Codes, piping

Design parameters as a function of temperature and design temperature limits are set forth in the ANSI/ASME B31 Piping Codes for a very broad range of materials. These codes, and the additional information available from manufacturers, vendors, and technical societies such as the National Association of Corrosion Engineers provide ample data for the selection of materials for piping systems (1—13). 

Pressure-Piping Code The code for pressure piping (ANSI B31) consists or a number of sections which collectively constitute the code. Table 10-14 shows the status of the B31 code as of December 1980. The sections are published as separate documents for simplicity and convenience. The sections differ extensively. 

FIG. 10-124 Scope of piping covered by the Chemical Plant and Petroleum Refinery Piping Code, ANSI B31.3 (FromASME Chemical Plant and Fetroleum Refinery Piping Code, ANSI B31.3—1980 reproduced with permission of the publisher the American Society of Mechanical Engineers, New Yorh.)... 

For flanges of nonstandard dimensions or for sizes beyond the scope of the approved standards, design shall be in accordance with the requirements of the ASME Boiler and Pressure Vessel Code, Sec. T11, except that requirements for fabrication, assembly, inspection testing, and the pressure and temperature hmits for materials of the Piping Code are to prevail. Countermoment flanges of flat face or otherwise providing a reaction outside the bolt circle are permitted if... 

Special note for the sixth edition At diis time, metric equivalents have not been provided for the allowable-stress tables of the piping code B31.3. Tliey may be computed by the following rela-tionsliips ( F - 32) x 9 = C Ibf/iir (stress) x 6.S9.5 x 10 = MPa. 

Extracted from the Chemical Plant and Petroleum Refinery Piping Code, ANSI B.31.,3-cal Engineers, New York. 

American National Standards Institute (ANSI), formerly American Standards Association (ASA). ANSI promulgates the piping codes used in the chemical-process industries. 

Maximum Allowable Working Pressure -As defined in the construction codes for pressure vessels, the maximum allowable working pressure depends on the type of material, its thickness, and the service conditions set as the basis for design. The vessel or equipment may not be operated above this pressure, or its equivalent stress at any other metal, temperature. However, ANSI B31.3, Petroleum Refinery Piping Code, permits variations above the maximum allowable working pressure, as follows ... 

Most refrigeration plants use freon as the refrigerant anti limit the lowest temperature to -20°F. This is because the ANSI piping codes require special metallurgy considerations below -20 F to assure ductility. 

American Society for Testing and Materials (ASTM). This society generates specifications for most of the materials used in the ANSI Piping Codes and the ASME Boiler and Pressure Vessel Codes. 

FIG. 10-127 Scope of work covered by process piping code ASME B31.3-2004. 

FIG. 10-172 Moments in bends. Extracted frcym the Process Piping Code, B31.3—2004, with permission of the publisher, the Ameriean Society of Mechanical Engineers, New York.)... 

---