HOW DOES HARD BODY ARMOR WORK
Hard body armor typically incorporates an ultra-hard, ballistic ceramic top layer combined with a laminated blend of unidirectionally-oriented fiber bundles which work together to stop bullets and fragments. Some ultra-light weight plates do not incorporate ceramics in their construction. These non-ceramic designs are effective against Level III threats. Ceramic hard armor works by disrupting the aerodynamic shape of the bullet and dissipating the energy through the shattering of the ceramic top layer. The blunted or shattered bullet and the ceramic fragments (secondary projectile) are caught in the laminated blend of high performance fibers, thereby inhibiting penetration.
In the United States, body armor levels are certified by the National Institute of Justice (NIJ). The levels are I, IA, II, IIIA, III, and IV. Based on extensive laboratory tests, researchers classify any new body armor design into one of seven categories: Category I body armor offers the lowest level of protection, and category IV offers the highest. The body armor classes are often described by what sort of weaponry they guard against. The lowest level body armor can only be relied on to protect against bullets with relatively low energy, which tend to have less force on impact. Some higher level body armor can protect against higher energy bullets (i.e. 44 magnum and 357 magnum). Categories I through IIIA are soft and concealable. Type III and Type IV use hard or semi-rigid plates to defeat high energy rifle rounds. PACA offers various ballistic systems from levels II - IV.
Body armor that is ballistic resistant does not necessarily make it stab or puncture resistant (and vice versa). Sharp edged and hand made instruments with pointed tips such as spikes, awls or shanks generally do not need to tear the fabric to penetrate – it merely moves the fibers aside. PACA utilizes a combination of super fine, ultra-dense materials, which prevent pointed objects from spreading or moving the individual yarns to stop penetration/puncture.
The NIJ rates body armor on resistance to hand-delivered stab threats – the NIJ 0115.00 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 applied, to push the breaking point of the armor, where 0.79" / 20mm of penetration is allowed. Ice-pick or improvised "Spike" weapons testing is regularly conducted by PACA through its independent laboratories. PACA offers several vest models that are stab-resistant in NIJ Spike Levels 1, 2, or 3 with the option for ballistic protection.
INSIDE HARD ARMOR PLATE
Ceramic plates are designed to stop rifle rounds and armor-piercing rounds which have a penetrating steel pin in the bullet. Plates are engineered by bonding a layer of ceramic to a hard panel made of multiple layers of ballistic material wrapped in a fabric covering.
As the bullet hits the plate, the hard ceramic strike face begins to break up the bullet while the ballistic material begins to absorb the energy of the penetration.
The round continues to break apart as the ballistic material extracts energy, decelerating the projectile and catching the fragments while limiting the effect of blunt trauma, the injury caused by an impacting bullet.