scope:

(a) This Standard covers manually operated thermoplastic valves in nominal sizes ½ through 6 (as shown in Table 5). These valves are suitable for use below ground in thermoplastic distribution mains and service lines. The maximum pressure at which such distribution piping systems may be operated is in accordance with the Code of Federal Regulation (CFR) Title 49, Part 192, Transportation of Natural and Other Gas by Pipeline; Minimum Safety Standards, for temperatrure ranges of −20°F to 100°F (−29°C to 38°C).

(b) This Standard sets qualification requirements for each nominal valve size for each valve design as a necessary condition for demonstrating conformance to this Standard.

(c) This Standard sets requirements for newly manufactured valves for use in below ground piping systems for natural gas [includes synthetic natural gas (SNG)], and liquefied petroleum (LP) gases (distributed as a vapor, with or without the admixture of air) or mixtures thereof.

(d) Standards and Specifications referenced under this Standard are shown in Appendix II.

(e) For the purpose of determining conformance with this Standard, the convention for fixing significant digits, where limits maximum or minimum values are specified, shall be "rounding off" as defined in ASTM Practice E 29. This requires that an observed or calculated value shall be rounded off to the nearest unit in the last right-hand digit used for expressing the limit. Decimal values and tolerances do not imply a particular method of measurement.

(f) The values stated in either inch units or metric units are to be regarded separately as standard. Within the text, the values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.

Definitions

fasteners: nuts, bolts, washers, clip rings, and other devices used in the assembly of valves.

pressure: unless otherwise stated, pressure is gauge pressure.

production pressure tests: pressure tests that include seat and closure member and shell tests.

seat and closure-member test: an internal pressure test of closure-sealing elements (seats, seals, and closure members such as gate, disc, ball, or plug).

shell test: an internal pressure test of the pressure containing envelope.

Quality Systems

Nonmandatory requirements relating to the product manufacturer's Quality System Program are described in Appendix A.