There have been considerable debate among testing facilities on the protocol for impact testing the single specimen test sample for elements that are substituted. This proposed language seeks to clarify the number of impacts on the test sample based on the elements being substituted in accordance with Annex A1. While there are certain provisions in Annex 1 that requires the window to be impacted by the large missile twice, based on the element being substituted, there are others where the impact of the fourth substitution method only requires a single impact. It further clarifies that when the only element being substituted is the anchorage and mounting element, that the test specimen shall only be impacted in a single location or allow for an engineering analysis to be accepted. In addition, section A1.3.1 of the standard already allows for the original three specimens to be identical in every way, except the anchorage and mounting systems. In each of these specimens, the window is only impacted with a single large missile.