There are various standards and testing methods that are used in order to categorise the security protection that different glass specifications and products can provide.
EN 356 tests and classifies glass in a building situation by its resistance to manual attack such as forced entry (burglary). The test specimen (the glass panel) is secured in a licenced testing facility such as the Rosenheim Institute in Germany. The glass panel to be tested is fixed in a horizontal testing bed and a hard body weighing 4.11kg is dropped onto the upturned glass surface to simulate a forced manual attack on the glass surface.
This object is dropped on the glass from varying heights with differing sequences of impacts, as the height of the fall and the number of impacts to the glass increases, as does its security rating according to EN356. These security rating categories range from P1A which means that glass withstood a total of three strikes in a triangle formation from a height of 1500mm, up to P5A which is 3x3 strikes in a triangle from a height of 9000mm. There are a further three categories (P6B – P8B) where the glass is tested for impacts with an axe.
EN 1063 classifies glass for resistance to attack against bullets. The main purpose of bullet resistant glass is to stop projectiles from penetrating the glass panel thus ensuring the safety of the internal occupants of a space. The security category of a glass unit based on EN 1063 is based on common weapons and ammunition in order of attacking power.
The weapons tested range from a rifle loaded with a lead round nosed bullet at category BR1 through hand guns up to a rifle loaded with pointed bullets with a full copper alloy jacket and hard steel core at BR7.
Glass panels are classified for resistance to explosive pressure in EN 13541. In controlled testing conditions, glass units are subjected to blast waves within a shock tube to simulate high explosive detonations ranging from 10kg to 2500kg TNT from 35m to 50m away.
The resulting classifications range from ER1 to ER4 Glass tested to these classifications nearly always break but the test is to determine the integrity of the glass panel without breach, held together with strengthening interlayers under these specific blast conditions.
These tests only test the glass unit’s resistance against these specific attacks but obviously, for a full security rating, the framing and fixings of the glass panels must be taken into account as well.
Rebecca is the Communications Director at the IQ Group and has worked in glazing specification for many years. She has a broad range of technical knowledge about all our glazing products and offers technical advice and guidance to architects for specification. Her easy to digest technical advice is often quoted in magazines and publications. You might also recognise her as one of the IQ Glass CPD presenters.