When considering force protection for a building or safe room three areas must be considered: Blast, Ballistics, and Forced Entry. United States Bullet Proofing has expertise in all of these areas resulting in a more robust product even when protecting against a single threat.
Blast Resistant Windows, Blast Resistant Doors
Blast protection must be considered in design when a facility is a potential target or when a building is located in the vicinity of a potential target. The blast from an explosion does not discriminate and will expand radially from its point of origin until it encounters a solid structure, such as a wall with windows and doors.
The blast then causes a pressure to be applied to the windows and doors for a period of time (duration). This creates an impulse or an amount of energy that is imparted to the window and/or door. A portion of this energy is absorbed by the window and/or door through the flexing of the glazing material. The remainder of the energy is transferred to the framing system and anchors.
Minimal rotation of the frame is allowed to ensure the glazing is retained. United States Bullet Proofing’s engineering professionals perform a complete computer analysis for each blast application. Anchor bolts are analyzed and furnished as part of a system package to ensure design criteria are satisfied during installation.
Blast Resistant Standards
The graph and table show the performance criteria for blast resistant products. Specify Pressure and impulse when ordering a blast resistant product.
Note: Ballistic and forced entry protection can also be specified and achieved in a blast resistant product.
Impulse = 1/2 x Pressure(psi) x Duration(msec)
Note: U.S. Bulletproofing products meet and/or exceed UL 752 Ballistic Standards, GSA Blast, and DOD Forced Protection/Anti-Terrorism Criteria. Test reports are available upon request
|Performance Condition||Protection Level||Hazard Level||Description of Window Glazing Response|
|1||Safe||None||Glazing does not break. No visible damage to glazing or frame.|
|2||Very High||None||Glazing cracks but is retained by the frame. Dusting or very small fragments near sill or on floor acceptable.|
|3a||High||Very Low||Glazing cracks. Fragments enter space and land on floor no further than 3.3 ft. from the window.|
|3b||High||Low||Glazing cracks. Fragments enter space and land on floor no further than 10 ft. from the window.|
|4||Medium||Medium||Glazing cracks. Fragments enter space and land on the floor and impact a vertical witness panel at a distance of no more than 10 ft. from the window at a height no greater than 2 ft. above the floor.|
|5||Low||High||Glazing cracks and window system fails catastrophically. Fragments enter space impacting a vertical witness panel at a distance of no more than 10 ft. from the window at a height greater than 2 ft. above the floor.|
Ballistic protection level ratings are based on the number of rounds and the size of the weapon(s) posing a threat – from small caliber handguns to high caliber rifles. High caliber, high velocity weapons fire projectiles that deliver a large amount of energy to a door, window or wall system. To be effective, the total system of anchor, frame, door material and glazing material must absorb the energy from the projectile. The framing system must also be capable of stopping the potential threat and retain the glazing system during attack. Installing bullet resistant glazing in a non-certified frame will not ensure the desired level of protection. Any ballistic glazing certified to meet a ballistic standard must be retained in a certified framing system. United States Bullet Proofing designs the total system of components to achieve the specified level of protection.
The most common ballistic standards are UL 752 and the National Institute of Justice (NIJ). Both are summarized below. When ordering products, please specify the required level of ballistic protection.
UL 752 Ratings of Bullet Resistant Materials
|Protection Level||Ammunition||No. of Shots|
|Level 1|| 9mm Full Metal Copper Jacket with 3. Lead Core||3|
|Level 2||357 Magnum Jacketed LeadSoft Point 3.||3|
|Level 3||44 Magnum Lead Semi-Wadcutter 3. Gas Checked||3|
|Level 4||30 Caliber Rifle Lead Core Soft Point(.30-06 caliber)||1|
|Level 5||7.62mm Rifle Lead Core Full Metal Copper 1 Jacket, Military Ball (.308 caliber)||1|
|Level 6||9mm Full Metal Copper Jacket with 5 Lead Core||5|
|Level 7||5.56mm Rifle Full Metal Copper Jacket with 5 Lead Core (223 caliber)||5|
|Level 8||7.62mm Rifle Lead Core Full Metal Copper||5|
NIJ Standard 0801.01 Ballistic Resistant Protective Materials
|Armor Type||Test Ammunition||Rqd. Hits per Specimen|
|I||LRHW Lead 38|
Special RN Lead
JSP 9mm FMJ
|II||357 Magnum JSP (higher velocity round)|
9mm FMJ (higher velocity round)
|III-A||44 Magnum, LeadSWC Gas Checked|
|III||7.62mm, 308Winchester FMJ||5|
AP – Armor Piercing
LRHV – Long Rifle High Velocity
FMJ – Fu MetalJacket
RN – Round Nose
JSP – Jacketed Soft Point
SWC – Semi-Wadcutter
Forced entry is the attempted penetration of a door, window and walls using a wide variety of tools. These tools may include, but are not limited to sledge hammers, pry bars, wood splitting mauls, fire axes, battering rams, gasoline, acetone, propane torches and CO2 fire extinguishers. The number of people, the tools used, and the duration of the attack vary among the standards used to measure forced entry resistance. One of the most stringent standards is used by the Department of State for overseas embassies and diplomatic facilities. United States Bullet Proofing is proud to be one of only a few companies in the world certified by the Department of State to build forced entry products to this standard. Other standards include ASTM F1233 for glazing material, ASTM F588 for windows, and ASTM F476 for doors. These standards have multiple levels of ratings based on the severity of the threat.