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Work at Height (WAH) is a key area of concern for workplace safety and health worldwide, as falls from height (FFH) has been the top contributor to workplace deaths over the years. FFH accounted for a significant amount of all workplace fatalities.
Many countries’ occupational health and safety governing authorities have great concern in this area, and establish legal regulatory requirements to provide governance, risk management, and most importantly, the need of risk mitigation measures to prevent harm arising from WAH to workers.
Defining work at height
Work at height is work in any place, including a place at, above, or below ground level, where a person could be injured if they fell from that place. Access and egress to a place of work can also be work at height. Examples of activities that are classified as working at height include:
- Working on scaffolding and mobile elevated work platforms
- Working on an inclined, oddly shaped, or flat roof
- Erecting false work or formwork
- Working on a ladder
- Working at ground level adjacent to an excavation
- Working on formwork within an excavation
- Working near, or adjacent to, fragile materials
- Working near building edges, floor openings, or open sides
- Working on plant, machinery, equipment vehicles or operation facilities at height
Duty of care
The employers, principals, and self-employed persons in all workplaces exercise their due diligence as a duty of care to:
- Conduct Risk Assessments (RA) to identify and control workplace safety and health risks
- Provide safe work environment, facilities and arrangements for workers
- Ensure safety in physical work environment and the work processes that interface machines, equipment, substances used, and work activities carried out
- Provide adequate instruction, information, training and supervision to workers
- Implement risk control measures for dealing with emergencies
Stakeholders should also ensure that all systems and equipment are installed in accordance with the occupational health and safety requirements and best practices for future downstream maintenance. This could mean safe access to cleaning, or delivering/removing heavy parts, such as chiller plants, water tanks, or diesel where standby generators are mounted on roof level (with the provision of a minimum space to carry out maintenance safely and ergonomically). All such considerations should be addressed
in a Maintenance Strategy Report.
Important standards to consider
The European Standards (EN) are technical standards which have been established by one of the three European standards organisations: European Committee for the Standardisation, the European Committee for Electrotechnical Standardisation, or the European Telecommunications Standards Institute.
Examples of EN standards are:
- EN13374:2013 for Temporary Edge Protection Systems – Product specification – test methods
- EN131-1:2015 for Ladders – Part 1 Terms, types, functional sizes
- EN 361:2002: Personal protective equipment against falls from height – Full body harnesses, on the requirements, test methods, marking, manufacturer information, and packaging specifications for full body harnesses
- EN354:2010 Personal fall protection equipment – Lanyards
- EN 355:2002 Personal protective equipment against falls from a height – Energy absorbers
- EN 358:2018 Personal protective equipment for work positioning and prevention of falls from a height
- EN 360:2002 Personal protective equipment against falls from a height – retractable-type fall arresters
The American National Standards Institute (ANSI) is a private non-profit organisation that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States.
These can also include standards from the American Ladder Institute (ALI), American Society of Safety Engineers (ASSE), American Society of Safety Professionals (ASSP), International Organisation of Standardisation (ISO), and the International Safety Equipment Association (ISEA).
Examples of ANSI standards are:
- ANSI/ASSP A10.8-2019 for scaffolding safety, which is designed to provide minimum guidelines for the safe erection, use and dismantling of scaffolding
- ANSI/ASSE A10.18-2007 for temporary roof and floor holes, wall openings, stairway safety, and other unprotected edges in construction and demolition operations.
British Standards (BS) are the standards produced by the British Standard Institute (BSI) Group, incorporated under a royal charter, which is formally designated as the national standards body (NSB) for the United Kingdom.
For example, their BS 8437:2005+A1: 2012 is the code of practice for selection, use and maintenance of personal fall protection systems and equipment for use in the workplace.
Prevention is better than protection
Risk control can be achieved through inherently safer design. Inherently safer design is achieved when FFH hazards are excluded at source by designing out the risks a worker faces while they are at work.
Working at Height can be made inherently safer by plant, building, structural and manufacturer design, by way of hazard avoidance or risk reduction by choosing safe design features, or minimising the interaction between worker and work environment.
Designing a personal fall arrest system
A Personal Fall Arrest System (PFAS) consists of three components:
- Anchorages
- Body Support
- Connections
Also known as the A-B-Cs of fall arrest systems, these components must be properly in place and used correctly in order to provide the expected level of protection.
Anchor devices and anchorages
An anchor is a known fixture or place where you can securely attach lifelines or workers. An anchorage, which can also be called an anchor point, is a part of an anchor that other equipment can be attached to. An anchor device on the other hand, is an element or series of components of a personal fall arrest system, which can feature one or more anchor points.
Body support devices
A full body harness (FBH) is a type of body support device that distributes the force of a fall across the body of the wearer. It is comprised of components such as fittings, straps, buckles and other elements to support the body of a user and restrain them during and after the arrest of a fall. They usually have a fall arrest attachment at the centre back to connect a fall arrest device. The harness may have other fittings for positioning, fall prevention, suspension or ladder climbing.
Classification of full body harnesses
Full body harnesses can be classed under A, D, E and P. At a minimum all FBHs should be Class A, and so should all have at least one fall arrest attachment element. A harness may have extra features depending on the work being operated. These additional attachment elements should only be connected to the controlled descent system, and not to the PFAS.
Class A is for fall arrest – Harnesses should incorporate at least one fall arrest attachment element. The fall arrest attachment element should be positioned so that it lies either at the back of the user or centrally in front of the chest at about sternum height.
Class D is for controlled descent or ascent – Harnesses should have additional attachment elements that allow the user to connect to a controlled descent system. They should have controlled descent and ascent attachment elements incorporated so that the wearer can adopt a rough sitting position while suspended.
Class E is for confined space access – Harnesses should have further attachment elements that allow the wearer to connect to a confined space access system. They should have a sliding attachment element on each shoulder strap to be used as pair, so that the wearer can comfortably assume an almost standing position while in suspended.
Class P is for work positioning – Harnesses should have attachment elements that allow the user to connect to a work positioning system. At least one work positioning attachment element is needed. If only one element is provided, it should lie in the middle of the torso. If more than one element is provided, then they should be placed symmetrically and used in pairs.
Using a full body harness
FBHs can be used for a couple of years (as per the manufacturer’s recommendation) starting from the date they are put into use. After the recommended period, the harness must be withdrawn from use and undergo a manufacturer’s detailed inspection. The inspection can be carried out by:
- The manufacturer of the harness
- Personnel recommended by the manufacturer
- A company recommended by the manufacturer
During inspection, the new admissible time of harness use till the next manufacturer’s inspection will be established. It is important to note that the harness must be withdrawn from use immediately and destroyed when it has been used to arrest a fall.
A harness must be worn correctly for it to protect a worker properly in the event of a fall. Important points to note are:
- The rear or dorsal D-ring should be located between the wearer’s shoulder blades
- The dorsal plate must be in good working condition
- The front chest strap must be fastened correctly
- The wearer must select the correct D-ring orientation
- The FBH must be correctly fitted and neither too loose nor too tight on the wearer
- The harness must be secured properly, as the fall energy could cause the wearer to fall out of the harness
Connectors
Connectors link other personal fall arrest system components together, such as between a lanyard and an anchor. Some connectors have a closure function, such as a screw sleeve or locking device, which is preferred as it provides protection against the accidental opening of a gate. The three main components for connectors, are the body (main device), gate (the attachment system) and locking gear (the closure system, also known as a safety latch).
According to BS EN 362:2004, there are five classes of connectors, namely:
- Class B connectors for general use
- Class M connectors for general use which may be loaded on either the major or minor axis. It is important to note the safe working load for a major and minor axis of a connector (as per manufacturer’s instructions and recommendations)
- Class T connectors come with a captive eye each
- Class A connectors are connectors used for specific type of anchors
- Class Q connectors are closed by a screw-motion gate that is a load-bearing part of the connector
The minimum required static strength of a connector is 20kN, while connectors with self-closing and self-locking gates; for screw-link connector is 25kN, according to BS EN 362: 2004.
Energy absorbers and lanyards
Energy absorbing lanyards, self-retracting lifelines (SRLs), rope grabs and retrieval systems are all critical links between the body support and the anchorages or anchor devices. These connection sub-systems will vary depending on whether the user is equipped for a personal fall arrest, work positioning or travel-restraint system.
For personal fall arrest, you will often find a lanyard equipped with an energy absorbing element to limit the arresting force to 6 kN in the event of a fall. SRLs can also be used as a connection to reduce free fall distance and energy loads from a fall.
For work positioning and travel restraint, a simple lanyard is preferred (with length adjuster) made from rope, web or wire rope.
All work positioning devices are designed to reduce potential free fall, and restraint lanyards need to be specific in length to prevent the user from reaching a fall hazard zone.
Adequacy for 100% tie-off
Many stakeholders have neglected a vital element of ensuring adequate and comprehensive coverage of “100% tie-off”, which means that a person must be properly tied-off at all times while exposed to a fall hazard. The use of two lanyards is required if a person must move or relocate a tie-off point while exposed to a fall hazard as to always ensure a positive tie-off connection during the move.
Emergency rescue
A written emergency response plan must be established. As rescue operations are often carried out under extreme stress, consideration should be given to all aspects of the rescue process. Elements of a work at heights emergency response plan should include:
- Rescue method or equipment required
- Procedures to gain access into less accessible areas
- Training required for rescuers and first aiders
- Details of additional support facilities, including the location, contact information and availability of emergency services, ambulance and hospitals
- An effective and readily available means of communication
Workers must be provided with information on the emergency plan including:
- Who to approach or call in the event of an emergency
- The procedures to follow for emergencies, including those for persons suspended in safety harnesses during fall arrest. It is recommended that training in self-rescue techniques be provided for workers using safety harnesses
The immediate rescue of a person after an arrested fall can prevent the onset of injuries such as suspension trauma which can occur when a person is suspended in a harness over a period of time. A conscious suspended person should be encouraged to exercise his legs gently to stimulate blood circulation or use suspension trauma relief equipment. It is critical to note that suspension trauma relief equipment can only work when the casualty is conscious, and they are not an alternative to rescue.
References
www.tal.sg/wshc
www.tal.sg/wshc/-/media/tal/wshc/resources/publications/wsh-guidelines/files/guidelines_
ppe.pdf
