ASME B16.44-2002 pdf free download.MANUALLY OPERATEDMETALLIC GAS VALVES FORU8E IN ABOVEGROUND PIPING SYSTEMS UP T05 PSI.
3 MATERIALS
3.1 Materials for Valve Bodies, Plugs, Bonnets, Unions, and Other External Parts Excluding Handles
Materials known to be acceptable for compliance with this Standard are listed in Table 2. Other metallic materials may be used when the product incorporating them meets the requirements of the Standard.
3.2 Lubricants and SeaLants
Lubricants and/or sealants shall be resistant to the action of fuel gases such as natural, manufactured and IP gases. The valve manufacturer is responsible for the selection of lubricants and sealants, and for the determination of their suitability for service conditions enumerated in para. 1 of this Standard.
3.3 Seating and Stem Seal Materials
3.3.1 Elastomer Components — Air Aging. Elastomer parts that are exposed to fuel gas shall be made from materials that, following 70 hr air aging in accordance with ASTM D 573 at 212°F (100°C), meet the elongation, tensile and hardness property requirements of 3.3.1.1 and 3.3.1.2.
3.3.1.1 Tensile tests shall be conducted on six dumbbells in accordance with ASTM D 412. Three dumbbells shall be air aged 70 hr in accordance with ASTM D 573 at 212°F (100°C). The dumbbells shall have a thickness of 2.0 ± 0.2 mm (0.08 ± 0.008 in.). The average of the three individual tests for the aged dumbbells shall exceed 60% retention of ultimate elongation and 60% retention of tensile strength at break. The average of the three individual tests for the non-aged dumbbells shall be the basis for percent retention calculation.
3.3.1.2 Hardness tests shall be conducted using specimens in accordance with ASTM D 395, Type 2. Three specimens shall be air aged 70 hr in accordance with ASTM D 573 at 212°F (100°C). The average of the three individual tests or the aged specimens shall not show a hardness change of more than ± 10 Shore hardness points relative to the average hardness of the non- aged specimens.
3.3.2 Elastomer Components — Swell Test. Elastomer parts that are exposed to fuel gas shall be made from materials that, after 70 hr exposure in n-hexane at 73°F (23°C), in accordance with ASTM D 471, meet the volume change, elongation, and tensile property requirements of paras. 3.3.2.1 and 3.3.2.2.
3.3.2.1 Volume change tests shall be conducted using six specimens in accordance with ASTM D 471, Section 8. Three specimens shall be exposed for 70 hr at 73°F (23°C) in n-hexane in accordance with ASTM D 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 more than 1%. The average of the three tests for the non-aged specimens shall be the basis for the percent retention change calculation.
3.3.2.2 Tensile tests shall be conducted on six dumbbells in accordance with ASTM 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 thickness of 2.0 ± 0.2 mm (0.08 ± 0.008 in.). The average of the three individual n-hexane tests shall exceed 60% retention of ultimate elongation and 60% 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 he exposed to fuel gas shall be made from materials having a compression set of no more than 25% after 22 hr at 2 12°F (100°C), in specimens in accordance with ASTM D 395, para. 5.2.
3.3.4 PTFE Materials. Polytetrafluoroethylene (PTFE) materials shall comply with ASTM D 4894 or D 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 Atmosphere. Those 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).