The National Institute of Justice, rates body armor on resistance to hand-delivered stab threats – NIJ Standard 0115.00. Slash threats have been found much easier to defeat than stab, and therefore are not specifically addressed by this Standard.
Maximum penetration of 0.28" / 7mm is allowed as serious injury is extremely unlikely with such a shallow wound. Also an "Over-test" is done, to push the breaking point of the armor, where 0.79" / 20mm of penetration is allowed.
Testing is done in two different categories of threat:
1. High quality commercial knives, called "Edged Blade" commonly Known as 'Stab'
2. Ice pick, prison-style improvised "Spike" weapons.
Hence stab vests are rated in two categories, "Edged Blade" or Stab and "Spike" and can be rated for either or both categories.
The Levels were derived from a study where several stabbing techniques of a male attacker were tested against the force generated. In general, Level 1 is designed to handle 85% of force levels encountered, Level 2, 90% and Level 3, 96%.
Levels of protection currently available include the following 3 Levels and are tested to protect against Stab Pressure with penetration Limit of 0.28" / 7mm
· Level 1 - Protects against pressure of 24 Joules (J)
· Level 2 - Protects against pressure of33 Joules (J)
· Level 3 - Protects against pressure of43 Joules (J)
· 5 years ago