Discussion on thickness of thermal insulation layer of smoke exhaust ducts

Technicalstandardforsmokemanagementsystemsinbuildings(GB 51251-2017) puts forward the requirements for the thermal insulation layer of smoke exhaust ducts in suspended ceilings, and clarifies that the thickness of the thermal insulation layer is not less than 40 mm. But the specification does not specify the thermal physical parameters such as the thermal conductivity of the thermal insulation materials. In this paper, the thermal insulation performance and the fire endurance of the thermal insulation layers and the composite clad ducts are discussed and analysed, which provides a reference for design, review and acceptance.