Experimental Analysis of Chimneys in Wooden Roofs

The number of fires in roofs crossed by chimneys is high. According to the manufacturers’ prescriptions, chimneys can be installed in direct contact with roof combustible materials or be spaced from them. In this paper, the influences of the installation mode and of the roof characteristics on the temperatures reached by the combustible materials are investigated by means of twelve experimental tests. Three roofs and four installation modes are analyzed to investigate whether and how they influence the temperatures of the materials surrounding the chimney and, hence, the consequent fire hazard. One roof is representative of the setup currently used in certification procedure, and the other two are representative of roofs in energy-saving buildings. The space between chimney and roof (clearance) has been left open to reproduce the condition in the certification procedure. Then, for reproducing the installation modes that may occur in real installations, the clearance has been sealed with metal sheets, sealed with insulating panels, and filled with insulating materials. Results show that temperatures are strongly affected by these variables, and in real installations, temperatures can be much higher than those measured in the certification procedure. For this, the existing standard should be reviewed accordingly.