ISO 4898:2008 specifies requirements and methods of testing for four categories of rigid cellular plastics thermal-insulation products for buildings. It covers rigid cellular plastics in the form of flat or profiled boards, with or without natural skins. They may also be faced or laminated with foil, plastic or metal films or sheets, mineral coatings, paper, cardboard or other materials.It is not applicable to materials used for the thermal insulation of pipes and vessels, for impact sound absorption or for acoustical insulation.It covers the following cellular materials used in the thermal insulation of buildings:— PF based on phenolic polymer;— EPS based on expanded polystyrene;— XPS based on extruded polystyrene;— PUR based on polyurethane.