Color
Standard Test Method for ASTM Color, ASTM D6045/1500
Color is a physical property of the oil. As a new oil test, a very low color is an indication of a highly refined oil and is a relative measure of the purity of the oil. A typical new oil value for color is less than 0.5 on the ASTM scale. As in-service oil ages and is oxidized, color typically increases, and the oil darkens, visibly. Care must be taken in interpreting color results for in-service oil because there can be relatively light colored oils that are unacceptable for continued use and there are some darker oils that continue to provide acceptable service. Maintenance decisions are rarely made based strictly on color, but an unacceptable color may indicate the need to more closely evaluate other test results that apply to oxidation of the oil.
For fluids other than transformer oil, there are both quantitative and qualitative determinations of color available. Frequently, we find it is most useful for fluids such as Askarel and Silicone fluid to provide a qualitative description of the color.
Color is a physical property of the oil. As a new oil test, a very low color is an indication of a highly refined oil and is a relative measure of the purity of the oil. A typical new oil value for color is less than 0.5 on the ASTM scale. As in-service oil ages and is oxidized, color typically increases, and the oil darkens, visibly. Care must be taken in interpreting color results for in-service oil because there can be relatively light colored oils that are unacceptable for continued use and there are some darker oils that continue to provide acceptable service. Maintenance decisions are rarely made based strictly on color, but an unacceptable color may indicate the need to more closely evaluate other test results that apply to oxidation of the oil.
For fluids other than transformer oil, there are both quantitative and qualitative determinations of color available. Frequently, we find it is most useful for fluids such as Askarel and Silicone fluid to provide a qualitative description of the color.