When PUWER is not enough

Many employers assume that if they carry out regular inspections of production machines, in line with the Provision and Use of Work Equipment Regulations (PUWER), that they have done all that is necessary to meet their legal obligations.

In particular, responsible organisations are careful to ensure that their machines are inspected in line with Section 6 of PUWER, which includes a requirement that if 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, machinery is safe. Unfortunately, if that machinery incorporates electro-sensitive protective equipment (ESPE), this may not be the case.

ESPE includes, light guards and laser scanners, and is increasingly taking the place of traditional guarding on machines. 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’.

The section of HSG180 that deals with inspection refers directly to Section 6 of PUWER and also states that "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."

The right timing

Of course, this raises the question of what a suitable interval is. The answer is provided in paragraph 124 of HSG180, which states that "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 in HSG180 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 the norm seems to be annual assessments. In many cases this will not be regular enough to meet the recommendations of HSG180 for ESPE installed on a machine. This means that that inspection of ESPE must be treated as a separate task, and not simply as part of the routine PUWER assessments.

The right person

HSG180 also raises the issue of the competence of the person performing the inspection as there are many factors that require skilful evaluation. These include ensuring that the equipment is the correct distance from the danger zone; ensuring suitable safeguards prevent access to the danger zone from directions not covered by the ESPE; testing the overall response time and the detection capability; inspecting the stopping performance monitor; and testing the primary machine control elements to ensure correct functionality.

Once the ESPE inspection has been completed it must also be documented so that evidence can be produced to verify that the appropriate inspection regime has been followed.

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. However, to ensure that ESPE dependably fulfils its purpose, simply relying on routine PUWER inspections is not enough and it must be regularly inspected and tested against the HSE guidance note HSG180. So, while this topic remains fresh in your mind, it is advisable to start making your ESPE inspection plans right now.