Grade FExtremely poor cleanliness (CI value< 0.29)
Grade DAllowable cleanliness (CI value = 0.49-0.30)
Air cleanlinessHierarchy chart
Grade CMedium cleaning (CI value = 0.69-0.50)
Grade BGeneral cleaning (CI value = 1.00-0.70)
Level ECritical value cleanliness (CI value = 0.29)
Grade ACleanest (CI value> 1.00)
