I am currently employed in a wood manufacturing industry, creating kitchen and bedroom furniture, we have a number of edge banding machines on site that are fitted with interlocks on the hoods which stop the machine should a hood be opened, the normal run down time for any milling heads or tools is around 10 seconds.

Can anyone clarify that the fitted interlocks with moving part run down times is acceptable, or would we need to fit locked interloocks which will not open until the machine has come to a complete stop.

I have had a look via HSE website at WIS27, WIS38 and I114 puublications but is seems to be a very grey area.

Edited by user 11 November 2019 11:14:20(UTC)  | Reason: Spelling

Hi RVThomson,

Thanks for the reply, the RA's do clearly state that the machinery has moving parts, but my question is do the hoods have to be physically locked until the machine stops or can the interlocks be used based on the tooling run down times of 10 seconds or less, taking human speed and distances from hazards to hoods into consideration

Are the machines CE marked?

If so then they should really comply with the Harmonised Standards, in this case ISO 18217.

If this is not utilised then the manufacturer of the machine must be able to prove that their approach is as safe, or safer than following the harmonised standard.

ISO 18217 requires guard locking where the rundown time of the cutters exceeds 10s.

All moveble guards must be interlocked and these must reach at least PL = c under ISO 13849.

Thanks for all your help, much appreciated and this has given me a lot to think about.

This is easily rectified. You can get interlocks that have a timed release from the machine power being cut. You set this to the 10 secs and you will have no problem. Any vaguely qualified engineer with a small amount of electrical experience should be able to fit this. It will just replace your current interlocks.

From experience, don't be tempted to over egg the stopping time. You will only end up frustrating the operator, especially if they feel under time pressure. They will be more tmepted to take shortcuts to circumnavigate the interlock.

From a different perspective, is it possible to reduce the stopping time of the machine? 

I was under the impression that just because a machine has been CE stamped does not mean you are to assume it is safe to use. You must still carry out a thorough inspection and assessment before placing into work. You have a duty to ensure the machine is made safe before it is put into use.

Furthermore "simple" replacements of parts does not invalidate the CE mark, or require a new conformity

"Simply repainting a machine, undertaking servicing and routine maintenance, changing motors, replacing parts such as guards with essentially identical new ones, even the replacement of original safety critical parts with newer better ones (eg modern higher quality interlocks wired into the control system in the same way as before) does not amount to a substantial change. However, compliance with existing law (PUWER, etc on users of work equipment, section 6 duty on suppliers etc) is required"

Maybe my understanding of this quote from the HSE is wrong? Or maybe I am stretching the definitions?

Firstly, you need to understand the origin of the 10 sec.  It is not, to prevent contact with the cutter, as has been said, a wodworking cuttng tool will do an awful lot of damage in 10 sec, plus with larger equipment this can be legitimately extended up to 35 sec.

The origin of this is such that when the equipment is stopped by one user, the cutter will have stopped rotating by the time another user approaches the machine to set it up.

As far as modifications to a CE marked machine goes, especially to functional safety circuits, and modifications to stop times go, these as Ian Bell2 has suggested will have ramifications outside those immediately obvious, in fact even like for like replacements can invalidate the CE mark, and the functional safety validations of a machine if the devices that are being fitted are not identical, as things like B10d values may differ, and differ by significant amounts, and other deviations between the specification of even similar parts which may "fit", may compromise the Performance Level of the safety function.

Thus, the 10s stop time is not to prevent access to the running down cutters, if you consider the same rules apply to open blade machinery such as bandsaws and circular saws, where by there is no prevention of access to the blade.