Tab 15. Device specific parameters
5) FUNCTIONAL SAFETY RELEVANT SPECIFICATIONS
5.1 Application and Environmental Limits
The tested device is intended for media such as Gas and Fluid. The applicable fluid shall be clean and non-corrosive fluid.Required
Air-quality-level in accordance to ISO 8573-1: 7–1–4 for particles – water – oil. The tested device is rated up to 4 bars and up to 8 bars.
For the detailed materials of construction of tested device, please refer to user manual, operation instruction, maintenance instruction.
The pneumatic actuator is intended for use in Indoor, Outdoor and/or Hazardous Area (ATEX II 2GD c T4) at temperaturerange of
–20 °C to 80 °C.
5.2 SIL Capability
The actuators are suitable for use in a safety instrumented system up to SIL 2 (low demand mode). Under consideration of the minimum
required hardware fault tolerance HFT = 1 the actuators may be used in a redundant architecture up to SIL 3.The development and
manufacturing process and the functional safety management applied by the manufacturer in the relevant lifecycle phases of the
product has been inspected and assessed as suitable for the use in applications with a maximum Safety Integrity Level of 3 (SC 3).
5.3 Requirements Of Other Components
In order to determine whether tested device is suitable for use in a certain safety-related system, it is necessary to determine the
PFDavg value of the overall system. Usually it is presumed that a final element (valve + actuator) uses up to 50 % of the total available
PFDavg value.
Route of Assessment 2H / 1S
Type of Sub-system Type A
Mode of Operation Low Demand Mode
Hardware Fault Tolerance
HFT
0
Lambda Dangerous
confidence level of calculation 1-α = 95 %
λ
D
3.50 E-07/h 350 FIT
Lambda Dangerous Undetected
assumed Diagnostic Coverage DC = 0 %
λ
DU
3.50 E-07/h 350 FIT
Mean Time To Dangerous Failure
MTTFD
2.86 E+06 h 326 a
Average Probability of Failure on Demand 1oo1
assumed Proof Test Interval T1 = 1 year
PFD
avg
(T
1
)
1.53 E-03
Average Probability of Failure on Demand 1oo2
assumed Proof Test Interval T1 = 1 year
assumed β1oo2 = 10 %
PFD
avg
(T
1
)
1.53 E-04
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