This test code is for laboratory use in determining the operating characteristics of air cleaners. It refers specifically to laboratory testing of oil bath, oil wetted, dry and multistage air cleaners. Other types should follow this recommended practice wherever applicable. Multistage types should be evaluated as a complete assembly although, if desired, a component stage can be tested separately in accordance with its individual type. This code contains alternate procedures and permits prescribing certain specific conditions of a test. Therefore reported results of tests are not complete unless accompanied by statements, where applicable, of the specific conditions such as: (1) rated air flow, (2) prescribed air flow, (3) steady or variable airflow, (4) fine or coarse dust, (5) amount of dust, and (6) maximum permissible restriction.