This document specifies requirements for elastomeric materials used in seals for supply pipes and fittings, ancillaries and valves at operating temperatures in general from ?5 °C up to 50 °C and in special cases from ?15 °C up to 50 °C, for the following:
a) general applications (see Table 4, type G series):
- — gaseous fuel [manufactured, natural and liquefied petroleum gas (LPG) in the gaseous phase],
- — hydrocarbon fluids with an aromatic content up to 30 % (by volume), including LPG in the liquid phase;
b) special applications (see Table 4, type H):
- — materials suitable for carrying gaseous fuels containing gas condensates and hydrocarbon fluids of unrestricted aromatic content.
General requirements for finished joint seals are also given; any additional requirements called for by the particular application are specified in the relevant product standards, taking into account that the performance of pipe joints is a function of the seal material properties, seal geometry and pipe joint design. This document is used where appropriate with product standards which specify performance requirements for joints.
This document is applicable to joint seals for all pipeline materials, including iron, steel, copper and plastics.
In the case of composite sealing rings, the requirements in 5.2.8 and 5.2.9 apply only when the materials used for any elastomeric parts come into contact with gaseous fuel or hydrocarbon fluid.
Elongation at break, tensile strength, compression set and stress relaxation requirements for materials of hardness classes 80 and 90 apply only when they constitute that part of the seal which participates directly in the sealing function or contributes directly to long-term stability.
This document is not applicable to the following:
— seals made from cellular materials;
— seals with enclosed voids as part of their design;
— seals required to be resistant to flame or to thermal stress;
— seals which contain splices joining pre-vulcanized profile ends.