The highest level of protection: NIJ Level IV
NIJ Level IV (or Level 4) is the highest rating for ballistic-resistant body armor plates under NIJ Standard 0101.06. Level IV hard armor plates are tested to stop a single hit of armor piercing (AP) rifle ammunition like the .30-06 M2 AP round with a specified mass of 10.8 g (166 gr) and velocity of 878 m/s ± 9.1 m/s (2880 ft/s ± 30 ft/s). In addition to the AP round, NIJ Level IV plates are also tested against the threats specified in NIJ Levels I to III. This includes 9mm and .44 Magnum handgun rounds, as well as high-powered rifles like the 7.62mm NATO. So Level IV offers the most comprehensive ballistic protection, making it suitable for high-risk tactical operations.| NIJ Armor Level | Test Rounds | Velocity |
|---|---|---|
| Level IV | .30-06 M2 AP | 878 m/s ± 9.1 m/s |
| Level III | 7.62x51mm NATO M80 | 847 m/s ± 9.1 m/s |
How Level IV plates are tested at NIJ-approved labs
To be certified as NIJ Level IV compliant, hard armor plates must be tested according to the NIJ Standard 0101.06 at an NIJ-approved testing laboratory. The standard specifies the test threats, ammunition, test conditions, and pass/fail criteria. The plates are mounted on a clay backing material to simulate wearing the armor against the body. During the test, a minimum of 6 shots are fired at specific locations on the plate from a set distance. The locations include the plate's apex, basic angle of attack, and edge. The velocity of each bullet is measured and must fall within specs. To pass, the plates must prevent any shots from penetrating through the armor, and the dent in the clay backing must not exceed 44mm.Why multi-hit protection matters
While the NIJ certification standard only requires Level IV plates to withstand a single hit from an armor piercing round, some manufacturers design their plates to handle multiple hits. Multi-hit protection provides an added margin of safety and could be the difference between life and death in an active shooter or combat situation. AR500 Armor's Level IV plates with Build Up Coat are independently tested to defeat multiple hits of M2 AP .30-06 ammunition. The extra layer of polyurea coating helps contain fragmentation and enables the plates to handle multiple impacts. This is an important consideration when choosing Level IV plates for critical missions.Understanding backface deformation (BFD)
Backface deformation refers to the dent in the clay backing material after a bullet impacts the armor plate during testing. It measures the blunt force delivered to the body. While some BFD is expected, the NIJ set a maximum allowable BFD of 44mm to reduce the risk of behind armor blunt trauma (BABT). Although the human torso can withstand higher BFD than the NIJ test limit without serious injury, designing armor plates to minimize BFD improves comfort and reduces the risk of BABT. Advanced Level IV plates often incorporate polyethylene or foam materials to reduce BFD by dissipating the force of the bullet impact.Special threats tested above the standard
Some manufacturers go beyond the NIJ .06 standard and have their Level IV plates tested against additional or higher velocity threats to give end users more confidence. For example, AR500 Armor's Level III+ and Level IV plates are special threat tested against the M855 and M193 5.56 rounds at velocities exceeding the NIJ specs. These special threat test reports are often available from the manufacturer upon request. Agencies can have plates tested against their own specific threat profile at an NIJ-approved lab. While special threat testing is not part of the standard NIJ certification, it provides additional data to evaluate Level IV plate performance in specific scenarios.Shelf life and durability considerations
The NIJ Standard 0101.06 also includes requirements for the useful life of the armor plates. Manufacturers must provide evidence that the plates will maintain their ballistic performance over the declared warranty period when stored in accordance with the care instructions. This typically involves artificially aging plates in an environmental chamber. Hard armor plates made from steel or ceramic materials generally have a longer shelf life than soft armor, which can degrade faster. Ceramics are brittle and can develop micro-fractures from rough handling, so always inspect plates for any cracks or chips. Following the manufacturer's care and maintenance instructions will help ensure the plates remain fit for service.How plate thickness and weight affect protection
In general, thicker and heavier plates provide more protection as there is more material to absorb and dissipate the energy of the bullet. However, this comes with a tradeoff in comfort and mobility. Level IV plates typically weigh between 6-8 lbs each and are around 1" thick, which is on the bulkier side. Manufacturers are continually working to develop lighter, thinner Level IV plates that maintain protection. New ultra high molecular weight polyethylene (UHMWPE) and boron carbide ceramic materials have enabled lighter Level IV plates in the 4-5 lbs range. It's important to verify that lighter plates still meet the full NIJ certification standards.Plate size and shot location requirements
The NIJ 0101.06 standard specifies the minimum allowable size for the strike face of Level IV hard armor plates. The plate must provide at least 0.79 ft² (730 cm²) of protective coverage area to ensure adequate protection of the vital organs. Smaller or non-rectangular plates must be evaluated to ensure they meet this minimum area. Additionally, the standard defines where the 6 shots can be placed on the plate during testing based on the size. For a standard 10x12" rectangular plate, all 6 shots must be at least 3" apart and 2-3" from the edge of the plate. If any shots are closer together, the plate will be retested with additional shots in the original location.Why Level IV certification is important
NIJ certification provides confidence that a particular model of armor plate has been rigorously tested by an independent third party and meets the stringent Level IV requirements. It's a way for agencies and end users to objectively compare the ballistic performance of plates and ensure they are getting adequate protection. Beware of armor plates falsely labeled as "Level IV" or "tested to NIJ standards" without specifying they are certified to the NIJ 0101.06 Compliant Products List. Uncertified plates may use inferior materials or have not actually passed the full NIJ certification test protocols. Sticking with NIJ-listed plates is the best way to guarantee performance and protection.Are Level IV plates worth the added weight?
Level IV plates are considerably heavier and bulkier than Level III or lower-rated plates, so it's a tradeoff between protection and mobility. For certain roles that may face armor piercing threats, like active shooter response teams, the highest level of rifle protection is a necessity. However, many patrol officers find that Level III or III+ plates offer sufficient threat protection against common high-powered rifles in a lighter, thinner, and more comfortable package for all-day wear. Carefully evaluate your threat profile and mission needs to determine if Level IV plates are worth the added weight and bulk.Standalone vs In Conjunction Level IV plates
Some Level IV plates are rated as standalone, while others are specified as in conjunction with Level IIIA soft armor. Standalone means the plate can be worn by itself in a carrier without a soft armor backer and still meet the Level IV threat protection. In conjunction plates must be worn with a Level IIIA backer to achieve the rated protection. Standalone plates offer more flexibility but tend to be thicker and heavier than in conjunction designs. Adding Level IV plates to concealable soft armor vests is an easy way to up-armor for active threats while maintaining a low profile in normal conditions. Again, it's best to choose plates based on your specific needs.How plate shape and curvature affects fit
The NIJ certification test does not specify any particular shape or curvature for the armor plate, only a minimum strike face area. However, plate shape and curvature can greatly affect the fit and comfort when worn in a carrier. Look for plates that are curved and contoured to fit the shape of your torso. Single-curve plates have one simple curve to wrap around the body, while multi-curve plates have additional curves to better match the chest and abdomen. Shooters cut plates feature cuts in the upper corners to improve shouldering a rifle. The shape of multi-curve, shooters cut plates provides better coverage and comfort but often at a higher cost.Material tradeoffs: steel, ceramic, polyethylene
Level IV plates can be made from a variety of materials, each with its own tradeoffs in terms of weight, thickness, durability, and cost. Steel and ceramic are the most common and economical materials, while polyethylene plates are the lightest and thinnest but also the most expensive.| Material | Pros | Cons |
|---|---|---|
| Steel | Inexpensive, durable | Heavy, can create spall |
| Ceramic | Lighter than steel, no spall | More expensive, can crack |
| Polyethylene | Lightest, thinnest, flexible | Expensive, lower shelf life |