The protective strength of a glazed shielding is rated based on the type of munitions, or threat level, it is capable of withstanding. There are 7 main standard threat levels: BR1-BR7 (also written as B1-B7), each corresponding to a different type of small arms fire. Additionally, there are two other threat levels (SG1 & SG2) corresponding to shotgun munitions.
To be given a particular rating, the glazing must stop the bullet for the specified number of strikes, with multiple strikes placed within 120mm of each other. The glazing should also be shatterproof and produce no spalls after each strike. Lastly, the classification levels are numbered in order of increasing protective strength. Thus any sample complying with the requirements of one class also complies with the requirements of previous classes. However, the SG (shotgun) classes do not necessarily comply with BR classes.
The precise test requirements and bullet types used are as follows:
|Calibre||Ammunition||Bullet / gr||Split||No Split||Test Range (m)||Velocity (m/s)|
|Shot Gun||Solid Slug 3||31,0+-0,5||SG1-S||SG1-NS||10||420+-20|
|Shot Gun||Solid Slug 3||31,0+-0,5||SG2-S||SG2-NS||10||420+-20|