Definition:
Concept Number: *131
English Master: Safety-Factor
Synonyms, Variations & Acronyms: Safety *131
Detailing
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Illustrations
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Type
Examples
Safety-Factor: 3X.
Notes
1. A Safety-Factor is used to communicate about Risk. It is used to ensure that the design compensates adequately for both Systems-Engineering and operational uncertainties.
2. Historically, Safety-Factors were applied to mechanical loads. We are using it here to describe the amount of Safety-Margin we Wish to have designed into the System. The target and Constraint Levels are specified at the required Levels and then the Safety-Factor is applied to allow Safety-Margins. (An Assumption is being made here that there is only one Safety-Factor involved; there could be several.)
3. A Safety-Factor is either prescribed by Standards, such as Engineering Rules or Policy, or it is specified at project Level.
4. A Safety-Factor is a dimensionless ratio. Compare to a Safety-Margin, which is either expressed using Units-of-Measure (as it is the difference between two Levels on a Scale), or as a percentage value based on the required target or Constraint Level being 100%.
Required Level | Estimated/Actual Level | Estimated/Actual Safety-Factor | Estimated/Actual Safety-Margin |
---|---|---|---|
100% | 100% | 1 | 0% |
100% | 50% | 0.5 | -50% |
100% | 200% | 2 | 100% |
This example assumes no specific Safety-Factor has been set. It calculates the estimated/actual Safety-Factor and Safety-Margin based on the required Level being 100%.
5. If we want to explicitly specify a Safety-Factor, we can do so in a variety of ways using the Safety-Factor Parameter.
Keyed-Icons:
nX “Where n is the numeric Safety-Factor.”
Example:
Safety-Factor: 3X.
Drawn-Icons
none
Related-Concepts
Safety-Deviation *405;
Safety-Margin *637.
History-of-Concept
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This Concept entered by Adore.
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