E2S AlertAlight AL112NH Instructions/Service Manual page 5

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:
The beacon and sounder units must be powered and monitored separately to be complaint.
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 (Sounder)
•
Failure to respond to an input by illuminating (Beacon)
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
Component of Combined unit
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
Sounder
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 5 of 5
Beacon
SIL2 & SIL1
0.84 pmh
0 pmh
0.84 pmh
0 pmh
0 pmh
B
0
>80%
-3
1.6 x 10
Up to 1 year
e2s.com D221-00-301-IS Issue 5 27/02/2024