The factor of safety is used in designing a machine component. Prior to selecting the correct factor of safety certain points must be taken into consideration such as: > The properties of the material used for the machine and the changes in its intrinsic properties over the time period of service. > The accuracy and authenticity of test results to the actual machine parts. > The applied load reliability. > The limit of stresses (localized). > The loss of property and life in case of failures. > The limit of initial stresses at the time period of manufacture. > The extent to which the assumptions can be simplified.