NEN EN 488 : 2015
Withdrawn
A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.
A Withdrawn Standard is one, which is removed from sale, and its unique number can no longer be used. The Standard can be withdrawn and not replaced, or it can be withdrawn and replaced by a Standard with a different number.
DISTRICT HEATING PIPES - PREINSULATED BONDED PIPE SYSTEMS FOR DIRECTLY BURIED HOT WATER NETWORKS - STEEL VALVE ASSEMBLY FOR STEEL SERVICE PIPES, POLYURETHANE THERMAL INSULATION AND OUTER CASING OF POLYETHYLENE
01-08-2020
12-01-2013
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
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