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High Priorities

Published: 27th Nov 2013 in OSA Magazine

Developing strategies for safe work at height

Across the world, the need to carry out work at height is increasing. With urban migration, more people are living in the already densely populated areas, land becomes premium, and buildings are constructed in taller dimensions to maximise every liveable and usable space. 

Many of us now live and work in high rise buildings, and the development of spaces at such altitudes is challenging. Building them increases the amount of work at height, which inevitably leads to a higher probability of a fall from height – such accidents remain one of the foremost causes of workplace fatalities in many countries. 

In Singapore, one out of three workplace fatalities was due to the victim falling from height in 2012 – and there were 17 fatal falls from height out of 56 workplace fatalities. While this is a lower number as compared to 2011, where 26 workers died from falling from height out of a total of 61 workplace fatalities, it remains an area of top priority where workplace safety is concerned.

Singapore strategies

In view of this, the industry-led Workplace Safety and Health Council (WSHC) and Ministry of Manpower (MOM) formed a National Work at Height (WAH) Safety Taskforce in August 2009 to address the concern of falls from height at workplaces. The Taskforce took on a more concerted effort to involve all stakeholders and developed a three-pronged plan to improve the safety of work conducted at height across workplaces, namely:

• Building strong capability through providing assistance materials to aid companies to develop fall prevention plans as well as setting national competency standards for working safely at height

• Promoting the benefits of WAH safety through outreach efforts to highlight good practise and the consequences of failure to ensure WAH safety

• Enhancing the intervention framework for WAH through legislation review and extending the enforcement outreach

Following this, in 2013, MOM enacted a set of regulations, the Workplace Safety and Health (Work at Heights) Regulations to help improve safety for work at height. It emphasised the importance of assessing and controlling risks associated with working at height through risk management and the use of a ‘permit to work’ system. 

It also requires certain workplaces to prepare and carry out a fall prevention plan as a means to identify and implement controls for risks related to work at height. To provide further assistance to the industry in making work at height safe, the Code of Practice on Working Safely at Height that was published by the WSHC in 2009 was revised in 2013, in collaboration with the Ministry.

In the ‘Safety Analysis & Recommendation Report on Work at Heights’ jointly published by WSHC, MOM and the Taskforce, it was highlighted that the top three contributing factors leading to fall fatalities are as follows:

• Lack of safe work procedures
• Lack of or improper use of individual fall arrest systems
• Poor working environment

In this paper, we will elaborate on the use of fall prevention or protection systems for personal protection, but it is important to note that such systems belong to the last line of defence in the hierarchy of control. Designing or engineering out the risk of falling should always be attempted first. Only in situations where such methods prove not to be reasonably practicable, should fall prevention or protection systems be used.

Falls from height are often difficult to survive, since a fall typically causes a large amount of blunt force trauma, which leads to multiple fractures and large amounts of bleeding.

Surviving a fall without the intervention of any control measures is usually merely due to chance. 

Control measures are broadly classified into two categories: those that provide collective protection and those that provide protection on a personal or individual level. Collective protection refers to measures that protect every person when they are implemented. Such measures are usually also passive, requiring no interaction or additional training for the persons to be protected. An example of collective protection would be the use of barricades or guard rails to prevent persons from falling off an open side. 

Prevention and protection systems

Personal protective equipment (PPE) is the category of control that is listed as the last layer of the hierarchy of control and provides protection on an individual level. PPE requires the user to be trained and to put in effort to carry out safe practises, such as wearing a harness properly and anchoring themselves to an anchorage point in order to be effective. 

PPE can be a good second layer of defence when used in conjunction with other levels of control, or as a short term protective measure for non-routine work.

A fall prevention or protection system consists of three main components: the anchor, the body support and the connections that link them together. 

The anchor can be an individual anchor point, a vertical or horizontal lifeline. The body support is usually a full body harness, with restraint belts and work positioning belts as possible options for other systems other than fall arrest systems. Connections include lanyards, shock absorbers, karabiners, snap hooks and other similar parts. 

All the components must be in good working condition and free from defects. Damaged or malfunctioning parts can cause the entire system to fail to provide the desired functionality.

Hence an inspection and maintenance programme is important to ensure the serviceability of all the components. 

It is also good practise for users to conduct a visual inspection of the components before using any system. Damaged parts must be taken out of circulation. Damaged components made of fabric or similar materials, such as the full body harnesses or lanyards cannot be repaired and must be disposed of or destroyed to prevent misuse. 

Metal components that are damaged may be sent to the manufacturer for inspection but may need to be replaced if they are deemed beyond technical or economical repair. 

PPE designed for working at height can be broadly classified into three main categories: fall arrest, travel restraint, work positioning. It is often easy to underestimate the complexities involved in these systems. 

Where possible, it is best to use a travel restraint system as it is a preventive system, and when it is used correctly, users are completely exempt from any injuries or ill effects. Fall arrest systems can be used in most situations, with the main limitation being fall clearance height. Work positioning is used only in specialised situations and requires a much higher level of skill and competency to use compared to the other two systems.

Fall arrest 

Fall arrest is a type of protection system that works by reducing the severity of the consequence of a fall on the user but not the chance or likelihood of a fall occurring. This is often the type of PPE that most people will think of where work at height is involved, but it is not always the best option. 

The effectiveness of a fall arrest system in its intended role depends on several factors. The anchor point has to be installed properly, the user has to anchor the lanyard correctly onto the anchor point, put the harness on and tighten it sufficiently and there must be sufficient clearance for the system to arrest a fall before striking the ground, or any obstacle, such as a protrusion on a building. Additionally, the energy absorber must deploy in order to soften the impact on the user. If the fall distance is too short, the energy absorber may not deploy properly.

The problem of insufficient fall distance can be circumvented by the use of self-retracting lifelines, which are also known by many other names including fall arrest blocks. A self-retracting lifeline works using a mechanism to keep the lifeline as short as possible, and arrests a fall via a locking mechanism similar to those used in car seat belts. The shortened fall distance decreases the forces exerted on the user. 

Self-retracting lifelines also incorporate an integrated or external shock absorbing component, depending on the model, negating the need for the use of a conventional shock absorber. The use of self-retracting lifelines also eliminates the hazard of users tripping over lanyards trailing along on the floor of the work surface, as the lifeline connects directly to the user’s harness. 

Lanyards must not be used with self-retracting lifelines, as this will result in a larger fall distance, defeating the purpose of using self-retracting lifelines. Self-retracting lifelines are, however,quite costly, which somewhat hinders the widespread usage of these devices. Also, they are usually not designed to work on the horizontal plane, unless specified by the manufacturer.

Lastly, even if a user is protected from a fatal fall by a fall arrest system, he or she may still suffer injuries. This can be compounded if the user is not wearing his harness properly or if the harness is worn too loosely.

Travel restraint

A travel restraint system works by limiting the user’s movement range, making it impossible to move into an area where a fall might accidentally occur. Such systems must be used with careful planning, however.

An improperly implemented travel restraint system can lead to users still being exposed to falling hazards, the situation made worse since they are not wearing the correct PPE.

The absence of an energy absorbing device means the user will experience the full force of a fall, which may cause severe injuries, or even death. 

Also, the anchor of the travel restraint system is usually rated for much lower forces than that of a fall arrest system. In the event of a fall it may be possible for the anchor to give way. Travel restraint systems are also used by operators of mobile elevated work platforms (MEWPs) to prevent any accidental climbing out of the platform’s cage. Hence, while travel restraint is the simplest and most effective type of system for improving safety for work at height, its success requires a high degree of planning and consideration of how the system is to be located. 

In certain circumstances, guard rails may need to be installed to ensure users do not enter unsafe zones. Also, work positioning systems are not suitable for situations where the user needs to carry out work in an area where a fall is likely, such as working on the facade of a building.

Work positioning 

Work positioning is a type of work at height where the user’s PPE is the means of work. For such a system, PPE and the worker’s expertise are the only safety provisions. In a work positioning system, the user makes use of a specific type of harness or belt to secure onto a work surface, which allows him to work using both of his hands. A basic work positioning system, by itself, is not capable of arresting a fall, should it occur, so a fall arrest system should be used in conjunction with the work positioning system to provide adequate protection for the user.

Industrial rope access is considered a highly specialised form of work positioning, usually used for performing work in areas that are difficult to reach. In this type of system, the operator is fully suspended and may be required to make decisions such as re-anchoring, if the situation requires this. This form of work positioning therefore requires a high level of expertise, supervision and training and should commence only after thorough planning and evaluation. 

Due to its versatility, however, it has become an increasingly popular method of working at height in Singapore. For instance, it is now common to see rope access operators doing cleaning work on building facades. It is important to note, however, that industrial rope access operators sometimes make use of hanging platforms and other support equipment.

This is implemented, for example, when it is deemed that the load of the equipment or the stresses created by the work would be too great for industrial rope access methods to be used on their own safely.

Case study

In October 2010, two workers were working on a scissor lift at a train station. They were lowering the scissor lift’s platform in order to move the lift to another work location when one side of the lift suddenly collapsed.

Both of the workers were thrown into the air but were saved from falling onto the ground below by the anchored safety harnesses they wore. Also, one of them was protected from injuries by the hard hat he was wearing when his head struck a nearby wall during the fall.

They were rescued by their co-workers, and underwent medical checks to ensure they were unharmed and were able to work again the next day. If they were not wearing their safety harnesses or did not anchor them properly, this incident might not have ended on such a happy note.

Human factors in using PPE

From one study, the lack of or improper use of individual fall arrest systems was identified as the second most common contributing factor to falls from height incidents. About one third of the incidents were due to workers not anchoring their individual fall arrest system, even though the anchor points were provided. Another one third was due to workers not wearing the individual fall arrest system provided. This indicates that the ‘human factor’, characterised by inconsistency and non-compliance, is a very important consideration in the successful use of PPE to make work at height safe. It can be classified in four main areas: 

Adherence – Whether or not the user uses the PPE as intended by the designer or manufacturer. Training and supervision is important to ensure that users know how to use the equipment correctly and continue using it in the intended manner. 

Compatibility – Whether or not the equipment selected is adequate or suitable for the task and the work conditions, such as clearance height and adverse conditions. For example, exposure to hot sparks or sharp edges which can damage the harness and compromise integrity of the equipment. Additionally, harnesses are sometimes worn at the same time with other PPE, such as luminous vests. In this particular case, the body harness should be worn over the vest, so that the functionality of the harness is not affected.

Ergonomics and ease of use – Fall arrest equipment requires a certain – high – degree of competence to use properly and safely. The system used should be as simple as reasonably practicable, so that the chance of unsafe usage is lessened, such as using incompatible parts in a single system.

Comfort – Comfort is more of an issue when the duration of the work is long. An uncomfortable body harness may end up being removed and cause the user to be at risk of falling from height. This is why the user must be taught properly the right way to wear the body harness – the harness must be tightened sufficiently but not so tight that it affects the user’s cardiovascular system.

Conclusion

In conclusion, work at height can be rendered safe through thorough risk assessment and implementing suitable control measures. Each work location has unique conditions and challenges that need to be dealt with individually. Planning and selection is critical to determine the success of control measures. 

It is better to implement collective, passive systems that do not require interaction by or training of the persons involved. When PPE is used, the user must be educated in its use and must follow safe practises to ensure that the equipment will safeguard them against injury or death. 

Published: 27th Nov 2013 in OSA Magazine

Author


Morris Hiang


Morris Hiang, Manager (WSH Practices)

About WSHC

The Workplace Safety and Health Council was established on April 1, 2008. It comprises 18 leaders from the major industry sectors, including construction, manufacturing, marine, petrochemicals and logistics, the government, unions and professionals from the legal, insurance and academic fields.

The Council works closely with the Ministry of Manpower (MOM) and other government agencies, the industry, unions and professional associations to develop strategies to raise workplace safety and health (WSH) standards in Singapore, and to realise the national WSH 2018 strategy.

The Council's main functions are to build industry capabilities to better manage WSH, promote safety and health at work and recognise companies with good WSH records and set acceptable WSH practises.


morris_hiang@wshc.gov.sg
http://www.wshc.sg

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