The post AutoQuiz: What Are Common Terms Used to Quantify Dangerous Industrial Failures? first appeared on the ISA Interchange blog site.
This automation industry quiz question comes from the ISA Certified Automation Professional (CAP) certification program. ISA CAP certification provides a non-biased, third-party, objective assessment and confirmation of an automation professional’s skills. The CAP exam is focused on direction, definition, design, development/application, deployment, documentation, and support of systems, software, and equipment used in control systems, manufacturing information systems, systems integration, and operational consulting. Click this link for more information about the CAP program.
a) probability of failure on demand (PFD) and nuisance trip rates
b) probability of failure on demand (PFD), risk reduction factor (RRF), and safety availability (SA)
c) mean time between failure, spurious (MTBFsp); nuisance trip rates; and safety availability (SA)
d) mean time between failure, spurious (MTBFsp) and risk reduction factor (RRF)
e) none of the above
PFD, RRF, and SA are extremely important in quantifying dangerous failures.
The correct answer is B, probability of failure on demand (PFD), risk reduction factor (RRF), and safety availability (SA). Spurious trips and nuisance trips are indicative of “safe” failure modes, not “dangerous” failures. This makes answers A, C, and D incorrect.
Reference: ANSI/ISA-84.00.01-2004 standard
Source: ISA News