AWWA C508:2009 pdf download.Swing-Check Valves for Waterworks Service, &In. Through 24-In. (50-mm Through 600-mm) NPS
The selection of materials is critical for potable water, wastewater, and reclaimed water service and distribution piping in locations where there is like- lihood the pipe will be exposed to significant concentrations of pollutants consist- ing of low molecular weight petroleum products or organic solvents or their vapors. Research has documented that pipe materials-such as polyethylene, polybutyl- ene, polyvinyl chloride, and asbestos cement-and elastomers, such as used in jointing gaskets and packing glands, are subject to permeation by lower molecular weight organic solvents or petroleum products. If a potable water, wastewater, or reclaimed water pipe must pass through such a contaminated area or an area sub- ject to contamination, consult with the manufacturer regarding permeation of pipe walls, jointing materials, and so forth, before selecting materials for use in that area.
4.3.2.2.2 Any brass or bronze alloy containing more than 16 percent zinc used in the cold-worked condition shall be capable ofpassing a mercurous nitrate test in accordance with ASTM B154 or a 10-day ammonia vapor test at 9.8-10.0 pH value per ASTM B858 to indicate minimum susceptibility to stress corro- sion. Following exposure, tested parts shall show no evidence of cracking under 25-times magnification or shall comply with the seat test stated in Sec. 5.2.2.
4.3.2.2.3 Waters in some areas of the United States have been shown by experience to promote galvanic corrosion in the form of dezincification or dealu- minization. In these waters, brass or bronze materials shall not contain more than 16 percent zinc. If aluminum bronze is used, the alloy shall he inhibited against dealuminification. The manufacturer shall he notified if these conditions exist.
4.3.2.4 Elastomers. Seat facing or O-ring seat facing used to provide a seating surface or resilient hinge material shall be made of a rubber compound, having uniform dimensions and of a size, shape, and resiliency as to withstand ordinary wear and tear, rough usage, compression stresses, and damage caused by pipe scale or foreign matter carried by the water. These materials shall have the fol- lowing characteristics.AWWA C508 pdf download.