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New machinery guarding standard

24 August 2015

EN ISO 14120 (Safety of machinery - Guards - General requirements for the design and construction of fixed and movable guards), a new common global standard for fixed and movable guards, is going through the approval process in the European Commission. Neil Dyson, business line manager for Machinery Safety at TÜV SÜD Product Service, explains the implications

In theory, the Standard will only apply to manufacturers of machinery. However, in reality, it will also apply to anyone who is adding new or additional guarding to an existing machine. Therefore, the machine user will need to be aware of the changes as they may be producing guarding themselves, or at the very least, specifying it from a supplier.

EN ISO 14120 replaces EN 953, and it is clear that it is more prescriptive in its requirements, leaving less room for interpretation by individual machinery builders. For the first time, the Standard specifically refers to verification methods. These are outlined in Annex C, which covers guidelines for the selection of guards according to the number and location of hazards.

If there is a safety problem further down the line, and a machinery builder cannot demonstrate that they followed the very specific guidance in Annex C, it may suggest that due diligence has not been followed and legal action may be taken.

Annex A in the old Standard now becomes Annex B (Guidelines for the selection of guards against hazards generated by moving parts) in EN ISO 14120. This provides a flow chart for the selection of guards against hazards generated by moving parts. In both standards, the flow chart asks: "Is access required only for setting, process correction or maintenance?” In the old Standard the answer "yes” would prompt the next question of: "Is access required more than once per shift?”, while the new Standard simply asks: "is frequency of access high (more than once per month)?”.

This of course has significant implications as a typical manufacturing day may include three shifts, each of which may require a different machine configuration, potentially more than 1,095 alterations a year. However, the new Standard asks manufacturers to only consider if access is required more than twelve times per year, whereas the old standard is more focused on the frequency of individual shifts.

Beyond this, the options in both Annex B and C of the new Standard (which were A and B in the old standard) have changed. For example, in the previous Standard where access was required more than once per shift, a fixed guard, or a movable guard with interlocking device or without guard locking could be used. However, the new Standard only allows a fixed guard to be used if replacement and removal is easy. This of course has significant implications for machinery that is currently in production as it may require additional costs for part redesigns on new builds.

Section 6 of both Standards covers the selection of types of guards. Both list the most important selection criteria as being:

  • the probability and foreseeable severity of any injury as indicated by the risk assessment
  • the intended use of the machine
  • the hazards present at the machine
  • the nature and frequency of access.

However, the new Standard introduces the concept of ‘the foreseeable misuse and defeat of the guards’. This new element requires a machinery builder to consider more deeply how an operator could disable a guard or interfere with a machine in order that it continues to operate without guarding i.e. looking beyond the obvious intended use. A thoroughly documented risk assessment is therefore vital to not only highlight where guarding is required, but also how the machinery builder has considered that it may be defeated.

Think more deeply

Section 9 of the old Standard now becomes section 8 (Information for use), with 8.3 (Installation) being greatly expanded. Whereas the old Standard simply stated: "Instructions shall be supplied for the correct installation of guards and associated equipment”, the new Standard will make machinery builders think more deeply about how installation is approached, with specific requirements for fixing when guards are attached to a structure.

The Standard now requires that consideration is given, but is not limited to:

  • fixing to a floor
  • assembling of movable guards
  • number and types of fixings
  • compliance with other relevant standards

Within the new Standard, Section 8.5 (Removal of guards) has also been expanded from requiring that: "information shall be provided indicating any actions to be taken before guards may be removed safely”, to a more detailed list which includes requirements on the appropriate use of a tools.

As some elements of the new Standard are now more thoroughly detailed, this will help to make risk assessments less subjective as it leaves less room for interpretation by individual machine builders. However, while these changes may be considered common sense by those who already have solid due diligence procedures in place, the new Standard’s sections and annexes have been renumbered, necessitating a full update of any documentation for everyone – not an insignificant task.

Key Points

  • EN ISO 14120, which replaces EN 953, is more prescriptive in its requirements, leaving less room for interpretation
  • The new Standard introduces the concept of ‘the foreseeable misuse and defeat of the guards’
  • The new Standard will make machinery builders think more deeply about how installation is approached

 

 
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