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Probability Modeling
Description
Companies are sometimes faced with the possibility of
catastrophic accident consequences and need to assess their likelihood
to determine what remediation may be necessary. In such cases, the
likelihood of an accident occurring is usually very low and must be
determined through probability modeling. Probability modeling techniques
such as fault tree and event tree analysis are used to assess the
likelihood of these process accidents and the reliability of process
systems. These analyses combine the probabilities of the events that
make up the accident scenario. The resulting event probabilities and
frequencies are also used as input into quantitative risk analysis and
reliability studies.
Both historical incident data and failure rate data
can be used to quantify fault and event trees and evaluate incident
probabilities. The studies may involve dependent failure analysis to
account for common cause failures and human reliability analysis to
quantify human error probabilities. Uncertainty analysis is used to
explore the effects of data uncertainties on the modeling results and
importance and sensitivity analysis help to identify the most important
and significant contributors.
Why model probabilities?
Increasingly, companies recognize that reliance on
purely qualitative analysis is insufficient where high consequence, low
probability accidents are concerned. Qualitative probability estimates
are subjective. Quantitative analysis provides a sounder basis for
decision making on the tolerability of catastrophic accident
probabillities.
Often, the first step in quantitative analysis is to
calculate the probability of an accident rather than calculate its
consequences. Uncertainties in accident probabilities are generally
greater than uncertainties in accident consequences and quantitative
analysis makes them more apparent so they can be addressed more readily
in decision making. Also, it is easier to calculate accident
probabilities than accident consequences.
Why Primatech?
Primatech performs event and fault tree analysis to
calculate the frequencies and probabilities of events. We have
compilations of failure rate data that are available for use in these
analyses. Also, Primatech is experienced in teaching others to perform
these analyses.
Services Offered
We calculate the frequencies of key event sequences
for a process and provide a report that documents the results.
We calculate the probabilities of important fault
tree top events and use them with event tree analysis to determine
overall hazard scenario frequencies. We provide a report that documents
the results.
We determine the input variables to which the results
of event and fault tree analysis are most sensitive. Also, we assess
which variables play the most important role in determining the results
of the analysis. We propagate uncertainties in the input variables
through the analyses to determine the uncertainties in the calculated
results. We provide a report that documents the calculations.
Training Courses Offered By Primatech
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