The Effect of an Air-gap Under Soft Body Armour on the Behind Face Signature

Abstract

Modern police body armour typically provides protection from sharp weapons and low-velocity (handgun) bullets. It is recommended that the armour is worn against the body i.e. no air-gaps are present between the wearer and the armour. In the case of formed or shaped armours it may be that airgaps exist (e.g. female specific armours in the breast region). Additionally some manufacturers are incorporating stand-off in their armour designs with the claim that these decrease thermophysiological loading on the user by increasing micro-climate cooling. In this paper the effect of stand-off (10 mm) on the measured back face signature (BFS) will be assessed. HG1/A+KR1 armour panels (400 mm x 400 mm) were mounted on calibrated #1 Roma Plastilina and impacted with 9x19mm FMJ (Dynamit Nobel DM11A1B2) ammunition (365 m/s ± 10 m/s). The resulting BFS was measured and compared to impacts on the same type of armour panels with no air-gaps.