API 610 Explained: What It Means for Centrifugal Pumps

API 610 is a standard from the American Petroleum Institute for centrifugal pumps used in petroleum, petrochemical and natural gas industries. It is identical to ISO 13709. When a refinery or petrochemical specification says “API 610 pump”, it is asking for a heavy-duty pump built to a stricter standard than general industrial pumps.

What API 610 covers

The standard sets requirements for design, materials, shaft and bearing life, seal chambers, nozzle loads, testing and documentation. It is meant for demanding duties: high temperature, high pressure, flammable or hazardous fluids and long continuous running.

Pump types and designations

• OH (overhung): single stage pumps with the impeller overhung from the bearings. OH1 is foot mounted, OH2 is centreline mounted for high temperature, and OH3 and OH6 are vertical or high-speed variants.
• BB (between bearings): impeller between two bearings, including axially split (BB1, BB2) and multistage designs (BB3, BB4, BB5).
• VS (vertically suspended): sump and vertical turbine type pumps, VS1 to VS7.

Related standards you will see alongside it

• API 682: mechanical seals and seal support systems.
• API 685: sealless centrifugal pumps for the same industries.
• API 675: controlled-volume (metering) pumps.
• API 676: rotary positive displacement pumps.

When you do not need API 610

Many chemical and general process duties are properly served by pumps built to other standards, such as ISO 2858 or ASME B73 chemical process pumps. API 610 adds cost, so use it where the client specification or the duty demands it. Ask whether the specification really requires it, or whether it was copied from a template.

What to ask a supplier

1. Does the pump fully comply with the API 610 edition in the specification, and which deviations are listed?
2. Which pump type designation is offered (OH2, BB2, VS and so on)?
3. What materials class and seal arrangement are included?
4. What performance test and documentation package is provided?

This guide is general information. Specifications differ between clients, so the right answer always depends on the project data sheet. See our centrifugal pumps page and the guide to types of centrifugal pumps.

If you have an enquiry with an API specification, send us the data sheet and we will tell you what we can offer. Contact us with your fluid, flow and pressure details and we will recommend a suitable pump.