NEN EN 488 : 2015

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
  4.1 Steel parts
      4.1.1 General requirements for valves
      4.1.2 Pressure ratings for valves
      4.1.3 Service temperatures for valves
      4.1.4 Steel service pipes
      4.1.5 Welding ends on valves
      4.1.6 Resistance to bending and axial forces
      4.1.7 Leak-tightness of valves
  4.2 Fusion welding of steel
  4.3 Casing
  4.4 Polyurethane rigid foam insulation (PUR)
  4.5 Valve assembly
      4.5.1 Ends of valve assembly
      4.5.2 End of stem construction
      4.5.3 Requirements for polyethylene welding
      4.5.4 Leak-tightness of the welded casing
      4.5.5 Increase in diameter of the casing pipe
      4.5.6 Minimum insulation thickness
      4.5.7 Tolerances on the main dimensions
5 Test methods
  5.1 General
  5.2 Test specimens
  5.3 Steel parts
      5.3.1 Constructional testing of valves
      5.3.2 Leak-tightness test of valves
      5.3.3 Testing of steel welds
  5.4 Casing
  5.5 Polyurethane rigid foam insulation
  5.6 Valve assembly
6 Marking
  6.1 General
  6.2 Steel valve
  6.3 Casing
  6.4 Valve assembly
7 Installation and maintenance
Annexes
A (informative) Guidelines for inspection and testing
    A.1 Manufacturer's type test
    A.2 Manufacturer's quality surveillance
    A.3 External inspection
    A.4 Extent of inspection
    A.5 Manufacturer's responsibility
B (informative) Guideline for installation of valves
Bibliography

Defines 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 pre-insulated pipe assemblies in accordance with EN 253.