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European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH www.e2s.com Tel: +44 (0)208 743 8880
Document No. D202-00-211-IS Issue 5 16-12-2022 Sheet 7 of 7
15) SIL 2 Reliability Data
Reliability and Functional safety IEC/EN61508 which has
been assessed and is considered suitable for use in low
demand safety function:
Random Hardware Failures and Systematic Failures
(route 2H)
As an unvoted item (i.e. hardware fault tolerance of
0) at SIL 2
The product was assessed against failure modes:
Failure to close a contact when the call point is
struck with specified force
Failure to open a contact when the call point is
struck with specified force
Spurious output despite no input
Integrity in respect of failure to close
SIL 2
System Type
A
Hardware Fault Tolerance
0
Safe Failure Fraction (credible claim)
75%
PFD (hazardous failure)
2.3 x 10
-3
Proof Test Interval
Up to 1 year
