factor of safety

American  

noun

1. the ratio of the maximum stress that a structural part or other piece of material can withstand to the maximum stress estimated for it in the use for which it is designed.

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factor of safety British  

noun

1. Also called: safety factor.  the ratio of the breaking stress of a material or structure to the calculated maximum stress when in use

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Etymology

Origin of factor of safety

First recorded in 1855–60

Example Sentences

“Metro added a 20% factor of safety to this rate to arrive at a proposed inspection interval of every eight days per wheelset,” she wrote.

From Washington Post • Nov. 4, 2021

The regulations and factor of safety requirements aren’t as strict because, if it fails, no one is going to die.

From Scientific American • Jul. 31, 2015

“The factor of safety is now back to being a high criterion when selecting an airline.”

From Time • Mar. 6, 2015

The factor of safety is invariably too low in this country, and is never too high in Europe.

From A History of the Growth of the Steam-Engine by Thurston, Robert H.

The outstanding feature of these machines is the high factor of safety, which attribute has astonished some of the foremost aviation experts in the world.

From Aeroplanes and Dirigibles of War by Talbot, Frederick Arthur Ambrose