Safety-related equipment

What Performance Level should be implemented for the machine's emergency stop if all the hazards are protected by fixed guards?

Question: In this specific case we have a machine, on which belt drives can cause irreversible injuries. Should the emergency stop still have a dual-channel design, even though the danger points are already protected by means of guards?


Answer: The classification of the emergency stop's PLr must be set out in the risk assessment.
Legislation stipulates that a risk assessment must be produced for each machine.

Hazard points and the required PLr are always classified without taking account of safeguards.
This means that each danger point is assessed and classified without safeguards.

If the emergency stop's PL (Performance Level) is not specified in a C standard, then it must be defined in the risk assessment.
The recommendation is always to classify the emergency stop based on the greatest hazard emanating from the machine.



Pilz Automation Safety L.P.
7150 Commerce Boulevard
Canton, MI 48187

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