Comparison of ASHRAE Dust Spot and Fractional Aerosol Efficiencies of Air Filters, 1994 Nonwovens Conference Proceedings
Kenneth Dale Montgomery
The importance of Indoor Air Quality (IAQ) has prompted the HVAC industry to require more stringent testing of air filters. ASHRAE has responded by proposing the development of a particle size based, fractional efficiency test method. This paper outlines the proposed method, compares it to the current standard and then compares the results of ASHRAE dust spot efficiencies with particle count equivalent dust spot efficiencies of 90% and 60% filters.
The test method used in this study was identical to ASHRAE 52-76 (traditional dust spot efficiency) except that fractional efficiency measurements were added. Filters were loaded with ASHRAE test dust at an air flow of 3400 m3/hr (2000 ft3/min) until a final resistance of 625 Pa (2.5” water) was obtained. Fractional efficiencies were obtained by using an optical particle counter with an ambient aerosol at each dust spot increment.