API 610 Pump Classifications
API 610 is the global benchmark for centrifugal pumps in petroleum, petrochemical, and natural gas industries. Pumps manufactured to this standard meet stringent requirements for material traceability, hydrostatic testing, rotor dynamics, and documentation that far exceed standard industrial pump specifications. B2B buyers in the oil and gas sector must understand API 610 classifications, material classes, and testing requirements to specify pumps that will operate reliably in hazardous areas, high-temperature hydrocarbon service, and critical process applications.
NOVAPUMP provides API 610-compliant pump solutions with full material certification, hydrostatic test reports, performance test curves, and NDE documentation per the purchaser's inspection and testing plan.
Table of Contents
API 610 Pump Classifications
Overhung Pumps (OH1, OH2, OH3)
OH2 centerline-mounted single-stage pumps are the workhorses of refinery services, handling flows to 1,000 cubic meters per hour and heads to 250 meters. Centerline mounting ensures thermal expansion occurs symmetrically, maintaining shaft alignment at process temperatures up to 450 degrees Celsius.
Between-Bearings Pumps (BB1, BB2, BB3, BB4, BB5)
BB2 one-stage and two-stage radially split pumps serve high-temperature applications. BB5 double-case barrel pumps handle the most demanding high-pressure services including boiler feed, water injection, and pipeline pumping at pressures exceeding 200 bar. For impeller technology insights, see our centrifugal pump impeller types guide.
Material Selection and Seal Plans
API Material Classes
Class S-4 (316SS) is the minimum for hydrocarbon service. Class C-6 (12% chrome) offers erosion resistance for crude oil with sand content. Class A-8 (duplex stainless steel) handles sour service with H2S partial pressure above 3.5 kPa per NACE MR0175.
API Piping Plans for Mechanical Seals
Plan 11 (discharge recirculation to seal) is the default for clean hydrocarbon services. Plan 53B (pressurized barrier fluid with bladder accumulator) is required for services with solids, polymerizing fluids, or emissions control.
Comparison Table: API 610 Pump Types
| API Type | Description | Max Pressure | Typical Applications |
|---|---|---|---|
| OH2 | Centerline-mounted single stage | 40 bar (CL300) | Refinery process, hot oil, light hydrocarbons |
| BB1 | Axially split, 1-2 stage | 40 bar (CL300) | Cooling water, firewater, large volume transfer |
| BB2 | Radially split, 1-2 stage | 100 bar (CL600) | High-temperature, high-pressure process services |
| BB5 | Double casing, multistage | 250+ bar | Boiler feed, water injection, pipeline |
Frequently Asked Questions
Q: What is the difference between API 610 and ISO 5199 pumps?
A: API 610 requires heavier casings with 3mm minimum corrosion allowance, centerline mounting, and full NDE testing. ISO 5199 allows lighter construction, foot mounting, and less rigorous testing. API 610 pumps typically cost 50-100% more but offer significantly longer MTBF in hydrocarbon service.
Q: Which API seal plan should I use?
A: Plan 11 (recirculation from discharge) is appropriate for 70% of applications. Use Plan 23 (cooled recirculation from pump discharge through a heat exchanger) for hot water above 80 degrees Celsius. Use Plan 53B for hazardous or polymerizing fluids.
Q: What testing is required for API 610 pumps?
A: Minimum: hydrostatic test at 1.5 times MAWP, performance test at rated and four additional points, NPSH test at rated flow, and vibration test per API limits. Optional: witnessed testing, sound level test, and full NDE of all pressure-containing welds.
For B2B buyers interested in API 610-compliant centrifugal pump solutions for petroleum applications, contact NOVAPUMP for competitive FOB pricing, technical specifications, and OEM customization options.