The Rotating Pressure Vessel Oxidation Test (RPVOT) is a standardized ASTM method (ASTM D2272) used to determine a lubricant’s oxidation stability. It reliably predicts how long a lubricant can perform effectively before oxidation-related degradation (such as sludge, varnish, and acid formation) begins. This is a key test for:
- Power generation plants (gas, steam, and hydro turbines)
- Manufacturing facilities using large circulating oil systems
- Industrial maintenance and condition monitoring programs
- Lubricant formulators and quality assurance labs to gauge and verify product stability
Turbine oils, compressor oils, hydraulic fluids, and other long-life lubricants are typically tested. Benefits include:
- Predictive Maintenance Value: Provides early warning of oxidation degradation before other properties (such as viscosity or acid number) change.
- Oil Life Extension: Helps optimize oil change intervals and reduce costs.
- Quality Assurance: Confirms that new lubricants meet OEM and industry specifications for stability.
- Comparative Analysis: Detects differences in oxidation resistance between new, used, and in-service oils.
- System Reliability: Prevents downtime due to varnish, sludge, and deposit formation caused by oxidation breakdown.
RPVOT measures the actual resistance to oil oxidation.[1] It is a proactive tool for identifying problems before permanent damage occurs to either the lubricant or the machine. The test is particularly valuable for large oil volumes with low makeup fluid requirements and severe-duty applications.
RPVOT is typically performed annually on very large oil reservoirs—such as steam turbines with capacities exceeding 10,000 gallons. Results are compared against the RPVOT of new oil to estimate remaining useful life as a percentage of the baseline value. The caution limit is generally set at 25% of the new oil RPVOT, though this may vary by application.
ASTM D2272[2]
ASTM D2272, also known as the Rotating Pressure Vessel Oxidation Test (RPVOT), is a standardized test method used to evaluate the oxidation stability of turbine oils and other lubricants under accelerated conditions.
Test Procedure
- A measured sample of oil is placed in a sealed pressure vessel with water and a copper catalyst coil.
- The vessel is pressurized with oxygen (typically to 90 psi) and heated to 150°C (302°F).
- The vessel rotates in a constant-temperature bath to ensure uniform exposure.
- As oxidation occurs, oxygen is consumed, and the pressure inside the vessel drops.
- The RPVOT value is the time (in minutes) until a significant pressure drop (usually 25 psi) is detected.
A longer RPVOT time indicates better oxidation stability and longer expected lubricant life.
To schedule RPVOT testing or for more information on working with Eurofins TestOil for oil analysis, fuel analysis or training visit https://testoil.com/company/contact-us/; call 216-251-2510; or email salesi@et.eurofinsus.com.
With more than 30 years of experience in the oil analysis industry, Eurofins TestOil focuses exclusively on assisting industrial facilities with reducing maintenance costs and avoiding unexpected downtime through oil and fuel analysis program implementation. As industry experts in diagnosing oil-related issues in equipment such as turbines, hydraulics, gearboxes, pumps, compressors and diesel generators, Eurofins TestOil provides customers with same-day turnaround on routine oil analysis testing.
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[1] Other tests detect oxidation that is already present in the oil.
