3.3.2 ELastomer Components — Swell Test. Elastomer parts that are eposed to fuel gas shall be made Irtim materials that, alter 70 hr exposure in n-hexane at 73°F (23°C). in accordance with AS1M I) 471. meet the voltime change, elongation, and tensile property requirements of paras. 33.2,1 and 3.32.2. Volume change tests shall be conducted using six specimens in accordance with ASTM 1)471. Section 8. Three specimens shall be exposed for 70 hr at 73°F (23°C) in n-hexane in accordance with ASTM 1)471. The average of the three individual n-hexane tests shall not show an increase in volume of more than 25% or a decrease in volume of mow than 1%. The average of the thne tests for the non-aged specimens shall be the basis for the percent retention change calculation. Tensile tests shall be conducted on six dumbbells in accordance with ASIM D 412. Three of the tensile tests shall be conducted on dumbbells exposed in n-hexane at 73°F (23°C) for 70 hr in accordance with ASTM D 471. The dumbbells shall have a thickncss of 2.0 ± 0.2 mm (0.08 ± 0.008 in.). The average of the three individual n-hexane tests shall exceed 6O’.. retention of ultimate elongation and h0°. retention of tensile strength at break. The average of the three tests for the non- aged specimens shall be the basis for the percent volume change calculation.
3.3.3 ELastomer Components — Compression Set. Elastomer parts, which may be exposed to fuel gas shall by made from materials having a compression set of no more than 25% after 22 hr at 212°F (100°C), in specimens in accordance with ASTM D395, para. 5.2.
3.3.4 PTTE MateriaLs. Polytetrafluomethvlene (PTFE) materials shall comply with ASTM D 489$ or 1)4895,
3.4 Temperature Resistance
The materials used for valve bodies, plugs, bonnets, unions, and other external parts, excluding handles, shall have a solidus temperature in excess of 800°F (427°C). Seals and lubricants are exempt from this requirement.
3.5 Corrosion Resistance
3.5.1 Indoor Atmosphece. These parts that are provided for automatic compensation for wear shall be corrosion-resistant with respect to indoor atmosphere (i.e., humidity and airborne contaminants such as chloride and ammonia).
3.5.2 SaIl Spray. Valves designated by the manufachirer for outdoor use shall meet the requirements of this section. Valve ends shall be sealed with appropriate fittings, The valve shall then be exposed for 96 hr to a salt spray (fog) test as specified in ASTh1 B 117. SaIl spray (fog) testing temperature shall be maintained between 92°F and 97F (33°C and 36°C). The saline solution shall consist of 5% sodium chloride and 95% distilled water by weight. Following the salt spray test, the valve shall be removed from the chamber and esamined with the unaided eye. The valve shall not show signs of corrosion or other deterioration that affects the function of the valve Following the salt spray test, the valve shall pass the leak tests specified in paras, 5.2.1 and 5.2.2 and shall open and close on application of a torque not to exceed that specified In Table 7. For valves with one pipe connection and one tubing connection, the lesser of the two torque limits specified in Table 7 shall apply.
5.2.1External Leakage. With the valve in the openposition with the outlet sealed, an internal air pressureof,first,2 in. (5 cm) water column and then i.5 timesthe pressure rating shall be applied to the inlet of thevalve.
The valve shall be immersed in a bath containingwater at a temperature of 73°F ± 15°F(23C :8 C) fora period of 15 sec. Leakage, as evidenced by the flow(breaking away ) of bubbles,shall not be permitted.Othermeans of leak detection may be used provided the meth-ods can be shown to be equivalent.
5.2.2 Internal Leakage Test.The valve shall then beturned to the closed position with the outlet open andthe test in para.5.2.1 repeated.