Product category:
Machinery/plant guarding and protection
News Release from: Pilz Automation Technology | Subject: Power press article
Edited by the Manufacturingtalk Editorial
Team on 27 October 2004
Power press users should expect
safetywise
Pilz provides an update on what the HSE is expecting from users of power presses now that HSG236, 'Maintenance and thorough examination of power presses', has been available for a year.
In this article Pilz provides an update on what the HSE is expecting from users of power presses now that HSG236, 'Maintenance and thorough examination of power presses', has been available for a year It is now one year since the HSE (Health and Safety Executive) published its new guidance document 'Maintenance and thorough examination of power presses', reference HSG236
This article was originally published on Manufacturingtalk on 28 Jul 2008 at 8.00am (UK)
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It replaces the old guidance PM 79 and the HSE will be looking for suitable maintenance and examination systems and records to be in place from March/April 2005.
The press examiners' organisation, the Safety Assessment Federation (SAFed), was one of the main contributors to this revision of PM79.
It is aware of the contents of HSG 236 and the lead-in time, and has actively been forwarding information to its members to keep them up-to-date with developments.
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The Confederation of British Metal forming (CBM), the Engineering Employers Federation (EEF) and the Metalforming Machinery Makers Association (MMMA) were also heavily involved in drafting the revision, and all have provided facilities for their members to find out about and discuss HSG 236.
The HSE (Health and Safety Executive) has been active in providing information to these bodies, mainly by running seminars to ensure sufficient understanding of the changes, particularly the additions regarding control systems.
At first sight, the clauses (96 to 107) could seem daunting to press users and examiners alike, but this is not necessarily the case.
To help, Appendix 4 of the guidance has a simple flow chart outlining the tests that need to be carried out on the safety related control systems.
Following the flow chart and ticking off the items using the check sheet shown in Appendix 3 is not difficult and should not add significantly to the time taken to carry out the six-monthly or annual check.
When the new guidance is used for the first time, the initial check may take longer as it will inevitably require that the drawings are checked to ensure that any obvious modifications and alterations are documented.
These inspections will also allow the user to determine the frequency of maintenance as mentioned in Appendix 5.
If the inspections show that the safety related systems are monitored 2-channel (dual redundant), then the maintenance periods can be extended accordingly.
If the press is a full revolution type, with a lever activated key-clutch, then the electrical inspection may be very simple, as, effectively, there is no electrical safety related control system involved in the press operation.
All that is necessary is to ensure that the motor starter is sufficiently well protected (fused and fitted with correct overloads), has lockable isolation facilities and is visually in good order with all the covers in place.
Subsequent inspections may well be only visual to see that nothing has changed.
Where the press is more complex, with a pneumatic or hydraulic clutch brake, the initial checks may require a little more care and understanding.
The rigor of safety system checks will be greater if the press is manually loaded and or unloaded.
Here the safety system would include gate switches or ESPD (electrosensitive protection devices), overrun cams and anti repeat systems.
There will also be included such items as dual PSV (press safety valve) with monitoring, air pressure switches and, in the case of variable speed presses, selectable stopping cams.
All of these items form part of the safety related systems.
Good clear drawings will aid the press examiner to get a grasp of how the system operates and which clauses in the guidance are relevant.
The most appropriate way for any press user to assist the press examiner is to keep a copy of all aspects of the maintenance history so that after the initial inspection to set the datum, future inspections are again not much more than visual checks to ensure that things have not changed to allow safety system degradation.
Generally the new guidance will not add significantly to the press downtime during statutory examination, providing that the documentation (including circuit diagrams) is available and that the control panels are tidy, with no 'birds nests' of cables making checking difficult.
If all covers are in place and all cables to sensors and valves are undamaged and well routed, with glands in place (indications of effective maintenance), the inspector may require no further action.
Further advice and assistance with safety related controls on presses is available from Pilz.
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