not be operated inside a confined space where only limited

natural or artificial ventilation is available.

3. A safe system of work for entry into confined space should be adopted and the necessary safety

precautions for entry to a confined space should be implemented and strictly followed. The

safety precautions should include the provision and use of approved breathing apparatus and

reviving apparatus, implementation of permit-to-work system.

4. Approved breathing apparatus and reviving apparatus should be provided and workers who

work in the confined space should be properly trained in using the apparatus.

5. When work is being carried out in a confined space, gas concentration in the confined space

should be continuously checked and monitored. Fresh air should be continuously supplied to

the confined space whenever practicable.

107

6. A person who is capable of pulling a worker out of a confined space should be placed outside the

confined space.

Reminder

1. All persons should be properly trained and safety procedures shall be strictlyfollowed before entering a confined space.

2. Mechanical ventilation should be provided to reduce the risk of gassing whenworkers are required to work in a confined space.

3. No person should be allowed to enter a confined space when there is a riskof having poisonous gases in the confined space unless that person is wearingan approved breathing apparatus.

4. A person who is capable of pulling a worker out of a confined space shouldbe placed outside the confined space.

108

C a s e 1 0 . 2

D R O W N E D I N A D E E P C A I S S O N

C a s e 1 0 . 2

D R O W N E D I N A D E E P C A I S S O N


case:

• Caisson workers

• Workers working in confined space

Sirnimary

A worker fell into a 10.5 metres deep caisson which was filled with water when he was climbing down

the caisson in an attempt to loosen a nylon rope. Two other workers attempted to rescue him by

climbing down the caisson one after the other but also fell to the bottom of the caisson. All the three

workers were drowned.

Circumstances

On the day of the accident, the caisson work area was flooded with rain water due to the heavy rain in

the previous days. Before starting to work, the caisson workers tried to find water pumps to pump

away stagnant water that was accumulated at ground level.

A worker noticed that there was a pump at the bottom of a caisson. He intended to lift up the water

pump by a winch at ground level by lowering a nylon rope with a live knot at its end. However, when

the live knot reached about the 4th concrete ring down the caisson, it clung to the pump hose and

could not be lowered further down. So the worker climbed down the caisson and loosened the knot.

He then attempted to lower the live knot further down. When he was lowering down the rope inside

the caisson, he accidentally slipped and fell into the water at the bottom of the caisson.

Having seen the accident, one of the workers then cut off the electricity supply and climbed down the

caisson to rescue his co-worker. As he reached about the 5th concrete ring inside the caisson, he held

his throat and showed difficulty in breathing. He soon fell into the water at the bottom of the caisson

where the first victim laid.

After ensuring the electricity supply to this area was cut off, another worker climbed down the caisson

to make the rescue. As soon as he reached about the 4th concrete ring, he yelled out "dangerous gas"

and after a while he also fell to the bottom of the caisson. By this time no one dared to go down the

caisson any more. The rescue operation was later conducted by the Fire Services personnel and the

three victims were certified dead on arrival at the hospital.

no

Observation

1. Investigation revealed that before the first worker went down the caisson, the caisson opening

had been sealed off with a wooden cover. Prior to the accident, no work had been carried out in

the caisson for about 10 days.

2. No testing of dangerous fumes nor the oxygen content inside the caisson was performed before

allowing workers to enter the caisson. The caisson was not examined and certified by a competent

person as being safe for entry without breathing apparatus.

3. No breathing apparatus was worn by the victims when they entered the caisson and the caisson

was not provided with any mechanical ventilation.

4. Neither breathing apparatus nor reviving apparatus was provided on the site.

5. None of the victims wore any safety harness with a rope attachment so that attendant persons at

the caisson top could pull them out in the event of emergency. There was also no other means

provided to enable person in the caisson to reach a position of safety in case of emergency.

6. Based on the analysis of the air samples collected from the caisson, this accident was probably

caused by oxygen deficiency inside the caisson. The oxygen concentration inside the caisson

might have been substantially reduced by biological action of certain micro-organisms in the

surrounding soils of the caisson.

Legal Implication


Factories and Industrial Undertakings (Confined Spaces) Regulations:

1. A proprietor shall provide and keep readily available in a satisfactory condition a sufficient

supply of approved breathing apparatus, suitable reviving apparatus, vessels containing oxygen,

belts and ropes.

2. No person shall enter or remain in any confined space in which the proportion of oxygen in the

air is liable to have been substantially reduced below the normal proportion unless either :

(a) that person is wearing an approved breathing apparatus; or

(b) that space is adequately ventilated and has been tested and certified by the proprietor as

being safe for entry without breathing apparatus.

Court Judgement


Recommendation1. Every caisson should be tested by suitable instrument for dangerous fumes and oxygen content

before allowing workers to enter the caisson. A record on the findings of every test for dangerous

fumes and oxygen content should be maintained at site and made available for inspection by a

Factory Inspector during the caisson construction period.

2. Any person who enters or remains in a caisson should be properly trained and is required wear

an approved breathing apparatus unless it has been tested by a competent person as being safe

for entry without breathing apparatus.

3. Any person who enters a caisson should wear a suitable safety harness with a rope securely

attached thereto and the free end of the rope shall be held by a person who is outside the caisson

and who is capable of pulling him out of the caisson in the event of emergency. Or alternatively,

a rescue lifting appliance should be provided and attended by a person outside the caisson who

will be capable of pulling the person out of the caisson in the event of emergency.

4. Every caisson should have a supply of fresh air to maintain the normal oxygen content inside

the caisson.

5. At least two sets of approved breathing apparatus should be provided and properly maintained

at caisson openings for use by workers in case of emergency.

Reminder

1. A permit to work system should be adopted and strictly followed by workersin entering a confined space.

2. All persons who are required to work in a confined space should be properlytrained.

3. Any person who enters or remains in a caisson should be properly trainedand is required wear an approved breathing apparatus unless it has beentested by a competent person as being safe for entry without breathingapparatus.

112

C a s e 1 1 . 1

W O R K E R S W E R E K I L L E D I N A

P A S S E N G E R H O I S T A C C I D E N T

C a s e 1 1 . 1

W O R K E R S W E R E K I L L E D I N A P A S S E N G E R

H O I S T A C C I D E N T


case:

• Passenger hoist owners

• Competent persons / examiners who certify passenger hoists

• Passenger hoist repair / maintenance technicians

• Passenger hoist operators

• Project managers, safety officers, safety supervisors

• All other construction site workers

Stimmary

On the day of the accident, a passenger hoist (herein and after called 'the hoist') plunged from the

upper floor level to the podium of a construction site. All the passengers inside were killed.

Circumstances and Observation

A multi-storey building was being constructed on a construction site. Installation of a passenger hoist

on the site was one of the contract terms between the principal contractor and the project developer. A

maintenance sub-contractor entered a contract with the principal contractor and was responsible for

the routine maintenance of the hoist.

The passenger hoist that was involved in the accident was of a rack and pinion type. It was designed

with a loading capacity of 1,000 kilograms and it consisted of five essential components, namely, a

CAGE, a BASE UNIT, a MAST, a MOTOR-GEARBOX assembly and an EMERGENCY BRAKE

assembly.

When the hoist was delivered to the site, the maintenance sub-contractor responsible for weekly inspection

of the hoist asked another sub-contractor to erect the hoist. The latter had no formal training in the

erection of a passenger hoist and he only relied on a 2-page catalogue and his past experience to install

the hoist.

The hoist mast was initially installed up to a height of about 43 metres. After the erection of the hoist

had been completed, a surveying firm was appointed to examine and certify the condition of the hoist.

The surveying company sent an assistant inspector to conduct test and examination of the hoist. The

assistant inspector did not have any academic background in engineering. The competent examiner

114

responsible for subsequent hoist certification was not actually involved in the test and examination of

the hoist.

The surveying company, under the Construction Sites (Safety) Regulations (CSSR), certified the

maximum permissible number of passengers and specified the working condition of the hoist was

SAFE.

The mast was later extended to the roof level but the hoist was not re-examined by a competent person

as required by the Law.

The maintenance sub-contractor had a checklist for inspection on all the crucial parts of the hoist. It

was contained in the company's "Overall Inspection Record (OIR)". However, maintenance of the

hoist by the sub-contractor was largely relied on the personal experience of two technicians CT15 and6T2\ Before the accident, the hoist had a number of regular inspections but the pinion or the setting

of the emergency brake disc spring loading packs had never been checked. The technicians admitted

that there was no clear and explicit instructions on how to carry out the hoist maintenance work. In

fact, they had never completed any OIR.

Weekly inspection of the hoist was the responsibility of a site engineer of a site management sub-

contractor. From time to time, the site engineer conducted visual checks on the rack and the tightness

of the mast tie assemblies. He also had to check if there was any unusual noise coming from the hoist

operation. Each of his inspections revealed that the hoist was "safe and secure".

On the day of the accident, technician CT1' of the maintenance sub-contractor was assigned to repair a

broken cable of the hoist. When he arrived at the site, the other technician 'T2' told him that the cable

problem had been rectified. However, cTl' was requested by CT2' to check the hoist's interlocking

switch at the top of the enclosure gate at the podium. After checking the switch and found out that it

functioned properly, he then left the site.

After the tea break in the same afternoon, there were a large number of workers at the podium waiting

for the hoist to bring them back to work on upper floors. Workers in excess of the permissible number

of passengers managed to squeeze into the cage, and the over-crowded hoist started to go upwards.

When the hoist was moving upwards, a loud cracking noise was heard. Following the noise, the hoist

began to fall and finally it crashed onto the podium.

All the workers inside the hoist were sent to the hospital and were certified dead on the same day.

Conclusion

The main cause of the accident was due to inadequate and improper maintenance of the hoist in that:

115

1. the driving pinion of the gearbox was made from a softer material than that specified by the

manufacturer and was worn out; and at the time of the accident it was disengaged from the

rack; and

2. the emergency braking system failed to stop the fast descending cage due to improper disc

spring pack settings.

There are other contributory factors leading to this tragedy:

1. The wearing out of the driving pinion of the motor gearbox assembly was undetected before the

accident.

2. There was no adequate instruction or information to assist the technicians in carrying out of the

maintenance/weekly inspection work and to uncover the serious defects of the hoist.

3. There was no reporting or monitoring system to ensure that the hoist was properly maintained.

4. There was inadequate supervision to ensure the safe operation of the hoist.

Legal Implication

The contractor(s) responsible for this site could be found in breach of the following provisions of the


1. Regulation 5(1) - The contractor responsible for a lifting appliance shall ensure that it is not

used unless

(a) it is of good mechanical construction, made of strong and sound materials,

and free from patent defect;

(b) it is properly maintained.

2. Regulation 31(3) (a) - The contractor responsible for a hoist shall, unless it is impracticable to do

so, provide and maintain efficient devices which will support its platform of

cage and its safe working load in the event of failure of the hoist rope or ropes

or any of the hoisting gear.

3. Regulation 34(2)(a) - In addition to paragraph (I), every such contractor shall ensure that, in the

case of a hoist used for carrying persons,

(i) the maximum number of persons to be carried at any one time shall be

clearly and legibly marked on its platform or cage; and

(ii). a greater number of persons shall not be so carried.

116

4. Regulation 35(2)(a) - The contractor responsible for a hoist shall ensure that it is not used for

carrying persons unless, since it was last erected or the height of the travel of

the cage was last altered, whichever is the later, and notwithstanding a

certificate in respect of the hoist under paragraph (1), it has been tested and

thoroughly examined by a competent examiner.

5. Regulation 36(b) - The contractor responsible for a hoist shall ensure that it is not used for

carrying persons unless each gate at a landing place in the hoistway enclosure

is fitted with efficient interlocking or similar devices to prevent the gate from

being opened except when the cages is at the landing place and to prevent the

cage from being moved away from the landing place until the gate at that

place is closed.

6. Regulation 6A(2)(a) - Without prejudice to the generality of proprietor's duty under subsection

(1), the matters to which that duty extends include in particular the provision

and maintenance of plant and system of work that are, so far as is reasonably

practicable, safe and without risks to health.

Recommendation

1. The contractor responsible for the passenger hoist should ensure that it is not used unless it is of

good mechanical construction, made of strong and sound materials and free from patent defect.

2. The contractor responsible for the passenger hoist should ensure that it is not used unless it is

properly maintained.

3. All components and spare parts of the passenger hoist should be of material conformed or

equivalent to the specifications as stipulated by the manufacturer of the hoist.

4. An efficient braking system which will support the hoist platform or cage in the event of the

failure of the hoist gear should be provided and maintained.

5. The contractor responsible for the passenger hoist should ensure that it is not used for carrying

persons, since it was last erected or the height of the travel of the cage was last altered, whichever

is the later, unless it has been tested and thoroughly examined by a competent examiner and has

been obtained from him in respect of the test and examination a certificate in the approved

form, which includes a statement to the effect that the hoist is in a safe working order.

6. An overload device should be installed on the passenger hoist and should operate when the load

is in excess of the maximum load allowed for the hoist. The 'overload device' means a device

that will, when the passenger hoist is overloaded, give an audible alarm or signal; and prevent

any movement of the hoist.

117

7. Regular inspection of the passenger hoist should be properly carried out by a competent person.

8. Test and examination of the passenger hoist should be properly carried out by a competent

examiner.

9. The number of persons carried by the passenger hoist should not exceed the maximum permissible

number of passengers as laid down in the certificate of examination.

10. The contractor responsible for the hoist should provide and maintain a safe system of work

which should include the provisions of:

a) an effective record system to ensure that maintenance, inspection, test and examination of

the hoist are properly carried out;

b) an effective arrangement such that the duties and responsibilities of relevant personnel in

the use of the hoist are well defined, communicated and understood; and

c) an effective monitoring system to ensure the above are properly implemented.

11. Adequate information, training, instruction and supervision on the proper maintenance and

safe use of the passenger hoist should be provided for all relevant personnel in the site to ensure

that they are fully aware of the safety requirements and implications.

12. All person employed in the site should follow the safety rules and procedures of the site and

should co-operate with the site management so that duties and requirements imposed on them

can be effectively carried out.

13. Any person who observes any defect or mal-function of a passenger hoist should inform the site

management immediately, and the passenger hoist should not be used until it has been properly

fixed and certified in good working condition.

Reminder1. The number of persons carried by the passenger hoist should not exceed

the maximum permissible number of passengers as laid down in the certificateof examination.

2. Passenger hoist operators should be properly trained and certified.

3. Passenger hoists should not be used for carrying persons unless they havebeen tested and thoroughly examined by competent examiners.

4. Passenger hoists should be properly and regularly maintained by competentpersons.

118

C a s e 1 1 . 2

A W O R K E R W A S K I L L E D A F T E R F A L L I N G

T O G E T H E R W I T H A W O R K I N G P L A T F O R M

S U S P E N D E D B Y A W I N C H

A worker was working on a power driven suspended scaffold and fell together with the scaffold to the

ground when the suspended scaffold suddenly collapsed. The cause of the accident was the sudden

failure of the anchorage support of the scaffold.

Circumstances

This accident occurred inside an oil company depot where maintenance work was being carried out on

the external surface of a field oil tank with a diameter of 33 metres and a height of 21 metres. On the

roof of the tank, railings made of angle bar were erected along the roof edges. The tank was protected

by a layer of insulation material which was covered by an aluminium sheet riveted to the insulation

material.

The maintenance work involved the fixing of screws to the aluminium insulation sheet as some of the

old rivets had disappeared due to wear and tear. A suspended scaffold operated by an external electric

winch was employed for the maintenance job. The lifting appliance consisted of :-

1. a winch with wire rope to raise and lower a suspended scaffold,

2. two ginwheels and one top pulley block,

3. a metal scaffold measuring 1.80 metres x 1.05 metres x 1.05 metres; and

4. a hand operated chain block that was needed to hold the scaffold close to the tank surface.

The top pulley block was anchored to the tank roof railing by means of a wire sling.

During the screw fixing work, the deceased was being carried in the suspended scaffold. He wore a

safety belt and the lanyard was anchored to a lifeline which was in turn tied to the same angle section of

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the railing where the top pulley block was secured. The end of the lifeline was further knotted to the

top pulley block.

The winch was operated by another worker at ground level.

On the day of the accident, fixing of screws started at the ground level and moved upwards, reaching

eventually to a height of about 15 metres. Having finished the work at this level , the deceased gave

signal to the winch operator to raise the scaffold upwards. Suddenly, the scaffold together with the

deceased fell to the ground. The deceased was rushed to a hospital where he was certified dead.

Observation

Investigation revealed that the portion of railing at the tank roof that was under loading failed and

broke into two cantilevers. The angle cantilever on which the top pulley block and the lifeline was

anchored was found to have yielded and bent. As a consequence the scaffold slid out of the railing

support and fell under gravity. On close examination of the welded joint of the broken railing, oxidization

and rust were found covering about 80% of the welded joint surface. It was further revealed that the

lifting system that had been installed ten days before the accident had not been tested and examined by

a competent examiner.

Legal Implication


Factories and Industrial Undertakings (Lifting Appliances & Lifting Gears) Regulations:

1. Regulation 5(1) - The owner of a lifting appliance shall ensure that it is not used unless it has

been thoroughly examined by a competent examiner at least once in the

preceding 12 months, and a certificate in the approved form in which the

competent examiner has made a statement to the effect that it is in safe working

order has been obtained.

2. Regulation 7A - The owner of a lifting appliance shall ensure that it is not used unless it has

been inspected within the preceding 7 days by a competent person and the

competent person has given the owner a certificate in the approved form in

which he has made a statement to the effect that the lifting appliance is in safe

working order.

3. Regulation 7C - The owner of any pulley block or gin wheel which is suspended from or

supported by a pole or beam shall ensure that the block or wheel is not used

for raising or lowering any load unless: ^ ^ jz. jg fyJ

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(a) it is effectively secured to the pole or beam; and

(b) the pole or beam is:

(i) of adequate strength for the purpose for which it is intended to be

used; and

(ii) adequately and properly secured so as to support the block or wheel

and the load with safety and to prevent undue movement of the pole

or beam.

Recommendation

This accident might have been prevented if the following preventive measures were adopted :

1. The anchorage point for the top pulley block should be properly designed and constructed and

should have sufficient strength for the anticipated loading.

2. The lifting system of the scaffold was tested and thoroughly examined by a competent examiner.

3. The lifting system of the scaffold was inspected and maintained regularly by a competent person.

4. The lanyard of the safety harness was anchored to an independent lifeline which was attached to

a secure anchorage that was separated from the point of suspension of the scaffold.

Reminder

1. Suitable safety harness with fall arresting system attached to an independentlife-line must be provided for every worker engaged in work at height.

2. Training should be provided for all workers working on suspended scaffolds.

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labour department, hong kong governmentebook.lib.hku.hk/hkg/b35840183.pdf · foreword by deputy...

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