The two common codes used for centrifugal pumps are API-610 “Centrifugal Pumps for General Refinery Services” and ANSI B73.1 “Specifications for Horizontal, End Suction Centrifugal Pumps for Chemical Process.” The API is more stringent in design requirements and quality control and is normally used for critical services where reliability is important.
Table 11-1 shows a comparison of some of the major requirements of these two standards. It can be seen that the API requirements are more stringent. ANSI pumps, or “ANSI type” pumps for pressure ratings in excess of the 150 Class, are less expensive and much more readily available. Wherever service conditions allow, considerable savings and time are possible by specifying an ANSI pump.