NBN EN 13501-3:2006

This European Standard specifies the procedure for classification of construction products and building elements used as components of building service installations, using data from fire resistance tests which are within the direct field of application of the relevant test method. Classification on the basis of extended application is outside the scope of this European Standard. For extended applications, however, the same classes need to be used as specified in this European Standard.
Products/elements for use in ventilation systems include (excluding smoke and heat exhaust ventilation):
fire resisting ducts;
fire dampers.