AWWA C227-17 pdf download.Bolted, Split-Sleeve Couplings
The selection of materials is critical for potable water, wastewater, and reclaimed water service, and like distribution piping in locations where there is likelihood the pipe will be exposed to signifcant concentrations of pollutants com- posed of low-molecular-weight petroleum products or organic solvents or their vapors. Documented research has shown that pipe materials, such as polyethylene and polyvinyl chloride, and elastomers, such as those used in jointing gaskets and packing glands, are subject to permeation by low-molecular-weight organic sol- vents or petroleum products. If a potable water, wastewater, or reclaimed water pipe must pass through such a contaminated area or an area subject to contamination, consult with the manufacturer regarding permeation of pipe walls, jointing materi- als, and so on before selecting materials for use in that area.
4.2.7 Special gaskets for electrical insulation. An insulating boot may be used on nonrestrained couplings, extending over both pipes a minimum of 1 in. (25 mm) beyond the end of the coupling, thereby preventing any metal-to-metal contact between the pipe ends. Te boot thickness shall be 1 in. (3.2 mm). Te purchaser must specify the insulation requirements.
4.2.8 Restraint mechanism/restraint ring. Restraint mechanisms/restraint rings shall be made from material that meets the requirements of ASTM A576, grade 1020, or ASTM A108, grade 1018, for carbon steel; or ASTM A276/A276M, type 304, for stainless steel. Other grades of material with equal or higher specifed minimum yield strengths may be used subject to review by the purchaser.
4.2.9.1 Materials. Similar materials to those used in the construction of the coupling shall be used for bolts, studs, nuts, and washers (when required) to minimize the possibility of galvanic corrosion. Caution should be used in bur- ied installations or where the environment is highly corrosive to ensure the bolts, studs, nuts, and washers (when required) are properly protected. Advice from a qualifed corrosion engineer is recommended.AWWA C227-17 pdf download.