In this incident, a worker was found dead on the ground floor of a construction site. Preliminary investigations revealed that the worker was carrying out plastering works at the balcony area within a unit on the 17th storey. The worker was found without any fall protection equipment and it was suspected that the worker fell from the edge of the balcony and landed on the ground. The guardrails that were installed were dislodged at one end.
A similar incident had occurred earlier this year. A worker carrying out plastering work on the external wall of an air conditioning ledge fell to his death from the 9th floor of a building.
Recommendations*
1. Conduct risk Assessment: A risk assessment must be carried out by experienced and knowledgeable persons before starting any work. Through the risk assessment, employers and workers can identify hazards and take appropriate actions to eliminate the hazard or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers. In these cases, one of the key control measures would be to prevent workers from falling while working at height.
2. Establish workplace safety and health management programme and safe work procedures: Employers should establish and implement a safety and health management system with proper control measures and the appropriate safe work procedures. This includes an effective fall protection plan (FPP) for any work that may subject workers to the risk of falling from height. The fall protection plan must be clearly communicated to all levels of personnel, such as through refresher courses or daily toolbox meetings. It is also crucial to ensure that the safe work procedures are adhered to by all sub-contractors to better manage the safety and health of all workers at the workplace.
3. Fall prevention/protection: Work at height must be made safe through fall prevention or protection measures. Examples include installing guard rails that prevent persons from falling over open sides, as well as travel restraint, fall arrest or engineered systems with anchorage points as explained below:
Travel Restraint: A travel restraint system prevents a worker from falling by restricting his body movement into hazardous areas, such as open sides. For such a system, a restraint belt or full body harness is suitable once anchored securely.
Fall Arrest: An individual fall arrest system protects the worker by stopping his fall sp that he does not strike the ground. A full body harness with a self-retracting lifeline or a shock absorber and a lanyard are suitable for fall arrest once anchored securely.
Engineered Systems: Engineered systems such as horizontal lifelines should be installed according to the design by the professional engineer. Deviating from the design can result in the system no functioning as it rightfully should and can result in potentially unsafe conditions for workers.
4. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who perform unsafe acts and do not comply with the safe work procedures.
Wednesday, September 29, 2010
A Case of Electric Shock
In a recent incident, a supervisor on night shift duty was installing an electrical device. While performing the job, he did not use the voltage tester nor put on rubber gloves. A short circuit occurred which was followed by a discharge. The supervisor suffered a mild electric shock.
Recommendations:
1. Conduct risk assessment: Before the start of any work, risk assessment must be conducted to identify potential hazards. Appropriate control measures should then be taken to eliminate the hazards or reduce the risks involved. The hazard relevant to this incident was the exposed electrical components that were still “live”.
2. Use of dry rubber insulating mat: Dry rubber insulating mat should be used where there is risk of electrocution. The rubber mat insulates the ground on which the worker stands, reducing the risk of electric current flow through him.
3. Provision of adequate training: All workers should be adequately trained in the identification and control of hazards at the workplace. Specialised electrical safety training must be provided to workers who need to work with or around exposed components of electric circuits. The training should include, but not be limited to, basic electrical theory, proper safe work procedures, hazard awareness, identification and control, proper use of personal protective equipment, proper lockout/ tagout procedures, first aid and rescue procedures. Provisions should also be made for periodic re-training or refresher training.
4. Lockout/ Tagout (LOTO): LOTO procedures should be established and implemented for the inspection, maintenance and repair of any machinery or equipment. All energy sources associated with the machinery or equipment should be isolated, disconnected or discharged to prevent the whole or part thereof of the machinery or equipment from being activated or energised.
5. Personal Protective Equipment (PPE): Appropriate PPE should be provided and used by workers who are potentially exposed to “live” components. These PPE can include electrical resistance or insulating rubber hand gloves and rubber-soled boots.
Recommendations:
1. Conduct risk assessment: Before the start of any work, risk assessment must be conducted to identify potential hazards. Appropriate control measures should then be taken to eliminate the hazards or reduce the risks involved. The hazard relevant to this incident was the exposed electrical components that were still “live”.
2. Use of dry rubber insulating mat: Dry rubber insulating mat should be used where there is risk of electrocution. The rubber mat insulates the ground on which the worker stands, reducing the risk of electric current flow through him.
3. Provision of adequate training: All workers should be adequately trained in the identification and control of hazards at the workplace. Specialised electrical safety training must be provided to workers who need to work with or around exposed components of electric circuits. The training should include, but not be limited to, basic electrical theory, proper safe work procedures, hazard awareness, identification and control, proper use of personal protective equipment, proper lockout/ tagout procedures, first aid and rescue procedures. Provisions should also be made for periodic re-training or refresher training.
4. Lockout/ Tagout (LOTO): LOTO procedures should be established and implemented for the inspection, maintenance and repair of any machinery or equipment. All energy sources associated with the machinery or equipment should be isolated, disconnected or discharged to prevent the whole or part thereof of the machinery or equipment from being activated or energised.
5. Personal Protective Equipment (PPE): Appropriate PPE should be provided and used by workers who are potentially exposed to “live” components. These PPE can include electrical resistance or insulating rubber hand gloves and rubber-soled boots.
2 Workers Fell to their Deaths
At about 1700hrs, two workers fell about 9 storeys from a building while working from the inside of a customised building maintenance gondola. Preliminary investigations revealed that the two men had fallen together with the gondola. They were pronounced dead at the scene by paramedics.
Recommendations*
1. Conduct risk assessment: Proper risk assessment must be carried out by experienced and knowledgeable persons before starting any work. Through the risk assessment, employers and workers can identify hazards and take appropriate actions to eliminate the hazards or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers. In this case, the general condition of the gondola, including the rail and trolley wheels, should be inspected before work is carried out. IN the event of any anomaly while operating the gondola, all work should cease immediately and proper recovery actions should be effected.
2. Establish workplace safety and health management programme: Employers should establish and implement a safety management system with proper control measures and the appropriate safe work procedures. This includes an effective fall protection plan for any works that may subject workers to the risk of falling from height. The safety and health programme must be clearly communicated to all levels of personnel, such as through refresher courses or daily toolbox meetings.
3. Implement fall prevention / protection / arrest system: Works that are carried out at height must be made safe through proper fall prevention or protection measures. This includes ensuring safe access and egress, and barricading or guarding all work areas to prevent falls. Fall arrest, travel restraint and engineered systems with appropriate anchorage points should also be provided:
Travel restraint: A travel restraint system prevents the worker from falling by restricting his movement into hazardous areas, such as open sides. The restraint belt or full body harness must be anchored securely.
Fall Arrest: An individual fall arrest system protects the worker by stopping his fall so that he does not strike the ground. The full body harness with a self-retracting lifeline or a shock absorber and a lanyard must be anchored securely.
Engineered Systems: Engineered systems such as horizontal lifelines should be installed according to the design by a professional engineer. Deviating from the design can result in the system not functioning as it should and can be unsafe.
4. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who exhibit unsafe acts and do not comply with the safe work procedures
Recommendations*
1. Conduct risk assessment: Proper risk assessment must be carried out by experienced and knowledgeable persons before starting any work. Through the risk assessment, employers and workers can identify hazards and take appropriate actions to eliminate the hazards or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers. In this case, the general condition of the gondola, including the rail and trolley wheels, should be inspected before work is carried out. IN the event of any anomaly while operating the gondola, all work should cease immediately and proper recovery actions should be effected.
2. Establish workplace safety and health management programme: Employers should establish and implement a safety management system with proper control measures and the appropriate safe work procedures. This includes an effective fall protection plan for any works that may subject workers to the risk of falling from height. The safety and health programme must be clearly communicated to all levels of personnel, such as through refresher courses or daily toolbox meetings.
3. Implement fall prevention / protection / arrest system: Works that are carried out at height must be made safe through proper fall prevention or protection measures. This includes ensuring safe access and egress, and barricading or guarding all work areas to prevent falls. Fall arrest, travel restraint and engineered systems with appropriate anchorage points should also be provided:
Travel restraint: A travel restraint system prevents the worker from falling by restricting his movement into hazardous areas, such as open sides. The restraint belt or full body harness must be anchored securely.
Fall Arrest: An individual fall arrest system protects the worker by stopping his fall so that he does not strike the ground. The full body harness with a self-retracting lifeline or a shock absorber and a lanyard must be anchored securely.
Engineered Systems: Engineered systems such as horizontal lifelines should be installed according to the design by a professional engineer. Deviating from the design can result in the system not functioning as it should and can be unsafe.
4. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who exhibit unsafe acts and do not comply with the safe work procedures
Toppling of Stacked Boom Section in a Crane Maintenance Workshop
A group of workers were dismantling a telescopic boom into its individual sections using an overhead travelling crane. After stacking a dismantled boom on top of another boom section, the Crane Operator began to hoist the chain slings away. As the slings were being hoisted away, the stacked boom toppled onto a nearby worker. He succumbed to his injuries.
Summary of Findings:
Investigation revealed that the incident occurred primarily due to the negligence of Man (Crane Operator and Worker). The Crane Operator did not do his due diligence to ensure that the chain slings were free from entanglement before hoisting away. The worker should have positioned himself in a safe location, away from the lifting zone.
Management also did not establish the necessary safe work procedure for the stacking of boom sections. All these led to the occurrence of this fatal incident.
Summary of Findings:
Investigation revealed that the incident occurred primarily due to the negligence of Man (Crane Operator and Worker). The Crane Operator did not do his due diligence to ensure that the chain slings were free from entanglement before hoisting away. The worker should have positioned himself in a safe location, away from the lifting zone.
Management also did not establish the necessary safe work procedure for the stacking of boom sections. All these led to the occurrence of this fatal incident.
Ladder Safety
Many fall-from-height incidents involve the use of ladders. To prevent injuries arising from such incidents, this article aims to provide some guidance on the correct and appropriate use of ladders.
When to use a ladder?
As a first step, consider if working at height is necessary. If so, decide whether a ladder is the most appropriate access equipment compared to other options.
In general, ladders should only be used as a means of access to or egress from a work area, or for light work of short duration. If a task involves extended periods of working at height or with restricted movement and vision (e.g. welding), a step platform is a safer alternative as it is more stable and provides a much larger work surface than a step ladder.
Is the ladder safe to use?
Before using a ladder, check that it is safe to use. This would include ensuring that the ladder:
- Has no visible defects
- Is clean from oil, grease, wet paint and other slipping hazards
- Has been maintained and stored in accordance with the manufacturer’s instructions
- Is suitable for the activity (e.g. in terms of load)
How to use the ladder safely?
The following provides some recommendations on the safe use of ladders: - Conduct a risk assessment before starting work to identify the hazards. For example, appropriate actions should be taken to prevent falls from height, as well as reduce the consequences of a fall. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers involved.
- Ensure that users are competent and trained to use the ladders safely. Workers should be provided with the appropriate personal protective equipment (e.g. helmet and proper footwear). In some situations, a safety harness, lanyard or lifeline may be necessary. When using such equipment, a proper anchorage point must be available for its proper use.
- Ensure that the ladder is secured firmly in place. Do not site the ladder on loose material or slippery surfaces. Ensure that the ladder is secured at the top using rope or footed at the bottom before usage. An alternative is for another worker to hold the ladder firmly in place while another is climbing. The ladder should not be moved while a worker is standing on it.
- Do not carry tools in hand when climbing a ladder. Use a tool belt instead. Maintain three points of contact when climbing a ladder (two hands and one foot or one hand and two feet).
- Cordon off the work area to prevent the ladders from being struck by vehicles, workers or pedestrians. Check that the ladders will not be pushed over by other hazards such as doors and windows.
- Check the weather and avoid outdoor work in rain or in strong winds.
Collapse of Crane Due to Overloading
In this incident, a mobile crane was deployed to carry out lifting work at a two-storey terrace house. While the Crane Operator was lifting a bag of sand to the designated location at the rear side of the roof, the crane’s Overload Radius Indicator (ORI) alarm sounded. The crane then toppled, and its boom crashed onto the roof of an adjoining house unit. The crane eventually came to rest on its side, with the Crane Operator inside the operator’s cabin. There were no injuries in this incident.
Summary of Findings:
Investigations revealed that when the ORI alarm sounded and the cut-off was activated, the Crane Operator by-passed the cut-off by switching off the Automated Moment Limiter. He continued to lower the boom over the roof. This unsafe behaviour led to the collapse of the crane.
Summary of Findings:
Investigations revealed that when the ORI alarm sounded and the cut-off was activated, the Crane Operator by-passed the cut-off by switching off the Automated Moment Limiter. He continued to lower the boom over the roof. This unsafe behaviour led to the collapse of the crane.
Importance of Maintenance of MEWPs
A number of workers have lost their lives in recent incidents involving the use of mobile elevated work platforms (MEWP). The workers were trapped between components of the boom lift or scissor lift and surrounding structures. Therefore, it is important to ensure the safe and proper operation of MEWP, including checking that the MEWP is functioning and properly maintained. The frequency and type of maintenance and inspections of MEWP will depend on its usage, environmental conditions and the nature of operations.
Pre-Use Checks:
Before work commences, a visual and functional routine checks should be conducted on the MEWP, including checking for:
Pre-Use Checks:
Before work commences, a visual and functional routine checks should be conducted on the MEWP, including checking for:
- lubrication and hydraulic oil levels
- leakages
- structural damages
- malfunction of controls and safety devices
- other functionality checks
Servicing:
Besides the routine pre-use checks, the MEWP must be serviced at stipulated timeframes, such as statutory inspection at least once in 6 months, or in accordance with the manufacturer’s recommendations. A preventive maintenance programme has to be devised by the user or owner based on his risk assessment and previous inspection/maintenance results. All inspections must be recorded and retained for inspection when the need arises.
Workers Fell from Height at Ventilation / Air-Condition Ducting
Two fatal incidents were reported recently; one in the marine and the other in the construction industry. Both workers fell to their death while working at the ventilation / air-condition ducting areas at their respective workplaces.
In the first incident, 2 workers were tasked to cover up a 1.5m (diameter) opening after one section of the ventilation duct was dismantled at the accommodation deck of a vessel. One worker lost his balance and fell into the opening. He landed at the bottom of the ventilation duct which was 14m below the opening (Figure 1).
In the second incident, a worker fell from a height of 8m when he and his co-worker were preparing work platforms for installing air-condition ducting above the false ceiling.The worker was sent to the hospital but succumbed to his injuries on the same day (Figure 2).
Recommendations*
1. Risk assessment: A risk assessment must be carried out by experienced and knowledgeable persons before starting any work. Through the risk assessment, employers and workers can identify hazards and take appropriate actions to eliminate the hazards or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers. In these cases, one of the key control measures would be to prevent workers from falling while working at height.
2. Workplace safety and health management programme: Employers should establish and implement a Safety and Health policy, and safety management system with proper control measures and safe work procedures. This includes a fall protection plan for any works that may involve workers falling from a height. The safety and health programme must be clearly communicated to all levels of personnel, such as through refresher courses or daily toolbox meetings.
3. Fall prevention / protection / arrest system: Work at height must be made safe through fall prevention or protection measures first. This can include safe access and egress where the workplace is adequately barricaded or guarded to prevent falls. Further control measures could be in the fall arrest system. Examples include travel restraint, fall arrest and engineered systems with anchorage points as explained below:
Travel restraint: A travel restraint system prevents the worker from falling by restricting his movement into hazardous areas, such as open sides. For such a system, a restraint belt or a full body harness is suitable once anchored securely.
Fall Arrest: An individual fall arrest system protects the worker by stopping his fall so that he does not strike the ground. A full body harness with a self-retracting lifeline or a shock absorber and a lanyard are suitable for fall arrest once anchored securely.
Engineered Systems: Engineered systems such as horizontal lifelines should be installed according to the design by a professional engineer. Deviating from the design can result in the system not functioning as it rightfully should and can result in potentially unsafe conditions for workers.
4. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who exhibit unsafe acts and do not comply with the safe work procedures.
In the first incident, 2 workers were tasked to cover up a 1.5m (diameter) opening after one section of the ventilation duct was dismantled at the accommodation deck of a vessel. One worker lost his balance and fell into the opening. He landed at the bottom of the ventilation duct which was 14m below the opening (Figure 1).
In the second incident, a worker fell from a height of 8m when he and his co-worker were preparing work platforms for installing air-condition ducting above the false ceiling.The worker was sent to the hospital but succumbed to his injuries on the same day (Figure 2).
Recommendations*
1. Risk assessment: A risk assessment must be carried out by experienced and knowledgeable persons before starting any work. Through the risk assessment, employers and workers can identify hazards and take appropriate actions to eliminate the hazards or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers. In these cases, one of the key control measures would be to prevent workers from falling while working at height.
2. Workplace safety and health management programme: Employers should establish and implement a Safety and Health policy, and safety management system with proper control measures and safe work procedures. This includes a fall protection plan for any works that may involve workers falling from a height. The safety and health programme must be clearly communicated to all levels of personnel, such as through refresher courses or daily toolbox meetings.
3. Fall prevention / protection / arrest system: Work at height must be made safe through fall prevention or protection measures first. This can include safe access and egress where the workplace is adequately barricaded or guarded to prevent falls. Further control measures could be in the fall arrest system. Examples include travel restraint, fall arrest and engineered systems with anchorage points as explained below:
Travel restraint: A travel restraint system prevents the worker from falling by restricting his movement into hazardous areas, such as open sides. For such a system, a restraint belt or a full body harness is suitable once anchored securely.
Fall Arrest: An individual fall arrest system protects the worker by stopping his fall so that he does not strike the ground. A full body harness with a self-retracting lifeline or a shock absorber and a lanyard are suitable for fall arrest once anchored securely.
Engineered Systems: Engineered systems such as horizontal lifelines should be installed according to the design by a professional engineer. Deviating from the design can result in the system not functioning as it rightfully should and can result in potentially unsafe conditions for workers.
4. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who exhibit unsafe acts and do not comply with the safe work procedures.
Worker Pinned by Toppled Forklift
In this incident, a worker was operating a forklift to transfer a container of plastic bottles. After emptying the container of plastic bottles, he did not lower the metal container. He reversed the forklift with its mast in the extended position. The forklift toppled and fatally injured the worker.
Summary of Findings:
At the time of the accident, the fork of the forklift (including the metal container) was at its highest position, about 4m in height from the ground. The forklift driver did not lower the load nor reduce the speed when he reversed the forklift and made a sharp turn. This destabilised the forklift and caused it to topple.
Summary of Findings:
At the time of the accident, the fork of the forklift (including the metal container) was at its highest position, about 4m in height from the ground. The forklift driver did not lower the load nor reduce the speed when he reversed the forklift and made a sharp turn. This destabilised the forklift and caused it to topple.
Working Safely at Height
Working at height is inherently hazardous, with falling from height and being struck by falling objects being the two leading incidents in such work. Unsafe conditions and inadequate attention on working at height may result in fatalities and serious injuries. To ensure that work at height is made safe, some of the measures to be taken include:
1. Conduct risk assessment: To ensure safe operations, thorough risk assessment and careful planning are required before commencement of work. Through the use of effective control measures, it is possible to remove or minimise the hazards of working at height.
2. Implement effective Engineering control methods: Guard rail systems and toe-boards, once properly erected, can effectively prevent persons from accidentally falling over open sides and objects from being knocked over unintentionally.
[1] Guard rails and toe-boards prevent persons from falling and will prevent objects from being dislodged.
[2] A safe means of access and egress must be provided.
3. Use appropriate PPE: The use of personal protective equipment (PPE) should be used in conjunction with other forms of fall prevention or protection, to provide a secondary layer of protection. In instances where other methods of control are not suitable, PPE may be used as a last resort to afford protection to workers.
4. Ensure proper housekeeping: Simple practices such as good housekeeping help to enhance safety for work at height. By keeping the work platforms and surfaces clear of materials and tools, falling objects and slips are prevented.
A good safety standard at work is also good for productivity. The safe workplace would enable the workers to concentrate on doing their work better.
1. Conduct risk assessment: To ensure safe operations, thorough risk assessment and careful planning are required before commencement of work. Through the use of effective control measures, it is possible to remove or minimise the hazards of working at height.
2. Implement effective Engineering control methods: Guard rail systems and toe-boards, once properly erected, can effectively prevent persons from accidentally falling over open sides and objects from being knocked over unintentionally.
[1] Guard rails and toe-boards prevent persons from falling and will prevent objects from being dislodged.
[2] A safe means of access and egress must be provided.
3. Use appropriate PPE: The use of personal protective equipment (PPE) should be used in conjunction with other forms of fall prevention or protection, to provide a secondary layer of protection. In instances where other methods of control are not suitable, PPE may be used as a last resort to afford protection to workers.
4. Ensure proper housekeeping: Simple practices such as good housekeeping help to enhance safety for work at height. By keeping the work platforms and surfaces clear of materials and tools, falling objects and slips are prevented.
A good safety standard at work is also good for productivity. The safe workplace would enable the workers to concentrate on doing their work better.
Suffocation from Air-Fed Helmet
In this incident, a technician was deployed to carry out surface preparation work, including bead-blasting, for aircraft components. Less than an hour after he had started work in a bead-blasting chamber, he was found lying unconscious on the floor. He was in his usual protective clothing, and was wearing his air-fed helmet with the air supply still turned on. He was sent to hospital but died due to suffocation from oxygen deficiency.
Summary of Findings:
Investigations revealed that some workers from another unit did not follow their operating instructions. Instead of using nitrogen gas for the control system of an autoclave for their work, they used the common compressed air supply. This caused a back-flow of higher pressured nitrogen gas into the air supply for the technician, reducing the supply of oxygen and leading to his suffocation.
Summary of Findings:
Investigations revealed that some workers from another unit did not follow their operating instructions. Instead of using nitrogen gas for the control system of an autoclave for their work, they used the common compressed air supply. This caused a back-flow of higher pressured nitrogen gas into the air supply for the technician, reducing the supply of oxygen and leading to his suffocation.
Worker Crushed by Toppled Pipe
In this incident, a worker was using a hand held power tool to grind/polish a welded joint on Pipe A within a pipe bridge. He was working in a 300mm gap between Pipe A and Pipe B, when Pipe B suddenly rolled towards Pipe A. The toppled Pipe B crushed and killed the worker.
Both pipes were about 300mm in diameter and weighed several tonnes. Each pipe was welded with supporting shoes at interval spacing of about 6m and rested on supporting I-beams. At various shoe locations on Pipe B, two brackets were welded to the I-beam to hold the shoe in place, and restrict the lateral movement of the pipe. The shoes were not permanently fixed to the I-beams to allow for longitudinal movements due to thermal expansion and contraction. At some of the shoe locations, timber blocks were also placed between the lateral restraining brackets. As the height of the timber blocks exceeded the height of the brackets, the pipe shoes were resting on the timber blocks and not secured by the brackets.
Recommendations*
1. Conduct risk assessment: Risk assessment must be carried out before starting any work. Through risk assessment, employers and employees can identify potential hazards and take appropriate actions to eliminate or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the employees involved. Risk assessment should also cover non-routine or emergency situations, so that measures can be planned for such situations. Potential hazards for this incident include:
- Unstable placement of pipes on timber blocks.
- Unsecured pipe that is not braced against toppling.
2. Implement Safety and Health Management System: It is important for the Management to put in place an effective workplace safety and health management programme to guide the establishment of a safety management system and proper work procedures. Some of the elements in a WSH Management Programme include:
- Risk management - As explained, proper risk assessment should be conducted to identify hazards and mitigate risks
- Safe work procedures - Establish safe work procedures for carrying out the task safely. Ensure proper supervision and implementation of the safe work procedures for the task. Supervisors should provide direct and close supervision of the tasks performed by the workers under their charge
- Safety training – All workers should be adequately trained in order for them to perform their work competently. They should also be properly briefed so that they are aware of the safety and health issues.
- Communication of safety and health issues – The safety management plans and work procedures should be clearly communicated to all supervisors and workers (e.g. at the daily toolbox meetings)
2. Secure pipes: Ensure that safety measures are in place. Pipes should be adequately secured, or restrained from uncontrolled movement, e.g. with the use of chain blocks before the start of any work.
3. Ensure effective communication channels: The occupier should put in place a good and effective communication system. This is to ensure that the different contractors are regularly updated and aware of the progress of on-going works and safety issues around the worksite, e.g. checking whether the adjacent pipes have been fully installed before commencing grinding / polishing work.
Both pipes were about 300mm in diameter and weighed several tonnes. Each pipe was welded with supporting shoes at interval spacing of about 6m and rested on supporting I-beams. At various shoe locations on Pipe B, two brackets were welded to the I-beam to hold the shoe in place, and restrict the lateral movement of the pipe. The shoes were not permanently fixed to the I-beams to allow for longitudinal movements due to thermal expansion and contraction. At some of the shoe locations, timber blocks were also placed between the lateral restraining brackets. As the height of the timber blocks exceeded the height of the brackets, the pipe shoes were resting on the timber blocks and not secured by the brackets.
Recommendations*
1. Conduct risk assessment: Risk assessment must be carried out before starting any work. Through risk assessment, employers and employees can identify potential hazards and take appropriate actions to eliminate or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the employees involved. Risk assessment should also cover non-routine or emergency situations, so that measures can be planned for such situations. Potential hazards for this incident include:
- Unstable placement of pipes on timber blocks.
- Unsecured pipe that is not braced against toppling.
2. Implement Safety and Health Management System: It is important for the Management to put in place an effective workplace safety and health management programme to guide the establishment of a safety management system and proper work procedures. Some of the elements in a WSH Management Programme include:
- Risk management - As explained, proper risk assessment should be conducted to identify hazards and mitigate risks
- Safe work procedures - Establish safe work procedures for carrying out the task safely. Ensure proper supervision and implementation of the safe work procedures for the task. Supervisors should provide direct and close supervision of the tasks performed by the workers under their charge
- Safety training – All workers should be adequately trained in order for them to perform their work competently. They should also be properly briefed so that they are aware of the safety and health issues.
- Communication of safety and health issues – The safety management plans and work procedures should be clearly communicated to all supervisors and workers (e.g. at the daily toolbox meetings)
2. Secure pipes: Ensure that safety measures are in place. Pipes should be adequately secured, or restrained from uncontrolled movement, e.g. with the use of chain blocks before the start of any work.
3. Ensure effective communication channels: The occupier should put in place a good and effective communication system. This is to ensure that the different contractors are regularly updated and aware of the progress of on-going works and safety issues around the worksite, e.g. checking whether the adjacent pipes have been fully installed before commencing grinding / polishing work.
Worker killed by Toppled Formwork
On the day of the incident, a group of workers was deployed to carry out formwork installation. The formwork was supported by out-riggers and timber props. When a section of the formwork was lifted away, the remaining formwork collapsed and toppled onto a worker. He subsequently died from his injuries.
Recommendations*
1. Conduct risk assessment: Prior to the commencement of work, a risk assessment should be carried out to determine the potential hazards and risks that might arise during the installation of formwork. Control measures and safe work procedures must be established to mitigate the risks, and be communicated and implemented to ensure the safety and health of the workers involved.
2. Secure formwork: The Workplace Safety and Health (Construction) Regulations requires that measures to be taken to ensure the stability of any formwork structure or parts of the formwork structure. All formwork components should be properly tied, footed, braced and supported to prevent toppling whether it is during erection or when it is not in use. Where original out-riggers provided by manufacturers as part of its design is used for bracing of formwork, such props or shores shall not be replaced with other forms of support not designed for or provided by the manufacturer.
3. Cordon off work area: Workers who are not directly involved in the formwork installation should be advised to keep away from the vicinity while formwork structures are being erected, or where there are placement of concrete or lifting of formwork sections. Appropriate measures such as the erection of proper barricades and warning signs, and briefing of workers should be carried out prior to the commencement of work. Workers should also stay away from the lifting zone and from any objects that are planned to be lifted.
4. Ensure supervision: A formwork supervisor should be present to oversee the proper erection of the formwork at site. Where an unsafe condition is discovered by the supervisor, the occupier should be notified immediately to rectify the situation.
Recommendations*
1. Conduct risk assessment: Prior to the commencement of work, a risk assessment should be carried out to determine the potential hazards and risks that might arise during the installation of formwork. Control measures and safe work procedures must be established to mitigate the risks, and be communicated and implemented to ensure the safety and health of the workers involved.
2. Secure formwork: The Workplace Safety and Health (Construction) Regulations requires that measures to be taken to ensure the stability of any formwork structure or parts of the formwork structure. All formwork components should be properly tied, footed, braced and supported to prevent toppling whether it is during erection or when it is not in use. Where original out-riggers provided by manufacturers as part of its design is used for bracing of formwork, such props or shores shall not be replaced with other forms of support not designed for or provided by the manufacturer.
3. Cordon off work area: Workers who are not directly involved in the formwork installation should be advised to keep away from the vicinity while formwork structures are being erected, or where there are placement of concrete or lifting of formwork sections. Appropriate measures such as the erection of proper barricades and warning signs, and briefing of workers should be carried out prior to the commencement of work. Workers should also stay away from the lifting zone and from any objects that are planned to be lifted.
4. Ensure supervision: A formwork supervisor should be present to oversee the proper erection of the formwork at site. Where an unsafe condition is discovered by the supervisor, the occupier should be notified immediately to rectify the situation.
Worker Crushed by Steel Frame Structure
A worker was killed when a steel frame structure weighing more than 250kg toppled and crushed him. The worker was reportedly carrying out welding works on the steel frame structure made with square hollow sections when the incident happened. To facilitate welding works, the worker, together with 3 other workers, manually tilted the frame structure to reposition it on its side. As they were doing so, the frame slipped, toppled and struck the worker. The other 3 workers were unhurt.
Recommendations*
1. Conduct risk assessment: Prior to the start of work, conduct a proper risk assessment to identify all potential hazards and the risks involved. Appropriate action must be taken to eliminate the hazards or to mitigate the risks. Some of the hazards relevant to this incident include:
Manual manoeuvring and handling of unsupported heavy structure
Unsafe positioning of workers while manoeuvring the structure
Castor wheels of the structure not equipped with effective locking devices, or the locking devices not properly engaged while work is being carried out.
2. Establish safe work procedures: Appropriate control measures and safe work procedures for welding operations, taking into consideration any manual manoeuvring of the structure, must be established, communicated and implemented to ensure the safety and health of the workers involved. As far as is reasonably practical, eliminate the need for workers to manually handle or re-position heavy objects (e.g. employ the use of proper lifting equipment).
3. Proper lifting and supporting system: Implement a proper system to lift, support and maneuver heavy object through the use of appropriate equipment such as chain block with correct load rating or crane to prevent it from collapsing. Metal forks can also be used to prop up structures, and prevent them from toppling during manual positioning operations (see figures 1 and 2 below).
4. Safe positioning of workers: Workers should position themselves such that they can maintain a firm grip of the object when it is being manoeuvred. This will allow the workers to have continued control and stability when tilting the object during the lowering process. They should also not stand in the path in which the object is being maneuvered, to prevent the object from collapsing onto them.
5. Adequate training and supervision: Workers must be adequately supervised to ensure that assigned tasks are carried out in a safe manner. The responsibilities of supervisors include regular inspections to identify and manage potential hazards at the worksite. For example, for the incident described above, supervisor should ensure that the castor wheels were equipped with the appropriate locking devices and that they are properly engaged prior to moving the structure. The supervisor should also instruct the workers on safe manoeuvring technique for structures with castor wheels. Adequate training of workers is also required to ensure that they can carry out the work properly and safely.
Recommendations*
1. Conduct risk assessment: Prior to the start of work, conduct a proper risk assessment to identify all potential hazards and the risks involved. Appropriate action must be taken to eliminate the hazards or to mitigate the risks. Some of the hazards relevant to this incident include:
Manual manoeuvring and handling of unsupported heavy structure
Unsafe positioning of workers while manoeuvring the structure
Castor wheels of the structure not equipped with effective locking devices, or the locking devices not properly engaged while work is being carried out.
2. Establish safe work procedures: Appropriate control measures and safe work procedures for welding operations, taking into consideration any manual manoeuvring of the structure, must be established, communicated and implemented to ensure the safety and health of the workers involved. As far as is reasonably practical, eliminate the need for workers to manually handle or re-position heavy objects (e.g. employ the use of proper lifting equipment).
3. Proper lifting and supporting system: Implement a proper system to lift, support and maneuver heavy object through the use of appropriate equipment such as chain block with correct load rating or crane to prevent it from collapsing. Metal forks can also be used to prop up structures, and prevent them from toppling during manual positioning operations (see figures 1 and 2 below).
4. Safe positioning of workers: Workers should position themselves such that they can maintain a firm grip of the object when it is being manoeuvred. This will allow the workers to have continued control and stability when tilting the object during the lowering process. They should also not stand in the path in which the object is being maneuvered, to prevent the object from collapsing onto them.
5. Adequate training and supervision: Workers must be adequately supervised to ensure that assigned tasks are carried out in a safe manner. The responsibilities of supervisors include regular inspections to identify and manage potential hazards at the worksite. For example, for the incident described above, supervisor should ensure that the castor wheels were equipped with the appropriate locking devices and that they are properly engaged prior to moving the structure. The supervisor should also instruct the workers on safe manoeuvring technique for structures with castor wheels. Adequate training of workers is also required to ensure that they can carry out the work properly and safely.
Working in Hot Environment
Workers who are exposed to extreme heat or work in hot environment may be at risk of heat stress. Heat stress can result in heat disorders such as heat stroke, heat exhaustion, or heat cramps. As such, it is important for employers to be able to identify symptoms of heat disorders, and determine the level of thermal stresses that workers are exposed to.
Collapse of Tower Crane during Dismantling Process
A tower crane collapsed while being dismantled at a construction worksite. The incident caused the death of a worker and injured 3 others.
Five workers were dismantling the tower crane using a ‘climbing cage’. During the process, the entire top section of the tower crane fell to the ground. The toppled section included the jib, counter-jib, counterweights, operator’s cabin and the slewing unit. One of the workers fell together with the toppled section of the crane. He was killed, while three other workers were injured.
Recommendations*
1) Conduct risk assessment: Risk assessment must be carried out prior to the start of any tower crane related activities such as the erection, alteration, use, maintenance and dismantling of the equipment. This is to identify the potential hazards and address the risks associated with the activity. Where the risks are significant, appropriate safety measures must be put in place to eliminate or reduce these risks.
Failure to safely erect or dismantle a tower crane may result in serious injuries, or even fatalities arising from the following:
i. crane collapse;
ii. falling objects; and
iii. falls from height while working on top of the tower crane.
2) Follow proper procedures: Only approved crane contractors should be permitted to erect or dismantle a tower crane. The approved crane contractor must erect or dismantle a tower crane in strict accordance with the crane manufacturer’s instructions. These instructions and other necessary safety precautions are found in the manufacturer’s manual. Failure to adhere to the instructions and safety precautions may result in catastrophic consequences, e.g. crane collapse and falls from height.
3) Conduct safety briefing: Before erecting or dismantling a tower crane, a pre-erecting/dismantling briefing should be conducted to ensure that all personnel involved understand their exact roles and responsibilities. This includes communicating to them the correct procedures/sequence of tasks.
4) Ensure workers are trained and qualified: When erecting or dismantling a tower crane, the approved crane contractor should ensure that the worker stationed in the crane’s cabin controlling the crane is a trained and registered crane operator. All personnel involved in the operation must also have received thorough training and instruction in the erection and dismantling procedures for the particular type and model of tower crane. All erection or dismantling operations should be carried out under the immediate supervision of a competent person.
5) Check weather conditions: Some manufacturers specify limiting conditions (such as wind velocity) whereby the tower crane must not be erected, climbed or dismantled. Approved crane contractors should adhere strictly to these conditions.
6) Maintain exclusion zone: Persons not involved in the erection /dismantling operation should be prevented from entering or working in the area of operation. The exclusion zone should be of sufficient size to contain any possible structural failure of the crane.
Five workers were dismantling the tower crane using a ‘climbing cage’. During the process, the entire top section of the tower crane fell to the ground. The toppled section included the jib, counter-jib, counterweights, operator’s cabin and the slewing unit. One of the workers fell together with the toppled section of the crane. He was killed, while three other workers were injured.
Recommendations*
1) Conduct risk assessment: Risk assessment must be carried out prior to the start of any tower crane related activities such as the erection, alteration, use, maintenance and dismantling of the equipment. This is to identify the potential hazards and address the risks associated with the activity. Where the risks are significant, appropriate safety measures must be put in place to eliminate or reduce these risks.
Failure to safely erect or dismantle a tower crane may result in serious injuries, or even fatalities arising from the following:
i. crane collapse;
ii. falling objects; and
iii. falls from height while working on top of the tower crane.
2) Follow proper procedures: Only approved crane contractors should be permitted to erect or dismantle a tower crane. The approved crane contractor must erect or dismantle a tower crane in strict accordance with the crane manufacturer’s instructions. These instructions and other necessary safety precautions are found in the manufacturer’s manual. Failure to adhere to the instructions and safety precautions may result in catastrophic consequences, e.g. crane collapse and falls from height.
3) Conduct safety briefing: Before erecting or dismantling a tower crane, a pre-erecting/dismantling briefing should be conducted to ensure that all personnel involved understand their exact roles and responsibilities. This includes communicating to them the correct procedures/sequence of tasks.
4) Ensure workers are trained and qualified: When erecting or dismantling a tower crane, the approved crane contractor should ensure that the worker stationed in the crane’s cabin controlling the crane is a trained and registered crane operator. All personnel involved in the operation must also have received thorough training and instruction in the erection and dismantling procedures for the particular type and model of tower crane. All erection or dismantling operations should be carried out under the immediate supervision of a competent person.
5) Check weather conditions: Some manufacturers specify limiting conditions (such as wind velocity) whereby the tower crane must not be erected, climbed or dismantled. Approved crane contractors should adhere strictly to these conditions.
6) Maintain exclusion zone: Persons not involved in the erection /dismantling operation should be prevented from entering or working in the area of operation. The exclusion zone should be of sufficient size to contain any possible structural failure of the crane.
Safety in Biologics Manufacturing
Biologics manufacturing is a growing sector within the pharmaceutical industry. Biologics include a wide range of biological products such as vaccines, hormones and antibodies. They are derived from blood, toxins and recombinant proteins using biotechnological means. Biologics manufacturing has its inherent hazards e.g. exposure to biological agents, ultra low temperatures and hazardous chemicals. However, such hazards can be effectively managed by adopting the hierarchy of controls, i.e. elimination, substitution, engineering controls, administrative controls and personal protection.
2 Workers Killed in a Chemical Explosion
An explosion caused the roof of an atmospheric Diethylene Glycol (DEG) storage tank to be blown off. Two workers who were installing nitrogen pipelines on the tank roof at the time of the accident were killed. Investigation is still in progress.
Recommendations
1. Conduct risk assessment: Prior to the start of work, a risk assessment should be carried out to determine the potential hazards and risks that might arise during the installation or replacement of a piping system. DEG has a flash point of 138 ºC (closed cup) and 143 ºC (open cup). Control measures and safe work procedures must be established to mitigate the risks, and be communicated and implemented to ensure the safety and health of the workers involved. Some of the hazards relevant to this incident include:
a) Excessive built-up of pressure in storage tank due to faulty breather valves
b) Hazards associated with hot work
c) Falls from height while working on top of the tank
2. Ensure proper supervision: It is important to ensure that any pipe replacement works are carried out under the close supervision of a competent person with adequate knowledge of the storage system, properties of the substances used and their associated dangers.
3. Establish safe work procedures: Safe work procedures must be appropriately documented to enable workers to identify the valves correctly, and to assist them on the proper steps to operate the different valves safely such that valves will not be opened or closed erroneously.
4. Inspect vessels / pipes regularly: Under the Workplace Safety and Health (General Provisions) Regulations, it is the duty of the owner of a pressure vessel or pipes that contain or convey hazardous substances to ensure that they are properly inspected before use. Thus it is important to inspect the valves, piping systems and storage tanks regularly to ensure that they are in good condition. Faulty valves must be reported to the supervisor who will assess if it is safe to continue with the work.
5. Check storage pressure: Workers are allowed to work on top of a storage tank only if the pressure inside the tank is known and it is safe for them to do so. Appropriate pressure gauges should be installed at strategic locations to indicate the pressure within. Whenever practicable, pressurised tanks should be purged to safe atmospheric pressure level before works are carried out at the top of the tank.
Recommendations
1. Conduct risk assessment: Prior to the start of work, a risk assessment should be carried out to determine the potential hazards and risks that might arise during the installation or replacement of a piping system. DEG has a flash point of 138 ºC (closed cup) and 143 ºC (open cup). Control measures and safe work procedures must be established to mitigate the risks, and be communicated and implemented to ensure the safety and health of the workers involved. Some of the hazards relevant to this incident include:
a) Excessive built-up of pressure in storage tank due to faulty breather valves
b) Hazards associated with hot work
c) Falls from height while working on top of the tank
2. Ensure proper supervision: It is important to ensure that any pipe replacement works are carried out under the close supervision of a competent person with adequate knowledge of the storage system, properties of the substances used and their associated dangers.
3. Establish safe work procedures: Safe work procedures must be appropriately documented to enable workers to identify the valves correctly, and to assist them on the proper steps to operate the different valves safely such that valves will not be opened or closed erroneously.
4. Inspect vessels / pipes regularly: Under the Workplace Safety and Health (General Provisions) Regulations, it is the duty of the owner of a pressure vessel or pipes that contain or convey hazardous substances to ensure that they are properly inspected before use. Thus it is important to inspect the valves, piping systems and storage tanks regularly to ensure that they are in good condition. Faulty valves must be reported to the supervisor who will assess if it is safe to continue with the work.
5. Check storage pressure: Workers are allowed to work on top of a storage tank only if the pressure inside the tank is known and it is safe for them to do so. Appropriate pressure gauges should be installed at strategic locations to indicate the pressure within. Whenever practicable, pressurised tanks should be purged to safe atmospheric pressure level before works are carried out at the top of the tank.
Lead
Lead is a poisonous substance that affects many parts of the body, particularly the nervous system such as the brain and nerves, as well as the blood system and kidneys. Lead poisoning occurs when too much lead enters the body. A person’s body absorbs lead when the person breathes in lead dust, fume or vapour. Eating with bare hands and environmental exposure can contribute to excessive lead absorption. Organic lead compounds can also be absorbed through the skin.
Lead poisoning is an occupational disease that adversely affects workers’ health.
Lead poisoning is an occupational disease that adversely affects workers’ health.
Ammonia in Refrigeration System
Ammonia is commonly used as a commercial refrigerant in large industrial refrigerators. Refrigeration grade ammonia is 99.98% pure. In refrigeration system, ammonia is liquefied under pressure.
Exposure to ammonia could lead to burning of the nose, throat and respiratory tract, skin or eye irritation, and in severe cases, blindness and death, Contact with liquefied ammonia could also lead to fostbite injury and corrosive burns.
Ammonia leaks can occur from corroded pipes, failure of seals and valves, and blockages. These could arise due to lack of safety awareness and procedures, lack of management focus on safety, and poor maintenance regime.
Exposure to ammonia could lead to burning of the nose, throat and respiratory tract, skin or eye irritation, and in severe cases, blindness and death, Contact with liquefied ammonia could also lead to fostbite injury and corrosive burns.
Ammonia leaks can occur from corroded pipes, failure of seals and valves, and blockages. These could arise due to lack of safety awareness and procedures, lack of management focus on safety, and poor maintenance regime.
Safe Installation and Maintenance of Aircon Systems in Highrise Buildings
Many of the air-conditioning (AC) systems of highrise apartments are mounted externally on the side of the building. An example is shown in the photos below.
The installation and maintenance of these external AC units pose various hazards. Access to the AC units is mostly through the windows which, if not managed carefully, can lead to fatal falls for the workers involved in the works. In addition, while work is being carried out, there is a risk of the AC unit, tools or brackets falling off and hitting passers-by below.
To ensure safe installation and maintenance of external AC units, please follow the safety recommendations listed below (list is not exhaustive):
1. Conduct risk assessment: Before the start of work, it is important to conduct an adequate risk assessment to identify all potential hazards and the risks involved. Control measures and safe work procedures must be established and implemented. In this situation of high-rise AC system installation or maintenance, the following should be considered and addressed before starting work:
a. Take steps to prevent the worker from falling from height;
b. Reduce the risk of falling objects;
c. Provide adequate supervision and appropriate personal protective equipment (PPE); and
d. Demarcate the hazardous area and place appropriate warning signs for the public.
2. Ensure proper supervision: It is important to appoint a competent person to supervise the workers. This person should ensure that :
a. Only trained and competent workers are allowed to work in such an elevated location;
b. Safe work procedures are being followed;
c. All reasonable precautions have been taken to mitigate the risk of the worker falling or being hit by falling objects (e.g. ensuring that workers don the appropriate PPE); and
d. Workers are not exposed to other hazards such as electrical hazards, ergonomic hazards, etc.
3. Provide personal protective equipment: Workers should be provided with a work restraint system. This would include the use of safety harnesses or restraint belts. When using safety harnesses or restraint belts, they must be securely anchored to a suitable anchor point or static line. Workers should also be equipped with an appropriate tool carrier harness. This is to secure the tools and prevents any tools from dropping accidentally while the work is being conducted.
4. Cordon off working area: It is necessary to cordon off the area underneath the working area so that it prevents inadvertent public access while work is being done above. Prominent signage is to be provided to alert the public.
The installation and maintenance of these external AC units pose various hazards. Access to the AC units is mostly through the windows which, if not managed carefully, can lead to fatal falls for the workers involved in the works. In addition, while work is being carried out, there is a risk of the AC unit, tools or brackets falling off and hitting passers-by below.
To ensure safe installation and maintenance of external AC units, please follow the safety recommendations listed below (list is not exhaustive):
1. Conduct risk assessment: Before the start of work, it is important to conduct an adequate risk assessment to identify all potential hazards and the risks involved. Control measures and safe work procedures must be established and implemented. In this situation of high-rise AC system installation or maintenance, the following should be considered and addressed before starting work:
a. Take steps to prevent the worker from falling from height;
b. Reduce the risk of falling objects;
c. Provide adequate supervision and appropriate personal protective equipment (PPE); and
d. Demarcate the hazardous area and place appropriate warning signs for the public.
2. Ensure proper supervision: It is important to appoint a competent person to supervise the workers. This person should ensure that :
a. Only trained and competent workers are allowed to work in such an elevated location;
b. Safe work procedures are being followed;
c. All reasonable precautions have been taken to mitigate the risk of the worker falling or being hit by falling objects (e.g. ensuring that workers don the appropriate PPE); and
d. Workers are not exposed to other hazards such as electrical hazards, ergonomic hazards, etc.
3. Provide personal protective equipment: Workers should be provided with a work restraint system. This would include the use of safety harnesses or restraint belts. When using safety harnesses or restraint belts, they must be securely anchored to a suitable anchor point or static line. Workers should also be equipped with an appropriate tool carrier harness. This is to secure the tools and prevents any tools from dropping accidentally while the work is being conducted.
4. Cordon off working area: It is necessary to cordon off the area underneath the working area so that it prevents inadvertent public access while work is being done above. Prominent signage is to be provided to alert the public.
Lifting Supervisor Jailed Four Weeks for Fatal Accident
From Singapore:
On 14 January 2010, a site supervisor was jailed 4 weeks for performing a reckless act that resulted in the death of one worker in a lifting accident on 12 October 2007.
The site supervisor was directly in charge of 20 workers who were involved in demolition and structural works. At the time of the accident, he instructed 2 other workers, including the deceased, to help in the lifting of a timber formwork using a mobile crane. During the lifting, the wire rope used in the lifting gave way. The formwork fell about 9 metres and hit one of the workers.
Investigations found that the trained lifting supervisor failed to ensure that the two workers involved were trained riggers and were properly briefed to perform the lifting activity. He also endangered the workers’ safety by exposing them to falling object hazard during the lifting activity.
The Commissioner for Workplace Safety and Health, Ho Siong Hin, said that the 4-week jail term passed by the Court underscores the gravity of the offence and the importance for supervisors to uphold workplace safety. The accident could have been prevented had the supervisor ensured that the necessary safety precautions were in place.
On 14 January 2010, a site supervisor was jailed 4 weeks for performing a reckless act that resulted in the death of one worker in a lifting accident on 12 October 2007.
The site supervisor was directly in charge of 20 workers who were involved in demolition and structural works. At the time of the accident, he instructed 2 other workers, including the deceased, to help in the lifting of a timber formwork using a mobile crane. During the lifting, the wire rope used in the lifting gave way. The formwork fell about 9 metres and hit one of the workers.
Investigations found that the trained lifting supervisor failed to ensure that the two workers involved were trained riggers and were properly briefed to perform the lifting activity. He also endangered the workers’ safety by exposing them to falling object hazard during the lifting activity.
The Commissioner for Workplace Safety and Health, Ho Siong Hin, said that the 4-week jail term passed by the Court underscores the gravity of the offence and the importance for supervisors to uphold workplace safety. The accident could have been prevented had the supervisor ensured that the necessary safety precautions were in place.
Safe Handling of Compressed Gas Cylinders
Compressed gas cylinders are commonly used in the different industries for a variety of operations. These cylinders are heavy, normally weighing about 80 kilograms each. They are specifically designed to contain gases, such as Oxygen, Nitrogen, Argon, Helium, Carbon Dioxide and Hydrogen. These gases are compressed and stored under high pressure. The gas is released through a valve which regulates its discharge.
Compressed gas cylinders are dangerous because:
• They may contain gas that may be toxic, asphyxiating or flammable. The gas is also stored under high pressure.
• They are usually heavy and can cause injury, such as sprains and strains, if not well handled.
• If the cylinders are tipped, dropped, heated or knocked, they may rupture and explode, sending sharp metal pieces, like shrapnel, blasting through the area.
• The release of pressure from a gas leakage could generate a huge amount of force. It may also propel the cylinder, leading to injuries;
Compressed gas cylinders are dangerous because:
• They may contain gas that may be toxic, asphyxiating or flammable. The gas is also stored under high pressure.
• They are usually heavy and can cause injury, such as sprains and strains, if not well handled.
• If the cylinders are tipped, dropped, heated or knocked, they may rupture and explode, sending sharp metal pieces, like shrapnel, blasting through the area.
• The release of pressure from a gas leakage could generate a huge amount of force. It may also propel the cylinder, leading to injuries;
Ensuring Safe Diving Operations
Commercial diving operations are inherently hazardous. Various hazards, such as tide and current changes, poor visibility and compression and decompression pressure injuries can jeopardise divers’ safety and lead to severe or even fatal injuries.
Accordingly, the risk of diving work activities needs to be effectively managed. Work activities underwater should be conducted in a controlled and safe manner. The diving contractor needs a clear understanding of the task and associated risks. Divers need to be adequately trained and competent to carry out work underwater. The type of equipment used should also be capable of carrying out the task safely, and backup systems should be available to cater for emergencies.
Accordingly, the risk of diving work activities needs to be effectively managed. Work activities underwater should be conducted in a controlled and safe manner. The diving contractor needs a clear understanding of the task and associated risks. Divers need to be adequately trained and competent to carry out work underwater. The type of equipment used should also be capable of carrying out the task safely, and backup systems should be available to cater for emergencies.
Unsafe Roof Work Resulted in Fatality
In recent years, a significant number of workers have been killed while working on roofs. Some of these accidents involved workers stepping on and falling through fragile roofs.
Worker Falling from Height during Lifting Process
A construction worker died after falling off a building under construction while erecting a formwork.
On the incident night, at around 9.40pm, the worker was stationed at the fourth level of a building under construction. An inner formwork was lifted to the same floor by a crawler crane and bolted to the floor slab. The worker then climbed onto the platform of the formwork to remove the 2 attachments for lifting the formwork. After removing them, the worker re-attached the lifting attachments onto the crane slings and the signalman gave the go-ahead for the crane to hoist the slings away.
However, one of the lifting attachments caught the rebar cage beside the formwork. The rebar cage was pulled out of its position by the crane and toppled 20m to the ground below. The worker who had earlier anchored his safety harness to the rebar cage fell together with it.
Recommendations*
For crane operators:
1. Prevent Entanglement of Load Line: Crane operators need to be alert throughout the entire lifting process. Before moving the crane’s load line, the crane operator must ensure that there is no entanglement of load line or slings with objects nearby. If the operator does not have a clear view of the lifting operations, he should adhere closely to the instructions of the signalman. In this incident, the slings (with the attachments) should have been raised sufficiently above the height of the rebar cage before slewing them over the cage.
2. Stop Slewing if movement is not smooth: The crane operator should avoid sudden movements of the load line at high speed. Start any lifting process slowly so that any abnormalities can be detected. If the operator feels abnormal resistance to the crane’s movement, he should halt the process and check (with the aid of the signalman) for possible entanglement.
For lifting crew:
3. Lifting Signalman: Lifting signalman must stay alert throughout the lifting operation, particularly during slewing of the load line. He must halt the lifting process immediately in the event of a load line entanglement.
4. Effective Communication: A system must be in place to ensure effective communication between lifting personnel, particularly between the operator and signalman. This could be done through:
• Hand signals if the signalman is in clear sight of the crane operator
• Suitable communication equipment such as walkie talkies. It is important that the operator and signalman can speak and understand a common language.
General recommendations:
5. Conduct Risk Assessment: Prior to the start of work, conduct an adequate risk assessment to identify all potential hazards and the risks involved. Appropriate control measures and safe work procedures must be established and implemented. For this case, some of the potential hazards include:
• Possible entanglement of load line with surrounding structures
• Poor visibility due to inadequate lighting
• Ineffective communications between signalman and crane operator
6. Safe Lifting Procedure: Companies should put in place procedures to mitigate the risk of load line getting entangled with the surrounding structures. These could include ensuring that:
• Lifting signalman have clear sight of the lifting process at all time
• Lifting signalman give clear instructions to crane operator
• There is sufficient lighting to ensure good visibility of the lifting process, especially if the work is carried out at night
7. Safe working at height: Companies involved in works carried out at height must implement appropriate fall protection measures for workers. When fall arrest systems are utilised, proper anchorage points or anchorage systems must be made available. In addition, if works are to be carried out at night, sufficient lighting must be provided.
On the incident night, at around 9.40pm, the worker was stationed at the fourth level of a building under construction. An inner formwork was lifted to the same floor by a crawler crane and bolted to the floor slab. The worker then climbed onto the platform of the formwork to remove the 2 attachments for lifting the formwork. After removing them, the worker re-attached the lifting attachments onto the crane slings and the signalman gave the go-ahead for the crane to hoist the slings away.
However, one of the lifting attachments caught the rebar cage beside the formwork. The rebar cage was pulled out of its position by the crane and toppled 20m to the ground below. The worker who had earlier anchored his safety harness to the rebar cage fell together with it.
Recommendations*
For crane operators:
1. Prevent Entanglement of Load Line: Crane operators need to be alert throughout the entire lifting process. Before moving the crane’s load line, the crane operator must ensure that there is no entanglement of load line or slings with objects nearby. If the operator does not have a clear view of the lifting operations, he should adhere closely to the instructions of the signalman. In this incident, the slings (with the attachments) should have been raised sufficiently above the height of the rebar cage before slewing them over the cage.
2. Stop Slewing if movement is not smooth: The crane operator should avoid sudden movements of the load line at high speed. Start any lifting process slowly so that any abnormalities can be detected. If the operator feels abnormal resistance to the crane’s movement, he should halt the process and check (with the aid of the signalman) for possible entanglement.
For lifting crew:
3. Lifting Signalman: Lifting signalman must stay alert throughout the lifting operation, particularly during slewing of the load line. He must halt the lifting process immediately in the event of a load line entanglement.
4. Effective Communication: A system must be in place to ensure effective communication between lifting personnel, particularly between the operator and signalman. This could be done through:
• Hand signals if the signalman is in clear sight of the crane operator
• Suitable communication equipment such as walkie talkies. It is important that the operator and signalman can speak and understand a common language.
General recommendations:
5. Conduct Risk Assessment: Prior to the start of work, conduct an adequate risk assessment to identify all potential hazards and the risks involved. Appropriate control measures and safe work procedures must be established and implemented. For this case, some of the potential hazards include:
• Possible entanglement of load line with surrounding structures
• Poor visibility due to inadequate lighting
• Ineffective communications between signalman and crane operator
6. Safe Lifting Procedure: Companies should put in place procedures to mitigate the risk of load line getting entangled with the surrounding structures. These could include ensuring that:
• Lifting signalman have clear sight of the lifting process at all time
• Lifting signalman give clear instructions to crane operator
• There is sufficient lighting to ensure good visibility of the lifting process, especially if the work is carried out at night
7. Safe working at height: Companies involved in works carried out at height must implement appropriate fall protection measures for workers. When fall arrest systems are utilised, proper anchorage points or anchorage systems must be made available. In addition, if works are to be carried out at night, sufficient lighting must be provided.
Shutting of Door on Worker at the Drill Floor
In this incident, workers were deployed to carry out grinding work on the drill floor of an offshore drilling rig. One of them was assigned to grind the “I” beams of a collapsible door on the drill floor. The door consisted of 2 heavy steel panels which could be swung open upwards, and secured in the open position with a security pin. The worker was later found with his head trapped between the 2 door panels. He was sent to hospital where he subsequently succumbed to his head injury.
Summary of Findings:
Investigations revealed that the worker did not secure the heavy steel door in the proper manner. Instead of the security pin, a piece of wire was found attached to the door panel. The wire was not strong enough to hold the heavy door panel, and led to the door panel shutting down on the worker.
Summary of Findings:
Investigations revealed that the worker did not secure the heavy steel door in the proper manner. Instead of the security pin, a piece of wire was found attached to the door panel. The wire was not strong enough to hold the heavy door panel, and led to the door panel shutting down on the worker.
Possible Case of Electrocution
In a recent incident, a worker was deployed to rectify a fault reported during the operation of a tower crane boom. The crane operator was in his cabin waiting for the repair work to be completed. When the cabin fan stopped unexpectedly, the operator looked out and saw the worker lying motionless on the platform in front of the control panel box.
Investigations showed that the worker was probably trying to measure or check the electrical installation inside the control panel box using multi-meter probes (an electrical measurement tool). The burnt marks and strands of hair found stuck on two of the connectors inside the control panel box suggest that he could have been electrocuted and died on the spot.
1. Conduct risk assessment: Prior to the start of any work, risk assessment must be carried out by employers and workers to identify potential hazards. Appropriate actions should then be taken to eliminate the hazards or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers involved. Some of the hazards relevant to this incident include:
a. Exposed wires/connectors/terminals that are still energized and “live”
b. Working at height while troubleshooting the fault
2. Live testing precautions: Before performing any electrical work, one should ensure that the work can be done without the system being energised. Work on or near live conductors should be avoided. Should live testing be necessary to trace a malfunction of the equipment, suitable safety precautions should be taken, including putting temporary insulating neoprene or polythene sheets over live components and/or applying insulation to parts that are at earth potential. These temporary insulating sheets can also help to prevent the risk of accidental short circuit from tools, components and conductors.
3. Use of dry rubber insulating mat: Where there is the possibility of electrocution, workers should be asked to use dry rubber insulating mats. The rubber mat insulates the floor on which the person stands, reducing the risk of the flow of electrical current through the person. Other electrical insulation methods such as rubber blankets, gloves, sleeves, properly designed and rubber-soled boots may also be used.
4. Provision of adequate training: All workers should be adequately trained in the identification and control of hazards in their workplace. Specialized electrical safety training must be provided to those who may need to work with or around exposed components of electric circuits. The training should include, but not be limited to, basic electrical theory, proper safe work procedures, hazard awareness and identification, proper use of personal protective equipment, proper lockout/ tagout procedures, first aid including CPR, and proper rescue procedures. Provisions should also be made for periodic re-training.
5. Buddy system: For certain electrical works, it is recommended to implement a buddy system. In an emergency, the buddy (i.e. a co-worker) could switch off the electrical supply immediately and render assistance on site.
6. Lock-out procedures: Lock out procedures must be established and implemented for the inspection, repair and maintenance of any machinery or equipment. All energy sources to the relevant machinery or equipment should be isolated, disconnected or discharged to prevent any part of the machinery or equipment from being inadvertently activated or energised.
7. Personal protective equipment: Those who are potentially exposed to live components should be provided with appropriate protective clothing and equipment, such as electrical protective resistance glove for measurement and testing work. Such equipment should be inspected regularly by a competent person. Those working at height (e.g. on platform) must also be provided with a proper fall protection system, incorporating safety harness and secured anchor points to reduce the risk of falling.
Investigations showed that the worker was probably trying to measure or check the electrical installation inside the control panel box using multi-meter probes (an electrical measurement tool). The burnt marks and strands of hair found stuck on two of the connectors inside the control panel box suggest that he could have been electrocuted and died on the spot.
1. Conduct risk assessment: Prior to the start of any work, risk assessment must be carried out by employers and workers to identify potential hazards. Appropriate actions should then be taken to eliminate the hazards or reduce the risks involved. Control measures and safe work procedures must be established, communicated and implemented to ensure the safety and health of the workers involved. Some of the hazards relevant to this incident include:
a. Exposed wires/connectors/terminals that are still energized and “live”
b. Working at height while troubleshooting the fault
2. Live testing precautions: Before performing any electrical work, one should ensure that the work can be done without the system being energised. Work on or near live conductors should be avoided. Should live testing be necessary to trace a malfunction of the equipment, suitable safety precautions should be taken, including putting temporary insulating neoprene or polythene sheets over live components and/or applying insulation to parts that are at earth potential. These temporary insulating sheets can also help to prevent the risk of accidental short circuit from tools, components and conductors.
3. Use of dry rubber insulating mat: Where there is the possibility of electrocution, workers should be asked to use dry rubber insulating mats. The rubber mat insulates the floor on which the person stands, reducing the risk of the flow of electrical current through the person. Other electrical insulation methods such as rubber blankets, gloves, sleeves, properly designed and rubber-soled boots may also be used.
4. Provision of adequate training: All workers should be adequately trained in the identification and control of hazards in their workplace. Specialized electrical safety training must be provided to those who may need to work with or around exposed components of electric circuits. The training should include, but not be limited to, basic electrical theory, proper safe work procedures, hazard awareness and identification, proper use of personal protective equipment, proper lockout/ tagout procedures, first aid including CPR, and proper rescue procedures. Provisions should also be made for periodic re-training.
5. Buddy system: For certain electrical works, it is recommended to implement a buddy system. In an emergency, the buddy (i.e. a co-worker) could switch off the electrical supply immediately and render assistance on site.
6. Lock-out procedures: Lock out procedures must be established and implemented for the inspection, repair and maintenance of any machinery or equipment. All energy sources to the relevant machinery or equipment should be isolated, disconnected or discharged to prevent any part of the machinery or equipment from being inadvertently activated or energised.
7. Personal protective equipment: Those who are potentially exposed to live components should be provided with appropriate protective clothing and equipment, such as electrical protective resistance glove for measurement and testing work. Such equipment should be inspected regularly by a competent person. Those working at height (e.g. on platform) must also be provided with a proper fall protection system, incorporating safety harness and secured anchor points to reduce the risk of falling.
Safety Guidelines for use of Gondolas
There were two recent accidents involving the use of gondolas, resulting in one worker injured and another killed.
Three key learning points are highlighted on the safe use of gondolas:
(i) Ensure the gondolas are properly designed, installed and tested
(ii) Ensure the regular inspection and maintenance of gondolas in accordance with the manufacturer’s recommendations
(iii) Provide adequate fall protection measures for workers on gondolas
Three key learning points are highlighted on the safe use of gondolas:
(i) Ensure the gondolas are properly designed, installed and tested
(ii) Ensure the regular inspection and maintenance of gondolas in accordance with the manufacturer’s recommendations
(iii) Provide adequate fall protection measures for workers on gondolas
Fatigue Attributed to the Death of a Prime Mover Driver
In this incident, a Terminal Prime Mover (TPM-2) in a container port swerved and collided onto the rear of another TPM (TPM-1) travelling in the opposite direction. As a result of the collision, the driver of TPM-2 was thrown out of the cabin and subsequently died in hospital.
Summary of Findings:
Investigation revealed that the incident occurred primarily due to Man (driver of TPM-2), with Management as a contributory factor. The driver did not take care of his own safety and health by adhering to the "Compulsory Short Break" (CSB) as required by the Management. He also did not fasten his seat belt, and the fatigue arising from long hours of work might have caused him to lose control of his TPM, and prevent him from applying the emergency brake in time.
Management contributed to the incident by not having a well designed work schedule for the drivers. Although Management instituted a good concept in CSB, it was inadequate for the drivers to recuperate sufficiently.
Summary of Findings:
Investigation revealed that the incident occurred primarily due to Man (driver of TPM-2), with Management as a contributory factor. The driver did not take care of his own safety and health by adhering to the "Compulsory Short Break" (CSB) as required by the Management. He also did not fasten his seat belt, and the fatigue arising from long hours of work might have caused him to lose control of his TPM, and prevent him from applying the emergency brake in time.
Management contributed to the incident by not having a well designed work schedule for the drivers. Although Management instituted a good concept in CSB, it was inadequate for the drivers to recuperate sufficiently.
Fall from Height
In a recent accident, a worker fell to his death while climbing the turntable ladder to the crane cabin of a tower crane. The lifeline was terminated at the top mast, and the worker had removed his safety harness when climbing from the turntable to the cabin. While he was ascending the turntable ladder, the worker slipped and fell onto the mast platform 6 m below.
Recommendations*
1. Conduct risk assessment before starting any work: Identify potential hazards and take appropriate actions to eliminate the hazards or reduce the risks involved. For this incident, the hazards include the failure to don proper Personal Protection Equipment (PPE). The risk assessment should also include non-routine or emergency situations so that measures can be adopted to minimise the risks for such situations.
2. Put in place an effective workplace safety and health management programme: Employers should establish and implement a Safety and Health policy, and safety management system with proper control measures and safe work procedures. This includes a fall protection plan for any work that may involve workers falling from a height. The safety and health programme must be clearly communicated to all levels of personnel, such as through refresher courses or daily tool box meetings.
3. Safe access on tower cranes: To prevent falls, employers must provide safe access for crane operators and other persons who need to carry out inspection and maintenance work on a tower crane. Safe access (ladders with hoop guards) to the operator’s cabin should include rest-landings at every interval not exceeding nine metres of the mast. If a mast has a continuous vertical ladder for access, an effective fall-arrest system that does not require the person to constantly hook on and off must be provided.
4. Issue appropriate PPE: Workers must be issued the appropriate PPE, such as full body harness that is securely anchored (through lanyard, shock absorbers and hook) at all times to protect against accidental falls. Additional lifeline should be employed specifically for the turntable to prevent falls. The workers must be trained on the safe and proper use of the PPE.
5. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who exhibit unsafe acts and do not comply with the safe work procedures.
Recommendations*
1. Conduct risk assessment before starting any work: Identify potential hazards and take appropriate actions to eliminate the hazards or reduce the risks involved. For this incident, the hazards include the failure to don proper Personal Protection Equipment (PPE). The risk assessment should also include non-routine or emergency situations so that measures can be adopted to minimise the risks for such situations.
2. Put in place an effective workplace safety and health management programme: Employers should establish and implement a Safety and Health policy, and safety management system with proper control measures and safe work procedures. This includes a fall protection plan for any work that may involve workers falling from a height. The safety and health programme must be clearly communicated to all levels of personnel, such as through refresher courses or daily tool box meetings.
3. Safe access on tower cranes: To prevent falls, employers must provide safe access for crane operators and other persons who need to carry out inspection and maintenance work on a tower crane. Safe access (ladders with hoop guards) to the operator’s cabin should include rest-landings at every interval not exceeding nine metres of the mast. If a mast has a continuous vertical ladder for access, an effective fall-arrest system that does not require the person to constantly hook on and off must be provided.
4. Issue appropriate PPE: Workers must be issued the appropriate PPE, such as full body harness that is securely anchored (through lanyard, shock absorbers and hook) at all times to protect against accidental falls. Additional lifeline should be employed specifically for the turntable to prevent falls. The workers must be trained on the safe and proper use of the PPE.
5. Ensure proper supervision: Employers should ensure that workers adhere to the established safe work procedures, e.g. by ensuring that workers follow the fall protection plan when working at height and disciplining workers who exhibit unsafe acts and do not comply with the safe work procedures.
Dust Control at Demolition Sites
Demolition work involves hacking, crushing, and cutting, which can generate large amount of dust and debris. If poorly managed, the clouds of dust can contain particulate emissions that may be hazardous to human health. They may also reduce visibility, delay demolition activities and cause property damage.
Working Safely with Electrical Equipment
Electricity is part and parcel of our daily lives, but it can cause significant danger or harm if mishandled. Accidents can be caused by electrical hazards such as defective equipment, damaged electrical cords, exposed wires, overloaded circuits and wet conditions. It is therefore important for all staff working at or near electrical equipment to understand basic electrical safety and adopt the necessary precautionary measures.
Flash Fire in Confined Space
In this incident, a team of 6 workers was doing roller painting in a confined space when a flash fire occurred. All the workers managed to climb out of the confined space. 4 of the workers sustained burns while 2 others were unhurt. One of the injured workers died later due to complications arising from inhalational injury and extensive burns.
Summary of Findings:
Investigations revealed that the flash fire was caused by the accumulation of flammable vapours and the use of poorly maintained non-flame proof lighting in the confined space. The preparation of the paint mixture in the confined space had accelerated the accumulation of flammable vapours, which could not be effectively diluted by the forced ventilation provided. There were no established procedures for eliminating the risk of vapour accumulation, and for the continuous monitoring of flammable vapour levels. Properly maintained flame proof lighting was also not provided.
Summary of Findings:
Investigations revealed that the flash fire was caused by the accumulation of flammable vapours and the use of poorly maintained non-flame proof lighting in the confined space. The preparation of the paint mixture in the confined space had accelerated the accumulation of flammable vapours, which could not be effectively diluted by the forced ventilation provided. There were no established procedures for eliminating the risk of vapour accumulation, and for the continuous monitoring of flammable vapour levels. Properly maintained flame proof lighting was also not provided.
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