The standards for fire protection are regulated by the German institution for standards. Here we have to differentiate between national DIN 4102 and the European current standards DIN EN 13501. Both classifications are applicable but you have to consider that these standards can not be compared with each other.

DIN 4102

The DIN 4102 was almost completely replaced by the DIN EN 13501 but there are still projects that use the old standards. These are defined by their inflammability and their fire resistance.

Fire protection glass is categorized in 3 classes

  • G-glazings: monolithic glazings. Protects from smoke, flames and gas. Heat radiation can still pass through the glazings.
  • F-glazing: multi-layer with chemical padding that becomes opaque when impacted by heat. These glazings protect from smoke, gas, flames and heat radiation.
  • T-glazings: Used in doors. These glazings protect from smoke, gas, flames and heat radiation.

DIN 13501

The DIN EN 13501 applicable for these products results in a much higher variation of classifications as the previous standard DIN 4102. Part 2 which is significant for fire resistant glass classifies construction products and designs in a in fire resistance test. Possible classifications:

  • load capacity [R]
  • insulation [E]
  • heat insulation [I]
  • time of burglar resistance [in minutes]
  • passing heat radiation [W]
  • mechanical stability [M]
  • limitation of smoke porousness [S]
  • self closing [C]
  • maintaining the power supply [P]


The El-glazing is a multiple layer glass compound structure that prevents the passage of fire into the room and has a heat insulation function that complies with DIN EN 13501. According to DIN 4102 this would be called F-glazing.

The multiple layer fire resistant glass contains a fire resistant substrate which creates a foam when subject to heat. This drastically reduces a significant amount of heat to be transmitted.

The water inside the fire resistance liquid evaporates when affected by heat, which leads to an effect called evaporation chill which leads to more heat resistance. The glass itself prevents toxic gasses from passing. If a higher resistance class is required, more layers are added.



E-Glazing is a single pane glazing system that prevents fire and smoke to enter through the glass. In accordance with DIN EN 13501 this also covers class E and according to DIN 4102 this also is compliant with class G.

This glass is often used in skylights. It is generally made of borofloat, tempered glass or glass ceramics. These glasses do not demonstrate much of a lateral expansion when they are exposed to heat.


EW-glazing adds an additional reduction of the heat radiation on the respective side.

Just like E-glazings fire resistant and transparent glass ceramics or borofloat is used as single-pane safety glass. A heat resistant coat is added which prevents fire and heat to pass through the glass.


At isophon glas we aim to give our customers the best possible, flexible, comprehensive and highest quality service. This includes a possibility to combine the different products we offer wherever possible.

Fire Resistant Glass with Additional Functions

One possible combination are the EI-glazings, which can be combined with other glazing systems in terms of sun protection or attack resistance and result in outstanding multifunctional glass upon request. This way we can deliver exactly the glass that you require.

Frames, Seals and Fittings

However, it is not only glass that makes a good fire resistance. All other components like the frame, seal and retainers are important as well. Feel free to contact us in case you have any questions.


Well-known brand names of our suppliers are Contraflam®, Fireswiss®, Pyrostop®, Pyrodur®, Pyroclear®, Pyranova® and Pyran®.

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