Southern New Hampshire Medical Center has variable air volume air handling units, which introduce a varied amount of fresh air into the building depending on building load. The exhaust systems throughout the facility are primarily constant volume. As a result, the building was negatively pressurized and the degree of negative pressure varied with building load.

Control Technologies, Inc. worked with Southern New Hampshire Medical Center to upgrade controllers, install various air flow stations, and implement a revised building pressure control sequence for all air handling units. The hospital now maintains the desired degree of positive pressurization.