The intent of this test procedure is to describe procedures for briefly applying a specified tensile load to continuous lengths of all Class I and Class IV, glass/glass optical fibers. This FOTP should not be applied to Class II (glass/plastic) and Class III (all-plastic) fibers. This method is intended to ensure a minimum strength for fiber that survives proof testing. The minimum strength is a key parameter for determining the minimum survival time at loads less than the minimum strength.