ÖNORM EN 488

This European Standard specifies requirements and test methods for valves of prefabricated thermally insulated valve assemblies comprising a steel valve, rigid polyurethane foam insulation and an outer casing of polyethylene for use in directly buried hot water networks with preinsulated pipe assemblies in accordance with EN 253. This standard applies only to insulated valve assemblies for continuous operation with hot water at various temperatures in accordance with clause 1 of EN 253:2003. Guidelines for quality inspection are given in annex A of this standard. Guidelines for installation of valves are given in annex B of this standard. NOTE 1 For this application the following valve types are commonly used: ball valves, gate valves, and butterfly valves. NOTE 2 This standard does not include rules for calculation of loads and stresses.