ASME B16.33-2002 pdf – MANUALLY OPERATEDMETALLIC GAS VALVES FORUSE IN GAS PIPING SYSTEMS UP TO 125 PSI.
3 MATERIALS
3.1 Metallic Materials or Valve Parts
Metallic materials known to be acceptable for coinpliance with this Standard are listed in Table I. Other metallic materials may be used when the product incorporating them mecis the requirements of this Standard.
3.2 Lubricants, Sealants, and Seating Materials
3.2.1 Lubricants and Sealants L.uhricanis and! u sealants shjll he itsistaflt Lu the uctiifl of fuei gases such as natural, manufactured. and IP gases. The valve manufacturer is responsible for the selection of lubricants and scalants, and for the determination of Lhcir suitability for the service conditions spedñed in the scope of this Standard
3.2.2 Seating and Stem Seal Materials. The valve manufacturer is responsible for selection of seating am! stem seal ,natcnals and for detennination of their suitability for the service conditions specihcd in the scope of this Standard.
3.2.3 Elastomer Components
3.2.3.1 Air Aging Tests. Elastomer pans that are esposed to fuel gas shall be made from materials that, following 70 hr air aging in accordance with A.crM I) 573 at 2l2F (l0tC). meet elongation. tensile, and hardness property requirements a follows:
Tensile tests shall be conducted on six dumbbells in accordance with AS1M I) 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 0.080 ÷ 0.4)08 in. (2.0 ± 0.2 mm). The average of the three individual tests for the aged dumbbells shall exceed 60°f retention of ultimate elongation and gy retention of tensile strength at break. The avenge of the three individual tests for the nonaged dumbbells shall be the basis for % retention calculation. Hardness tests shall be conducted using specimens in accordance with ASTM D 395. Type 2. Three specimen’ shall be air aged 70 hr in accordance with ASTM I) 573 at 212°F (100°C). The average of the three individual tests for 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.
3.2.32 Swell Tests. Elastomer parts. which are exposed to fuel gas. shall be made from materials that. after 70 hr exposure in n•hexane at 74°F (23°C). in accordance with ASTM D 471. meet the volume change. elongation, and tensile property requirements as follows:
Volume change test shall be conducted using six specimen in accordance with ASTM 1) 471. Section & Three specimen shall be exposed (or 70 hr at 74°F (23°C) in n-hexane in accordance with ASTM I) 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 I %. The average of the three tests for the non ‘aged specimen shall be the basis for the I retention change calculation.
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 nhexane at 74°F (23°C) for 70 hr in accordance with ASTM D 471. The dumbbells shall have a thickness of 0.080 + 0,008 in. (2.0 ± 0.2 mm). The average of the three indtvidual n-hexane tests shall exceed 60% retention of ultimate elongation and 601f retention of tensile strength at break. The average of the three tests for the non-aged specimen shall be the basis for the % volume change calculation.
3.2.3.3 CompressIon Set Tests. Elastomer pans. which may be exposed to fuel gas. shall he made from materials having a contpression set of no more than 25% after 22 hr at 212°F (l(XYC. in accordance with ASTM I) 395. Method b. using standard test specimen in accordance with ASTM D 395 tSee
Flora. 5.2).
3.2.4 PTFE Components. Polytetrafluoroethyknc (PTFE) materials shall comply with ASTM I) 4894 or ASTM I) 4895.