7
Call points BG/pB Ex E VErsions
TM244 May 2019 www.eaton.com
Call points BG/PB Ex e Versions
English
Assessment of functional safety
The PB Call Point is intended for use in a safety system
conforming to the requirements of IEC61508 . UL has
conducted a Failure Modes Effect and Diagnostic
Analysis (FMEDA) of the PB Push Button unit against the
requirements of IEC61508-2 using a proof test interval
of 8760hrs .
The results are shown below and are based on Route 1
H
.
The Call Point is classed as a Type A device .
pB pushbutton
Safety Function of PB Push Button:
‘To raise the alarm upon pushing the button’
Architectural
constraints:
Type A
HFT=0
SFF= 79.7%
Proof Test Interval
=8760Hrs
MTTR = 8 Hrs
SIL2
Random hardware
failures:
λ
DD
= 0
λ
DU
= 3.43E-08
λ
SD
= 0
λ
SU
= 1.34E-07
Probability of failure
on demand:
PFD
AVG
=1.50E-04
(Low Demand Mode)
SIL3
Probability of
Dangerous failure on
safety function:
PFH = 3.43E-08
(High Demand Mode)
SIL3
Hardware safety
integrity compliance
[1]
Route 1
H
Systematic safety
integrity compliance
Route 1
S
Systematic Capability
SC2
Overall SIL-capability
achieved
SIL 2 (Low Demand)*
SIL 2 (High Demand)*
*Limited to SIL 2 due to SFF value
0.0000
0.0020
0.0040
0.0060
0.0080
0.0100
0.0120
0.0140
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75
PF
D
(avg)
Time (years)
PB
Proof Time Interval versus SIL contribution
SIL
2
à
cause
d
e
contraintes
d'archite
cture
(SFF
)
Conditions of safe use
The following conditions apply to the installation,
operation and maintenance of the assessed equipment .
Failure to observe these may compromise the safety
integrity of the assessed equipment:
1 . The user shall comply with the requirements given in
the manufacturer’s user documentation (This Safety
Manual and Technical manual) in regard to all relevant
functional safety aspects such as application of use,
installation, operation, maintenance, proof tests,
maximum ratings, environmental conditions, repair, etc;
2 . Selection of this equipment for use in safety functions
and the installation, configuration, overall validation,
maintenance and repair shall only be carried out by
competent personnel, observing all the manufacturer’s
conditions and recommendations in the user
documentation .
3 . All information associated with any field failures of
this product should be collected under a dependability
management process (e .g ., IEC 60300-3-2) and
reported to the manufacturer .
4 . The unit should be tested at regular intervals to identify
any malfunctions; in accordance with this safety manual .
