ISO 16486-4 pdf download – Plastics piping systems for the supplyof gaseous fuels – Unplasticized polyamide (PA-U) piping systems with fusion jointing and mechanical jointing 一 Part 4:Valves.
5.1.1 Compound
The compound from which the valve body with spigot or electrofusion socket Is made shall be In accordance with ISO 16486-1.
The PA-U components of the valve shall be made from virgin material conforming to ISO 16486-1.
5.1.2 Fusion compatibility
umponenLs made from PA•U 11 shall be heat fusion jointed only Lu components made from PA•U 11.
Components made from PA-U 12 shall be heat fusion jointed only to components made from PA-U 12.
Components made from PA-U are not fusion compatible with components made from other polymers
5.2 Material for non-potyamide parts
5.2.1 General
All components shall conform to the relevant ISO International Standard(s). Alternative standards may be applied In cases where a suitable ISO International Standard does not exist.
In all cases, fitness for purpose of the components shall be demonstrated.
The materials and the constituent elements used in making the valve (including elastomers, greases and any metal parts used) shall be as resistant to the external and internal environments as the other elements of the piping system and shall have an expected lifetime under the following conditions at least equal to that of the PA-U pipes conforming to ISO 16486-2, with which they are intended to be used:
a) during storage,
h) under the effect of the fluids being conveyed, and
c) taking Into account the service environment and operating conditions.
The requirements for the level of material performance of non-polyamide parts shall be at least as stringent as that of the PA4J compound for the piping system.
Other materials used in valves in contact with the PA-U pipe shall not adversely affect pipe performance or initiate stress cracking.
The valve manufacturer shall ensure that any transition joint between polyamide and non-polyamide parts and the valve body fulfil the requirements of ISO 16486.3,
5.2.2 Metal parts
All parts susceptible to corrosion shall be adequately protected, providing this Is necessary for the durability and function of the system.
When dissimilar metallic materials are used which can be in contact with moisture, steps shall be taken to avoid the possibility of galvanic corrosion.
A.2 Test pieces
The test piece shall be a complete valve with the open ends closed of f by. for example, covers, plugs, flexible seals or end connectors.
The setting time of moulded or fusion-jointed components, specified by the manufacturer shall be completed before commencing conditioning.
A.3 Test procedure
A.3.1 Conditioning
Condition the test piece in accordance with this document (see 112).
A.32 Internal leaktlghtness test (fully closed valve test)
Conduct the following procedure, where, in case of bi-directional valves, both sides of the valves shall he tested.
a) Connect one end of the test piece to the pressure line and the other end(s) to a device capable of detecting leakage.
h) Fill the closed test piece with air or nitrogen at the specified temperature.
c) Close the valve.
d) Raise the pressure progressively and smoothly in such a way that the test pressure specified in this document is attained within 30s.
e) Maintain the pressure and temperature for the length of time specified in this document.
0 Observe and record any signs of leakage.
g) Depressurize the test piece.
Valves with Independent double seating (such as two-piece obturator or double-seated valves) can be tested hy applying pressure between the seats and having each side of the closed valve checked for leakage.
A.3.3 External Leaktightness test (half open valve) Conduct the following procedtire.
a) Put the valve in half open position.
ISO 16486-4 pdf download – Plastics piping systems for the supplyof gaseous fuels – Unplasticized polyamide (PA-U) piping systems with fusion jointing and mechanical jointing 一 Part 4:Valves
