How to Answer: What is a Factor of Safety (FoS), and when would you use it?
Advice and answer examples written specifically for a Mechanical Engineer job interview.
32. What is a Factor of Safety (FoS), and when would you use it?
How to Answer
Your interviewer will likely ask you knowledge-based questions to understand how well you are able to explain concepts to others. Be prepared for questions like this one by practicing a few possibilities ahead of time. In this case, a Factor of Safety (FoS) expresses the degree to which a system is reinforced to avoid failure at a given load. In order to have a Factor of Safety, a system must be able to have a determinable failure point as well as nominal load. For example, a steel walkway with a FoS of 4 means that it is designed to withstand quadruple the nominal load without breaking. Using a FoS may be a legal requirement in some industries, typically when the failure of a machine would cause loss of life or injury.
Written by Jason Toby on October 12th, 2020
Answer Example
"A Factor of Safety refers to how much stronger a system is compared to what it needs to be for a given load. I would utilize this when designing a system with a known nominal load, such as a bike pedal arm, to ensure that it would not break during operation and cause injury to the user. I also know that regulations may call for a certain minimum Factor of Safety depending on the type of equipment being designed."
Written by Jason Toby on October 12th, 2020