Falls from height

This compilation of case studies on fatalities in the construction industryis initiated by the Workplace Safety and Health Council, and put togetherby the WSH Construction Committee in collaboration with the Ministryof Manpower. This booklet depicts how the accidents occurred andprovides valuable learning points on how they may have been prevented.This is the first in a series of such booklets to be published.

As much as the next few years promise to be exciting for the constructionindustry, they also pose a great challenge to the industry to maintainworkplace safety and health. Construction sites have customarily beenviewed as high-risk workplaces, which more often than not have a higherincidence of workplace fatalities. We must address this perception andchange the reality. While construction workers strive to complete a buildingor facility, it is important that they do not risk life and limb. It is crucialthat these workers go home safely after work each day.

This booklet of case studies offers insights to all in the industry on howthese tragic accidents occurred, so that we may glean important, life-saving lessons from the experience. In learning from our past mistakes,we can and must prevent these mishaps from happening again. Togetherwith your help, we can transform construction sites into safe and healthyworkplaces for our workers.

Mr Lee Tzu Yang ChairmanWorkplace Safety and Health Council

PREFACE

CONTENTSFalls from Height

Case 1 Fall through a roof 04

Case 2 Fall from a scaffold 06

Case 3 Tripped by an electrical extension 08

Case 4 Fall of formwork 10

Case 5 Fall off a toppling scaffold 12

Case 6 Killed by a plunging hoist 14

Case 7 Fall through an opening 16


Case 9 Collapse of a platform 20

Case 10 Fall from a formwork shoring 23

Case 11 Tipping and fall of a table formwork 26

Case 12 Fall of a formwork panel 29

Case 13 Fall through an open side 32


Case 15 Hit by a rubber hose 38

Case 16 Fall from an open side 41

Case 17 Fall off an open platform 44

Case 18 Fall through a skylight 47

Case 19 Fall from an attic 49

Case 20 Fall due to an unstable scaffold 51

Case 21 Fall while dismantling a platform 54

Case 22 Fall of a gondola platform 57


FALLS FROM HEIGHT

04

1. Roof tiles removed

1. Height of fall = 4.8m2. Place where the deceased worker landed

1

2

Description of Accident

A worker was installing lifelineson a pitched roof at a worksite.He stepped on one of the rooftiles which then broke under hisweight. The worker sufferedsevere head and chest injuriesand eventually succumbed tothe injuries.

Causes and ContributingFactors

• When the worker went up theroof to install the lifelines,he had stepped onto themidsection of the roof tileswhere there was no support structure. The roof tile hencebroke under his weight.

• He fell from a height of4.8m through the roof.

CASE 1FALL THROUGH A ROOF

Recommendations

Conduct a proper risk assessment prior to the commencementof a job.

Use a boom lift to send workers to the roof-top to install the lifelinesinstead of working directly on a pitched roof.

Use crawl boards or ladders provided on rooftops for safe accessby the workers.

Evaluation of loss • One worker killed

Type of contact • Fall from height to lower level

Immediate cause(s) • Improper position for task

Basic cause(s) • Lack of experience• Inadequate work standards• Inadequate leadership and/or supervision

Failure of SMS • Hazard analysis and risk assessment

Root Cause Analysis

05

Follow-up

A Stop Work Order was issued to stop all work at the premises.

The main contractor was instructed to conduct risk assessment anddevelop safe work procedures for removing roof tiles whichcontained asbestos.

1. The deceased landed here2. The suspended scaffold was

re-positioned here3. The position of the suspended scaffold

at the time of the accident

1. The lifeline installed outside thesuspended scaffold

2. A lifeline installed in between the ledgesand kitchen area

3. A worker attached the fall arrestordevice to a lifeline

4. One of the cross beams5. The suspended scaffold installed at

the façade

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1

2

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4

5

3

4

06

CASE 2FALL FROM A SCAFFOLD


A worker was intending to paintthe walls adjacent to a ledge. Hetried to climb out of a suspendedscaffold onto the building ledgebut lost his footing and fell fromthe nineth storey of the building.


• The worker was not wearingany safety harness or safety belt.

• The suspended scaffold hadlast been examined in August2002, contrary to the legal requirement which statesthat such equipment must be thoroughly examined andcertified for use by an approvedperson once every 12 months.

07

Recommendations

Provide safe access and egress routes for workers.

Install an independent lifeline for anchoring personal fallprotection equipment.

Brief workers on the hazards and risks of the job.



Immediate cause(s) • Improper position of worker for task• Inadequate or improper protective equipment

Basic cause(s) • Lack of knowledge• Inadequate leadership and/or supervision

Failure of SMS • Hazard analysis and risk assessment• WSH rules, permits and

personal protective equipment

Root Cause Analysis

Follow-up

A Stop Work Order was issued which required the occupier to conduct hazard analyses and develop safe work procedures for the above works.

The occupier was required to engage an approved person to examine the suspended scaffolds in the worksite.

08


A worker was carrying out drillingoperations at the 33rd level of abuilding. While he was searchingfor an electrical socket outlet toconnect an electrical tool,he accidentally tripped onan electrical extension wire thathe was holding and fell throughan opening within a woodenbarricade. He landed belowon the 32nd level.


• The 33rd level floor slab opening measured approximately 4m in length and 2.7m in width. The depth from the 33rd level tothe 32nd level measuredapproximately 4m.

• The floor slab opening was meantfor the staircase before it was dismantled. It was not guardedby any effective barrier toprevent falls.

1

1. The electrical distribution boxat the corner of the floor slab opening

2. Partition wall beside the floor slabopening

3. The floor slab opening was meant fora staircase before it was dismantled

4. The 32nd level worksite below

2

4

3

1

1. The electrical distribution box at thecorner of the floor slab opening

2. The red-white tape and nylon ropeused to barricade the two sides ofthe floor slab opening

3. The "Danger No Entry" signage4. The wooden barricade (guarding

only one side of the opening andnot the remaining three)

2

3

4

CASE 3TRIPPED BY AN ELECTRICAL EXTENSION

09

Recommendations



Immediate cause(s) • Inadequate guards or barriers provided• Improper placement

Basic cause(s) • Lack of knowledge

Failure of SMS • Communication/group meeting• WSH training and competence

Root Cause Analysis

Provide barriers to guard floor openings to prevent falls or coverfloor openings with a cover (if appropriate).

Provide appropriate lighting and display suitable warning signs towarn operators of potential dangers at the work area.

10

1. Jumpform fell off from here


A site supervisor and a worker werekilled when a jumpform panel thatthey were working on fell off fromits position to the ground below.The jumpform was fixed at the16th storey of a building that wasunder construction at the timeof the accident.


• The jumpform panel that droppedwas one of the two panels that hadbeen shifted from the 15th storey of the building using a towercrane in the morning prior tothe accident.

• Investigations revealed that the bracket of the collapsed jumpformpanel was not securely attached onto its support mechanism. Asa result, the bracket slipped offfrom its support and the entire panel fell off subsequently.

• Significant changes were noted during the installation processof the formwork which affected its integrity.

CASE 4FALL OF FORMWORK

1. Injured was caught in the net herebelow the third storey

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Immediate cause(s) • Failure to secure jumpform

Basic cause(s) • Lack of skill• Inadequate leadership and/or supervision• Inadequate monitoring of construction

Failure of SMS • Hazard analysis and risk assessment• WSH practices and procedures• WSH training and competence

Root Cause Analysis

Follow-up

The occupier was instructed to review the design of the formworksystem and to revise the safe work procedures for the workers beforework on the jumpform structure was allowed to continue.

Safety measures such as additional brackets and wire ropes forsecuring purposes were also introduced to increase system reliability.

• The subcontractor did not conduct hazard analysis or

develop safe work procedures for the new installation process.

Recommendations

Develop safe work procedures.

Conduct proper supervision of the erection process and checkingof the panel support.

Ensure that the bracket hook’s design is such that it can bechecked easily.

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1. The fourth storey roof beam2. The toppled mobile scaffold at

the fourth storey corridor3. The factory building4. The location where the deceased

had landed5. The driveway

1. The toppled mobile scaffold with the cantilevered structure

2. The two metal decking which wereto be tied

3. The fourth storey corridor4. The parapet wall5. The castor wheels


A worker was assigned to servicesome roof painting work at abuilding. He was erecting a mobilescaffold along a corridor at thefourth storey of the building whenthe scaffold toppled. As a result,the worker fell off from the scaffoldand out of the building onto theground 12m below.


• The mobile scaffold (with a cantilevered structure) was notin a stable position and was not secured to the building structure or metal railing along the building corridor at the timeof accident.

• When the worker climbed ontothe mobile scaffold to tie themetal deckings to the cantileveredstructure, the mobile scaffold toppled and the worker fell off from the scaffold and building.

CASE 5FALL OFF A TOPPLING SCAFFOLD

Recommendations

Conduct risk assessment prior to job commencement.

Use an alternative method of work, or institute safe workprocedures for such work.

Ensure proper safety measures are in place such as securing ofmobile scaffold to the building structure and provision of lifelinesfor the workers.



Immediate cause(s) • Improper position for task• Inadequate or improper protective equipment• Failure to secure scaffold

Basic cause(s) • Lack of experience• Inadequate work standards

Failure of SMS • Communication/group meeting• Hazard analysis and risk assessment• WSH training and competence

Root Cause Analysis

13

Follow-up

The main contractor was instructed to conduct a risk assessmentand review the safe work procedures for all works at the site.

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1. The control unit

1. The dislodged machinery plate


A worker, employed as a plasterer,was seen moving up in thePassenger and Material (PM) hoist.The PM hoist suddenly plunged tothe ground and the worker diedon the spot.


• The PM hoist involved in the accident had been retrofitted by the hoist supplier with a machineryplate with a motor drive unit anda safety device.

• The most probable cause of the accident is the failure of the mounting bolts of the machinery plate. The fracture of these bolts caused the machinery plate to detach from the hoist cage.

• The hoist cage slammed ontothe top of the drive unit, and knocked off the machinery plate with the drive unit from the rack, resulting in the free-fallingof the hoist.

CASE 6KILLED BY A PLUNGING HOIST

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Recommendations

Have a regular maintenance system as per maintenance regimeof CP79.

Replace bolts when installing the PM hoist at a new location.



Immediate cause(s) • Defective tools, equipment or materials

Basic cause(s) • Inadequate maintenance• Excessive wear and tear

Failure of SMS • Maintenance regime of machinery

Root Cause Analysis

Follow-up

A Stop Work Order was issued to cease all hoisting operationsinstalled onsite.

The occupier was instructed to dismantle all hoists and replacethem with another brand from another supplier.

16


A worker was to carry out paintingwork. While he was getting readyto paint the wall at the void area,he fell into the opening at the10th level and landed about 30mbelow on a platform.


• Directly above the platform wereopenings which were found atall levels from the first level to the12th level. The opening measuredabout 700mm x 900mm.

• The painting supervisor didnot check the work area tobe plastered/painted forcompliance to the safety requirements listed in thePermit-to-Work.

• The worker was not wearing asafety belt/harness. He had been working on site for two weeksprior to the accident. Investigationsrevealed that the worker had not attended the Safety Orientation Course (construction).

CASE 7FALL THROUGH AN OPENING

1. External scaffolding2. Desceased was found lying at the

platform of the external scaffolding3. Passenger hoist

1. External scaffolding2. Guardrail3. External wall4. Void area5. Barricade of wire rope with orange

netting

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Recommendations

Ensure all workers attend the Construction Safety Orientation Course.

Implement a safety induction programme on the use of personalprotective equipment prior to starting work.

Supervisors should be responsible to check and ensure the useof appropriate personal protective equipment.

Conduct regular briefings on the dangers of working at heights.



Immediate cause(s) • Improper position for the task• Inadequate or improper protective equipment

Basic cause(s) • Lack of knowledge• Inadequate leadership and/or supervision

Failure of SMS • WSH practices and procedures• Hazard analysis and risk assessment• WSH training and competence

Root Cause Analysis

Follow-up

The occupier was instructed to review the Permit-to-Work systemon site and implement it on a daily basis.

The occupier was instructed to only engage painters who haveattended the safety orientation course at the worksite.

18


Worker A and his co-workerswere instructed to tidy up metalscaffolds above a courtyard areaat a worksite. The group took uptheir positions on the metalscaffolds and the worker was thenon a scaffold next to the classroomblock. Worker A was to work onthe working platforms at thefifth lift of the scaffold next tothe classroom block. He fell tohis death and was found lying onthe ground at the first storey.


• The location that Worker A landed was right below thescaffold that he was working onand the ground was scattered with damaged cross bracings,metal decking, scaffold framesand metal pipes.

• The group of workers woresafety belts but there was nolifeline found on the scaffolds forthem to anchor their safety belts.

1. The loose frame scaffold that was to beremoved by the deceased

2. A patched wall tie hole where thecement was still wet

3. The working platform at the fifth lift ofthe scaffold where the deceased hadstood on when working on the scaffold


1. The deceased was working on the working platform laid on the fifth lift of the scaffold

2. The corridor where the dismantled scaffolding items were stored

3. A wall tie at the second lift of the scaffold4. The deceased had landed here where

the scaffolding items had scattered

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• The workers were not trained scaffold erectors and had not

undergone any course forscaffold erection.

Recommendations

Install independent lifelines.

Supervisors should be responsible to check and ensure the use ofappropriate personal protective equipment.

Conduct regular briefings on the dangers of working at heights.

Follow-up

The occupier was issued with a Stop Work Order to install lifelineson the scaffold and to engage trained scaffold erectors to dismantlethe scaffolds.

Root Cause Analysis



Immediate cause(s) • Improper use of personal protective equipment

Basic cause(s) • Lack of knowledge• Lack of skill

Failure of SMS • WSH training and competence• Hazard analysis and risk assessment

20


Three workers were carrying outinstallation of a clothes drying rackat the 10th level of an HDB flat. Theinstallation was done from a mastclimbing platform in the worksite.Upon completion of the work, theywere about to descend when theplatform suddenly came down.All three workers fell; two of themdied while the other was injured.


• The bottom motor of the driveunit of the platform was notthe original motor fitted tothe platform.

• The gearboxes of both the topand bottom motors were produced by the same manufacturer, but were ofdifferent type.

• The top motor was a two stage gearbox while the bottom motor was a three stage gearbox. Use ofthese two gearboxes with differentoutput speed induces great stresswithin the gears in the gearboxes.

1. The platform had split open afterthe incident

1. Top motor2. Bottom motor

CASE 9COLLAPSE OF A PLATFORM

• The moment the gearboxesfailed, the platform

descended suddenly andcrashed to the ground.

Evaluation of loss • Two workers killed and one injured



Basic cause(s) • Inadequate maintenance• Inadequate replacement of unsuitable

materials

Failure of SMS • Maintenance regime• WSH practices and procedures

Root Cause Analysis

Follow-up

A Stop Work Order was issued.

The occupier was instructed to stop using all mast climbing workplatforms (MCWP) at the worksite.

The occupier was also instructed to carry out the following:

• To inspect all MCWPs and make good any defect found.

• To inspect that all motors in each drive unit of every MCWP usedat the worksite were of the same type.

• To have the MCWP inspected, examined and certified by an approved person prior to the start of work.

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Recommendations

Conduct functional checks, regularly, and before use.

Ensure that the specifications of the different units of anyequipment are compatible.

Have fall protection equipment as an additional safety measure.

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23


Worker A and his co-worker wereinvolved in the transfer of threeunits of formwork shoring from thethird storey to the second storeyof the building that was underconstruction.

They were climbing up the frameof a unit of the formwork shoringon the third storey so as to attachthe hooks of the chain slingsfrom the tower crane when theformwork shoring suddenlytilted and toppled to the floor.

Worker A fell from the shoringand landed on the third storey.He sustained serious headinjuries from the fall and diedon the spot. The other workersuffered minor scratches as hemanaged to jump to the flooras the shoring toppled.


• Worker A was standing ona formwork frame about 4.28m from the floor when theshoring toppled.

1. The deceased landed here2. The toppled formwork shoring

1. The toppled formwork shoring2. Width: 1.2m3. The inner props

CASE 10FALL FROM A FORMWORK SHORING

• The ratio of the height of theshoring against its width wasabout 4.74m. It was tall and slim and hence proneto toppling.

• There was no outrigger installed on the shoring to ensure the stability of the shoring. It was thus unsafefor workers to work onthe shoring.

• The worker who was to rig upthe shoring had not attendedthe Rigging Operation Courseand he was not an appointedrigger. There was no lifting supervisor appointed for thetransfer of shoring using the tower crane.

Evaluation of loss • One worker killed and one injured


Immediate cause(s) • Failure to secure shoring

Basic cause(s) • Lack of knowledge• Inadequate work standards• Inadequate leadership and/or supervision

Failure of SMS • Hazard analysis and risk assessment• WSH training and competence

Root Cause Analysis

24

Recommendations

A safe width to height ratio must be ensured.

Proper access such as a monkey ladder should be provided.

Follow-up

To prevent recurrence, the factory occupier was instructed toimplement the following safety measures:

• Provide ladders on the shoring or riggers to gain access to a higher level for rigging up the shoring.

• Provide working platform of at least 635mm width as foothold on the shoring for the riggers.

• Appoint a qualified lifting supervisor to co-ordinate the lifting of the shoring before the commencement of work.

• Appoint qualified riggers to carry out the rigging work.

25


Worker A and his co-worker wereworking on a table form(formwork) that was partially setup on the eighth level. The tableform tipped towards the edge ofthe building and fell to the ground.Worker A fell together with thetable form and landed on theground. He died on the spot.


• The table form was not setup on the eighth level in accordance with the design ofthe professional engineer.

• The formwork subcontractor claimed that due to space constraints, the position of the front props for the table form could not be put up accordingto the design of the professionalengineer. However, the subcontractor did not requestthe professional engineer to redesign the table form to suitthe actual site situation.

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CASE 11TIPPING AND FALL OF A TABLE FORMWORK

1. The metal frames of the table form thatfell from the eighth level

1. The rear corner props2. The intermediate props3. The front corner props

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Immediate cause(s) • Improper placement of table form

Basic cause(s) • Inadequate evaluation of changes


Root Cause Analysis

• According to the design, whilesetting up the table form,four props at the four corners were to be put up first followedby two intermediate props. However at the time of accident, the table form was supported by two props at the rear corners

and two placed at intermediatepositions.

• The position of Worker A and his co-worker were outsidethe four supporting pointsand the combined weight caused the table form to tip over and fall over the edgeof the building.

Follow-up

A Stop Work Order was issued to stop work on the table form.

The occupier and subcontractor were instructed to implementthe following safety measures:

• To redesign the table form using a professional engineer.The revised design should enable it to be supported byfour props at the four corners.

• To ensure that a formwork supervisor is present to supervise the erection of the formwork at the site.

• To conduct safety training to instruct the supervisors andworkers on the proper way to set up the table forms.

Recommendations

Ensure that a table form is fully supported by all necessaryprops at all times.

Ensure formwork supervisor is present at all times to supervisethe proper erection of the formwork at the site.

Conduct safety training to instruct supervisors and workers on theproper way to set up the table forms.

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1. Working platform at the top section2. Modular formwork panels

1. Connecting brackets between internaland external formwork panels

2. Deceased was standing around thisposition on the working platform of the formwork panel prior to the incident

3. The formwork panel had “peeled” off, exposing the concrete wall

4. The deceased fell about 6m to thefirst level. The formwork panel alsocame down and landed on him


A worker was involved in thedismantling of metal formworkpanels. He was standing on theworking platform of a metalformwork panel when the panelgave way. He fell about 6mtogether with the panel andit landed on him. He died onthe spot.


• Investigations revealed thatthe day prior to the accident,the tie rods at the top sectionof the formwork structure hadbeen removed. The stability ofthe formwork structure was compromised as a result.

• The foreman had noticed thisbut he did not proceed tocheck the tie rods at the topsection of the other panels ofthe formwork structure,although he was aware that something was amiss.

CASE 12FALL OF A FORMWORK PANEL

• As the worker was standingon one end of the working platform of the formwork panel, the formwork panel peeled off from the concrete

wall structure. The workerlost his balance and fell fromthe working platform. The formwork panel also came down and landed on him.



Immediate cause(s) • Failure to secure formwork

Basic cause(s) • Inadequate work standards

Failure of SMS • WSH practices and procedures

Root Cause Analysis

30

Recommendations

Ensure that the formwork supervisor closely supervises the work.

Check and secure all formwork at all times.

Use written work procedures and signage to remind workers notto remove tie rods.

Follow-up

The occupier was instructed to implement the followingimprovements/measures at the worksite:

• A written work procedure on the installation and dismantling ofthe formwork system to be instituted and implemented at theirworksites.

• Warning signages to be installed at the top section of the formwork structure to remind workers not to remove the tie rodsat the top section prior to hoisting by a tower crane.

31


Worker A and his co-workerwere getting ready to carry outplastering work to a columnon the fifth level of a buildingat a worksite.

Subsequently Worker A wasseen falling through the openside next to the column to beplastered. He landed on theground level 15m below anddied subsequently.

1. Fifth level2. Open side3. The deceased was found here


• The open side where the workerfell off was not barricaded.

• There was a lot of building materials, wooden pallets, formwork materials and other materials placed on the flooron the fifth level. These materialswere placed haphazardly and obstructed access. Worker Ahad to maneuver his waythrough these materials tohis workplace.

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1. Column to be plastered2. Open sides3. Scaffold

CASE 13FALL THROUGH AN OPEN SIDE

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• Worker A was last seen standing at the column near the open side, holding his safety belt in his hand. He wasseen falling off the edge.

• The accident probably occurred when Worker A was

inspecting the column locatednext to the open side. He mayhave tripped on some object on the ground and lost his balance.

• A similar accident had happened three months ago.



Immediate cause(s) • Inadequate guards or barriers

Basic cause(s) • Inadequate work standards• Inadequate storage of materials• Poor housekeeping


Root Cause Analysis

Follow-up

The occupier was instructed to carry out the following:

• To cover all openings and put up barricades for opensides on site.

• To place materials properly so as not to obstruct the passageway.

• To carry out housekeeping regularly on site.

Recommendations

Provide barricades with rigid materials for all open sides andsecure at both ends.

Stack materials properly.

Clear debris frequently.

Ensure close supervision so that personal protective equipmentare used correctly.

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35


Worker A and his two co-workerswere involved in the dismantlingof an external scaffolding of ablock. One of the co-workersdescended from the scaffold andcalled out to Worker A and anotherco-worker to come down fromthe scaffold for lunch.

As the co-worker was waiting atthe foot of the block, Worker Afell from the scaffold and hit him.Worker A was seen bleeding fromthe back of his head and wassent to the hospital where hesubsequently passed away.


• The scaffold supervisor wasnot with the worker when the dismantling work was inprogress. He had left theworksite to buy lunch for his workers.

• Worker A was found withhis safety harness on his waistafter the accident.

1. Block 102. External scaffolding being dismantled

1. External scaffolding2. The deceased was found here


• There were no eye-witness accounts as to how Worker A fell from the scaffold. Upon hearing his co-worker’s call tocome down, the worker mighthave detached his safety harness from the lifeline.The accident probably happened when he was descending from the scaffold,and lost his footing. When hefell, he hit the scaffold along the path of his fall and hit theworker who was waiting at thefoot of the block.

• Worker A and one of theco-workers involved in the dismantling work had not undergone any training coursefor the work. The safety manager and the scaffold supervisor were aware thatthe two workers did not havescaffold erectors certificates.It was reported that the workers were scaffold assistants and were expectedto be stationed on the ground, not on the scaffold.



Immediate cause(s) • Making safety devices inoperative

Basic cause(s) • Lack of knowledge• Lack of skill• Inadequate supervision

Failure of SMS • WSH training and competence

Root Cause Analysis

36

Recommendations

Assign only certified erectors to carry out dismantling work.

Provide proper training.

Follow-up

The occupier was instructed to engage only trained scaffolders tocarry out the scaffolding work on site.

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38


A concrete pump operator andhis co-workers were carrying outcleaning work on a platform whichwas erected about 10m abovethe bottom of the shaft.

The cleaning work was carried outby means of inserting a spongeball into one end of the pipelineand feeding the pipeline withcompressed air. The other endof the pipeline was equippedwith a rubber hose to dischargethe leftover concrete into acontainer. The workers weregripping the rubber hose whilethe pump operator held downthe rubber hose with a steel tube.

When the sponge ball wasforced out from the rubber hose,the hose swung suddenly andhit the pump operator. He wasflung off the platform andlanded on the bottom of theshaft. He died on the spot.

1. Concrete pump2. Rubber hose3. Timbers on the platform4. Scaffold frame

1. Deceased was standing here priorto the accident

2. Rubber hose was placed on ascaffold frame

CASE 15HIT BY A RUBBER HOSE


• There were some pieces of timber placed on the platformwhere the cleaning workwas carried out. Workers mentioned that it had, to someextent, hampered their work.

• Investigations revealed thatthe rubber hose was not secured in position to preventit from moving during the cleaning operation.

• Towards the end of the cleaning operation, particularlyat the time when the sponge ball was forced out from the hose, the sudden release of thecompressed air probably created some lateral forces. Thiscaused the hose to swing andresulted in the workers losingtheir grip on the hose.

• The hose swung and hit the pump operator, pushing him over the guardrail.



Immediate cause(s) • Failure to secure the rubber hose• Poor housekeeping

Basic cause(s) • Improper storage of materials• Inadequate work standards

Failure of SMS • WSH practices and procedures• Hazard analysis and risk assessment

Root Cause Analysis

39

Recommendations

Follow-up

The occupier was instructed to submit safe work procedures (SWP)for pipeline cleaning work involving compressed air and toimplement and ensure that all the workers adhered tothe SWP.

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Ensure at least two tag lines to hold the end of the rubber hosein position.

Workers should be provided with and trained in the use of fall protection equipment.

Ensure close and continuous supervision of such hazardousoperations.


A subcontractor was engagedto carry out block-laying and plastering works at Blocks A andB of a building site. The foremanhad given instructions to a workerat Block A to clear some woodenpalette at the workplace afterwhich he walked towards Block B.

About five minutes later, theforeman was seen sitting on topof a pile of debris at the secondstorey of Blk B. He was bleedingon the left side of his head andwas pronounced dead by theambulance officer.


• A wooden pallet was foundbroken among the pile of debrisat Block B. There were fresh blood stains on the pallet. A worker confirmed that he found theforeman on the broken palette.

• The pile of debris was situatedright below a side of the building with a series of open sides.

1. Open side2. Debris3. Precast concrete components

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CASE 16FALL FROM AN OPEN SIDE

1. The deceased was found here

• Investigations revealed thatthe open sides at the seventhstorey were barricaded. Allthe other open sides at Block B, i.e. first to sixth storeyand the eighth storey werenot barricaded.

• Debris was also seen placed close to the edge of anopen side on the seventh storey of Block B. The debris

could fall and potentiallyhit a person standing below.

• The foreman was believedto have fallen from one ofthe open sides. He might havelost his footing when he was working near an unbarricadedopen side at Block B. He may have fallen and landed on thepile of debris at the second storey of Block B.



Immediate cause(s) • Inadequate guards or barriers at open sides• Poor housekeeping



Root Cause Analysis

42

Recommendations

Follow-up

The occupier was instructed to undertake the followingimprovements to the work practices/conditions at the site:

• Cover openings/put up barricades to open sides on site.

• Remove loose materials from the edge of the buildings.

• Carry out proper housekeeping on site.

Provide barricades with rigid materials to all open sides and secureat both ends.

Develop proper method statements on putting up barricades.

Stack materials properly.

Debris to be cleared frequently.

There should be close supervision to ensure that personal protectiveequipment are used properly.

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A worker was engaged to carryout painting work in a schoolbuilding. He was assigned to paintthe roof purlins and the supportingmetal frames for a featured rooflocated above the staircase roofslab of a six-storey building. Hewas later found lying at the footof the building with serious injuriesand was pronounced dead byambulance officers.


• Investigations revealed that a scaffold with a working platformhad been erected below the partof the featured roof that was protruding beyond the staircaseroof slab.

• There was no guardrail erected on the open side of the workingplatform to prevent falls. There was also no ladder provided on the scaffold for access to the working platform.

44

1. Purlin near the edge of the featured roof

1. The featured roof2. Purlin near the edge of the featured roof3. Working platform on the scaffold4. The staircase roof slab5. Roof slab above the sixth storey

3

CASE 17FALL OFF AN OPEN PLATFORM



Immediate cause(s) • Inadequate guard or barrier

Basic cause(s) • Inadequate engineering(inadequate assessment of loss exposures)


Root Cause Analysis

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• It is probable that prior to theaccident, the worker had goneup to the working platform on the scaffold to paint the purlin that was located near the edge of the featured roof.

While painting the purlin,he may have fallen over the open side of the working platform and landed at the foot of the building.

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Recommendations

Provide lifeline for all work at heights.

Brief workers regularly on the use of personal protective equipmentand fall protection measures.

Erect scaffolds with proper access and guardrails.

Follow-up

Occupier was instructed to implement the following safetymeasures:

• The scaffold should be properly erected and used for painting the purlin and metal frames located near the edge of the roof.

• Guardrails of at least 1.1m height should be erected on the opensides of the working platform and the staircase roof slab, to prevent fall of persons working there.

• Access ladders should be provided for the workers to reach the working platform.

• Painters should anchor their safety belts while working on the working platform.

1. This row of skylight was to bewaterproofed

2. Location where the deceased fellthrough the skylight


Worker A and three otherco-workers, each carried a pailcontaining waterproofing materialup a roof in preparation for thecoating of the skylight of a roof.

While they were on the roof,one of the co-workers heard abreaking sound coming fromthe roof sheets. He turned hishead and saw a broken skylight.

Worker A had fallen through theskylight of the roof (at a heightof 8m) and landed on the ground.


• Investigations revealed that priorto starting work, the site supervisorhad briefed the workers not tostep on the skylight.

• Investigations revealed thatno safety measures such ascrawling boards or planks had been provided as foothold forthe workers to stand on whileworking on the roof.

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1. The deceased fell about 8m and landed here

CASE 18FALL THROUGH A SKYLIGHT

• According to the workers,the site supervisor told them that there were no anchoragepoints on the roof and hence

they would not be able touse their safety belts while working on the roof.



Immediate cause(s) • Inadequate or improper protective equipment


Failure of SMS • WSH practices and procedures• WSH training and competence

Root Cause Analysis

Recommendations

Install appropriate lifelines and anchorages.

Provide crawling boards, planks or ladders as a foothold forworkers working on the roof.

The occupier was instructed to implement a written safe workprocedure immediately.

The employer was instructed to provide suitable crawling boardsor planks and to install suitable and sufficient anchorage points/lifelines on the roof.

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Follow-up


Worker A, seven other co-workersand a signalman were doingconcreting work on the roof beamsof a building at a worksite.

While waiting for a truckload ofconcrete, Worker A was seen restingon the staircase at the attic. Momentslater, Worker A was found on theground bleeding from his head.


• The workers confirmed thatthey were not wearing safetybelts while carrying out the concreting work. Even if theyhad worn their safety belts, there was no anchorage pointfor them to secure theirsafety belts.

• There were no working platforms provided for the workers for the concretingof the roof beams.

• Worker A was seen sitting onthe plywood placed on some timbers at the opening of the attic.

1. Roof beams2. Attic level3. The deceased was found at the fifth level

1. Deceased was seen resting here2. Plywood3. Opening

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CASE 19FALL FROM AN ATTIC

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• The accident could have occurred when Worker A wasresting on the plywood. The plywood could have broken and Worker A may have lost

his footing and fallen throughthe opening. His head would have hit the concrete floorand the head injury couldhave caused his death.



Immediate cause(s) • Inadequate guards or barriers• Inadequate or improper protective equipment

Basic cause(s) • Improper motivation• Lack of supervisory/management

job knowledge

Failure of SMS • WSH practices and procedures• WSH training and competence

Root Cause Analysis

The occupier was instructed to provide working platforms forthe workers for the concreting work at the roof.

Follow-up

Provide proper working platform.

Provide proper personal protective equipment.

Provide proper training.

Recommendations


A worker was instructed to installa special fixture called “bondingbars” at the service duct area onthe fourth storey of a buildingunder construction.

An hour later, he was found tohave fallen together with a mobilescaffold from the corridor of thefourth storey of the building.He landed on the ground floor.He was sent to the hospital anddied on the same day.


• There were no eye-witnessesto the accident. The workerwas probably using themobile scaffold when hefell together with the scaffold from the fourth storey tothe ground floor.

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1. Tower scaffold2. Unsecured decking3. Bonding bars

1. Tower scaffold at service duct area2. Mobile scaffold3. Parapet wall4. Two caster wheels found on the

fourth storey5. Uneven floor

CASE 20FALL DUE TO AN UNSTABLE SCAFFOLD

• The following factors could have contributed to the accident:

i. The mobile scaffold erected was not tied to the building or other structures despite the fact that its height (3.47m)was more than three times the lesser dimension of the base (0.8m). In addition, it was

placed on an uneven floor. The mobile scaffold would have been unstable on sucha floor and any person usingit could cause it to topple.

ii. The mobile scaffold was erected without any supervision from a scaffold supervisor to ensure thatit was properly erectedand stable.



Immediate cause • Inadequate or improper protective equipment

Basic cause(s) • Inadequate leadership and/or supervision


Root Cause Analysis

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Recommendations

Ensure proper inspection by a trained scaffold supervisor.

Secure mobile scaffold using ties if the scaffold is greater than4m in height and is close to an opening.

Protect workers working close to an opening at a height greaterthan 4m with fall arrest equipment.

Follow-up

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The occupier was instructed to implement a Permit-to-Work systemto control the use of tower and mobile scaffolds at the site.

CASE 21FALL WHILE DISMANTLING A PLATFORM


Worker A and his co-workerswere to dismantle a metalplatform erected on a scaffoldsupport. For this, they would haveto remove the clips that held thepieces of metal formwork togetherso as to take them apart.

Worker A was later found lyingon the ground beside thescaffold support. He was takento the hospital where he passedaway on the same day.


• The metal platform was about 4.5m above the ground.

• Worker A was last seen by the foreman 7 to 8 minutes prior to the accident. He was doing some work on the groundbelow the metal platform that was to be dismantled.

1. The metal platform that was tobe dismantled

2. The scaffold support3. The deceased was found lying here

after the accident

1. The underside of the metal platformthat was to be dismantled

2. The metal clip holding adjacent piecesof metal formwork together

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• Investigations revealed thaton the day of the accident,a safe means of access or egressfrom the metal platform,such as a ladder ramp was notprovided on the scaffold.

• The accident probably happened when Worker A climbed up the scaffold support to dismantle the metalplatform and lost his grip on the scaffold frame and fell to the ground.



Immediate cause(s) • Inadequate or improper protective equipment

Basic cause(s) • Inadequate engineering• Inadequate work standards


Root Cause Analysis

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Recommendations

Provide proper access to the formwork level.

Develop and implement safe work procedures.

Ensure that the formwork supervisor is present during thedismantling of formwork and its components.

Provide lifelines and fall protection for all work at heights.

Brief the workers on the safety aspects of working at heights priorto the commencement of work. This should be done by thesupervisor-in-charge.

Follow-up

The occupier was instructed to implement the following safetymeasures:

• Provide a working platform of at least 635cm width for use as footing by workers dismantling the metal platforms.

• Provide a safe means of access, such as a ladder or an access rampwith handrails for workers to gain access to the working platformon the scaffold support.

• Workers must stand on the working platform and anchortheir safety belts to the scaffold frames while dismantling the metal platform.

• The supervisor-in-charge is to brief the workers on the safety aspects involved in the dismantling of the platform prior to thecommencement of work.

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In the early morning, two workershad started on the externalwindow and façade cleaning ofa building, using a permanentgondola located at the rooftopof the building.

About an hour later, the gondolabecame jammed and the twoworkers were left stranded in thegondola between the 31st and28th storey of the building.

About three hours later, the servicetechnicians from the gondolasupplier arrived on site. Whilerectifying the fault, the platform ofthe gondola together with the twoworkers suddenly plummeted andcrashed onto the rooftop of thepodium at the fifth floor. Oneworker died on the spot.


• The platform together withthe two workers plummeteddue to the fracturing of the gearbox shaft holding the emergency safety brake.

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CASE 22FALL OF A GONDOLA PLATFORM


In the early morning, two workershad started on the externalwindow and façade cleaning ofa building, using a permanentgondola located at the rooftopof the building.

About an hour later, the gondolabecame jammed and the twoworkers were left stranded in thegondola between the 31st and28th storey of the building.

About three hours later, the servicetechnicians from the gondolasupplier arrived on site. Whilerectifying the fault, the platform ofthe gondola together with the twoworkers suddenly plummeted andcrashed onto the rooftop of thepodium at the fifth floor. Oneworker died on the spot.

1. The rooftop where the gondola crashed

1. The gondola

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• The safety devices, hydraulic pressure switch and electrical thermal relay for the hoisting motor were also found to be incorrectly set. The wrong setting allowed the gondolato operate in an overloaded condition without the power being automatically cut off.

• Investigations revealedthat the gondola had earlier experienced numerous repetitive defects andfailures that resulted in thenon-functioning of the gondola.However the gondola supplier had not taken any measuresto establish the causes for the recurring fault and rectify them.

• Whenever the technicians fromthe gondola supplier were called in, they would rectify by resetting the over-speed deviceand pumping the pressure up so as to release the safety brakes and render the gondolamobile. This practice is contraryto the instructions given by themanufacturer. The system thus deteriorated until the day of the fatal accident.

• The occupier had not registered the premises as a factory even though the external cleaning of windows and façade was for a term contract of two years and they had been working for more than two months.




Basic cause(s) • Inadequate maintenance• Inadequate tools and equipment

Failure of SMS • Maintenance regime

Root Cause Analysis

Recommendations

Plan regular maintenance for the gondola.

Ensure the regular inspection of the mechanical and electricalequipment by competent persons.

Ensure emergency and rescue procedures are strictly followed.

Avoid overloading equipment.

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• Guardrails were provided onthe open sides of the working platform. However guardrailson both the left and right endsof the working platform wereonly secured on one side.It was done this way so that the guardrails could be swung openfor workers to get onto the working platform when they went up there to work.


Worker A and his co-workers wereworking on a working platform ona metal scaffold on the fourthstorey of a building. They werepreparing a beam for skim coating.Worker A was wetting the beamwith a pail and was seen walkingbackward while wetting the beam.A few minutes later, Worker A wasfound lying on the floor beside themetal scaffold. He was taken to thehospital where he passed away afew days later.

1. The deceased was wetting this beamprior to the accident

2. The guardrail on the right end ofthe scaffold

3. The deceased probably fell from here4. The working platform5. The deceased landed here after

the accident

1. The deceased was wetting this beamprior to the accident

2. The scaffold3. The deceased landed here after

the accident

• No ladders or steps were provided for workers to gain access to the working platform.

• Both Worker A and theco-worker who erected the scaffold had not undergonea training for scaffold erection.The erection of the scaffoldwas also not performed under the supervision of a scaffold supervisor.

• Worker A got up from one side of the working platform. It is probable that as he was walkingbackwards while wetting the beam, he failed to stop at theend of the platform and fell to the floor.

• It is also possible that the deceased, after having finished wetting the beam, was climbingdown the scaffold when he fell to the floor.



Immediate cause(s) • Inadequate guards or barriers

Basic cause(s) • Inadequate leadership and/or supervision

Failure of SMS • Hazard analysis and risk management

Root Cause Analysis

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Recommendations

Secure end guardrails similar to the longitudinal guardrails.

Provide proper access such as ladders or steps.

Follow-up

The occupier was instructed to implement the following safetymeasures:

• All guardrails on the working platform to be secured.

• Steps must be provided on the scaffold for access to the workingplatform or different levels of the scaffold.

• The erection of the scaffold is to be done by workers who have undergone a course of training approved by the Chief Inspector.

• The erection must be supervised by a scaffold supervisor.

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Published in June 2008 by theWorkplace Safety and HealthCouncil in collaboration withthe Ministry of Manpower.

All rights reserved. Thispublication may not bereproduced or transmitted inany form or by any means,in whole or in part, without priorwritten permission. Theinformation provided in thispublication is accurate as at timeof printing. All cases shared in thispublication are meant for learningpurposes only. The learning pointsfor each case are not exhaustiveand should not be taken toencapsulate all the responsibilitiesand obligations of the user of thispublication under the law. TheWorkplace Safety and HealthCouncil does not accept anyliability or responsibility to anyparty for losses or damage arisingfrom following this publication.

Law

Falls from height