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Machine Guards White Paper 6 – PUWER

1st edition – September 2016

The requirements for machinery guarding with respect to PUWER

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    Jeremy Procter, a Member of international and UK standards committees ISO/TC 199/WG 6 (Safety distances and ergonomic aspects) and BSI MCE/3 (Safeguarding of machinery), and Managing Director of Procter Machine Guarding, explains the requirements for machinery guarding with respect to PUWER (the Provision and Use of Work Equipment Regulations 1998).


    The Provision and Use of Work Equipment Regulations 1998, usually abbreviated to PUWER, are UK regulations that are intended to ensure the safety of people at work who are using ‘work equipment’ – which encompasses everything from scissors to CNC machining centres. This White Paper focuses on the specialist subject of machine guarding, as this is often not understood fully and the consequences of inadequate machine guarding can be very severe or, in the worst cases, fatal. Power presses, because of their particular hazards, have their own requirements and are outside the scope of this White Paper. Advice on power press is available on the Health and Safety Executive (HSE) website.

    When is a PUWER assessment required? 
    Today, standards and regulations tend to take a ‘lifecycle’ approach. As far as PUWER and machine guarding are concerned, we therefore need to think about all aspects of the ‘use’ of the work equipment (machine), from the commissioning, operation, adjustment, cleaning and maintenance, through to the end-of-life decommissioning and disposal.

    Clearly if the machine is PUWER-assessed at the commissioning stage or when it is first put to use, that is not the end of the story. Periodic assessments must be conducted to ensure that the safety-related aspects are continuing to perform as required. For example, guards may sustain damage due to impacts from forklift trucks, or they may be the subject of unauthorised modifications that have the unintended consequence of compromising the safeguarding function. Periodic inspections can identify these situations and others so that rectifications can be carried out in a timely manner before an accident occurs.

    Depending on the type of machine, the hazards present, any history of issues coming to light during assessments, and the likelihood of deterioration, PUWER assessments should generally be carried out every six or 12 months. There are no formal guidelines on this, but 12 months is typical and six months may be more appropriate in some circumstances. On the other hand, little-used, low-risk machines could justifiably be inspected at longer intervals.

    At the end of the machine’s life, the instructions need to be consulted and a risk assessment conducted prior to decommissioning and disposal. Generally the guards will not pose a significant problem during these phases of the machine’s lifecycle, but care needs to be taken if parts of the machine are still hazardous when they are exposed by removal of the guards (such as sharp blades), and the guards themselves can be large, heavy and unwieldy.

    What does PUWER require?

    Regulation 11 of PUWER addresses the needs relating to dangerous parts of machinery, and this is the regulation of most interest with respect to machine guarding. In essence, regulation 11 (1) requires employers to take effective measures (specified in regulation 11 (2)) to prevent access to dangerous parts of machinery or to stop the movement of dangerous parts before any part of a person enters a danger zone (note that regulation 11 applies equally to a rotating stock-bar extending beyond a lathe headstock). In addition, regulation 11 (3) lays down specific requirements for guards and protection devices, and regulation 11 (4) states which measures in 11 (3) apply to ‘protection appliances’ such as jigs, holders and push-sticks.

    Which standards do machine guards need to comply with? 

    PUWER does not make any direct reference to standards, and the Approved Code of Practice and guidance (ACOP) published by the Health & Safety Executive (Safe use of work equipment, reference L22), makes little mention of them. There is therefore no legal obligation to work to the current standards nor, indeed, is there an obligation to follow the ACOP. Nevertheless, following the ACOP and applying standards is normally sufficient and will be the easiest way to demonstrate that ‘best practice’ has been applied when conducting a risk assessment, analysing the risks and implementing appropriate risk reduction measures in order to comply with the law. If an HSE inspector visits, he or she will expect to see that the ACOP has been followed. For a guide to machine guarding standards, see the Useful Resources section below.

    Which safeguarding measures need to be applied?
    For preventing access to dangerous parts of machines, PUWER provides a hierarchical list of measures that can be summarised as follows:

    1. fixed guards
    2. other guards or protection devices
    3. protection appliances (jigs, holders, push-sticks, etc); and
    4. information, instruction, training and supervision

    Note that the ACOP states that information, instruction, training and supervision will be needed regardless of the other protective measures implemented. In reality, most machines will need a combination of fixed guards, other guards or protective devices (perhaps an opening guard or a safety light curtain), and information, instruction, training and supervision. Often different types of safeguard will be required at different points on the machine, but this should be highlighted by the risk assessment when each hazard is considered in turn.

    For selecting the safeguarding measures, the ACOP advises that the hierarchical order should be applied ‘so far as it is practicable to do so, provided that they contribute to the reduction of risk.’ For example, it is not necessary to design and install complex guarding if the hazard being safeguarded might only cause a very minor injury and the chance of that injury occurring is minimal. In all cases, the risk assessment plays a crucial role in helping to determine the appropriate measures.

    Bear in mind that some of the measures that are appropriate will change according to the circumstances. For example, a combination of fixed and movable guards is usually the most effective way to reduce risks to an acceptable level during machine operation but, during set-up, cleaning, maintenance and repair, it may be necessary to open some of the movable guards or remove some of the fixed guards. At these times, there may have to be a greater reliance on information, instruction, training and supervision. Another option, particularly when maintenance is taking place, is temporary perimeter guarding installed around the unguarded part of the machine so only authorised personnel have access.

    What to look for
    The following is not an exhaustive list of points to examine during a PUWER inspection, but it provides some tips for things to look for in relation to machine guarding, based on experience of what is commonly missed by people who are unfamiliar with machine guarding inspections.

    When carrying out a periodic PUWER inspection, it is important to check that any guards that have been removed for maintenance have been replaced correctly and that all of the fasteners have been used (if they have not, it may be possible to access dangerous parts of the machine through the resultant gap). Another common issue is that the interlocks on movable guards are defeated so the machine can be operated without the guards being closed. Elsewhere, parts of machine casings (which can provide a protective function by preventing access to dangerous parts) may be cut away so that the machine can be adapted or upgraded, and the modification may result in dangerous parts becoming accessible.

    If perimeter guards are installed, checks should be made that they have not been moved closer to the machine (perhaps to widen a gangway or install other equipment), nor that the machinery has been modified without the safety distances being confirmed against the requirements in BS EN ISO 13857 (Safety of machinery. Safety distances to prevent hazard zones being reached by upper and lower limbs). Another problem that can arise with perimeter guards is that anything installed outside the guarding – such as low-level barriers to prevent damage from forklift trucks – could be stood on, enabling a person to reach dangerous parts of the machine. If this is considered likely, the height of the guard might have to be increased accordingly. For an easy-to-use Safety Distance Calculator, see the Useful Resources section below.

    Any guards that have been repaired since the last PUWER inspection should be inspected carefully to ensure that the correct materials have been used – for example, that acrylic has not been used in place of polycarbonate, and that wire mesh has not been replaced with an alternative having a larger aperture size – and that the correct fasteners have been used. Note that BS EN ISO 14120 makes it clear that quick-release fasteners such as quarter-turn screws should not be used to secure fixed guards from outside the guarded area, and the standard also specifies when retained fastenings should be used. We would not recommend that retained fastenings should be retrofitted to every appropriate guard, but a sensible approach should be taken. For example, if a particular guard or machine type has a history of fastenings becoming lost after a fixed guard has been removed, then it would be prudent to retrofit retained fastenings. Or if an older machine uses quarter-turn fasteners to attach some of the guards, then due consideration should be given to upgrading these.

    If a machine is modified it must be risk-assessed, which should result in any necessary guarding modifications being undertaken correctly. However, that may not be the case, so any machine that has been modified or upgraded since the last PUWER assessment should have the guarding checked very carefully. If an outfeed conveyor has been added, for example, the interface between the main machine and the conveyor should be checked – as should the conveyor guarding as well, of course. Or if a machine has been improved to increase throughout, it might be that the hazards are now ‘high’ instead of ‘low’, meaning that the safety distances need to be checked against the requirements in BS EN ISO 13857.

    Another subtle point to consider is who uses the machine during operation, setting and cleaning. If there has been a move towards less-skilled or inexperienced labour, this can increase the risk and render the original safeguards inadequate. Or if instructions are in English and the current users do not have English as their native language, risks can increase.

    Similarly, if there has been a change in the material being processed, this can alter the risks. For instance, if a lathe is being used to turn components from magnesium instead of aluminium, there is a significant risk of fire that necessitates very careful handling of swarf. This has implications for operation and cleaning of the lathe, as well as the need to keep the correct extinguishing media close at hand. It may even be necessary to retrofit a fire suppressant system to the machine.

    PUWER and CE marking

    So far we have been assuming that the PUWER assessment relates to a machine that has been operating for some time. But, as the word ‘Provision’ implies, a PUWER assessment should also be conducted on new machinery before it is put into use. New machinery in the UK should be CE marked by the manufacturer or supplier, even if the machinery has been designed and built in-house for the company’s own use. Bear in mind that the CE mark only indicates a claim of compliance and not all suppliers are as diligent in their CE marking procedures as others. A PUWER assessment of a new machine will often highlight areas of non-compliance, so a close inspection of the machine, including the guarding, is essential.

    PUWER assessment documentation

    Documenting the PUWER assessment is very important, as this provides the evidence to show that the assessment has been conducted correctly. If photographs are included, these can help to identify whether a machine or its guards have been modified since the previous assessment or if anything has altered externally that could influence the machinery safety – such as low-level barriers being installed adjacent to perimeter guards.

    Machine guarding compliance surveys

    Procter Machine Safety offers free Machine Guarding Compliance Surveys of standalone machinery and assemblies of machines, old or new, to support companies’ PUWER assessment regimes. After an initial telephone consultation, Procter’s safety engineers can make an appointment to undertake a site visit and assess the machinery safeguards. As part of the free survey, the safety engineers provide a short written report that identifies areas of non-compliance and actions that can be taken to reduce risk, improve safety and comply with PUWER. Importantly, rather than just leaving a list of ‘problems’, the company can also provide ‘solutions’ in the form of a quote and, if requested, work can be carried out to make the machinery compliant.

    Useful resources

    All can be downloaded from www.machinesafety.co.uk/free-downloads/free-machine-safety-guides or email [email protected]

    Machinery Guards White Paper 7 – BS EN ISO 14122
    Note that the standard is sometimes incorrectly referred to as, for example, BS 14122, EN 14122 or BS EN 14122, but the correct usage in the UK is BS EN ISO 14122.

    Machinery Guards White Paper 8 – Acoustic Enclosures
    The Machinery Directive lays down requirements not just for machinery but also for safety components. Annex V contains an indicative list of safety components and this includes noise/vibration reduction systems.

    Free Risk Assessment Calculator
    Based on the requirements of BS EN ISO 12100 and designed to be simple to use.

    Free Safety Distance Calculator
    Establishes machine guard safety distances and heights in accordance with BS EN ISO 13857.

    Free Guide to the New Machinery Directive 2006/42/EC
    To help companies comply with the Directive that came into force on 29 December 2009.

    Free White Paper: Machinery Directive and Fixings for Fixed Guards
    Explaining the amended requirements for Guard Fixings under the new Machinery Directive.

    Free White Paper: CE Marking of Machine Guards
    Explaining the requirements relating to CE marking of guards under the Machinery Directive.

    Free White Paper: EN 349, Minimum Gaps to Avoid Crushing
    Explaining the requirements of the standard for minimum gaps to prevent crushing.

    Free White Paper: Differences Between BS EN 953 and BS EN ISO 14120
    Explaining what changes have been introduced in BS EN ISO 14120, which replaces and supersedes BS EN 953.

    Free White Paper: Conveyor Guarding
    Explaining the hazards associated with conveyors, regulations and standards, and how to safeguard conveyors without adversely affecting productivity.

    Free White Paper: The 2014 Edition of PD 5304
    Explaining the changes in the new edition of BSI’s Guidance on safe use of machinery.

    Free Guide to Work Shop Safety
    A guide to guarding small machine tools typically used in workshops.

    Free Machine Accident Investigation Kit
    To help companies meet their statutory obligations and prevent future accidents.

    Free Ergonomics Guidance
    European Commission publication Guidance on the application of the essential health and safety requirements on ergonomics.
    Download: http://eceuropa.eu/growth/sectors/mechanical-engineering/machinery/index_ex.htm