Back-Face Deformation (BFD)
Definition
The indentation left in Roma Plastilina No. 1 clay backing material behind an armour panel after a bullet impact that does not penetrate. Maximum 44 mm under NIJ 0101.06. Exceeding this limit constitutes test failure because the blunt trauma to the wearer's thorax at this deformation level exceeds the 25% serious-injury probability threshold from Wayne State University biomechanical studies.
Related terms
- 10% Ordnance Gelatin (FBI Protocol)
- Porcine or bovine gelatin at 10 g per 100 mL water, chilled to 4°C, calibrated with a 4.5mm steel BB at 590...
- 20% Ordnance Gelatin (NATO Protocol)
- Gelatin at 20 g per 100 mL water, at 10°C. Higher concentration produces greater penetration resistance, modelling the full human body including...
- Clear Ballistics (Permagel)
- A synthetic polymer-based ballistic test medium formulated to match 10% ordnance gelatin at 4°C. Optically clear (allows high-speed video of bullet penetration),...
- IS 17051-2018
- The Bureau of Indian Standards specification for personal body armour, published 2018. Defines four protection levels tested against 9mm FMJ, 7.62x25mm Tokarev...
- NIJ Standard 0101.06
- The National Institute of Justice (US DOJ) body armour performance standard, published 2008. Defines five protection levels (IIA, II, IIIA, III, IV)...
Explained in
- Ballistic Gelatin, Body Armour and Standardised TestingThe indentation left in Roma Plastilina No. 1 clay backing material behind an armour panel after a bullet impact that does not penetrate. Maximum 44 mm under N...