IRF = Inverse Reserve Factor (IRF) defines the inverse margin to failure. Load divided with IRF is equal to the failure load. IRF >1 discloses failure.

MoS = Margin of Safety (MoS) defines the margin to failure. MoS is defined as (1/IRF - 1). MoS < 0 discloses failure.

RF = Reserve Factor (RF) defines the margin to failure. Load multiplied with RF is equal to the failure load. RF < 1 discloses failure.