Cleanliness Codes (Lubrication)

A means of reporting lubrication cleanliness by converting the contamination particle count results into classes or codes. The International Organization For Standardization (ISO) created cleanliness code 4406:1999 to quantify particulate contamination levels per milliliter of fluid for three particle sizes: 4-, 6-, and 14-µm.

(Example: An ISO code of 20/17/14 relates to the contaminant level code for 4-, 6-, and 14-µm particle sizes. An increase from one code number to the next generally indicates a doubling of the particle contamination level.)