Earle<unk>  of Temple University (Philadelphia, Pennsylvania) in a 1939 paper on disinfection of surgical instruments in a chemical solution proposed "a strategy for sterilization or disinfection of inanimate objects and surfaces based on the degree of risk involved in their use". In order to simplify the nature of the disinfection process,<unk>  classified instruments and items used in patient care according to infection risk into "critical", "semicritical", and "noncritical" categories. He also classified levels of germicidal activity as "high", "intermediate", and "low". While influential, the<unk>  scheme is susceptible to oversimplification and can be difficult to implement.
Spaulding classification
Wassel classification
Frykman classification
Pipkin classification
Herbert classification
Nissen-Lie classification
Seinsheimer classification
Schenck classification