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February 17, 2010

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Collective protection and working at height

Gary Gallagher considers the role of collective protection in relation to the hierarchy of risk management contained in the Work at Height Regulations, and stresses the importance of scaffold planning and product selection at the outset.

Collective protection methods (sometimes referred to as ‘passive’) involve the use of equipment in a way that removes the risk of an individual falling from height, and do not rely on personal protection equipment (PPE) to ensure safety throughout the system-of-work process. Innovative and erection/dismantling systems of work that eliminate the risk of falls are now more widely available, while new equipment and methods for system scaffolds (access and shoring), aluminium towers, and tube-and-fitting scaffolding can provide not only improvements in safety but also greater efficiency and reductions in cost.

The Work at Height Regulations (WAHR) 2005 impose an obligation to follow a simple hierarchy of controls when planning and selecting equipment for work at height.1 According to this hierarchy, collectiveprotection measures that prevent the risk of falls are given priority over PPE and measures that can only minimise the height and consequences of a fall.

Basic selection principles
Designs should aim to include the information necessary to erect, dismantle, and alter temporary structures safely, without risk, and in full compliance with the Regulations. Alternatively, this information should be included in the scaffold plan to provide the system of work.
There are two types of design:

1    Those published by manufacturers/suppliers, which normally cover only basic scaffold configurations. These are generally known as erection guides;

2    Specific scheme designs for all scaffold configurations (typical examples of scaffolds requiring specific design are listed in the HSE Scaffold checklist).2

When selecting the product, the user should first study the guidance available from the supplier or service-provider, and ask themselves if the procedures shown eliminate the risk — throughout every stage of the process — of a person falling?

If the answer is yes, and the guidance provides a system of work without the risk of a fall, the user should be in a position to make a selection that complies with the hierarchical concept contained within the WAHR, or justify why this option cannot be selected. If the answer is no, then the user risks his or her selection being called into question and compared unfavourably with practice methods that eliminate the risk altogether — albeit, probably only in the event of a fall.

Inadequate guidance
While there are many scaffolding systems, towers and shoring products to choose from, few offer the option of a system of work that fully complies with reg.6.3 of the WAHR, which states: “Where work is carried out at height, every employer shall take suitable and sufficient measures to prevent, so far as is reasonably practicable, any person falling a distance liable to cause personal injury.”

In most instances, users and clients are offered design guidance detailing practice that contains, at best, mitigation against falls, i.e. practice methods dependent on the use of safety harnesses, with no other choice provided for duty-holders.

Moreover, there is a great deal of equivocation surrounding most of the scaffold product guidance currently available in relation to fall prevention, and system-of-work processes are often portrayed as collective when they are not.

To compound the problem, many planners, and others responsible for the system-of-work process selected, do not understand that justification of choice should be made against what can happen, before it happens. For basic scaffold configurations, responsible suppliers should be helping the user make sensible justifications, with relevant information reflected in their published guidance, or proposed in the specific design to be used. Unfortunately, however, many suppliers leave it to the users to address how their particular equipment should be used in accordance with reg.6.3 of the WAHR.
Confusing messages from some industry sectors and product suppliers can also develop, providing differing interpretations of the Regulations. This could conceivably be due to commercial considerations in relation to asset stock held, but there is also reluctance by some to invest in and develop collective protection products that will enable users to comply with the Regulations.

While sensible product selection, together with appropriate product guidance and design, makes compliance possible, it is also important to consider other factors, notably training and product standards.

Training
Awareness training for planners, supervisors, managers and safety auditors is required to plan, select, organise, supervise and check that the system of work is being carried out correctly.

Practical erection training is also essential for scaffold erectors. This type of training is additional to most training provided through national schemes, as the concepts are new and generally specific to the products or designs provided. The training could cover any equipment that can prevent the risk of a fall during the complete system-of-work process, and will most likely include advanced guardrails, which may either be independent types (additional equipment), or intended to form part of the scaffold configuration (integral), once complete.

Evidence that planners, supervisors, managers, etc. have taken awareness training, which includes the collective protection options that can lead to compliance, may be necessary to prove competence. Likewise, proof that erectors have undertaken practical assessment may also be required to ensure they have a sufficient level of understanding and capability.

To guard against possible prosecution, the duty-holder should ask themselves the following question: “Can we prove we are in a position to make a compliant selection, or allow personnel to make use of this new type of equipment, if training has not been provided for those involved in achieving this best practice?”

With widely-available collective equipment now making fall prevention possible, and shown through site experience to be practicable, it would also be foolish to rely on justification on the basis of the term “where reasonably practicable”.

Product standards and approvals
It should go without saying that the equipment chosen to provide the collective system-of-work process should also either directly meet the appropriate product standard or, if no product standard applies, be subject to product testing to the nearest relevant standard and, if necessary, additional testing in relation to foreseeable use and abuse.

For example, as integral advanced guardrails form a permanent part of the structure, they should be tested to verify compliance with the appropriate scaffold product standard during erection, use, and dismantling.

The relevant standards for system scaffolds, tube-and-fitting scaffolds, and aluminium towers are as follows:

  • BS EN 12810: Scaffolds made of prefabricated components;
  • BS EN 12811: Scaffolds in general; and
  • BS EN 1004: Mobile aluminium towers.

External advanced guardrails are deemed ‘additional’ items and are not covered directly by scaffolding product standards. However, their main guardrail loading capability should be tested to meet loading requirements of relevant product standards and be fit for purpose. BS EN 13374 is the standard for edge protection.

Safety harnesses
According to the hierarchy of risk management, the use of ‘PPE planned fall restraint’ is preferable to PPE that can only arrest a fall, and neither should be relied on without good justification to back up that selection. Again, to be clear, there is justification when the product guidance, or specific design, or scaffold plan, cannot guarantee that the risk can be eliminated through collective protection means.

Harnesses, in the way they are normally used with the lanyard clipped on to the scaffold, will not prevent but only mitigate the effects of a fall by reducing the distance an individual travels. Although harnesses can be used as a means of restraint to prevent a fall occurring, it is not normally evident in most common scaffold configuration guidance, or in general erection operations relying on arrest measures as the norm.

Importantly, there are many freestanding scaffolds, towers and shoring configurations that are not erected against the application/
structure being worked on, which consequently prevent hooking-off to the application, or even hooking-on to the scaffold. Reliance on harnesses hooked on to an untied scaffold could even make the scaffold itself overturn in the event of a person falling.

Scaffold erectors who rely on hooking on to the scaffold as it is being assembled cannot normally prevent the risk of themselves falling to the ground until they are above the second lift (boarded level), invariably at a height above four metres. And even when above this height, the scaffolder, when hooked on, can still fall. Traversing or tunnelling, which involve scaffolders relying on harnesses to move along the length of an exposed edge on each lift before they fit the guardrails of the scaffold, also expose scaffolders to the risk of falling, unless a collective process is deployed.

Harnesses are not normally used during the erection and dismantling of aluminium-tower scaffolds, as they may be too light to resist the forces applied by the fall of the person being arrested. On a further note, when selecting measures and equipment that can only mitigate the effects of a fall, it is worth remembering that the WAHR removed the so-called two-metre rule, so now any place of work from which a person can fall and be injured is designated a place of work at height.

Rescue procedures
Even if the harness-dependent system-of-work process works as it should — i.e. prior to embarking on the work-at-height task, the person has hooked on to a point capable of taking the impact load of the fall, and the arrest of the fall takes place as intended — any fall victim will still need to be rescued. The duty-holder should therefore prepare for a fall emergency by producing a rescue plan, detailing the available rescue resources within the overall scaffold plan.

A person suspended in a harness awaiting rescue should be removed from suspension as soon as possible. There is the risk that a suspended person may suffer loss of consciousness, which, in some cases, may occur within a short time. In a worst-case scenario, if suspension is prolonged, it could result in death. Clearly, the situation is more serious if the person is already unconscious at the time of fall arrest. Rescuers therefore need to be trained in how to deal with both conscious and unconscious individuals in suspension.

Aluminium towers
Aluminium towers are one of the most common forms of scaffold access system used in the UK. Two processes relating to this type of equipment were approved by the HSE and the Prefabricated Access Suppliers’ & Manufacturers’ Association (PASMA) as options for users in 2004, a year before the WAHR were introduced. These are currently illustrated in HSE Construction Information Sheet No 10 (revision 4)3 and the HSE/PASMA-produced video, ‘Don’t Fall for It’.4

The fully-collective advanced guardrail option, which uses telescopic advanced guardrails, has now been substantially improved in terms of ease of use, simplicity and efficiency, through the introduction of ‘integral advanced guardrails’, leading to the aforementioned industry guidance now being subject to review.

Contrary to popular belief, the common option, known as 3T, is not collective throughout the erection, use and dismantling system-of-work process, as the title 3T, which stands for ‘Through The Trap’ would indicate. Using this approach, when the operative is positioned through the open trap of the tower, fixing the tower guardrails, he or she is inevitably exposed to the risk of a fall. This approach neither deals with the consequences nor the distance of that potential fall.

There are some PASMA training providers offering advanced-guardrail options in the practical part of the training. However, with many organisations delivering courses that only cover the 3T method within the practical element of the training, it is likely to continue as the most common practice adopted for towers for some time.

Conclusion
Regardless of the process that is selected, the planner, duty-holder or user has a choice to make and, with that selection, a justification to document within each job a specific risk assessment.

References

1    HSE (2007): ‘Work at Height Regulations 2005 (as amended), a brief guide’, INDG401 www.hse.gov.uk/pubns/indg401.pdf
2    HSE Scaffold checklist, www.hse.gov.uk/construction/
scaffoldinginfo.htm
3    HSE (2005): Construction Information Sheet No 10 (revision 4) (under review) www.hse.gov.uk/PUBNS/cis10.pdf
4    HSE/PASMA video, ‘Don’t Fall for It’ (under review); tel: PASMA on 0845 2304041, or visit www.pasma.co.uk

Further reading

  • BS 8437: 2005, ‘Code of Practice for selection, use and maintenance of personal fall protection systems and equipment for use in the workplace’
  • National Access Scaffolding Confederation (NASC) (2008): TG20:08 ‘A guide to good practice for scaffolding with tubes and fittings’
  • NASC (2008): ‘SG4:05 Appendix A Interim guidance on collective fall-prevention systems in scaffolding’, www.nasc.org.uk/NASC_news/collective_protection_interim_guidance Section 2 (1) — (4) is most relevant to this article)


Gary Gallagher is managing director of Turner Access Ltd.

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