Secondary Author(s)

Withers Jr., Charles; Fairey, Philip; McKendry, Bruce; Moyer, Neil

Report Number




Buildings; Air Flow; Ducts; Air Quality; Florida


Field investigations were done in 68 commercial buildings to identify uncontrolled air flows and pressure imbalances. Results from eight buildings (six restaurants and two sports facilities) are reported in this paper. Testing included building airtightness tests, identification of building air barrier location, duct system airtightness, characterization of pressure differentials, building air flow balance, and infiltration/ventilation rates. Six restaurants and one sports facility were found to operate at negative pressures which ranged from -0.003 inWC (-0.8 Pa) to -0.173 inWC (-43 Pa) and averaged -0.051 inWC (-12.7 Pa) under normal operation. A second sports facility operates partially at positive pressure and partially at negative pressure. Variables which affect depressurization include large exhaust fans, missing or undersized make-up air, intermittent outdoor air caused by the cycling of air handlers, dirty outdoor air and make-up air filters, ceiling return plenums leaking to outdoors, undersized return air pathways, and building airtightness. These uncontrolled air flows and pressure imbalances impact energy use, ventilation rates, sizing of heating and air conditioning systems, indoor comfort, relative humidity, moisture damage to building materials, mold and mildew growth, operation of combustion equipment, and indoor air quality.

Date Published



Reference Publication: Cummings, J. B., C.R. Withers, P. Fairey, B. McKendry, and N.A. Moyer, 1995, "Indoor Air Quality Impacts of Uncontrolled Air Flow and Depressurization in Eight Commercial Buildings in Central Florida". Proceedings of the Eighth Annual Indoor Air Pollution Conference. Tulsa, OK, September, 1995.

Local Subjects

Buildings - Air Flow; Buildings - Air Quality; Buildings - Ducts; Florida


FSEC Energy Research Center® Collection



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