Preliminary Guide Lines for Testing Filters for the Removal of Suspended Substances from Air and other Gases (Including Radioactive Dusts, Mists, Bacteria and Viruses)
ARMY BIOLOGICAL LABS FREDERICK MD
Filters for removing suspended substances will be termed dust filters. Dust filters of special type S must retain from the gas or gas mixture to be purified the stable and fluid suspended substances, bacteria and viruses to an optimum percentage.
Trans. of Staub (West Germany) v23 n1 p21-27 1963.