Compressor Intake Filter (CIF) Corrosion Assessment

Purafil offers a comprehensive Corrosion Assessment service to determine whether or not your centrifugal compressor is at risk of corrosion damage. As part of this service, Purafil places a copper and silver Corrosion Classification Coupon at the air intake of your compressor. Both copper and silver metals are required to test for the broad range of potential gases present. Purafil’s laboratory analyzes the coupon to determine the level of corrosion present in the intake air. This measurement is then correlated to the appropriate environmental classification, listed below, as defined by the Instrumentation, Systems, and Automation Society (ISA) Standard 71.04-1985.

Purafil recommends an environmental classification of G2 or better to ensure the reliable operation of your compressor. An environmental classification of G2 or greater indicates that gas-phase filtration is needed.

• Class G1: A well-controlled environment in which corrosion is not a factor in determining equipment reliability.
• Class G2: An environment in which the effects of corrosion are measurable and may be a factor in determining equipment reliability.
• Class G3: An environment in which there is a high probability that corrosive attack will occur.
• Class GX: An environment in which only specially designed and packaged equipment are expected to survive.

Other tests can also be performed to determine your compressor’s risk of corrosion:

• Acidity Condensate Index (ACI): used to classify the acidity and copper content of the compressor condensate. Values of pH between 0 and 7 are considered acidic, while pH values between 7 and 14 are considered basic. Acidic condensate will attack metals like copper and steel, while basic condensate will attack metals like aluminum.
• Condensate Copper Content: An indicator if copper metal from the intercooler tubes is being lost due to corrosion