The phrase "average probability of failure" is correct and usable in written English.
It can be used in contexts related to risk assessment, statistics, or reliability engineering when discussing the likelihood of failure in a given scenario.
Example: "The average probability of failure for this component is estimated to be 5% over its lifespan."
Alternatives: "mean failure probability" or "typical likelihood of failure".
The average probability of failure on demand (PFD) is taken as the objective function.
It also introduces a new safety index, average probability of failure on actual demand (PFaD), and an availability index, manifested availability (mAv).
The objectives to optimize are the average probability of failure on demand, which represents the system safety integrity, Spurious Trip Rate and Lifecycle Cost.
For the chemical process industry (CPI), SIL verification often means calculation of average probability of failure on demand (PFDavg) of a SIS.
Approximation formulas for evaluation of average probability of failure on demand (PFDavg) involving degradation are developed within different subsequent proof testing intervals, and Weibull distributions are adopted to model the degradation processes of the final elements.
In addition, the down time tc1 shown in the standard is newly defined because it is the basis to get the results of average probability of failure on demand of system architectures and its meaning is not clearly explained.
This requirement is closely related to their probabilistic performance measures which are either their average probability of dangerous failure on demand (PFDavg) or their average frequency of failure (PFH: Probability of Failure per Hour).
The key idea of the method proposed is to perform RBD analysis and calculation of average probability of dangerous failure on demand (PFDG) at each stage of system degradation, which is caused by failures of redundant channels.
Key idea of the method is to calculate average probability of dangerous failure on demand (PFDG) at each stage of system degradation, which is caused by failures of redundant channels.
The objectives to optimize are the Average Probability of Dangerous Failure on Demand, which represents the system safety integrity, the Spurious Trip Rate and the Lifecycle Cost.
To research SIS's safety performance comprehensively, multiple failure modes and safety impact factors are considered when calculating a system's Probability of Failure on Demand (PFD), average Probability of Failing Safely (PFS) and average availability, while the Markov model and reliability block diagram are combined to construct a safety model.
