ASTM International, recently approved a new standard for testing the varnish potential of in-service lubricants: ASTM D7843 – Standard Test Method for Measurement of Lubricant Generated Insoluble Colour Bodies in In-Service Turbine Oils using Membrane Patch Colorimetry.

MPC testing has already been globally adopted as the most common methodology for testing the varnish potential of turbine oils and other non-detergent lubricants. The new standard however will increase testing consistency and precision. Improvements in test reproducibility are expected as not all commercial labs are performing the test in the same manner.

"Varnish has plagued turbine oil users in recent years," states Dr. David Wooton, the Chair of the ASTM Work Group that developed and balloted the new Standard. "The new MPC test standardizes a powerful predictive tool for turbine and compressor users allowing them to be aware of impending varnish problems."

Fluitec has been a strong supporter of the MPC test for years. Two of Fluitec’s employees developed and commercialized the industry’s first varnish potential test, the predecessor to the MPC test, in 2005. "We view the MPC test as a powerful complement to our RULER technology," claimed Greg Livingstone, Fluitec’s CMO. "Trending antioxidant health and soft contaminant formation are critical to understanding the remaining useful life of your lubricants."

For more information on ASTM D7843, please visit