ISO 16486-4 pdf download Plastics piping systems for the supply of gaseous fuels — Unplasticized polyamide (PA-U) piping systems with fusion jointing and mechanical jointing — Part 4: Valves
5.1Compound for valve body5.1.1 Compound
The compound from which the valve body with spigot or electrofusion socket is made shall be inaccordance with ISO 16486-1.
The PA-U components of the valve shall be made from virgin material conforming to IS0 16486-220.127.116.11Fusion compatibility
Components made from PA-U 11 shall be heat fusion jointed only to components made from PA-U 11.Components made from PA-U 12 shall be heat fusion jointed only to components made from PA-U12.Components made from PA-U are not fusion compatible with components made from other polymers.5.2 Material for non-polyamide parts
All components shall conform to the relevant ISO International Standard(s).Alternative standards maybe 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,greasesand any metal parts used) shall be as resistant to the external and internal environments as the otherelements of the piping system and shall have an expected lifetime under the following conditions atleast equal to that of the PA-U pipes conforming to iS0 16486-2, with which they are intended to beused:
b) under the effect of the fluids being conveyed, and
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 asstringent as that of the PA-U compound for the piping system.
Other materials used in valves in contact with the PA-U pipe shall not adversely affect pipe performanceor initiate stress cracking.
The valve manufacturer shall ensure that any transition joint between polyamide and non-polyamideparts and the valve body fulfil the requirements of lSO 16486-3.
All parts susceptible to corrosion shall be adequately protected, providing this is necessary for thedurability and function of the system.
When dissimilar metallic materials are used which can be in contact with moisture, steps shall be takento avoid the possibility of galvanic corrosion.
Elastomeric materials used for the manufacture of seals shall be in accordance with lSo 16010.0thersealing materials are permitted if proven suitable for gas service.
As a regional requirement for CEN member countries, elastomeric seals shall conform to EN 618.104.22.168Greases and lubricants
Greases or lubricants shall not exude onto fusion areas and shall not affect the long-term performanceof the valve materials.
Ancillary components of valves shall be assembled according to the manufacturer’s procedures and anycomponent used in the assembly shall not prevent conformity of the valve to this document.
6 General characteristics
6.1 Appearance of the valve
When viewed without magnification, the internal and external surfaces of valves shall be smooth, cleanand free from scoring, cavities or other surface defects to an extent that would prevent conformity tothis document.
No component of the valve shall show any signs of damage,scratches,pitting,bubbles, blisters,inclusions, or cracks to an extent that would prevent conformity of the valves to this document.
The colour of the PA-U parts of valves shall be either black or yellow.6.3Design
The valve shall be designed to provide the fluid flow passageway and the body ends.
The pressure resistance of the valve shall be specified by the manufacturer according to the design SDRand material classification.
6.3.2 Valve body
The valve body shall be such that it cannot be dismantled.
An operating stop system shall be provided at the fully open and closed positions.6.3.3 valve terminal ends
PA-U spigot ends or electrofusion sockets shall conform with the requirements as reported inISO 16486-3.