Login
When working at height, or when exposed to the risk of falling, there are numerous ways of keeping individuals safe.
Removing the risk entirely would be ideal, by either completing the required work at ground level or away from the potential fall area, but in most cases this is not possible. Access platforms, guardrails, nets and other collective means of protection, followed by restraint equipment, are the next best means of protection as they ensure that individuals cannot actually have a fall. Again, these options are not always viable when completing the work required. As a final option, items of fall arrest PPE can be used to create a fall protection system and ensure a safe means of working.
The main aim of a fall arrest system is to safely arrest the user in the event of a fall and to stop them hitting the ground. A typical system will consist of an anchorage point(s) fixed or placed on the structure, a full body harness worn by the individual and a fall arrest device connecting between the anchor and harness. This is the area of the fall protection system that I will focus on in this article.
There are two factors to consider with all fall protection systems: the arrest distance and the arrest force. The arrest distance is measured from the point at which the user falls to when they are brought to a stop. The arrest force is the dynamic force generated and exerted on both the system and user when a fall occurs. The job of a fall arrest device is to arrest the user’s fall whilst limiting both of these factors.
From the moment a fall arrest device starts to engage, a balance must be struck between both of these factors. Stopping the user quickly would generally lead to higher arrest forces on the structure, which could cause failure of the system, and the quick deceleration of the user could potentially cause injury to internal organs. The counter to this would be stopping the user over a longer distance. While this would generally create much lower arrest forces and slower deceleration, the longer distance could increase risk from objects that could be hit during the fall. Fall arrest devices are therefore designed and tested to ensure that a balance of both of these factors is met by adhering to the requirements set out in product standards.
Other considerations when selecting fall arrest devices include the weight of the user, including tools and other elements located on their person, to ensure they do not exceed the maximum user weight specified. Fall arrest devices will be tested to this maximum user weight as, if exceeded, it is likely to increase arrest distance, peak force and even the risk of the product failing. Having a rescue plan and knowing how to remove a user safely from a fall arrest device are also both worth consideration.
There are a number of different fall arrest devices which are commonly used when working at height. Some of these include:
- Single leg and twin leg energy absorbing lanyards
- Single leg and twin leg retractable type fall arresters (RTFAs)
- Guided type fall arresters (GTFAs) for use on rigid or flexible anchor lines
Each device has its advantages and disadvantages depending on the situation or location of use. It is important that the correct devices are used so as to ensure that no additional risks occur and that the user remains safe.
Energy absorbing lanyards
An energy absorbing lanyard is made up of several components. The main part is the energy absorber itself, which is normally a tightly packed length of tear webbing and, in most cases, a backup strap contained within a plastic wrapper or other protective sleeve. Once the energy absorbing lanyard starts to arrest the user during a fall, the tear webbing will begin to split, keeping the force on the user and in the system down to an acceptable level.
This energy absorber component is then connected to a lanyard made of wire, webbing or rope at one end, followed by one connector at either end. The total length of the energy absorbing lanyard including connectors can be any length up to a maximum of 2m. This is to ensure that the maximum free fall a user could potentially see is 4m. However, good practice when working at height is to never climb above your anchorage point and therefore limit the free fall to around 2m. Whilst an energy absorbing lanyard is fairly mobile, the arrest distance is usually far greater when compared with other options. This means that the user is at risk of hitting objects during the fall and would need to ensure that there was sufficient ground clearance if choosing this option.
“never climb above your anchorage point and therefore limit the free fall to around 2m”
Single-and twin-leg versions of energy absorbing lanyards are both available. Single-leg lanyards are beneficial for when a connection with the anchorage point is always maintained when moving, such as when connected to a horizontal anchor line. Twin-leg lanyards are more beneficial for when movement is required between multiple anchorage points, such as when climbing a ladder, as it allows one leg to always be connected whilst the other is moved. This device would be slower when compared with both SRLs and GTFAs due to the amount of connecting and disconnecting required.
The applicable standard for energy absorbing lanyards within Europe is EN 355. This standard gives the minimum requirements for an energy absorbing lanyard to comply with the essential health and safety requirements of the PPE Regulation (EU) 2016/425. The main tests include the following:
- A dynamic performance test, where a 100 kg mass is dropped a distance of twice the length of the lanyard (2 x Lt), to simulate the worst possible fall. The arrest distance and peak arrest forces and measured and are required to be ≤2 x Lt + 1.75 m and ≤6 kN
- A static strength test, where the energy absorber has a force of 15 kN applied for three minutes to ensure a 2.5 times safety factor
- A static pre-load test to 2 kN to ensure the energy absorber does not unintentionally deploy at forces below this
- All metallic elements are subjected to a corrosion test
This standard must be marked on the product along with ideally any limitations such as maximum user weight which as a minimum would be 100 kg. Should the manufacturer wish to claim a higher user weight, then the product would also need to meet the applicable tests with this higher mass. For the EU the device should also be CE marked to show that the product has been certified against the PPE Regulation (EU) 2016/425. The UK will also now require that the product be UKCA marked following assessment by an approved body
In the USA, the applicable standard is ANSI Z359.13. Both EN 355 and ANSI Z359.13 contain similar methods and requirements for testing, certification, marking and user information, but there are some differences to both the arrest distance and peak arrest force requirements. There are also additional dynamic tests in ANSI Z359.13 following hot/humid, wet and cold preconditioning to simulate the different ambient conditions to prove that the product will still perform.
In other parts of the world there are additional standards required, such as AS/NZS 1891.5 in Australia/New Zealand and CSA Z259.11 in Canada.
Retractable type fall arresters (RTFAs)
An RTFA typically comprises of an encased mechanism with a lanyard wound around the drum. The user then connects one end to an anchorage point and themselves to the other end. As they move, the internal mechanism extracts or retracts the lanyard keeping the slack to a minimum, ensuring the free fall arrest distance is minimal, when compared to energy absorbing lanyards. When a fall occurs, the movement of the drum causes the pawls of the mechanism to engage, locking off the lanyard and causing the brake or energy absorber to deploy.
RTFAs come in differing lengths each designed for different applications. For example, small lightweight devices designed for short distances or larger heavy-duty devices designed for much longer distances. The lanyard itself can be made from wire rope, webbing or rope. Some RTFAs also include other functions such as a rescue winch, which can be engaged following a fall to rescue the user by lifting them back up to safety. They could also include an automatic descender which after arresting a fall can lower a user to the ground safely. Other variants which are now commonplace are twin RTFAs, which are similar in design to twin energy absorbing lanyards. Twin RTFAs consist of two short RTFAs joined together, where the housing can be connected to the user’s harness, allowing the individual to climb with two attachment points.
“all fall protection PPE should be visually inspected before use”
All fall protection PPE should be visually inspected before use to determine whether there is any damage or issue with the product. In addition, RTFAs must be regularly serviced, usually annually, to ensure the mechanical element continues to function correctly. This should be performed by the manufacturer or an approved servicing company.
The applicable standard for RTFAs within Europe is EN 360 (currently under review and being updated). This standard provides the minimum requirements for a self-retracting lanyard, to comply with the essential health and safety requirements of the PPE Regulation 2016/425. The main tests include the following:
- A dynamic performance test, where a 100 kg mass is dropped a distance of 600 mm free fall. The arrest distance and peak arrest forces and measured and are required to be ≤2 m and ≤6 kN
- A static strength test, where the self-retracting lanyard has a force of 15 kN for textile or 12 kN for wire rope applied for three minutes to ensure a 2.5 / 2 times factor of safety
- A locking test after conditioning to hot, cold and wet pre-treatments
- All metallic elements are subjected to a corrosion test
This standard must be marked on the product along with ideally any limitations such as maximum user weight which as a minimum would be 100 kg. Should the manufacturer wish to claim a higher user weight then the product would also need to meet the applicable tests with this higher mass. For the EU the device should also be CE marked to show that the product has been certified against the PPE Regulation (EU) 2016/425. The UK will also now require that the product be UKCA marked following assessment by an approved body.
Some RTFAs also allow for horizontal use, where the lifeline of the device would run over an edge should a fall occur. Whilst a worker should always try to avoid situations where their lifeline could be cut over an edge. The group of notified bodies for fall protection equipment, VG11, have put together the sheet PPE-R/110.60 which gives requirements to be met before claiming this mode of use. These test methods are being incorporated into the revised version of EN 360.
In the USA, the applicable standard is ANSI Z359.14. EN 360 and ANSI Z359.14 both have similar methods and requirements for testing, certification, marking and user information but contain some differences to the arrest distance and peak arrest force requirements. As with the energy absorbing lanyards, there are also additional dynamic tests following hot/humid, wet and cold preconditioning to simulate the different ambient conditions and prove that the product will still perform. Additional tests also exist for the force required to retract the lanyard and also a dynamic strength test.
In other parts of the world there are additional standards required, such as AS/NZS 1891.3 in Australia/New Zealand and CSA Z259.2.2 in Canada.
Guided Type Fall Arresters (GTFAs)
A guided type fall arrester is essentially a shuttle or traveller connected to a vertical anchorage line or rail, with a connection to the user’s harness. The user can then freely climb with the GTFA following up and down the anchorage line as required. Anchorage lines can be either wire rope rail or textile. Rigid anchorage lines are normally fixed to ladders, allowing the user to climb with their hands and feet either side, with the GTFA running up the centre. Flexible anchorage lines are much more portable and more freedom of movement is allowed. A GTFA usually has a very short connecting element between it and the user (sometimes only a connector), which would result in fairly short arrest distances. Some GTFAs do come with energy absorbers and lanyard extensions attached. The user should never change or add components between the connection of a GTFA as this will alter the performance of the system.
The applicable standard for GTFAs for use on a rigid anchor line within Europe is EN 353-1. This standard gives the minimum requirements for a GTFA to comply with the essential health and safety requirements of the PPE Regulation (EU) 2016/425. The main tests include the following:
- A dynamic performance test, where a 100 kg mass is dropped a distance of twice the length of the connecting element. The arrest distance, locking distance and peak arrest forces at both the GTFA and anchorage point are measured and are required to be ≤1 m, ≤0.5 m and ≤6 kN respectively
- A cold dynamic function test to ensure the GTFA still locks on following conditioning at a minimum of -30 °C
- A series of dynamic tests including minimum distance of test mass from anchor line and a fall-back test, using both maximum and minimum user weight
- A static strength test, where the GTFA and anchor line has a force of 15 kN applied for three minutes to ensure a 2.5. This force is increased for the anchor line should the force from the dynamic test on the anchor be greater than 6 kN
- All metallic elements are subjected to a corrosion test
The applicable standard for GTFAs for use on a flexible anchor line within Europe is EN 353-2. This standard gives the minimum requirements for a GTFA to comply with the essential health and safety requirements of the PPE Regulation (EU) 2016/425. The main tests include the following:
- A dynamic performance test, where a 100 kg mass is dropped a distance of twice the length of the connecting element. The arrest distance and peak arrest force are measured and are required to be ≤1 m + 2 x length of connecting element and ≤6 kN
- A static strength test, where the GTFA and anchor line has a force of 15 kN applied for three minutes to ensure a 2.5. This force is increased for the anchor line should the force from the dynamic test on the anchor be greater than 6 kN
- A locking test after conditioning to hot, cold and wet pre-treatments
- All metallic elements are subjected to a corrosion test
The relevant standard must be marked on the product along with the maximum user weight, which as a minimum would be 100 kg. For the EU the device should also be CE marked to show that the product has been certified against the PPE (EU) Regulation 2016/425. The UK will also now require that the product be UKCA marked following assessment by an approved body.
In the USA, the applicable standard for GTFAs on flexible lines is ANSI Z359.15 and for rigid lines is ANSI Z359.16. All of these standards contain similar methods and requirements for testing, certification, marking and user information but there are some differences to the arrest distance and peak arrest force requirements. Like with the energy absorbing lanyards and SRLs, there are also additional dynamic tests following hot, wet and cold preconditioning to simulate the different ambient conditions and prove that the product will still perform. There are also additional tests in case of manual override of one of the locking features of the GTFA.
In other parts of the world there are additional standards required, such as AS/NZS 1891.3 in Australia/New Zealand and CSA Z259.2.4 & CSA Z259.2.5 in Canada.
Conclusion When fall protection PPE is required as a last resort to complete a job, there are numerous types of product available. It is important to consider what the best components to use in your fall arrest system in order to ensure that you or your employee is safe, whilst also allowing the required work to be carried out effectively.
