Process and pipeline pumps in modern industry are usually designed and built in accordance with one of the three most prevalent industry standards for pumps.
ASME B73.1 & ISO 5199
The widely referenced centrifugal pump standard known as ASME B73.1 can trace its origins to 1974 when, after combining and consolidating the ASME standard with a similar Hydraulic Institute (HI) standard, the two became ANSI B73.1. This new standard has been periodically updated and the current version is called “Specification for Horizontal End Suction Centrifugal Pumps for Chemical Processes.”
In the International Organization for Standardization (ISO) community where 50-hertz (Hz) power systems are the norm, ISO 5199:2002 represents a “Technical Specification for Centrifugal Pumps—Class II.” ASME B73.1 or ISO 5199 are not fully interchangeable; separation is based on the regionally prevailing electric power frequency, B73.1 for 60 Hz and ISO 5199 for 50 Hz. Both standards are widely referenced worldwide for centrifugal pump projects, even outside of chemical process applications. The core coverage of these standards encompasses single-stage end suction, centerline (self-venting) discharge, back pull-out and frame mounting. However, either standard can be useful in applications involving other frequencies—variable frequency drives (VFDs) in all types and sizes of process pumps.
Broadly speaking, the same thought processes govern the dimensional interchangeability limited to pumps made in compliance with ASME and pumps made in accordance with ISO standards. In either case, principal dimensions include, but are not limited to, the distance from base-mounting surfaces to the shaft centerline, and the elevations and distances from pump suction to discharge nozzles.
ANSI & ISO vs. API Pumps
ANSI/ASME and ISO-compliant pumps usually have their mounting pads (feet) incorporated in the casing’s base. The thermal rise of the shaft centerline of ANSI/ASME and ISO-compliant pumps can be as much as three times greater than that of centerline-mounted American Petroleum Institute (API) pumps. For many decades, the API has issued pump standard API 610 for products considered flammable, toxic or prone to explode under reasonably possible circumstances.