BUILDING PHYSICS 33 Example of typical fire resistance classifications of components in timber construction: Designation Requirement Component example R 30, R 60, R 90 Load-bearing component supports, wall, beams, ceiling EI 30, EI 60, EI 90 room partitioning, heat insulating component non-carrying partitioning components, shaft walls, bulkheading, suspended ceiling REI 30, REI 60, REI 90 carrying and room partitioning, heat insulating component carrying partitioning component Source: Teibinger and Matzinger, 2013 Moreover, special requirements may apply in the individual case such as • M = resistance to mechanical effects (fire wall replacement wall) • K2 30 or K2 60 for effective protection for 30 and 60 minutes respectively to prevent that timber structures protected by planks also catch fire In Germany, there are the designations of “fire-retardant” or “highly fire-retardant” according to DIN 4109, which is equivalent of 60 and respectively 90 minutes of fire resistance. Proof of the fire resistance of timber components is provided either by classification reports pursuant to EN 13501-2 based on large fire experiments or through a measurement pursuant to EN 1995-1-2 in combination with the respective national application document. All component assemblies contained in the Solid Timber Construction Manual have been rated in terms of fire protection by accredited institutes. The rating and the boundary conditions to be kept for this purpose (component dimensions and loads) are indicated on the individual datasheets. Fire behaviour of building materials Besides the fire resistance of the components, additional requirements may apply for the fire behaviour of building materials. In the evaluation of the fire behaviour of building materials, numerous characteristics such as ignitability, flammability, flame propagation and smoke development are considered. To make different materials comparable, there is a standardised testing procedure that is regulated by EN 13501-1. This standard evaluates all materials according to the following three criteria: Fire behaviour • non-flammable (A1, A2) • hardly flammable (B, C) • normally inflammable (D, E) • easily flammable (F) Smoke development • Classes s1, s2, s3 (s1 = lowest value) Blazing dripping • Classes d0, d1, d2 (d0 = lowest value, non-dripping) binderholz cross laminated timber CLT BBS components are attributed pursuant to EN 13501-1 to the Euro class D-s2-d0. This equals a normal flammability, the smoke development is modest and there is no blazing dripping. (see Figure 18) Gypsum board or gypsum fibre board are attributed to the Euro class A2-s1-d0 and thus non-flammable. Insulating materials made of mineral wool are non-flammable and attributed to the Classes A1 or A2. Figure 18 – Test procedure pursuant to EN 13501-1 to test the fire behaviour
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