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Safety Manual SIL KCD2-STC-(Ex)1.HC(.SP), HiC2025HC
Abbreviations
5
Abbreviations
DCS
D
istributed
C
ontrol
S
ystem
ESD
E
mergency
S
hut
d
own
FIT
F
ailure
I
n
T
ime
FMEDA
F
ailure
M
ode,
E
ffects and
D
iagnostics
A
nalysis
λ
s
Probability of safe failure
λ
dd
Probability of dangerous detected failure
λ
du
Probability of dangerous undetected failure
λ
no effect
Probability of failures of components in the safety path that have
no effect on the safety function
λ
not part
Probability of failure of components that are not in the safety path
λ
total (safety function)
Safety function
HFT
H
ardware
F
ault
T
olerance
MTBF
M
ean
T
ime
B
etween
F
ailures
MTTR
M
ean
T
ime
T
o
R
epair
PFD
avg
Average
P
robability of
F
ailure on
D
emand
PFH
P
robability of dangerous
F
ailure per
H
our
PTC
P
roof
T
est
C
overage
SFF
S
afe
F
ailure
F
raction
SIF
S
afety
I
nstrumented
F
unction
SIL
S
afety
I
ntegrity
L
evel
SIS
S
afety
I
nstrumented
S
ystem
T
proof
Proof Test Interval