The European ballistic protection standard EN 1522 requires multiple tests. For example, to qualify for a FB6 rating the test frame must pass the FB6 test and all the lower ratings such as the FB1, FB2, FB3, FB4 and FB5 tests as stated in the EN 1522 standard.
The abbreviation "FB" is defined in the standard EN 1522 and is used to indicate the protection level of opaque (non-transparent) materials such as armor steel, which are often used in armored cars.
EN1522 FB6 class requirements for testing with hand guns and rifles:
Type of Weapon
Test Range (m)
Bullet Velocity (m/s)
5.56 x 45*
Rifle (see note)
* To achieve the stated values for [5.56 x 45], the recommended barrel twist length = (178± 10)mm
(a)FJ=Full copper alloy jacket
(b)FJ=Full steel jacket (plated)
PB pointed bullet
SC soft core (lead)
SCP1 soft core (lead) with steel penetrator (type SS109)
Note 1: When a shot is to be fired at a single point the test range may be reduced to achieve the firing accuracy as defined in Section 6 of EN 1523. In this case it may not be possible to measure the velocity of the bullet.
Note 2: To be classified FB6 the specimen shall be tested with both calibres listed.
The armor steel and so on materials achieve ballistic testing to EN1522 FB6 class, meaning they are certified to protect against a level FB6 weapon attack.