FLAMMABILITY CLASSES


Construction material classification by flammability

The relationship between the degree of flammability requirements and a class of reaction to fire according to ČSN 33 2312 edition 2.
Flammability class Fire reaction class
A A1
A2
B B
C1 C
C2 D
C3 E
F

The difference between the degree of flammability of a class of reaction to fire
The basic difference between the degree of flammability and reaction to fire consists in the fact that the degree of flammability evaluates separate individual materials, while reaction to fire evaluates the entire construction product in the final version - for example, sandwich walls, insulation systems, etc.

Classification of construction products according to their fire class
For the classification of construction products according to their fire class, the following tested procedure is used:

Class E
A product to be classified as class E, shall be tested in accordance with ČSN EN ISO 11925-2 using flame applied for a period of 15 s.

Classes D, C, B
A product to be classified in classes D, C or B, shall be tested according to ČSN EN ISO 11925-2 using flame applied for a period of 30 s. The product meeting the requirements for test results according to ČSN EN ISO 11925-2, is further tested according to ČSN EN 13823 or ČSN EN ISO 9239-1 - this applies to floor coverings.

Classes A1, A2
Homogeneous products
Product classified as class A1 shall be tested according to ČSN EN ISO 1182 and ČSN EN ISO 1716. Product classified as class A2 shall be tested in accordance with either ČSN EN ISO 1182 or ČSN EN ISO 1716.

Non-homogeneous products
Any substantial component of non-homogeneous product classified as class A1 shall be tested separately according to ČSN EN ISO 1182 and ČSN EN ISO 1716. In addition, each product containing external non-substantial component and meeting the PCS criterion is tested according to ČSN EN 13823 or ČSN EN ISO 9239-1 – this applies to floor coverings. Any substantial component of non-homogeneous product classified as class A2 shall be tested either separately according to ČSN EN ISO 1182 or ČSN EN ISO 1716.
Non-substantial components of non-homogeneous products are tested separately, and only in accordance with ČSN EN ISO 1716.

Another condition for class A2
All products to be classified as class A2 shall be also tested according to ČSN EN 13823 or ČSN EN ISO 9239-1 for floor coverings.

Until 31 December 2007 individual building materials were evaluated and graded according to ČSN 73 0862 "Determination of flammability of construction materials". This standard was discontinued as of 31 December 2003, but in order to ensure continuity in the evaluation of materials within the design standards, the results of the tests under this standard as well as the Value standard ČSN 73 0823 remained valid until 31 December 2007. According to this standard, construction materials were classified under the above classes. With effect from 1 July 2003 a new way of flammability classification became valid in the Czech Republic, known as "reaction to fire", summarized in the classification standard ČSN EN 13501-1. ČSN 33 2312:85 "Electrical regulations. Electrical equipment in and on flammable substances" allowed the use of conversion table to use both designations in relation to the flammability of construction materials. As of 1 October 2007 the provision of this standard was repealed for boxes in relation to the standard ČSN EN 60 670-1, i.e. the validity of ČSN 33 2312:85 was terminated for wiring boxes, but continues to apply to wiring trunkings, channels and pipes.
The applicability of the standard ČSN 37 0100 "Wiring boxes" was terminated as of 1 October 2007. It has been replaced by ČSN EN 60 670-1 "Boxes and enclosures for electrical accessories for household and similar fixed electrical installations."



© 2017 KOPOS KOLÍN a.s., Jan Vrzáček