Protection Levels

Body armor is available at different levels of protection, which are standardized by the US National Institute of Justice (NIJ) and the UK Centre for Applied Science and Technology (CAST). 

Ballistic Levels

Ballistic levels of protection outline the exact strength of attack each level of bulletproof body armor can protect against. As the levels go up, you will be protected from a wider range of gun threats. The levels of protection for body armor are: 

		NIJ Level IIA	NIJ Level II	NIJ Level IIIA	NIJ Level III	NIJ Level IV
	Areal Density	3.5 kg/m	4.2 kg/m	5.9 kg/m	25.9 kg/m	32.5 kg/m
	Thickness	4mm	5mm	6mm	15mm	20m
.22mm short		X	X	X	X	X
.9mm		X	X	X	X	X
.45mm		X	X	X	X	X
.380mm		X	X	X	X	X
.38mm		X	X	X	X	X
.22mm long			X	X	X	X
.44 Magnum				X	X	X
.30 Carbine					X	X
5.56mm					X	X
7.62mm NATO					X	X
.30-06					X	X
.30 Armor Piercing (M2 AP)						X

 

Edged Blade Levels

CAST standardizes stab proof vests and has identified different levels of protection to bulletproof vests. This is because although the materials in bulletproof and stab proof vests are developed in the same way, a stab proof vest requires a much tighter weave and the addition of materials like chain-mail or laminate to be effective. Multi-threat vests that can protect against ballistics and knives will still need to be graded according to the levels outlined above and below:

	Knife Resistance Level 1		Knife Resistance Level 2
Energy Level	E1	E2	E1	E2
Energy (joules)	24	36	33	50
Velocity	5 m/sec	6.2 m/sec	5.9 m/sec	7.3 m/sec
Total Missile Mass	1.9 kg	1.9 kg	1.9 kg	1.9 kg
Maximum Penetration	7 mm	20 mm	7 mm	20 mm

Spiked Weapon Levels

Neither bulletproof nor stab proof vests are equipped to protect against spiked weapons, which have their own standardized levels of protection. Spike protection can be added to stab and bulletproof vests as a laminate coating, but it is important to make sure it adheres to proper testing. The threat levels for spike proof vests are:

 

	Knife Resistance Level 1 & Spike Protection Level 1		Knife Resistance Level 2 & Spike Protection Level 2
Energy Level	E1	E2	E1	E2
Energy (joules)	24	N/A	33	N/A
Velocity	5 m/sec	N/A	5.9 m/sec	N/A
Total Missile Mass	1.9 kg	N/A	1.9 kg	N/A
Maximum Penetration	KR1 = 7 SP1=0	N/A	KR2 = 7 SP2=0	N/A