Chimneys in wooden roofs: a 3D steady numerical model for the prediction of the temperatures

Chimneys convey exhaust gas produced in domestic heat appliances to the external environment and to do this they have to pass through floors and roofs: if these elements are made up of flammable materials, the fire hazard may occur. This article presents the verification of a 3D numerical model set for the determination of the stationary temperatures reached on the flammable materials in the vicinity of chimneys. The verification has been done comparing the temperatures measured in experimental tests with those estimated by means of the numerical model. Results show that the 3D numerical model is a valid tool for the analysis of heat transfer between chimney and roof. Since in the experimental tests it is not always possible to reach stationary temperatures, a lumped element model to estimate them is also proposed and it could support the chimney certification.