Flowserve MX Electronic Actuator SIL Safety IOM - Manual (Page 2)

Limitorque MX Electronic Actuator FCD LMENIM2350-01 – 9/13
2
FLOWSERVE PROPRIETARY INFORMATION
Use or disclosure of this information is subject to the restrictions on the title page of this document
Contents
1 Scope 5
1.1 System Overview 6
2 Safety Integrity Level [SIL] 7
2.1 Failure Rates/Failure Modes 7
2.1.1 Safe, but Detected (
λ
SD
) 7
2.1.2 Safe, but Undetected (
λ
SU
) 7
2.1.3 Dangerous, but Detected (
λ
DD
) 7
2.1.4 Dangerous, but Undetected (
λ
DU
) 7
2.2 Mission Time (Tmission) 7
2.3 Partial Stroke Test Period 7
2.4 Proof Test Period (Tpt) 8
2.5 FIT 8
2.6 Mean Time to Restoration (MTTR) 8
2.7 SFF 8
2.8 PFD
avg
8
2.9 RRF 8
2.10 SIL vs. PFD
avg
vs. RFF 8
3 Safety Requirements 9
3.1 Monitor Relay Annunciation 9
3.2 Local Control Knobs Sensors 9
3.3 ESD Override for Knobs 9
3.4 The LCD Display May Also Indicate Warnings and Alarms 9
3.5 Partial Stroke Test Interval 9
3.6 Proof Test Interval 10
3.7 Basic Safety Configuration Requirements 10
3.8 Optional Emergency Overrides 10
3.9 Labeling 10
4 Design for Safety 11
4.1 LimiGard™ 12
4.2 Optional Safety Add-ons 12
4.2.1 Fire Protection 12
4.2.2 Safety Critical User Wiring 13
5 Limitorque MXa Safety Functions 14
5.1 Emergency Shutdown Open (ESD-Open) 14
5.2 Emergency Shutdown Close (ESD-Close) 14
5.3 Emergency Shutdown ‘Move To’ (ESD-Position) 14
5.4 Emergency Shutdown Stop (ESD-Stop) 14
5.5 Emergency Shutdown Ignore (ESD-Ignore) 14
5.6 Fail No-Action (Stay Put) Operation 15
5.7 Multiple ESD Functions for Basic PST 15
6 MXa Safety 16
6.1 PFDavg for MXa Actuator without PST 16
6.2 PFDavg for MXa Acutator with Monthly PST 17
7 Partial Stroke Testing [PST] 18
7.1 Basic PST Description 18
7.2 Enhanced PST Description 18
7.2.1 Monitor Relay Behavior When Configured as Enhanced PST 19