Standard Specification for Performance of Gasketed Mechanical Couplings for Use in Piping Applications

Abstract

This specification provides the performance characteristics and qualification tests required for gasket mechanical couplings (GMCs) including grooved-type mechanical couplings for grooved end pipe, mechanical restraint couplings for plain end pipe and mechanical compression couplings for plain end pipe. These couplings are for use at temperatures within the recommended temperature range of their respective gaskets. The GMCs are classified into two types: Type I which are the groove mechanical couplings and Type II which are plain end mechanical couplings. Also, they can be classified into various grades based on successful completion of testing. They can also be grouped into three classes in accordance to joint characteristics: Class 1 which is rigid and restrained, Class 2 which is flexible and restrained, and Class 3 which is flexible and unrestrained. The housings of grooved GMCs shall be made from either ductile iron, aluminum alloy, or iron-chromium-nickel alloy. Bolts of these couplings shall be made from carbon steel and corrosion resistant materials. As for plain end GMCs, their housings or center sleeves shall be made from either ductile iron or steel materials. Their bolts shall be constructed with carbon steel and corrosion resistant materials. Standard qualification tests for GMC shall consist of the following: performance test, specimen examination, pneumatic proof test, vacuum test, hydrostatic proof test, flexibility test, hydrostatic burst test, rigidity test, bending moment proof test, and bending moment ultimate test.