API std 2510:2001 pdf download.Design and Construction of LPG Installations
1 Scope
This standard covers the design, construction, and location of liqueÞed petroleum gas (LPG) installations at marine and pipeline terminals, natural gas processing plants, reÞneries, petrochemical plants, or tank farms. This standard covers storage vessels, loading and unloading systems, piping, or and related equipment. 1.1 The size and type of the installation; the related facili- ties on the site; the commercial, industrial, and residential population density in the surrounding area; the terrain and cli- mate conditions; and the type of LPG handled shall be con- sidered. Generally speaking, the larger the installation and the greater the population density of the surrounding area, the more stringent are the design requirements. 1.2 Design and construction considerations peculiar to refrigerated storage, including autorefrigerated storage, are covered in Section 9 of this standard. 1.3 In this standard, numerical values are presented with U.S. customary units only. These U.S. customary values are to be regarded as the standard values. 1.4 This standard shall not apply to the design, construc- tion, or relocation of frozen earth pits, underground storage caverns or wells, underground or mounded storage tanks, and aboveground concrete storage tanks. 1.5 This standard does not apply to the following installa- tions: a. Those covered by NFPA 58 and NFPA 59. b. U.S. Department of Transportation (DOT) containers. c. Gas utility company facilities; reÞnery process equipment; reÞnery and gas plant processing equipment; and transfer sys- tems from process equipment upstream LPG storage. d. Those tanks with less than 2000 gallons of storage capacity.
4.2 DESIGN PRESSURE AND TEMPERATURE
4.2.1 The design pressure of LPG vessels shall not be less than the vapor pressure of the stored product at the maximum product design temperature. The additional pressure resulting from the partial pressure of noncondensable gases in the vapor space and the hydrostatic head of the product at maximum Þll shall be considered. Ordinarily, the latter considerations and the performance speciÞcations of the relief valve require a dif- ferential between design pressure and maximum product vapor pressure that is adequate to allow blowdown of the pres- sure relief valve (see API RP 520). 4.2.2 Both a minimum design temperature and a maximum design temperature shall be speciÞed. In determining a maxi- mum design temperature, consideration shall be given to fac- tors such as ambient temperature, solar input, and product run down temperature. In determining a minimum design temper- ature, consideration shall be given to the factors noted in the preceding sentence as well as the autorefrigeration tempera- ture of the stored product when it ßashes to atmospheric pres- sure. ASME Section VIII, Division 1, has special rules for conditions where reduced temperature, as a result of autore- frigeration or ambient temperature, is caused by coincident with a reduction in pressure. In such case it is required to evaluate the material (by impact testing if necessary) at the temperature of the product corresponding to a pressure that stresses the vessel shell to approximately 10% of the ultimate tensile strength of the shell material. When the vessel is repressurized, this must be done slowly to allow the tempera- ture to increase as the pressure is increased.