scope:

This Pressure-Temperature Rating Stand· ard pertains to pipe flanges made of the particular material specifications as listed in Table 1, with dimensions as listed in ANSI 816.5-1968 for the various pressure classes as listed therein. Ex· cept for aluminum bronze, Alloy 9A, all materials are for forged flanges only. No coverage of fittings or valves is intended.

Low Temperature Ratings

The lowest listed service temperature rating is -20F to 100F (normally considered to be atmospheric or room temperature). It is recognized that these non-ferrous materials also are used in lower temperature services. The ratings for -20F to 100F range may be applied directly to pipe flanges used at temperatures below -20F. The materials listed in Table 1 tend to increase in strength without undergoing a marked drop in impact resistance at sub-zero temperatures; therefore, no additional requirements are specified for these materials when used !it temperatures down to -325F. For temperatures below -325F, the user should satisfy himself by appropriate test, or otherwise, that the material is suitable for the intended service.

Particular attention should be given to the selection of the proper bolting and gasket material when flanges of these materials are being used at temperatures below -20F.