PREFACE. Mr Lee Tzu Yang Chairman Workplace Safety and Health Council

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2 PREFACE This compilation of case studies on fatalities in the construction industry is initiated by the Workplace Safety and Health Council, and put together by the WSH Construction Committee in collaboration with the Ministry of Manpower. This booklet depicts how the accidents occurred and provides 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 construction industry, they also pose a great challenge to the industry to maintain workplace safety and health. Construction sites have customarily been viewed as high-risk workplaces, which more often than not have a higher incidence of workplace fatalities. We must address this perception and change the reality. While construction workers strive to complete a building or facility, it is important that they do not risk life and limb. It is crucial that these workers go home safely after work each day. This booklet of case studies offers insights to all in the industry on how these tragic accidents occurred, so that we may glean important, lifesaving lessons from the experience. In learning from our past mistakes, we can and must prevent these mishaps from happening again. Together with your help, we can transform construction sites into safe and healthy workplaces for our workers. Mr Lee Tzu Yang Chairman Workplace Safety and Health Council

3 CONTENTS Falls 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 8 Fall from a scaffold 18 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 14 Fall from a scaffold 35 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 Case 23 Fall from a scaffold 60

4 FALLS FROM HEIGHT

5 CASE 1 FALL THROUGH A ROOF Description of Accident A worker was installing lifelines on a pitched roof at a worksite. He stepped on one of the roof tiles which then broke under his weight. The worker suffered severe head and chest injuries and eventually succumbed to the injuries. Causes and Contributing Factors 1. Roof tiles removed When the worker went up the roof to install the lifelines, he had stepped onto the midsection of the roof tiles where there was no support structure. The roof tile hence broke under his weight. 1 He fell from a height of 4.8m through the roof Height of fall = 4.8m 2. Place where the deceased worker landed 04

6 Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Improper position for task Lack of experience Inadequate work standards Inadequate leadership and/or supervision Hazard analysis and risk assessment Follow-up A Stop Work Order was issued to stop all work at the premises. The main contractor was instructed to conduct risk assessment and develop safe work procedures for removing roof tiles which contained asbestos. Recommendations Conduct a proper risk assessment prior to the commencement of a job. Use a boom lift to send workers to the roof-top to install the lifelines instead of working directly on a pitched roof. Use crawl boards or ladders provided on rooftops for safe access by the workers. 05

7 CASE 2 FALL FROM A SCAFFOLD Description of Accident A worker was intending to paint the walls adjacent to a ledge. He tried to climb out of a suspended scaffold onto the building ledge but lost his footing and fell from the nineth storey of the building. Causes and Contributing Factors The worker was not wearing any safety harness or safety belt. The suspended scaffold had last been examined in August 2002, contrary to the legal requirement which states that such equipment must be thoroughly examined and certified for use by an approved person once every 12 months. 1. The deceased landed here 2. The suspended scaffold was re-positioned here 3. The position of the suspended scaffold at the time of the accident 1. The lifeline installed outside the suspended scaffold 2. A lifeline installed in between the ledges and kitchen area 3. A worker attached the fall arrestor device to a lifeline 4. One of the cross beams 5. The suspended scaffold installed at the façade

8 Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Improper position of worker for task Inadequate or improper protective equipment Lack of knowledge Inadequate leadership and/or supervision Hazard analysis and risk assessment WSH rules, permits and personal protective equipment 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. Recommendations Provide safe access and egress routes for workers. Install an independent lifeline for anchoring personal fall protection equipment. Brief workers on the hazards and risks of the job. 07

9 CASE 3 TRIPPED BY AN ELECTRICAL EXTENSION Description of Accident A worker was carrying out drilling operations at the 33rd level of a building. While he was searching for an electrical socket outlet to connect an electrical tool, he accidentally tripped on an electrical extension wire that he was holding and fell through an opening within a wooden barricade. He landed below on the 32nd level. Causes and Contributing Factors The 33rd level floor slab opening measured approximately 4m in length and 2.7m in width. The depth from the 33rd level to the 32nd level measured approximately 4m. The floor slab opening was meant for the staircase before it was dismantled. It was not guarded by any effective barrier to prevent falls. 1. The electrical distribution box at the corner of the floor slab opening 2. Partition wall beside the floor slab opening 3. The floor slab opening was meant for a staircase before it was dismantled 4. The 32nd level worksite below 1. The electrical distribution box at the corner of the floor slab opening 2. The red-white tape and nylon rope used to barricade the two sides of the floor slab opening 3. The "Danger No Entry" signage 4. The wooden barricade (guarding only one side of the opening and not the remaining three)

10 Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Inadequate guards or barriers provided Improper placement Lack of knowledge Communication/group meeting WSH training and competence Recommendations Provide barriers to guard floor openings to prevent falls or cover floor openings with a cover (if appropriate). Provide appropriate lighting and display suitable warning signs to warn operators of potential dangers at the work area. 09

11 CASE 4 FALL OF FORMWORK Description of Accident A site supervisor and a worker were killed when a jumpform panel that they were working on fell off from its position to the ground below. The jumpform was fixed at the 16th storey of a building that was under construction at the time of the accident. Causes and Contributing Factors The jumpform panel that dropped was one of the two panels that had been shifted from the 15th storey of the building using a tower crane in the morning prior to the accident. 1. Injured was caught in the net here below the third storey Investigations revealed that the bracket of the collapsed jumpform panel was not securely attached onto its support mechanism. As a result, the bracket slipped off from its support and the entire panel fell off subsequently. Significant changes were noted during the installation process of the formwork which affected its integrity. 1. Jumpform fell off from here 10

12 The subcontractor did not conduct hazard analysis or develop safe work procedures for the new installation process. Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Failure to secure jumpform Lack of skill Inadequate leadership and/or supervision Inadequate monitoring of construction Hazard analysis and risk assessment WSH practices and procedures WSH training and competence Follow-up The occupier was instructed to review the design of the formwork system and to revise the safe work procedures for the workers before work on the jumpform structure was allowed to continue. Safety measures such as additional brackets and wire ropes for securing purposes were also introduced to increase system reliability. Recommendations Develop safe work procedures. Conduct proper supervision of the erection process and checking of the panel support. Ensure that the bracket hook s design is such that it can be checked easily. 11

13 CASE 5 FALL OFF A TOPPLING SCAFFOLD Description of Accident A worker was assigned to service some roof painting work at a building. He was erecting a mobile scaffold along a corridor at the fourth storey of the building when the scaffold toppled. As a result, the worker fell off from the scaffold and out of the building onto the ground 12m below. Causes and Contributing Factors The mobile scaffold (with a cantilevered structure) was not in a stable position and was not secured to the building structure or metal railing along the building corridor at the time of accident. 1. The fourth storey roof beam 2. The toppled mobile scaffold at the fourth storey corridor 3. The factory building 4. The location where the deceased had landed 5. The driveway 12 When the worker climbed onto the mobile scaffold to tie the metal deckings to the cantilevered structure, the mobile scaffold toppled and the worker fell off from the scaffold and building. 1. The toppled mobile scaffold with the cantilevered structure 2. The two metal decking which were to be tied 3. The fourth storey corridor 4. The parapet wall 5. The castor wheels

14 Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Improper position for task Inadequate or improper protective equipment Failure to secure scaffold Lack of experience Inadequate work standards Communication/group meeting Hazard analysis and risk assessment WSH training and competence Follow-up The main contractor was instructed to conduct a risk assessment and review the safe work procedures for all works at the site. Recommendations Conduct risk assessment prior to job commencement. Use an alternative method of work, or institute safe work procedures for such work. Ensure proper safety measures are in place such as securing of mobile scaffold to the building structure and provision of lifelines for the workers. 13

15 CASE 6 KILLED BY A PLUNGING HOIST Description of Accident A worker, employed as a plasterer, was seen moving up in the Passenger and Material (PM) hoist. The PM hoist suddenly plunged to the ground and the worker died on the spot. Causes and Contributing Factors 1. The control unit The PM hoist involved in the accident had been retrofitted by the hoist supplier with a machinery plate with a motor drive unit and a 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 onto the top of the drive unit, and knocked off the machinery plate with the drive unit from the rack, resulting in the free-falling of the hoist. 1. The dislodged machinery plate 14

16 Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Defective tools, equipment or materials Inadequate maintenance Excessive wear and tear Maintenance regime of machinery Follow-up A Stop Work Order was issued to cease all hoisting operations installed onsite. The occupier was instructed to dismantle all hoists and replace them with another brand from another supplier. Recommendations Have a regular maintenance system as per maintenance regime of CP79. Replace bolts when installing the PM hoist at a new location. 15

17 CASE 7 FALL THROUGH AN OPENING Description of Accident A worker was to carry out painting work. While he was getting ready to paint the wall at the void area, he fell into the opening at the 10th level and landed about 30m below on a platform. Causes and Contributing Factors Directly above the platform were openings which were found at all levels from the first level to the 12th level. The opening measured about 700mm x 900mm. The painting supervisor did not check the work area to be plastered/painted for compliance to the safety requirements listed in the Permit-to-Work. The worker was not wearing a safety belt/harness. He had been working on site for two weeks prior to the accident. Investigations revealed that the worker had not attended the Safety Orientation Course (construction). 1. External scaffolding 2. Desceased was found lying at the platform of the external scaffolding 3. Passenger hoist 1. External scaffolding 2. Guardrail 3. External wall 4. Void area 5. Barricade of wire rope with orange netting 16

18 Root Cause Analysis Evaluation of loss One worker killed Type of contact Fall from height to lower level 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 Follow-up The occupier was instructed to review the Permit-to-Work system on site and implement it on a daily basis. The occupier was instructed to only engage painters who have attended the safety orientation course at the worksite. Recommendations Ensure all workers attend the Construction Safety Orientation Course. Implement a safety induction programme on the use of personal protective equipment prior to starting work. Supervisors should be responsible to check and ensure the use of appropriate personal protective equipment. Conduct regular briefings on the dangers of working at heights. 17

19 CASE 8 FALL FROM A SCAFFOLD Description of Accident Worker A and his co-workers were instructed to tidy up metal scaffolds above a courtyard area at a worksite. The group took up their positions on the metal scaffolds and the worker was then on a scaffold next to the classroom block. Worker A was to work on the working platforms at the fifth lift of the scaffold next to the classroom block. He fell to his death and was found lying on the ground at the first storey. 1. The loose frame scaffold that was to be removed by the deceased 2. A patched wall tie hole where the cement was still wet 3. The working platform at the fifth lift of the scaffold where the deceased had stood on when working on the scaffold 18 Causes and Contributing Factors The location that Worker A landed was right below the scaffold that he was working on and the ground was scattered with damaged cross bracings, metal decking, scaffold frames and metal pipes. The group of workers wore safety belts but there was no lifeline found on the scaffolds for them to anchor their safety belts. 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 scaffold 4. The deceased had landed here where the scaffolding items had scattered

20 The workers were not trained scaffold erectors and had not undergone any course for scaffold erection. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Improper use of personal protective equipment Basic cause(s) Failure of SMS Lack of knowledge Lack of skill WSH training and competence Hazard analysis and risk assessment Follow-up The occupier was issued with a Stop Work Order to install lifelines on the scaffold and to engage trained scaffold erectors to dismantle the scaffolds. Recommendations Install independent lifelines. Supervisors should be responsible to check and ensure the use of appropriate personal protective equipment. Conduct regular briefings on the dangers of working at heights. 19

21 CASE 9 COLLAPSE OF A PLATFORM Description of Accident Three workers were carrying out installation of a clothes drying rack at the 10th level of an HDB flat. The installation was done from a mast climbing platform in the worksite. Upon completion of the work, they were about to descend when the platform suddenly came down. All three workers fell; two of them died while the other was injured. 1. The platform had split open after the incident Causes and Contributing Factors The bottom motor of the drive unit of the platform was not the original motor fitted to the platform. The gearboxes of both the top and bottom motors were produced by the same manufacturer, but were of different type. The top motor was a two stage gearbox while the bottom motor was a three stage gearbox. Use of these two gearboxes with different output speed induces great stress within the gears in the gearboxes. 1. Top motor 2. Bottom motor 20

22 The moment the gearboxes failed, the platform descended suddenly and crashed to the ground. Root Cause Analysis Evaluation of loss Type of contact Two workers killed and one injured Fall from height to lower level Immediate cause(s) Defective tools, equipment or materials Basic cause(s) Failure of SMS Inadequate maintenance Inadequate replacement of unsuitable materials Maintenance regime WSH practices and procedures Follow-up A Stop Work Order was issued. The occupier was instructed to stop using all mast climbing work platforms (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 used at 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. 21

23 Recommendations Conduct functional checks, regularly, and before use. Ensure that the specifications of the different units of any equipment are compatible. Have fall protection equipment as an additional safety measure. 22

24 CASE 10 FALL FROM A FORMWORK SHORING Description of Accident Worker A and his co-worker were involved in the transfer of three units of formwork shoring from the third storey to the second storey of the building that was under construction. They were climbing up the frame of a unit of the formwork shoring on the third storey so as to attach the hooks of the chain slings from the tower crane when the formwork shoring suddenly tilted and toppled to the floor. Worker A fell from the shoring and landed on the third storey. He sustained serious head injuries from the fall and died on the spot. The other worker suffered minor scratches as he managed to jump to the floor as the shoring toppled. Causes and Contributing Factors 1. The deceased landed here 2. The toppled formwork shoring 1. The toppled formwork shoring 2. Width: 1.2m 3. The inner props Worker A was standing on a formwork frame about 4.28m from the floor when the shoring toppled. 23

25 The ratio of the height of the shoring against its width was about 4.74m. It was tall and slim and hence prone to toppling. There was no outrigger installed on the shoring to ensure the stability of the shoring. It was thus unsafe for workers to work on the shoring. The worker who was to rig up the shoring had not attended the Rigging Operation Course and he was not an appointed rigger. There was no lifting supervisor appointed for the transfer of shoring using the tower crane. Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed and one injured Fall from height to lower level Failure to secure shoring Lack of knowledge Inadequate work standards Inadequate leadership and/or supervision Hazard analysis and risk assessment WSH training and competence 24

26 Follow-up To prevent recurrence, the factory occupier was instructed to implement 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. Recommendations A safe width to height ratio must be ensured. Proper access such as a monkey ladder should be provided. 25

27 CASE 11 TIPPING AND FALL OF A TABLE FORMWORK Description of Accident Worker A and his co-worker were working on a table form (formwork) that was partially set up on the eighth level. The table form tipped towards the edge of the building and fell to the ground. Worker A fell together with the table form and landed on the ground. He died on the spot. Causes and Contributing Factors 1. The metal frames of the table form that fell from the eighth level The table form was not set up on the eighth level in accordance with the design of the 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 according to the design of the professional engineer. However, the subcontractor did not request the professional engineer to redesign the table form to suit the actual site situation. 1. The rear corner props 2. The intermediate props 3. The front corner props 26

28 According to the design, while setting up the table form, four props at the four corners were to be put up first followed by 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 intermediate positions. The position of Worker A and his co-worker were outside the four supporting points and the combined weight caused the table form to tip over and fall over the edge of the building. Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Improper placement of table form Inadequate evaluation of changes Hazard analysis and risk assessment 27

29 Follow-up A Stop Work Order was issued to stop work on the table form. The occupier and subcontractor were instructed to implement the following safety measures: To redesign the table form using a professional engineer. The revised design should enable it to be supported by four 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 and workers on the proper way to set up the table forms. Recommendations Ensure that a table form is fully supported by all necessary props at all times. Ensure formwork supervisor is present at all times to supervise the proper erection of the formwork at the site. Conduct safety training to instruct supervisors and workers on the proper way to set up the table forms. 28

30 CASE 12 FALL OF A FORMWORK PANEL Description of Accident A worker was involved in the dismantling of metal formwork panels. He was standing on the working platform of a metal formwork panel when the panel gave way. He fell about 6m together with the panel and it landed on him. He died on the spot. Causes and Contributing Factors 1. Working platform at the top section 2. Modular formwork panels Investigations revealed that the day prior to the accident, the tie rods at the top section of the formwork structure had been removed. The stability of the formwork structure was compromised as a result. The foreman had noticed this but he did not proceed to check the tie rods at the top section of the other panels of the formwork structure, although he was aware that something was amiss. 1. Connecting brackets between internal and external formwork panels 2. Deceased was standing around this position 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 the first level. The formwork panel also came down and landed on him 29

31 As the worker was standing on one end of the working platform of the formwork panel, the formwork panel peeled off from the concrete wall structure. The worker lost his balance and fell from the working platform. The formwork panel also came down and landed on him. Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Failure to secure formwork Inadequate work standards WSH practices and procedures 30

32 Follow-up The occupier was instructed to implement the following improvements/measures at the worksite: A written work procedure on the installation and dismantling of the formwork system to be instituted and implemented at their worksites. Warning signages to be installed at the top section of the formwork structure to remind workers not to remove the tie rods at the top section prior to hoisting by a tower crane. 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 not to remove tie rods. 31

33 CASE 13 FALL THROUGH AN OPEN SIDE Description of Accident Worker A and his co-worker were getting ready to carry out plastering work to a column on the fifth level of a building at a worksite. Subsequently Worker A was seen falling through the open side next to the column to be plastered. He landed on the ground level 15m below and died subsequently. 1. Fifth level 2. Open side 3. The deceased was found here Causes and Contributing Factors The open side where the worker fell off was not barricaded. There was a lot of building materials, wooden pallets, formwork materials and other materials placed on the floor on the fifth level. These materials were placed haphazardly and obstructed access. Worker A had to maneuver his way through these materials to his workplace. 1. Column to be plastered 2. Open sides 3. Scaffold 32

34 Worker A was last seen standing at the column near the open side, holding his safety belt in his hand. He was seen falling off the edge. The accident probably occurred when Worker A was inspecting the column located next to the open side. He may have tripped on some object on the ground and lost his balance. A similar accident had happened three months ago. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Inadequate guards or barriers Basic cause(s) Failure of SMS Inadequate work standards Inadequate storage of materials Poor housekeeping WSH practices and procedures Follow-up The occupier was instructed to carry out the following: To cover all openings and put up barricades for open sides on site. To place materials properly so as not to obstruct the passageway. To carry out housekeeping regularly on site. 33

35 Recommendations Provide barricades with rigid materials for all open sides and secure at both ends. Stack materials properly. Clear debris frequently. Ensure close supervision so that personal protective equipment are used correctly. 34

36 CASE 14 FALL FROM A SCAFFOLD Description of Accident Worker A and his two co-workers were involved in the dismantling of an external scaffolding of a block. One of the co-workers descended from the scaffold and called out to Worker A and another co-worker to come down from the scaffold for lunch. As the co-worker was waiting at the foot of the block, Worker A fell from the scaffold and hit him. Worker A was seen bleeding from the back of his head and was sent to the hospital where he subsequently passed away. 1. Block External scaffolding being dismantled Causes and Contributing Factors The scaffold supervisor was not with the worker when the dismantling work was in progress. He had left the worksite to buy lunch for his workers. 1. External scaffolding 2. The deceased was found here Worker A was found with his safety harness on his waist after the accident. 35

37 There were no eye-witness accounts as to how Worker A fell from the scaffold. Upon hearing his co-worker s call to come down, the worker might have detached his safety harness from the lifeline. The accident probably happened when he was descending from the scaffold, and lost his footing. When he fell, he hit the scaffold along the path of his fall and hit the worker who was waiting at the foot of the block. Worker A and one of the co-workers involved in the dismantling work had not undergone any training course for the work. The safety manager and the scaffold supervisor were aware that the two workers did not have scaffold erectors certificates. It was reported that the workers were scaffold assistants and were expected to be stationed on the ground, not on the scaffold. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Making safety devices inoperative Basic cause(s) Failure of SMS Lack of knowledge Lack of skill Inadequate supervision WSH training and competence 36

38 Follow-up The occupier was instructed to engage only trained scaffolders to carry out the scaffolding work on site. Recommendations Assign only certified erectors to carry out dismantling work. Provide proper training. 37

39 CASE 15 HIT BY A RUBBER HOSE Description of Accident A concrete pump operator and his co-workers were carrying out cleaning work on a platform which was erected about 10m above the bottom of the shaft. The cleaning work was carried out by means of inserting a sponge ball into one end of the pipeline and feeding the pipeline with compressed air. The other end of the pipeline was equipped with a rubber hose to discharge the leftover concrete into a container. The workers were gripping the rubber hose while the pump operator held down the rubber hose with a steel tube. When the sponge ball was forced out from the rubber hose, the hose swung suddenly and hit the pump operator. He was flung off the platform and landed on the bottom of the shaft. He died on the spot. 1. Concrete pump 2. Rubber hose 3. Timbers on the platform 4. Scaffold frame 1. Deceased was standing here prior to the accident 2. Rubber hose was placed on a scaffold frame 38

40 Causes and Contributing Factors There were some pieces of timber placed on the platform where the cleaning work was carried out. Workers mentioned that it had, to some extent, hampered their work. Investigations revealed that the rubber hose was not secured in position to prevent it from moving during the cleaning operation. Towards the end of the cleaning operation, particularly at the time when the sponge ball was forced out from the hose, the sudden release of the compressed air probably created some lateral forces. This caused the hose to swing and resulted in the workers losing their grip on the hose. The hose swung and hit the pump operator, pushing him over the guardrail. Root Cause Analysis Evaluation of loss One worker killed Type of contact Fall from height to lower level 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 39

41 Follow-up The occupier was instructed to submit safe work procedures (SWP) for pipeline cleaning work involving compressed air and to implement and ensure that all the workers adhered to the SWP. Recommendations Ensure at least two tag lines to hold the end of the rubber hose in position. Workers should be provided with and trained in the use of fall protection equipment. Ensure close and continuous supervision of such hazardous operations. 40

42 CASE 16 FALL FROM AN OPEN SIDE Description of Accident A subcontractor was engaged to carry out block-laying and plastering works at Blocks A and B of a building site. The foreman had given instructions to a worker at Block A to clear some wooden palette at the workplace after which he walked towards Block B. About five minutes later, the foreman was seen sitting on top of a pile of debris at the second storey of Blk B. He was bleeding on the left side of his head and was pronounced dead by the ambulance officer. 1. Open side 2. Debris 3. Precast concrete components Causes and Contributing Factors A wooden pallet was found broken among the pile of debris at Block B. There were fresh blood stains on the pallet. A worker confirmed that he found the foreman on the broken palette. The pile of debris was situated right below a side of the building with a series of open sides. 1. The deceased was found here 41

43 Investigations revealed that the open sides at the seventh storey were barricaded. All the other open sides at Block B, i.e. first to sixth storey and the eighth storey were not barricaded. Debris was also seen placed close to the edge of an open side on the seventh storey of Block B. The debris could fall and potentially hit a person standing below. The foreman was believed to have fallen from one of the open sides. He might have lost his footing when he was working near an unbarricaded open side at Block B. He may have fallen and landed on the pile of debris at the second storey of Block B. Root Cause Analysis Evaluation of loss One worker killed Type of contact Fall from height to lower level Immediate cause(s) Inadequate guards or barriers at open sides Poor housekeeping Basic cause(s) Failure of SMS Inadequate work standards WSH practices and procedures 42

44 Follow-up The occupier was instructed to undertake the following improvements 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. Recommendations Provide barricades with rigid materials to all open sides and secure at 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 protective equipment are used properly. 43

45 CASE 17 FALL OFF AN OPEN PLATFORM Description of Accident A worker was engaged to carry out painting work in a school building. He was assigned to paint the roof purlins and the supporting metal frames for a featured roof located above the staircase roof slab of a six-storey building. He was later found lying at the foot of the building with serious injuries and was pronounced dead by ambulance officers. 1. Purlin near the edge of the featured roof Causes and Contributing Factors Investigations revealed that a scaffold with a working platform had been erected below the part of the featured roof that was protruding beyond the staircase roof slab. There was no guardrail erected on the open side of the working platform to prevent falls. There was also no ladder provided on the scaffold for access to the working platform. 1. The featured roof 2. Purlin near the edge of the featured roof 3. Working platform on the scaffold 4. The staircase roof slab 5. Roof slab above the sixth storey 3 44

46 It is probable that prior to the accident, the worker had gone up 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. Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Inadequate guard or barrier Inadequate engineering (inadequate assessment of loss exposures) WSH practices and procedures 45

47 Follow-up Occupier was instructed to implement the following safety measures: 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 open sides 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. Recommendations Provide lifeline for all work at heights. Brief workers regularly on the use of personal protective equipment and fall protection measures. Erect scaffolds with proper access and guardrails. 46

48 CASE 18 FALL THROUGH A SKYLIGHT Description of Accident Worker A and three other co-workers, each carried a pail containing waterproofing material up a roof in preparation for the coating of the skylight of a roof. While they were on the roof, one of the co-workers heard a breaking sound coming from the roof sheets. He turned his head and saw a broken skylight. Worker A had fallen through the skylight of the roof (at a height of 8m) and landed on the ground. Causes and Contributing Factors 1. This row of skylight was to be waterproofed 2. Location where the deceased fell through the skylight Investigations revealed that prior to starting work, the site supervisor had briefed the workers not to step on the skylight. Investigations revealed that no safety measures such as crawling boards or planks had been provided as foothold for the workers to stand on while working on the roof. 1. The deceased fell about 8m and landed here 47

49 According to the workers, the site supervisor told them that there were no anchorage points on the roof and hence they would not be able to use their safety belts while working on the roof. Root Cause Analysis Evaluation of loss Type of contact Immediate cause(s) Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Inadequate or improper protective equipment Inadequate work standards WSH practices and procedures WSH training and competence Follow-up The occupier was instructed to implement a written safe work procedure immediately. The employer was instructed to provide suitable crawling boards or planks and to install suitable and sufficient anchorage points/ lifelines on the roof. Recommendations Install appropriate lifelines and anchorages. Provide crawling boards, planks or ladders as a foothold for workers working on the roof. 48

50 CASE 19 FALL FROM AN ATTIC Description of Accident Worker A, seven other co-workers and a signalman were doing concreting work on the roof beams of a building at a worksite. While waiting for a truckload of concrete, Worker A was seen resting on the staircase at the attic. Moments later, Worker A was found on the ground bleeding from his head. Causes and Contributing Factors The workers confirmed that they were not wearing safety belts while carrying out the concreting work. Even if they had worn their safety belts, there was no anchorage point for them to secure their safety belts. There were no working platforms provided for the workers for the concreting of the roof beams. Worker A was seen sitting on the plywood placed on some timbers at the opening of the attic. 1. Roof beams 2. Attic level 3. The deceased was found at the fifth level 1. Deceased was seen resting here 2. Plywood 3. Opening 49

51 The accident could have occurred when Worker A was resting on the plywood. The plywood could have broken and Worker A may have lost his footing and fallen through the opening. His head would have hit the concrete floor and the head injury could have caused his death. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Inadequate guards or barriers Inadequate or improper protective equipment Basic cause(s) Failure of SMS Improper motivation Lack of supervisory/management job knowledge WSH practices and procedures WSH training and competence Follow-up The occupier was instructed to provide working platforms for the workers for the concreting work at the roof. Recommendations Provide proper working platform. Provide proper personal protective equipment. Provide proper training. 50

52 CASE 20 FALL DUE TO AN UNSTABLE SCAFFOLD Description of Accident A worker was instructed to install a special fixture called bonding bars at the service duct area on the fourth storey of a building under construction. An hour later, he was found to have fallen together with a mobile scaffold from the corridor of the fourth storey of the building. He landed on the ground floor. He was sent to the hospital and died on the same day. Causes and Contributing Factors 1. Tower scaffold at service duct area 2. Mobile scaffold 3. Parapet wall 4. Two caster wheels found on the fourth storey 5. Uneven floor There were no eye-witnesses to the accident. The worker was probably using the mobile scaffold when he fell together with the scaffold from the fourth storey to the ground floor. 1. Tower scaffold 2. Unsecured decking 3. Bonding bars 51

53 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 such a floor and any person using it could cause it to topple. ii. The mobile scaffold was erected without any supervision from a scaffold supervisor to ensure that it was properly erected and stable. Root Cause Analysis Evaluation of loss Type of contact Immediate cause Basic cause(s) Failure of SMS One worker killed Fall from height to lower level Inadequate or improper protective equipment Inadequate leadership and/or supervision WSH practices and procedures 52

54 Follow-up The occupier was instructed to implement a Permit-to-Work system to control the use of tower and mobile scaffolds at the site. Recommendations Ensure proper inspection by a trained scaffold supervisor. Secure mobile scaffold using ties if the scaffold is greater than 4m in height and is close to an opening. Protect workers working close to an opening at a height greater than 4m with fall arrest equipment. 53

55 CASE 21 FALL WHILE DISMANTLING A PLATFORM Description of Accident Worker A and his co-workers were to dismantle a metal platform erected on a scaffold support. For this, they would have to remove the clips that held the pieces of metal formwork together so as to take them apart. Worker A was later found lying on the ground beside the scaffold support. He was taken to the hospital where he passed away on the same day. 1. The underside of the metal platform that was to be dismantled 2. The metal clip holding adjacent pieces of metal formwork together Causes and Contributing Factors 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 ground below the metal platform that was to be dismantled. 1. The metal platform that was to be dismantled 2. The scaffold support 3. The deceased was found lying here after the accident 54

56 Investigations revealed that on the day of the accident, a safe means of access or egress from the metal platform, such as a ladder ramp was not provided on the scaffold. The accident probably happened when Worker A climbed up the scaffold support to dismantle the metal platform and lost his grip on the scaffold frame and fell to the ground. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Inadequate or improper protective equipment Basic cause(s) Failure of SMS Inadequate engineering Inadequate work standards Hazard analysis and risk assessment 55

57 Follow-up The occupier was instructed to implement the following safety measures: 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 ramp with handrails for workers to gain access to the working platform on the scaffold support. Workers must stand on the working platform and anchor their 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 the commencement of work. Recommendations Provide proper access to the formwork level. Develop and implement safe work procedures. Ensure that the formwork supervisor is present during the dismantling 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 prior to the commencement of work. This should be done by the supervisor-in-charge. 56

58 CASE 22 FALL OF A GONDOLA PLATFORM Description of Accident In the early morning, two workers had started on the external window and façade cleaning of a building, using a permanent gondola located at the rooftop of the building. About an hour later, the gondola became jammed and the two workers were left stranded in the gondola between the 31st and 28th storey of the building. About three hours later, the service technicians from the gondola supplier arrived on site. While rectifying the fault, the platform of the gondola together with the two workers suddenly plummeted and crashed onto the rooftop of the podium at the fifth floor. One worker died on the spot. 1. The gondola 1. The rooftop where the gondola crashed Causes and Contributing Factors The platform together with the two workers plummeted due to the fracturing of the gearbox shaft holding the emergency safety brake. 57

59 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 gondola to operate in an overloaded condition without the power being automatically cut off. Investigations revealed that the gondola had earlier experienced numerous repetitive defects and failures that resulted in the non-functioning of the gondola. However the gondola supplier had not taken any measures to establish the causes for the recurring fault and rectify them. Whenever the technicians from the gondola supplier were called in, they would rectify by resetting the over-speed device and pumping the pressure up so as to release the safety brakes and render the gondola mobile. This practice is contrary to the instructions given by the manufacturer. 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. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Defective tools, equipment or materials Basic cause(s) Failure of SMS Inadequate maintenance Inadequate tools and equipment Maintenance regime 58

60 Recommendations Plan regular maintenance for the gondola. Ensure the regular inspection of the mechanical and electrical equipment by competent persons. Ensure emergency and rescue procedures are strictly followed. Avoid overloading equipment. 59

61 CASE 23 FALL FROM A SCAFFOLD Description of Accident 60 Worker A and his co-workers were working on a working platform on a metal scaffold on the fourth storey of a building. They were preparing a beam for skim coating. Worker A was wetting the beam with a pail and was seen walking backward while wetting the beam. A few minutes later, Worker A was found lying on the floor beside the metal scaffold. He was taken to the hospital where he passed away a few days later. Causes and Contributing Factors Guardrails were provided on the open sides of the working platform. However guardrails on both the left and right ends of the working platform were only secured on one side. It was done this way so that the guardrails could be swung open for workers to get onto the working platform when they went up there to work. 1. The deceased was wetting this beam prior to the accident 2. The guardrail on the right end of the scaffold 3. The deceased probably fell from here 4. The working platform 5. The deceased landed here after the accident 1. The deceased was wetting this beam prior to the accident 2. The scaffold 3. The deceased landed here after the accident

62 No ladders or steps were provided for workers to gain access to the working platform. Both Worker A and the co-worker who erected the scaffold had not undergone a training for scaffold erection. The erection of the scaffold was 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 walking backwards while wetting the beam, he failed to stop at the end of the platform and fell to the floor. It is also possible that the deceased, after having finished wetting the beam, was climbing down the scaffold when he fell to the floor. Root Cause Analysis Evaluation of loss Type of contact One worker killed Fall from height to lower level Immediate cause(s) Inadequate guards or barriers Basic cause(s) Failure of SMS Inadequate leadership and/or supervision Hazard analysis and risk management 61