Toxic gas and smoke measurement with the British Fire Propagation test. II: Hydrogen chloride evolution from UPVC building products

摘要

AbstractExtension of the British Standard Fire Propagation test (BS 476 Part 6) as a combustion mode for measuring smoke and toxic gas production from small panels of UPVC building products has been investigated. Hydrogen chloride gas concenatrations in the test room have been measured continuously with a method developed to ensure high collection efficiency from the fire gases. Using this method, the influences of test conditions (room temperature and humidity, room surface finish, reactivity of fire box interior) on HCl gas concentrations were examined to explain the fate of HCl gas after its evolution. The relative humidity (RH) in the room was the most critical factor influencing HCl gas concentrations during tests. Although HCl evolution early in the test was influenced little by RH and closely matched smoke production, maximum HCl gas concentrations in the room attained later varied markedly with RH. Generally, no more than one‐third of the HCl expected theoretically remained airborne under any test condition. Further investigations suggested that this loss and the effect of RH are associated with HCl plate‐out on room surfaces. Using test conditions set to minimize the influence of RH, HCl evolution from a series of UPVC building products was investigated. HCl concentrations in the test room did not exceed incapacitating levels for those products where less than a certain quantity of UPVC was combusted. This observation is discussed in relation to French regulations, which limit the total quantity of chlorine in some synthetic materials within building compartme