The impact velocity at which the probability of perforation is 50% for a certain projectile and target is called v50 and is a measure that, together with areal density, is used to compare different armour materials. There are today a number of relevant standards, mainly MIL-STD-662F, STANAG 2920, STANAG 4164 and TOP 2-2-710. They all use the same perforation criteria - v50BL(P). In this report the requirements and registrations that should be made according to the standards above. Future work should be focused on estimate the consequences of the demands on measurements and precision set on ballistic tests and on, using analytical methods and simulations, compare different types of v50BL(P) measures and various statistic methods.