body armor vs common threats

Question
Hello Doug,

First, let me apologize if you're not the right person to ask this to and/or if this is a stupid question.  Anyway, this is what I'm wondering about:

I see numerous articles about the effectiveness of different types of kevlar vests vs various calibers of bullets.  What I was wondering is are Type I and IIA kevlar vests effective against knife attacks as well?

Thank You,
Frank

Answer
Frank,

I am happy to try and answer your questions.  By the way, for the record, there are no 'stupid' questions on this site.

Type I body armor is primarily 'old technology'.  The fibers used in the vest are generally early generation fibers that don't provide good ballistic protection.  They are also quite bulky.  I would say they would be great protection for rocks and sticks (like riot gear) or paintball, but nothing else.

Type II-A is the thinnest body armor, but is generally the minimum recommended.  It will stop a 9mm at 1090 fps or .357 Magnum round at 1250 fps, but not much more.  You would also sustain quite a bit more blunt trauma injury in a thinner vest like II-A.

Personally, I would go for a minimum of a Type II vest.  It provides a good balance between protection and thickness, it protects against higher velocity rounds (9mm at 1175 fps or a .357 Magnum at 1400 fps) and gives better protection against blunt trauma.

Regarding the level of protection against a knife attack, vests generally are pretty good for protecting again slashing attacks, but not against thrusting or stabbing attacks.  The point of the knife can 'get between' the woven kevlar fabric resulting in penetration and injury to the wearer.  Don't get me wrong, it is way better to have a vest on that nothing, but in general, vests are designed to stop 'blunt' projectiles.  The type II-A will provide better protection against a knife that the type I would.

Hope this gives you what you need...

Doug