YOKOGAWA RAKD series, User Manual, Page: 68 / 72

<A1. SAFETY INSTRUMENTED SYSTEMS INSTALLATION>
A1-6
IM 01R01B30-00E-E 6th edition October 01, 2014 -00
All Rights Reserved. Copyright © 2003, Rota Yokogawa
Table 3: Summary for RAKD ([V1]) with standard limit switches 7 – Failure rates
Profile 2 Profile 4
Fail Safe Detected ( λ SD) 0 FIT 0 FIT
Fail Safe Undetected ( λ SU) 163 FIT 205 FIT
Fail Dangerous Detected ( λ DD) 4 FIT 19 FIT
Fail Dangerous Undetected ( λ DU) 101 FIT 147 FIT
SFF
4
62.4% 60.3%
MTBF 375 years 261 years
SIL AC
5
SIL2 SIL2
Safety metrics according to ISO 13849-1
6
:
MTTF
d
(years) 1730 899
DC 6% 15%
Category (CAT) CAT 1 CAT 1
Performance Level (required) PL
r
= c PL
r
= c
Performance Level (calculated) 6.60E-08 1/h 1.27E-07 1/h
T[Proof] = 1 year T[Proof] = 5 years T[Proof] = 10 years
PFDAVG = 2.96E-04 PFDAVG = 1.37E-03 PFDAVG = 2.72E-03
Table 4: Summary for RAKD ([V2]) with fail-safe limit switches 3 – Failure rates
Profile 2 Profile 4
Fail Safe Detected (
λ
SD) 0 FIT 0 FIT
Fail Safe Undetected ( λ SU) 162 FIT 215 FIT
Fail Dangerous Detected ( λ DD) 4 FIT 19 FIT
Fail Dangerous Undetected ( λ DU) 84 FIT 139 FIT
SFF
4
66.3% 62.7%
MTBF 399 years 259 years
SIL AC
5
SIL2 SIL2
Safety metrics according to ISO 13849-1
6
:
MTTF
d
(years) 1297 723
DC 5% 12%
Category (CAT) CAT 1 CAT 1
Performance Level (required) PL
r
= c PL
r
= c
Performance Level (calculated) 8.80E-08 1/h 1.58E-07 1/h
T[Proof] = 1 year T[Proof] = 5 years T[Proof] = 10 years
PFDAVG = 4.01E-04 PFDAVG = 1.86E-03 PFDAVG = 3.68E-03