Heat penetration and thermal response due to firebrand accumulation on the exterior walls of dwellings

This paper presents an extensive experimental investigation campaign concerning the thermal fire reaction of firebrands, as they accumulate on the exterior walls of dwellings, a common occurrence in southern Europe. Three types of wall core layers were studied: bricks, designed according to the Exterior Thermal Insulation Composite Systems (ETICS) methodology, cross-laminated timber (CLT) and normal wood (NW), both utilizing the sandwich methodology. The wall specimens are made of a combination of materials such as three types of mortar (Tria, Sika, and Weber), and various thermal insulation materials, such as agglomerates of composite cork, impermeable membranes, rigid rock wool, fireproof paint, and extruded polystyrene rigid foam (XPS), which are recommended for their good performance against fire and high temperatures. Firebrands are then deposited on the localized surfaces of the wall specimens, and the temperature is recorded in each layer. This study aims to precisely verify the firebrand reaction to fire, including the type of ignition, smoke and droplet production. The insulation capabilities of each insulation and wall system will also be analyzed.