E2S AlertAlarm A121 Instructions/Service Manual page 6

INSTRUCTION & SERVICE MANUAL
A121 AlertAlarm Sounder
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:
1. Random Hardware Failures and Systematic Failures and (route 2
2. As an unvoted item (i.e. hardware fault tolerance of 0) at SIL 2.
The product was assessed against failure modes:
•
Failure sound or annunciate
3. When employing the device in a SIL2 compliant system the user should ensure frequent or continuous automatic
monitoring of continuity and current draw, refer to specific model nominal current draw data.
E2S Warning Signals Impress House, Mansell Road, Acton, London W3 7QH
Integrity in respect of failure to function
Total Failure rate
"Hazardous" failure rate (revealed)
"Hazardous" failure rate (unrevealed)
"Safe" failure rate (revealed)
"Safe" failure rate (unrevealed)
System type
Hardware Fault Tolerance
Diagnostic Coverage
PFD (hazardous failure)
Proof Test Interval
).
H
SIL2 & SIL1
0.55 pmh
0 pmh
0.55 pmh
0 pmh
0 pmh
B
0
>80%
-3
2.4 x 10
Up to 1 year
Sheet 6 of 6 e2s.com D221-00-051-IS Issue 6 10/06/2024