Doubling up on Body Armor - What effect?


February 13, 2003, 01:42 PM
Just out of curiosity since it would be extremely uncomfortable and bulky to actually wear; What effect would doubling up on body armor have?

Different levels of body armor are just increasing layers of Kevlar right?

Two IIa vests would equal what level of protection?
Two II vests ?
Two IIIa vests?

Anyone ever tested this or read about this kind of test?

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February 13, 2003, 01:57 PM
I think I just answered my own question. I should have waited to post. Oh well, here's a list of how many layers of Kevlar each protection level uses. So it's easy to figure out what doubling up would do.
Level II-A
(16-20 Layers of Kevlar)

Level II
(20-24 Layers of Kevlar)

Level III-A
(24-28 Layers of Kevlar)

Double Naught Spy
February 13, 2003, 03:21 PM
I would not expect that doubling up on IIIA armor would even begin to approach level III hard armor when it comes to protection against rifle rounds. Soft armor really just can't handle such high velocity rounds (especially the pointy type that punch through like an ice pick would) unless you go up to hundreds of layers and then it is just bulk friction slowing the projectile.

The N. Hollywood bank robbers wore multiple layers, hard over soft and soft wrapped around arms and legs. The military using a hard chest plate over level IIIA. The combination of hard over soft allows the hard armor to stop the round and dissipate much of the energy and the underlying soft IIIA layer provides additional protection against blunt force as well as protection against handgun ammo.

So maybe you double up some IIA armor and get IIIA Armor protection (or maybe not). That is going to be about the best you are going to get for soft protection against ballistic projectiles.

February 13, 2003, 03:35 PM
Keep in mind the NIJ tests vests by how much backface deformation they make. For example, a level IIA vest may be able to stop a .44 magnum from penetrating, but the resulting backface deformation would exceed NIJ standards and the vest would not pass. It would also cause a hell of a dent in your body.

I procured an old Kevlar panel from eBay a couple months ago. I opened up the cover and counted 12 layers of Kevlar, which is not even up to level IIA standards. Nevertheless, I shot it with some Triton +P .45ACP rounds and it absorbed them pretty well.

February 13, 2003, 08:00 PM
seeing how FN's P90's round will penetrate something like 50 + layers of kevlar (and its a pistol round, kinda like a smaller 223)

soft armor wont protect you from rifle rounds.

Double Naught Spy
February 13, 2003, 10:44 PM
I think you are talking about the Fn 5.7 (Five Seven). The rounds made for the gun are specifically designed armor piercing rounds that apparently were designed specifically to pierce soft armor. I am not sure how well they are supposed to perform against Level III or Level IV hard armors.

Kevlarman, whether or not a material is up to a given standard, say IIA, is not just due to the number of layers used. It is the number of layers relevant to the weave of those layers and performance of the particular type of material. As such, you might have only 12 layers, but those may be 12 thicker layers.

February 14, 2003, 12:25 AM
Even so, the panel is pretty old - late 70s or 80s manufacture.
It's amazing what fabric will stop.

Double Naught Spy
February 14, 2003, 08:46 AM
Oh, no doubt! I have bought a couple of panels on ebay for the exact purpose of blasting them. I have been surprised at how well they stopped handgun rounds and how easily .223 and .308 passed through - both being IIIa rated.

I now have a collection of kevlar-stopped slugs that look just like yours. One thing I have noticed is that like your hollowpoint round, hollowpoints tend to collapse around the hollow and expand behind it in a manner not intended by the maker of the round. As such, the hollowpoints tend to be much more effectively stopped by kevlar, usually in few layers, and energy dispersed over a larger area because of the expansion as compared to ball ammo that penetrates more deeply and expands much less.

February 14, 2003, 01:10 PM
Check this out guys. Add some Kevlar to your every day wardrobe. This is geared towards bikers, looks like cool stuff.

I like the shirts and cargo pants.

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