On your guard

14 November 2013

Machine guards can only provide protection if they are properly designed, manufactured, installed and remain in position but the requirements in this area can be confusing and are often misinterpreted. Jeremy Procter offers some clarification.

Within its Essential Health and Safety Requirements, The Machinery Directive 2006/42/EC contains three points relating to fixings: fixed guards must be fixed by systems that can be opened or removed only with tools; their fixing systems must remain attached to the guards or to the machinery when the guards are removed; and, where possible, guards must be incapable of remaining in place without their fixings. There is still a degree of confusion and misinterpretation of these points but, before considering them in detail, it should be noted that the machine instructions must make it clear that only trained persons should be authorised to remove machine guards and there needs to be a culture in the workplace that does not ‘turn a blind eye’ to dangerous practices.

Regarding the use of a tool, fasteners with a straight slot are inappropriate because they can be removed using improvised tools such as coins and rulers. Fasteners requiring spanners, cross-head screwdrivers or hexagonal (Allen) keys are generally acceptable. Some consultants make the point that such tools are readily accessible to operatives and maintenance technicians, and these fasteners should therefore not be used for guards. However, this is not what is stated in the European Commission’s Guide to application of the Machinery Directive 2006/42/EC and, in several decades’ involvement in machine guarding, the author has never been given this advice from the UK health and safety authorities. Indeed, the EC guide states, in relation to Section of the Essential Health and Safety Requirements: "Fixed guards may thus be fixed, for example, by means of bolts, screws or other fasteners that can only be removed by using tools such as keys or wrenches.” The guide explains: "This requirement aims to restrict the removal of fixed guards to competent or authorised persons.” However, the guide also emphasises the need for a risk assessment.

Regarding the need for fixings to remain attached to the guard or machine when the guards are removed, the EC guide states: "The requirement applies to any fixed guards that are liable to be removed by the user with a risk of loss of the fixings, for example, to fixed guards that are liable to be removed during routine cleaning, setting or maintenance operations carried out at the place of use. The requirement does not necessarily apply to fixed guards that are only liable to be removed, for example, when the machinery is completely overhauled, is subject to major repairs or is dismantled for transfer to another site.” As above, the application of this requirement depends on the risk assessment.

The requirement for guards to be incapable of remaining in place without fixings is intended to prevent a situation arising in which operatives are unaware that a fixed guard has not been properly replaced or fastened, as such guards might not provide adequate protection.

While the EC guide is not legally binding, it is the closest we have to an authoritative interpretation of the Machinery Directive. At the time of writing, we can work to British Standard BS EN 953:1997 +A1:2009, Safety of machinery. Guards. General requirements for the design and construction of fixed and movable guards. However, this will soon be superseded by an International Standard ISO 14120, the current draft of which contains statements about fixings for fixed guards that are almost identical to those in the EC guide. Once ISO 14120 has been Harmonised as EN ISO 14120, it can be used to claim a presumption of conformity to the relevant EHSRs of the Machinery Directive.

Procter Machine Guarding has published a free White Paper, Fixings for Fixed Guards, which explains the requirements relating to fixings and also provides information to assist designers in selecting fasteners for particular guarding applications. Copies of the White Paper can be accessed by visiting the Downloads section at: 
Jeremy Procter is a member of BSI's MCE/3 committee, former Convenor of the European Standards Committee responsible for Machine Guards (CEN TC114 WG11), and managing director of Procter Machine Guarding.