NIJ0115.00 Levels of Protection
In the US, the National Institute of Justice (NIJ) is responsible for setting standards for body armor, and their standard 0115.00 is designed specifically for stab-resistant body armor. It was developed by the NIJ with the collaboration of the Police Scientific Development Branch (PSDB) from the UK, where stab protection vests are a lot more prevalent and regularly used by law enforcement officers and police body armor.
The NIJ 0115.00 standard dividends stab-proof body armor into three different protection levels. These are Level 1,2 and 3. Here is a more detailed analysis of these three levels and what kind of stabs knife protection they can offer.
How does the stab armor rating system work?
First of all, you need to know how these stab-resistant vests are tested to ensure protection. The ideal is to replicate the force with which an average mad would stab. The stab tests are done using two kinds of knives, and a spike, which are used to attach the vest straight on and at a 45-degree angle.
Two levels of energy are used, the first level, E1 is how much energy the stab resistant body armor needs to stop, and the second, E2 is E1 plus 50% more energy, to test the penetration against the energy that the vest is not rated for. For the E2 level, only a few millimeters of penetration is permitted, which would break the skin but prevent any serious injury or damage to any vital organs.
Level I protection:
A Level I stab proof vest needs to resist knife attacks of up to 24 joules, and allow only 7 mm of penetration at most for an edged blade of spike attack of up to 36 joules. This is the lowest level of knife protection available on the market and is typically used as a standard for concealable stab protection.
Level II protection:
The level II vests are designed to prevent knife penetration with the energy of up to 33 joules and allow only 7 millimeters of penetration at most from an attack of up to 50 joules. These vests are more common and are used as overt armor by law enforcement, and police officers.
Level III protection:
This is the highest level of stab, slash, and spike protection that you can get. According to the NIJ standards, it needs to stop knife penetration with up to 43 joules, and allow minimal penetration with forces of up to 65 joules. Level III stab vests are used by law enforcement and correctional officers in prisons, and apart from stopping attacks from edged blades, and spikes, they can also dampen the force of an attack from blunt objects.