AWWA C700:2002 pdf download.Cold-Water Meters—Displacement Type, Bronze Main Case
4.1.5 Pistons and discs. Pistons and discs shall be such that the specific gravity approximately equals that of water and shall be made of a vulcanized hard rubber, such as those classified per ASTM D2135; or a suitable engineering plastic, such as polystyrene per ASTM D4549, polyphenylene sulfide (PPS) per ASTM D4067, styrene-acrylonitrile (SAN) per ASTM D4203, polyphenylene oxide (PPO) per ASTM D2874, or polycarbonate (PC) per ASTM D3935. Pistons and discs shall have sufficient dimensional stability to retain operating clearances at working temperatures up to 80°F (27°C) and shall not warp or deform when exposed to operating temperatures of 100°F (38°C).
4.1.6 Measuring-chamber diaphragms. Measuring-chamber diaphragms shall be made of monel, such as UNS N04400 as listed in ASTM B127; phosphor bronze as listed in ASTM B103; or austenitic stainless steel as listed in ASTM A167; a hard rubber as classified per ASTM D2135; or a suitable engineering plastic, such as nylon (N) per ASTM D4066, polyphenylene sulfide (PPS) per ASTM D4067, polyphenylene oxide (PPO) per ASTM D2874, or styrene-acrylonitrile (SAN) per ASTM D4203.
Measuring-chamber diaphragms shall have sufficient dimensional stability to retain operating clearances at working temperatures up to 80°F (27°C) and shall not warp or deform when exposed to operating temperatures of 100°F (38°C).
4.1.8 Register gear trains. Frames, gears, and pinions of gear trains shall not be exposed to water and shall be made of metals such as copper alloys per ASTM B16, brass alloys per ASTM B36, silicon-bronze alloys per ASTM B98; or any copper-based alloys per ASTM F467 and ASTM F468; stainless steel, such as those listed in ASTM A276, ASTM A493, and ASTM A582; or suitable engineering plastics, such as acrylonitrile-butadiene-styrene (ABS) per ASTM D4673, polycar- bonate (PC) per ASTM D3935, thermoplastic polyester (TPES) per ASTM 4507, polystyrene (PS) per ASTM D4549, or acetal per ASTM D4181.AWWA C700 pdf download.