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 thus are not specifically
addressed by this Standard.
of 0.28" / 7mm is allowed as serious injury is extremely unlikely
with such a shallow wound. Also an "Overtest" is applied,
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 high quality commercial
knives, called "Edged Blade" aka Stab, and ice pick, prison-style
improvised "Spike" weapons. So 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 for the force generated. In general, Level 1 is designed
to handle 85% of force levels encountered, Level 2, 90% and Level