WFRGENT NV

The classification of construction products and buildings elements provides a means of expressing the fire resistance of those elements. The classification is based on data from fire resistance and smoke leakage tests which are within the direct field of application of the relevant test method.

The fire resistance classification is declared in minutes using one of the periods: 10, 15, 20, 30, 45, 60, 90, 120, 180, 240 or 360.

Designatory letters for declaration of performance

Combination of these designatory letters, as appropriate, shall be used as part of the classification of performance. They shall be supplemented by the time, in elapsed completed minutes of the nearest lower class during which the functional requirements are satisfied.

R: Load bearing capacity

Loadbearing capacity R is the ability of the element of construction to withstand fire exposure under specified mechanical actions, on one or more faces, for a period of time, without any loss of structural stability.

The criteria which provide for assessment of imminent collapse will vary as a function of the type of loadbearing element.

They shall be either:

• for flexurally loaded elements e.g. floors, roofs, a rate of deformation (rate of deflection) and a limit state for the actual deformation (deflection), or
• for axially loaded elements e.g. columns, walls, a rate of deformation (rate of contraction) and a limit state for the actual deformation (contraction).

E: Integrity

Integrity E is the ability of the element of construction that has a separating function, to withstand fire exposure on one side only, without the transmission of fire to the unexposed side as a result of the passage of flames or hot gases. They may cause ignition either of the unexposed surface or of any material adjacent to that surface.

The assessment of integrity shall generally be made on the basis of the following three aspects:

• cracks or openings in excess of given dimensions
• ignition of a cotton pad
• sustained flaming on the unexposed side

I: Thermal Insulation

Thermal insulation I is the ability of the element of construction to withstand fire exposure on one side only, without the transmission of fire as a result of significant transfer of heat from the exposed side to the unexposed side. Transmission shall be limited so that neither the unexposed surface nor any material in close proximity to that surface is ignited.

W: Radiation

Radiation W is the ability of the element of construction to withstand fire exposure on one side only, so as to reduce the probability of the transmission of fire as a result of significant radiated heat either through the element or from its unexposed surface to adjacent materials.

The classification shall be given by the time for which the maximum value of radiation, measured as specified in the test standard, does not exceed a value of 15 kW/m².

M: Mechanical resistance

Mechanical action M is the ability of the element to withstand impact, representing the case where structural failure of another component in a fire causes an impact on the element concerned.

The element is subject to impact of predefined force shortly after the time for the desired R, E and/or I classification period. The element shall resist the impact without prejudice to the R, E and/or I performance to have the classification supplemented by M.

C: Self closure

The self closing C is the ability of an open door or window to close fully into its frame and engage any latching device that may be fitted, without human intervention, by stored energy, or by mains power backed up by stored energy in case of power failure.

S: Smoke leakage

The smoke leakage S is the ability of an element of construction to reduce or eliminate the passage of hot and/or cold gases or smoke from one side of the element to the other.

G: Soot fire’ resistance

Soot fire resistance classification for chimneys and chimney related products stands for the ability of the element(s) to be resistant to soot fires. This includes aspects of leakage and thermal insulation.

K: Fire protection (coverings)

The fire protection ability K is the ability of a wall or ceiling covering to provide for the material behind the covering protection against ignition, charring and other damage for a specified period of time. Coverings are the outermost parts of building elements, such as walls, floors and roofs.