Worker Crushed by Toppled Pipe

WSH Alert - 9 Jun 2010, Ref: 1011024

Incident

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.

Figure 1. Pipe B toppled and crushed the worker.

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 Fell from Mezzanine Floor

WSH Alert - 26 May 2010

Incident

In this incident, a worker was found dead on the ground beside the staircase of a factory. He was alone in the premises when the incident happened. A stool was found at the mid landing of the staircase. It is suspected that the worker might have tried to access a resting area on the mezzanine floor by using the stool to climb over the handrail of the staircase. He could then have fallen from the open side of the unbarricaded mezzanine floor and landed on the ground 3m below.

Recommendations*

1. Provide safe means of access or egress: The Workplace and Safety Health Act (WSHA) stipulates that the occupier has to take reasonably practicable measures to ensure that the workplace and all means of access to or egress from the workplace are safe. For this incident, there was no safe and proper access to the mezzanine floor, except by climbing over the staircase.

2. Conduct risk assessment: Proper risk assessments should be conducted to identify all potential hazards and risks. Appropriate actions must be taken to eliminate the hazards or to mitigate the risks. Some of the hazards relevant to this case include:

1. Lack of proper and safe means of access to the resting area;
2. Lack of proper and safe means of access to the stored materials (e.g. the veneer and wooden planks) at the mezzanine floor beside the resting area;
3. Lack of proper handhold and barricade at the mezzanine level; and
4. Improper storage of materials which could lead to them toppling.

3. Provide and maintain safe arrangements and facilities: Employers are also required under the WSHA to take reasonably practicable measures to protect the safety and health of employees. This includes maintaining the facilities and providing safe arrangements to ensure their welfare at work. In this incident, such measures could include:

1. Ensuring that the workers’ resting areas are adequate, safe and without risk (e.g. properly barricaded); and
2. Ensuring that workers are not exposed to hazards from the storage of materials beside the resting area.

4. Establish safe work procedures: Appropriate control measures and safe work procedures, such as on accessing and moving materials from the storage area, must be properly established, communicated and implemented to ensure the safety and health of the workers involved.

5. Proper storage of goods: All goods, articles and substances in a workplace should be properly stored, stack or placed:

• in such as manner as not to obstruct the use of passageways;
• on a firm foundation not liable to settle;
• in such manner as not to overload the foundation or floors;
• using appropriate supporting structures to ensure their stability; and
• not against a wall or partition unless they are of sufficient strength to withstand the pressure.

Bound materials should also be placed on racks, and secured by stacking, blocking, or interlocking to prevent them from sliding, falling, or collapsing.

Further Information

1. Workplace Safety and Health Act (Chapter 354A)
2. Workplace Safety and Health (General Provisions) Regulations
3. Workplace Safety and Health (Risk Management) Regulations
4. OSHA’s guide on Materials Handling and Storing, please click HERE.

* Please note that the information provided is intended to enhance workplace safety and health so that a similar recurrence may be prevented, and is not exhaustive. The information provided should not to be construed as implying any liability to any party nor should it be taken to encapsulate all the responsibilities and obligations of the reader of WSH Alert under the law.

Worker Crushed by Steel Frame Structure

WSH Alert – 1 Jun 2010, Ref: 1011020

Incident

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 (SWP): 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).

Figure 1: Use of metal fork to prop up metal structures

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.

Further Information

1. Workplace Safety and Health Act (Chapter 354A)
2. Workplace Safety and Health (General Provisions) Regulations
3. Workplace Safety and Health (Risk Management) Regulations
4. Singapore Standard CP 92: 2002 – Code of Practice for Manual Handling
5. Canadian Centre for Occupational Health and Safety – Pick Up Tips on How to Lift Safely, please HERE.

* Please note that the information provided is intended to enhance workplace safety and health so that a similar recurrence may be prevented, and is not exhaustive. The information provided should not to be construed as implying any liability to any party nor should it be taken to encapsulate all the responsibilities and obligations of the reader of WSH Alert under the law.

Worker killed by Toppled Formwork

WSH Alert – 4 Jun 2010

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.

Further Information

1. Workplace Safety and Health Act
2. Workplace Safety and Health (Risk Management) Regulations 2006
3. Workplace Safety and Health (Construction) Regulations
4. Singapore Standard CP 23: 2000 Code of Practice for Formwork

* Please note that the information provided is intended to enhance workplace safety and health so that a similar recurrence may be prevented, and is not exhaustive. The information provided should not to be construed as implying any liability to any party nor should it be taken to encapsulate all the responsibilities and obligations of the reader of WSH Alert under the law.