Reports on field investigations in 7 Florida restaurants to identify uncontrolled airflows and pressure imbalances. Testing included building airtightness tests, identification of building air barrier locations, duct system airtightness, characterisation of pressure differentials, building airflow balance and infiltration/ventilation rates. All restaurants were found to operate at negative pressures, averaging -0.051 in. w.c. (-12.7 Pa) under normal operation. The variable that affect depressurisation are 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 and building airtightness.

KEYWORDS: year 1996, Restaurants, USA, testing, air flow, depressurisation