ABSTRACT
The complete evaluation of an air filter or filter installation involves more than a single measurement of its efficiency in retaining particles of a standard test material, although it is the particulate efficiency which is generally of prime importance. Tests are properly carried out in the design state and also on the complete filter. They are described in various documents, published by bodies such as the US Atomic Energy Commission, the UK Atomic Energy Authority, Underwriterts Laboratory, Inc. (US), and by manufacturers. Testing of the filter medium is carried out in the laboratory on small quantities of the material. Most high-efficiency tests rely on small samples for measurement of the concentration of particles. The detection/measurement system must be of adequate sensitivity and should, ideally, respond quickly in a calculable manner to the aerosol. For example, flame photometry gives a measurement of the mass concentration of the penetrating particles.
