When PUWER isn't enough
Many employers believe that provided they carry out regular inspections of their production machines in line with PUWER, they have done all that is necessary to meet their legal obligations in respect to machine safety. But if the machine incorporates electro-sensitive protection equipment that may not be true, says Gary Trewhitt of Safety Systems Technology, a division of TÜV SÜD Product Service.
The Provision and Use of Work Equipment Regulations 1998 (PUWER) are wide ranging, and most organisations in the manufacturing sector have become used to implementing their provisions. In particular, responsible organisations are careful to ensure that their machines are inspected in line with Section 6 which requires, among other things, that if the machines are exposed to conditions that may lead to deterioration, the inspections must be repeated "at suitable intervals".
Since, in reality, every machine is exposed to conditions that may lead to deterioration, the requirement effectively means that all machines must be regularly inspected. It would seem reasonable to assume that, provided these PUWER inspections are conducted conscientiously and at appropriate intervals, employers have done all that is needed to ensure that their production machinery is safe. Unfortunately, if that machinery incorporates electro-sensitive protective equipment (ESPE), this may not be the case. ESPE which includes, for example, light guards and laser scanners, and is increasingly widely used on modern machines, where it often takes the place of traditional guarding. Because of the growing popularity of ESPE and the need to ensure that it is properly used and maintained, the Health and Safety Executive (HSE) has published guidance note HSG180, 'Application of electro-sensitive equipment using light curtains and light beam devices to machinery'.
Justifying the decision
This document, which can be downloaded free-of-charge from the HSE website (www.hse.gov.uk), is provided for guidance only. Nevertheless, because the use of ESPE is almost always safety related, any employer who chooses to disregard HSG180 should be very sure that they could justify their decision if they are called upon to do so - quite possibly in a court of law.
The section of HSG180 that deals with inspection refers directly to Regulation 6 of PUWER, which as we have seen, includes a requirement for inspections to be conducted on a regular basis. If it stopped there, then regular PUWER inspections would indeed comply with the recommendations of HSG180. But there is more - paragraph 118 of HSG180 goes on to state, "inspection and testing is required where the safe operation [of the ESPE] is critically dependent on its condition in use and deterioration would lead to a significant risk to the operator or other worker. If this is the case, then installations using ESPE should be inspected at suitable intervals."
Of course, this instantly raises the question of what a suitable interval is. The answer is provided in paragraph 124 of HSG180, which states, "the recommended maximum period between each periodic inspection and test is six months for type 4 ESPE and twelve months for type 2 ESPE, but this will depend on the equipment it is fitted to and the risk as a whole." The "types" of ESPE referred to are defined in IEC 61496-1, 'Safety of machinery, Electro-sensitive protective equipment; Part 1: General requirements and tests'. Type 2 ESPE has a means of periodic test to reveal a failure to danger, while type 4 will not fail to danger for a single fault and is resistant to an accumulation of single faults.
By now it will be clear that the frequency of periodic testing required for ESPE depends on multiple factors, and that a six-month interval will apply in many cases.
Now consider the periodic PUWER assessments. There is, of course, no simple answer to the question of how often these should be carried out, but there are very few cases where the interval between assessments is as short as six months. In fact, the norm seems to be for assessments to be carried out annually, which, in many cases will not be sufficiently often to meet the recommendations of HSG180 for ESPE installed on the machine.
In other words, it is perfectly possible that inspection of ESPE will need to be treated as a separate task, and not simply as part of the routine PUWER assessments. But even that is not quite the end of the story, because HSG180 raises the issue of the competence of the person performing the inspection. This is not an issue that can be dismissed as trivial - inspecting ESPE installations may appear to be an easy task but, in reality, there are many factors that have to be carefully and skilfully evaluated.
These include inspecting the positioning of the equipment to make sure that it is the correct distance from the danger zone, ensuring that suitable safeguards are in place to prevent access to the danger zone from directions not covered by the ESPE, testing the overall response time, testing the detection capability, inspecting the stopping performance monitor if one is fitted, and testing the primary machine control elements to ensure correct functionality. And, once the ESPE inspection has been completed it must, of course, be documented so that evidence can be produced, if required, to verify that the appropriate inspection regime has been followed.
When all of these factors are taken into account, it is apparent that there are likely to be many companies that have neither the in-house expertise nor the capacity to perform these additional ESPE assessments. For this reason, Safety Systems Technology has a new standalone ESPE periodic inspection and test services that can be tailored to meet the precise needs of individual sites.
The use of ESPE on machines offers many benefits and, if correctly applied, can provide levels of safety at least as good as those offered by more conventional guarding and protection techniques. For ESPE to dependably fulfil its purpose, however, it must be regularly inspected and tested as recommended in HSG180 - as we have seen, simply relying on routine PUWER inspections is not enough. So, while it is still fresh in your mind, it could be a very good idea to start making your ESPE inspection plans right now.
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