Honeywell krom schroder BCU 440 - Safety-Specific Characteristic Values

BCU 440 · Edition 01.17 31
Technical data
9.1 Safety-specific characteristic values
In the case of ionization control,
suitable for Safety Integrity Level
SIL 3
Diagnostic coverage DC 92.7%
Type of subsystem Type B to EN 615082, 7.4.3.1.4
Operating mode
High demand mode pursuant to
EN 615084, 3.5.12
Mean probability of dangerous
failure PFH
D
1.92 x 10
8
1/h
Mean time to dangerous failure
MTTF
d
MTTF
d
= 1/PFH
D
Safe failure fraction SFF 98.8%
The specified values apply for the combination with
flame rod (sensor) and a unit of the BCU 400 series.
No characteristic values are available for flame control
with UVS sensor.
For flame control in continuous operation using a UV
sensor UVD 1 or a flame detector UVC 1, safety-spe-
cific characteristic values are available for the Safety
Integrity Level SIL. Further information can be found in
TI UVD 1 or TI UVC 1 in the Docuthek.
Relationship between the Performance Level (PL)
and the Safety Integrity Level (SIL)
PL SIL
a –
b 1
c 1
d 2
e 3
Pursuant to EN ISO 138491:2006, Table 4, the BCU
can be used up to PL e.
Max. service life under operating conditions:
20 years after date of production.
For a glossary of terms, see page 34 (Glossary).
For further information on SIL/PL, see www.k-sil.de