AT-84-12-1 -- Air Tightness of Fire Dampers for Smoke Exhaust Systems in High-Rise Buildings PDF

Venting the fire region of a building to the exterior significantly reduces smoke problems This is often achieved by means of a smoke exhaust shaft with dampered caused by a fire. In the event of fire, the dampers at the top and on the fire floor openings on each floor are opened to exhaust smoke to the exterior.

The performance of the smoke exhaust shaft is seriously affected by any extraneous air. Tests have been conducted leakage through closed dampers located on the non-fire floors before and after fire exposure to measure the air leakage characteristic of proprietory fire dampers currently used for smoke shaft application.

The pre-fire test ratios of leakage area to damper area were generally below 21 percent. After exposure to the standard time-temperature, the ratios were generally below 4%. Restricting the maximum furnace temperature to 1000°F (540°C) considerably reduced the increase in leakage area ratio due to fire exposure.