This Standard specifies requirements for materials used in unreinforced elastomeric and reinforced and unreinforced compressed non-asbestos fibre flange gaskets and elastomeric O-rings suitable for jointing flanges that comply with AS 4087, AS/NZS 4331.1, AS/NZS 4331.2, AS/NZS 4331.3, AS 2129 and other flange standards, for—
(a) cold potable water supply (up to 40°C); and
(b) drainage and sewerage systems (continuous flow up to 45°C and intermittent flow up to 95°C).
While recognising that elastomeric gaskets are often reinforced with fabric (commonly known as ‘insertion gaskets’), this Standard does not address fibre reinforced or composite elastomeric gaskets. Gaskets and O-rings manufactured in materials complying with this Standard may be used for PN 14, 16, 21 and 35 flange joints for all metallic pipeline materials, including iron, steel, copper and copper alloys. Compressed non-asbestos fibre sheet used to manufacture gaskets can be classified as a Type 7 Class 1 material as described in ASTM Classification F 104.
General requirements for finished flange gaskets and O-rings 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 Standard should be used, where appropriate, with product Standards that specify performance requirements for joints.
Means for demonstrating compliance with this Standard are given in Appendix A. Type tests are conducted at fluid temperatures up to 25°C. Where fluid operating temperatures up to 50°C are applicable, additional type testing should be carried out at temperatures that reflect the actual equilibrium operating temperature of the gasket taking into account heat transfer between the fluid and the pipeline components and the surrounding environment.
For information on purchasing guidelines see Appendix B.
While gasket and O-ring dimensions are outside the scope of this Standard, guidance on gasket dimensions for ductile iron and steel flanges complying with AS 4087 is given in Appendix C.