What does the "factor of safety" compare?

The "factor of safety" is a crucial concept in engineering that helps to ensure structures and components can withstand loads beyond what they would typically experience in service. It specifically compares the tensile strength of a material to the actual working stress that it encounters during operation.

In practical terms, tensile strength refers to the maximum amount of tensile (pulling) stress that a material can withstand before failure, while working stress is the stress that the material experiences in a real-world application. By establishing a factor of safety, engineers incorporate a margin of safety into their designs, ensuring that when materials are subjected to forces, they are well within their capacity to handle those forces without failure. This is important for maintaining safety standards and preventing catastrophic failures.

The other options focus on different relationships that don’t align with the concept of the factor of safety. For instance, comparing design pressure to operational pressure concerns another aspect of engineering safety but doesn't directly address material strength and working conditions.