Manufacturers do not typically document efficiency data for nominally-rated filters as they do for absolute filters. Nominal ratings are meant only as a guide and typically rank a cartridge filter’s efficiency compared to other cartridges in the same product line. For example, a 5-micron filter from a manufacturer will be more efficient than their 10-micron but less than the 1-micron cartridge. For more information on the distinction between absolute and nominal ratings, see the associated application bulletin in the SUEZ library.