ASME B16.38-2007 pdf download

ASME B16.38-2007 pdf download.Large Metallic Valves for Gas Distribution.
1.1 Valve Types
ASME B16.38 covers requirements for manually operated metallic valves in nominal sizes 2 ‘2 (DN 65) through 12 (DN 300) having the inlet and outlet on a common centerline. These valves are intended for controlling the flow of gas from open to fully closed positions, for use in distribution and service lines where the maximum gage pressure does not exceed 125 psig (8.6 bar). Valve seats, seals, and stem packing may be nonmetallic.
1.2 AppLication
This Standard sets forth the minimum capabilities, characteristics, and properties that a newly manufactured metallic valve must possess in order to be considered suitable for use in piping systems indicated above, carrying natural gas, manufactured gas [includes synthetic natural gas (SNG)], and liquefied petroleum gases (distributed as a vapor, with or without the admixture of air) or mixtures thereof.
1.3 Referenced Standards
Standards and specifications adopted by reference in this Standard and the names and addresses of the sponsoring organizations are shown in Mandatory Appendix
1. It is not considered practical to refer to a specific edition of each of the standards and specifications in the individual references. Instead, the specific edition references are included in Mandatory Appendix I. A product made in conformance with a prior edition of reference standards will be considered to be in conformance, even though the edition reference may be changed in a subsequent revision of the standard.
1.4 Quality Systems
Nonmandatory requirements relating to the product manufacturer’s Quality System Program are described in Nonmandatory Appendix A.
1.5 Convention
3.3.2 Seat Test. Following the shell test, and after removing the outlet cap, with the valve in the full-closed position, air or gas pressure of first 4 psig ± 2 psig (0.3 bar ± 0.13 bar) and then 200 psig (13.8 bar) shall be applied to one end of the valve with the valve immersed in a bath of water at a temperature of 74°F ± 15°F (23°C ± 8°C). Leakage (as evidenced by the breaking away of bubbles) shall not he permitted over the time periods specified in Table 1.
The test pressures shall then be applied to the other valve end and under the same test conditions and acceptance criteria.
3.4 Operational Test
The test valve shall provide a shutoff as determined in para. 3.3 after having been operated for ten cycles between the limits of full closed to full open and back to full closed when subjected to an internal air or gas pressure of 125 psig (8.6 bar) with the outlet capped.
3.5 Temperature Resistance
All test valves shall be operable at metal temperatures ranging from —20°F (—29°C) to 150°F (66°C) without affecting the capability of the valve to control the flow of gas and without leakage to atmosphere.
3.5.1 Method of Test
3.5.1.1 The valve shall be maintained at a temperature of —20°F (—29°C) for a period long enough to allow all parts to come to an equilibrium temperature. With the valve subjected to an internal air or gas pressure of 125 psig (8.6 bar) and the outlet side sealed, the valve shall be closed and opened 10 times to establish that it can be opened and closed in a normal manner, i.e., within 15% of the valve manufacturer’s specified operating torque.
3.5.1.2 The test valve shall then be maintained at a temperature of 150°F (66°C) for a period long enough to allow all parts to come to equilibrium temperature. With the valve subjected to an internal air or gas pressure of 125 psig (8.6 bar) and the outlet sealed, the valve shall be closed and opened 10 times to establish that it can be opened and closed in a normal manner, i.e., within 15% of the manufacturer’s specified operating torque.
3.5.1.3 The test valve shall then be allowed to return to a temperature of 74°F ± 15°F (23°C ± 8°C) and subjected to the tests outlined in paras. 3.3.1 and 3.3.2.