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Rescue from height
Examining the systems and methods available for the recovery of a user whose fall has been arrested by personal protective equipment.
Image © Matthew Collingwood | Dreamstime.com
Fall arrest PPE is widely used in a number of jobs carried out at height. The basic principle of such equipment is to prevent the user hitting an injurious object by catching them at an earlier stage – namely, before the energy associated with the fall reaches terminal levels (either when hitting the floor or due to decelerations that are likely to cause death). However, one factor that is quite often overlooked in such systems is how the user is likely to be recovered once he or she suffers a fall.
This is especially important where fall arrest is used, as the potential for permanent injury and possibly fatal consequences will increase the longer the user is left suspended following a fall. As well as the need for treating any injuries sustained in a fall, there is the effect of suspension trauma (constriction of blood vessels and pooling of blood in the limbs) to consider, which can have fatal consequences if the pressure on the user is not released within good time. The need for suitable training is therefore important, to ensure that operatives are able to carry out the rescue in as short a time as possible. In such training, the worst-case scenario should be considered, where the user who has fallen has lost consciousness. In such circumstances, they are often referred to as the ‘casualty’.
When a CE mark is required
In Europe, equipment intended for rescue only is outside the scope of the PPE Regulation and, therefore, does not need CE marking. There are exceptions to this rule, such as where rescue equipment is integrated into fall arrest equipment. As an example, a retractable fall arrester which includes an integrated rescue winch facility would require CE marking, as would a rescue harness intended to be worn when commencing work and which incorporates other fall protection attachment points.
There are a number of systems and methods available for the rescue or recovery of a user whose fall has been arrested, including both systems integrated into a fall arrest device and standalone products. The system and method in use will depend on the location, type of work and the type of fall arrest equipment in use and should, therefore, be tailored to each individual job.
A number of European standards exist for typical equipment available, although the need to tailor individual systems will inevitably mean that not all products on the market will fall into the scope of a standard. Even in such circumstances, it is essential that complete systems are subject to suitable tests. These tests should include overload conditions using suitable safety factors to ensure that they are safe for use.
EN 1496:2017 details requirements and test methods for rescue lifting devices. These devices are designed to lift users from their place of rest up to a safe location after a fall, and are divided into ‘type A’ (lifting only) and ‘type B’ (lifting and limited lowering) devices. Rather than intended for lowering users down to the ground, type B devices are used for lifting casualties upwards, and for lowering over short distances of less than 2m, in order to negotiate obstacles. The standard includes design and material requirements for the device, including any ropes or wires used alongside the device. It also includes requirements for the strength of the device, which are defined as at least ten times the maximum rated load, with a minimum of 12kN test force (120kg user mass). This ties in with the requirements for man-riding devices under normal lifting and lowering conditions (LOLER in the UK). The standard also includes a test for the function of the device in overload conditions. The device should be capable of lifting and holding a mass equal to 1.5 times the maximum rated load of the device. An ergonomics test is also included – the device must be able to be operated under a maximum applied load (for example, to the lifting handle) of 250N.
A dynamic performance test is carried out on type B devices. The device must be capable of arresting a mass equal to the maximum rated load after a 600mm freefall, with a maximum force applied to the mass of 6kN. This is included as a provision for if the device becomes snagged in use, leading to a small amount of freefall when the casualty is released. The maximum allowed force of 6kN ensures that the user is not subjected to excessive forces in such cases. Practically, this would usually mean that a lifting and lowering device would need to include a system for energy absorption or use rope with some inherent stretch (such as dynamic rope).
EN 1497:2007 details requirements and test methods for rescue harnesses. Rescue harnesses can be in the form of an individual harness intended to be worn by the casualty, or as a component of a fall arrest harness (for instance, additional attachments on a fall arrest harness). In the latter case, the tests would be applicable to each attachment – a harness could, for instance, include a fall arrest attachment on the back, and a rescue attachment on the front. EN 1497 includes similar requirements to those specified in EN 361:2002 (fall arrest harnesses), with a lower energy dynamic performance test to reflect the reduced severity of falls likely to be seen in use. A rescue harness should not be used in a scenario where freefall is likely to be encountered. As a result, the test is intended to cover only small-distance freefalls, such as where slack is encountered in the lifting line. Unlike fall arrest standards, the forces used in EN 1497 are based on the maximum rated load for the harness, rather than the 6kN maximum allowed arrest force.
The dynamic performance test is, therefore, carried out using a dummy of mass equivalent to the maximum rated load. The static strength test is carried out using a force of ten times the rated load, with a minimum of 15kN.
EN 1498:2006 details requirements and test methods for rescue loops. If these loops are in the form of slings or cradles, intended to fit under the arms of the user, they are referred to as ‘Class A devices’. If they hold the user in a sitting position, they are referred to as ‘Class B devices’, with ‘Class C devices’ fitting around the ankles of the user. This standard includes dynamic performance and static strength requirements, carried out in a very similar manner to those specified in EN 1497 for rescue harnesses. In the case of class C devices, the test dummy is replaced by a solid test mass to apply the force, with the device fitted around a test form to simulate the ankles of the user.
Additional systems used for rescue can incorporate components subject to other standards and test methods. One common method involves abseiling to the casualty, in which case a descender device complying with EN 341 (descender devices) or EN 12841 (rope adjustment devices) will be included, along with suitable ropes and connectors to make up the whole ‘kit’.
Although rescue equipment does not fall within the scope of the PPE Regulation, it is important that all equipment sold for the purposes of rescue has been properly tested and checked for suitability for use.
Where a specific standard exists, buyers should always request copies of independent test reports to support any claims of compliance by manufacturers. In the absence of the formal procedure for checking ongoing compliance of manufacturing, such as defined in Modules C2 and D of the regulation for PPE, it is also advisable to check that the manufacturer has a suitable quality system in place. In addition, although a product intended for rescue only cannot be CE-marked, it is always advisable that if a product could be misused as part of a fall arrest system, it should be tested as such.
Further information on SATRA's PPE certification and testing services is available at www.satra.com/ppe
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