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definition-Safety-Factor

Definition:

A Safety-Factor is the dimensionless ratio of “conscious over-design” that is either required, or actually applied to some part of a System.

Alternative Names

Concept Number: *131
English Master: Safety-Factor
Synonyms, Variations & Acronyms: Safety *131

Detailing

none


Illustrations

none


Type

Metric, Parameter.


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


Safety-Deviation *405;
Safety-Margin *637.


History-of-Concept

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This Concept entered by Adore.
Table of contents:

Created by system. Last Modification: Thursday 11 of July, 2019 20:23:34 CEST by Admin (Kai).

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