Manual 26710V1 ProTechTPS Total Protection System
Woodward 105
The ProTechTPS meets SIL3 with the following numbers:
PFH
7.8E-8 1/h
PFD
PFD Proof Test Interval
3.7E-5 6 month
5.6E-5 9 month
7.5E-5 1 year
Safe Failure Fraction
SFF > 90%
Diagnostic Coverage
DC > 90%
Table 6-2. SIL Specifications
Failure Rate Data
The Mean Time to Failure (MTTF) is a measure of time between failures that
cause a complete process shutdown. In determining this number, IEC61508
evaluation takes into account safe failure and dangerous detected failures that
cause a module trip.
MTTF
> 54 000 years
Table 6-3. Failure Rate
Because of the nature of the 2oo3 voting structure, a single module trip does not
shut down the process.
Response Time Data
The response time for a safety system must be less than the process safety time.
The system integrator must determine the process safety time and the response
time of all elements (sensors, ProTechTPS, actuators, etc.) that make up the
total process safety time. For this purpose, the ProTechTPS response time is
given in this manual. Refer to Chapter 3 of this manual and Figures 3-17 to 3-21
for ProTechTPS based response time information.
Limitations
When proper installation, maintenance, proof testing, and environmental
limitations are observed, the product life of the ProTechTPS is 20 years.
Management of Functional Safety
The ProTechTPS is intended for use according the requirements of a safety
lifecycle management process such as IEC61508 or IEC61511. The safety
performance numbers in this chapter can be used for the evaluation of the overall
safety lifecycle.
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