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Smoke Exhaust System:
In most new buildings and in major retrofits of older buildings a smoke exhaust system is required. This usually consists of a duct riser through the building with sufficient capacity to exhaust one complete floor of the building. This is accomplished via a series of combination fire/smoke dampers located at each floor to allow only the floor where the smoke condition exists to be exhausted. In some jurisdictions the system is manual and set up to exhaust smoke after the fire, however, under other jurisdictions the system is automatic and is activated on the initiation of the smoke detector on the smoke floor. Atrium smoke exhaust systems are always the automatic type.

Combination Smoke and Fire Dampers:
Combination smoke and fire dampers are generally required in ductwork passing through 2-hour rated walls or smoke barriers. The activation of the dampers may be local but in most cases they are activated by the detection of smoke within a system closing down the dampers and maintaining the integrity of the fire/smoke walls.

Stair Pressurization Systems:
When stair pressurization systems are required they consist of a supply fan unit providing outside air at multiple points within a stair riser. The stair pressurization system is generally initiated by the activation of any alarm device within the building. This is to create an area of refuge (positive pressure) within the stair immediately upon activation of any alarm to keep out smoke.

Tamper and Water Flow Switches:
Tamper and water flow switches are associated with the fire standpipe and sprinkler systems. The fire alarm system's function is to monitor and activate an alarm or trouble condition upon actuation of a tamper or water flow switch.

Mechanical System Smoke Detectors:
Systems over 2,000 cfm require smoke detectors located in the supply discharge of the AC unit and systems over 15,000 cfm require duct mounted smoke detectors in the supply and return portions of the systems. These detectors turn off their corresponding system and initiate an alarm at the central fire alarm panel.

Elevator Recall System:
This system consists of smoke detector(s) at each elevator lobby. (New York City requires two detectors cross connected to minimize false alarms. The first detector indicates trouble, the second returns the elevator. The city is now accepting "alarm verification" for single detectors). Upon actuation of the elevator recall system the elevator will automatically return to a predetermined floor (usually the lobby). If the predetermined floor has the smoke condition, the elevator will return to a predetermined alternate floor.

The following additional systems may also be monitored at the Fire Alarm Panel.