KROHNE TT 51 SERIES EN - Manual (Page 17)

SAFETY-RELATED CHARACTERISTICS
7
17
TT 51 SERIES
www.krohne.com 09/2010 - 4000869801 - AD TT 51 SIL R01 en
Single TC sensor
Dual TC sensor
Failure category SFF PFD
avg
at T
proof
= PFH SIL AC
λ
SD
λ
SU
λ
DD
λ
DU
[FIT] [%] 1 year 2 years 5 years 10 years
Close
coupled low
stress
0 146 483 45 93.3 2.26E-04 4.22E-04 1.01E-03 1.98E-03 4.50E-08 SIL 2
Close
coupled high
stress
0 146 2288 140 94.5 7.325E-04 1.33E-03 3.15E-03 6.19E-03 1.40E-07 (SIL 2)
Extension
wires low
stress
0 146 1288 140 91.1 6.99E-04 1.31E-03 3.13E-03 6.16E-03 1.40E-07 (SIL 2)
Extension
wires high
stress
0 146 18388 2040 90.0 1.02E-02 1.90E-02 4.56E-02 8.98E-02 2.04E-06 (SIL 1)
The boxes marked in light grey in the following tables mean that the calculated PFD
avg
and/or
PFH values are within the allowed range for SIL 2 according to table 2 / 3 of IEC 61508-1 but do not
fulfill the requirement to not claim more than 35% of this range, i.e. to be better than or equal to
3.50E-03 respectively 3.50E-07 1/h.
The boxes marked in medium grey mean that the calculated PFD
avg
and PFH values are within the
allowed range for SIL 2 according to table 2 / 3 of IEC 61508-1 and do fulfill the requirement to not
claim more than 35% of this range, i.e. to be better than or equal to 3.50E-03 respectively
3.50E-07 1/h.
The boxes marked in dark grey indicate that the PFD
avg
respectively the PFH values do not fulfill
the requirements for SIL 2 of table 2 / 3 of IEC 61508-1.
Failure category SFF PFD
avg
at T
proof
= PFH SIL AC
λ
SD
λ
SU
λ
DD
λ
DU
[FIT] [%] 1 year 2 years 5 years 10 years
Close
coupled low
stress
0 146 588 41 94.7 2.10E-04 3.88E-04 9.21E-04 1.81E-03 4.10E-08 SIL 2
Close
coupled high
stress
0 146 4378 50 98.9 3.44E-04 5.61E-04 1.21E-03 2.30E-03 5.00E-08 SIL 2
Extension
wires low
stress
0 146 2378 50 98.0 2.96E-04 5.13E-04 1.16E-03 2.25E-03 5.00E-08 (SIL 2)
Extension
wires high
stress
0 146 40188 240 99.4 2.11E-03 3.15E-03 6.27E-03 1.15E-02 2.40E-07 (SIL 1)
.book Page 17 Thursday, September 9, 2010 4:19 PM