Fire safety study of a perlite concrete chimney and wooden ceilings used in buildings based on experimental tests and CFD analysis

Abstract

The operation of fuel-burning heating equipment results in soot build-up in the flues. Its ignition poses a significant fire risk to the building, as the flue temperature can reach 1000°C. Wooden structural elements located near the chimney (ceilings and roof penetrations) are particularly vulnerable. To date, research has focused on the fire safety of wooden ceiling elements. This is where, due to heat radiation from the chimney, wooden elements significantly increase their temperature and become the location of fire initiation in the buildings. The task of chimney designers is to limit the temperatures of heated wooden building components near these structures. The present work analysed a ceramic and concrete chimney with air space with an innovative perlite concrete casing with a dual-function (load-bearing and thermal insulation). Computational Fluid Dynamics (CFD) analyses verified by a full-scale experiment were conducted to evaluate the fire safety of wooden building ceilings. The tests showed that a high level of safety characterised the chimney under study. The maximum temperature of the casing when testing the soot fire reached 38°C, and the wooden elements simulating the ceiling reached 28°C - this result is almost four times better than the chimney standard requirement. Furthermore, a developed CFD model exhibited high accuracy compared to the experimental results and can be used for designing this type of chimney and other research and expert work, such as that performed after fires in buildings originating from the chimney. The article describes CFD analyses and tests of an innovative chimney in a perlite-concrete casing. The described research showed the high safety of such a chimney during soot fires. The results obtained can be used to develop changes in standards to improve the safety of chimneys and design safer and more efficient ones. The author’s chimney model and CFD analysis make it possible to determine the temperatures in the chimney during a soot fire. This CFD model allows you to assess the fire safety of the chimney and the building elements located in its vicinity.