Air Pressurizing System

A Combined system/Dilute Ventilation system using both exhaust and supply systems can be more effective than extract only in large offices, as controlled mechanical intake can be used to give positive gentle air movement in warm weather to create a feeling of freshness. It also reduces the number and size of openings required in the structure for replacement fresh air. Heat Recovery units can be incorporated in this type of system for energy saving during the Winter months and under certain conditions, a degree of cooling during spring and early summer. Where buildings are air conditioned, these savings will continue in the summer.

Positive Pressure

Positive pressure is when a room inside the building is held at a higher pressure than the surrounding rooms. Or to put it another way, positive pressure occurs when more airflow is pumped into a room than airflow drawn out. This ensures any air leaks in the room will flow from inside the room to the outside. This is most commonly used in clean room applications to prevent airborne contaminants from outside the room leaking in.

Negative Pressure

Negative pressure is when a room inside the building is held at a lower pressure than the surrounding rooms. Or to put it another way, negative pressure occurs when more airflow is drawn out of a room then airflow pumped in. This ensures any air leaks in the room will flow from outside the room to the outside. This is most commonly used in hospital isolation rooms to prevent airborne viruses or bacteria from escaping the room into other rooms.