Regulation 11 of The Provision and Use of Work Equipment Regulations (PUWER) requires that measures are taken to prevent access to dangerous moving parts of machinery or to stop those dangerous parts before they can be reached. Dangerous moving parts are defined in law as those parts which could cause injury if the machine is being used in a foreseeable way.

Regulation 3 of the Management Regulations require risk assessments to be conducted which can help identify the hazards. These hazards can be mitigated by the use of fixed guards, interlocking movable guards, adjustable guards or safety devices such as light curtains.

All guards should:
  • be suitable for purpose
  • be of good construction
  • well maintained
  • not give rise to an increased risk
  • not be easily bypassed or disabled
  • be at a sufficient distance from the danger zone
  • not restrict the view of the process if it is necessary
  • allow necessary maintenance
The Machinery Directive gives legal requirements for new machines being placed on the market.

Annex 1 is the Essential Health and Safety Requirements (EHSRs) and 1.3.8 is titled “Choice of protection against risks arising from moving parts”. This has similar general requirements for guards but has additional specific requirements for different types of guard.

The requirements for fixed guards are:
  • Fixings must require tools for opening or removal
  • Fixings must remain attached to the guards or the machine
  • Where possible guards must be incapable of remaining in place without their fixings
The requirements for interlocking movable guards are:
  • If possible, remain attached to the machinery when open
  • Can only be adjusted by means of an intentional action
  • The interlocking device should prevent the start of hazardous machinery functions until they are closed
  • The interlocking device should give a stop command when they are no longer closed
  • If it is possible to reach the danger zone before hazardous movement has stopped, guard locking should prevent opening of the guard until this movement is stopped
The requirements for adjustable guards are:
  • Adjust manually or automatically without the use of tools
European standards are produced in support of the legislative requirements and although the requirements have no force in law, compliance with standards give a presumption of conformity with legal requirements and are therefore a good tool to use to ensure that requirements are met. The standard for guards is EN ISO 14120 Safety of Machinery – Guards – General requirements for the design and construction for fixed and movable guards. This standard gives more specific requirements in relation to guards.

There is a reference to the safety distances detailed in EN ISO 13857 Safety of machinery – Safety distances to prevent hazard zones being reached by upper and lower limbs, which gives the required distance to danger zones by reaching over, under or through guards.

Additionally reference is made to EN ISO 13855 Safety of machinery – Positioning of safeguards with respect to the approach speeds of parts of the human body, which will enable the required distance from an interlocking movable guard to a moving part of the machine to be identified.

Guards should not create hazardous crushing or trapping points and there should be no sharp edges. They should withstand foreseeable impacts and ejections, this requirement also applies to viewing panels. The design should prevent climbing, for example by avoiding horizontal structural members on the outside surface of mesh guards.

The standard gives additional information for selection of types of guards, for example if access is likely to be at more than once a week then an interlocking movable guard should be selected over a fixed guard.

All guards should be verified using the following methods:
  • Visual inspection
  • Practical tests
  • Measurement
  • Observation during operation
  • Review of task-based risk assessment
  • Review of specification, layout and documentation
In summary, all guards should be fit for purpose. The requirements for new machinery based on the Machinery Directive and the standard EN ISO 14120 can be used to ensure that existing guards are adequate. These requirements should be fully implemented when the guarding system is updated or if guards are replaced due to damage.

Contact a Pilz representative to discuss PUWER or guards on or call 01536 460766