Specifies a method of vertical impact testing, the testing procedure and how the results of tests should be presented. It may be performed either as a single test to investigate the effects of vertical impact or as a part of a sequence of tests designed to measure the ability of a sack to withstand a distribution system that includes a vertical impact hazard. The principle of the method is raising the filled sack above a rigid surface and releasing to strike this surface after a free fall, the atmospheric conditions, the height of the drop and the position of the package being set in advance.