PIPA Industry Guidelines ‘Metal Backing Flanges for use with Polyethylene (PE) Pipe Flange Adaptors’ highlights areas that a specifier of a PE flange joint should consider when making an informed choice about which gasket (if any) should be used. It is recommended that specifiers consult with the gasket supplier. The following is a list highlighting elements of the application and joint assembly that should be considered when selecting a suitable gasket. This list does not attempt to cover all aspects and hence specifiers should not be limited to only those the aspects raised below. Aspects to consider in gasket selection:

• Operating pressure, including surge allowance.
• The ability of the gasket to seal at the clamping pressure imposed and resist blow-out without suffering excessive stress relaxation.
• Operating temperature
• Materials of mating flanges and the potential impact of surface finish, flatness, surface roughness and coatings.
• Compatibility of the gasket materials with the medium being transported within the pipe at the operating temperatures and pressures. For flanged joints intended for use with potable water the gasket material must comply with AS/NZS 4020.

Gaskets may not be necessary when using PE flanges provided sufficient compressive load can be applied (i.e. sufficient bolt torque) and the sealing surfaces are not excessively rough or damaged. Non-gasketed joints are common place in the US and to a lesser extent in the UK and Europe. Historical Australian practice has been to use gaskets. Acu-Tech also sells flange bolts and gaskets, blind flanges, and galvanised backing rings, or steel backing rings.