HVAC controls after an outside contaminant release

For that study, two tests were conducted to study the effects of HVAC system operation on contaminant uptake and distribution : two scenarios of tracer gas experiments were performed on an existing building simulating an external release. For the first experiment there was no action by the building controls. For the second one the outside air-handling unit was shut off along with the closing of the outside air damper, simultaneously with the beginning of release. The results are presented. Several additional operational issues should be addressed.