Do we need to seal off HVAC supply diffusers or return air grills?
• In a negative pressure room, it is necessary to seal off any air returns to ensure that the only air exhausted from the room must pass through the HEPA-CARE unit or units. It may also be necessary to damper down supply air to ensure that more air is exhausted from the room than supplied to it. If this is not possible, and supply air volume is substantial, additional or larger HEPA-CARE units may be required to maintain the proper pressure differential. In positive pressure rooms, the reverse applies. Supply air diffusers must be sealed off and return air volume must be controlled relative to the exhaust airflow of the HEPA-CARE unit.
