This part of ISO 8873 outlines requirements for the application of rigid cellular plastic spray polyurethane foam for thermal insulation. The primary application of the material is for use as thermal insulation. Spray polyurethane foam can also be used as the air barrier material which forms part of an air barrier assembly in buildings. Under specific application conditions, the material can be used in vapour barrier applications in a building assembly (details of the conditions can be obtained from the manufacturer). The application requirements are for the installation of spray polyurethane foam whether applied on a building site or in a prefabrication (manufacturing) facility. This part of ISO 8873 can be used for non-building applications when agreed to by the supplier and the purchaser.