prBAS EN 1366-8:2025

This document specifies a test method for determining the fire resistance of smoke extraction ducts. It is applicable only to smoke extraction ducts that pass through another fire compartment apart from the compartment from where smoke needs to be extracted in case of fire. It represents fire exposure of a fully developed fire. This method of test is only applicable to fire resistant ventilation ducts (same construction) with the following classification according to EN 13501-3: - fire from inside and outside i ↔ o; - applicable to a pressure difference up to 500 Pa in fire conditions; NOTE 1 It is assumed that the duct A test(s) in accordance with EN 1366-1 has been performed with an under-pressure of minimum 500 Pa. - with integrity (E) and insulation (I) criteria equal to or higher than the intended classification for the smoke extraction duct. For the purposes of the test described in this document, the duct is referred to as duct C. This test method has been designed to cover both vertical and horizontal smoke extraction ducts. A vertical system need not be evaluated to this method provided that: - both horizontal (ho) and vertical (ve) classification according to EN 13501-3 has been obtained for the ventilation duct; - it has been tested in a horizontal orientation to this method. If the ventilation duct in practise is only used for vertical applications in smoke extraction systems, only vertical (ve) classification is obtained in accordance with EN 13501-3 and tested only in a vertical orientation to this test method. This test method is suitable for ducts constructed from non-combustible materials (class A1 and A2-s1, d0 according to EN 13501-1). NOTE 2 Reaction with components of the duct can affect the oxygen concentration inside the duct leading to inaccurate calculation of the leakage rate. If it is determined this has happened refer to Annex D. This document applies to four sided rectangular and circular ducts only (with fire exposure on all sides). Ducts that utilize elements of construction for one, two or three sides are not covered. An alternative test method for one, two and three sided ducts will be developed separately.