Experimental testing of an innovative steel chimney with expanded perlite insulation in the context of fire safety of buildings

This study examines the thermal performance of a prototype double-walled steel chimney system insulated with expanded perlite, proposed as an environmentally sustainable alternative to conventional mineral wool insulation. Expanded perlite is a chemically inert material that does not emit harmful substances, addressing the environmental and health concerns associated with mineral wool. This research aimed to evaluate whether perlite provides sufficient thermal insulation to meet the requirements for chimney systems under both normal operating and soot fire conditions. Two full-scale experimental tests were conducted: a normal operating condition test with a flue gas temperature of up to 700 °C and a soot-fire test, in which the temperature was increased to 1000 °C for 30 minutes. Under normal operating conditions, the wooden ceiling and roof components reached approximately 40 °C, comparable to values reported for mineral-wool-insulated chimneys operating at lower flue gas temperatures. During the soot-fire test, the maximum temperatures recorded on wooden elements were 64 °C (ceiling) and 52 °C (roof), demonstrating adequate thermal protection. The chimney casing temperature did not exceed 130 °C during operation and remained below 200 °C during the soot-fire test, despite internal flue gas temperatures exceeding 750 °C. These results confirm the high thermal resistance of expanded perlite insulation and its capacity to limit heat transfer to adjacent structures. Overall, the tested chimney system satisfies the requirements of PN-EN 1856-1 and PN-EN 1859, indicating its suitability for certification and potential commercial implementation. The findings support the use of expanded perlite as a viable and environmentally favourable replacement for mineral wool in chimney insulation applications. • Fire safety assessment confirmed the applicability of perlite-insulated chimneys in buildings • Expanded perlite can replace mineral wool insulation in chimneys • Perlite-insulated chimneys kept wood at 40 °C under 700 °C flue gas. • Wood stayed below 64 °C under 1000 °C flue gas.