Fire and Smoke Dampers

Some laws have been implemented to improve the safety of buildings against fire by the authorities due to the increase of under-construction buildings. One of the applied laws is related to ventilation systems in parking to control the amount of smoke and fire which would be done by exhaust fans, riser duct systems, smoke and fire dampers, and jet fans.

Parking smoke and fire dampers are utilized to seal and control airflow rates in garage exhaust ducts. In the United States, these products are manufactured and classified according to the UL555s standard which is categorized in 1 to 3 leakage classes based on leakage rate in different pressure, and also the airflow rate measurement. Additionally, this standard includes structural requirements, operational performance tests, temperature degradation, salt spray test, and cycling tests. Operational performance tests include 20 thousand disconnections for on/off dampers and 10 thousand disconnections for modulating dampers. In projects that decreased amount of leakage does not affect the control system’s performance smoke damper with leakage class of 2 or 3 can be utilized but in places where gas leakage such as acid gases is significant to use dampers with 1 class or zero leakage or bubble-tight dampers.

Parking smoke and fire dampers are utilized to seal and control airflow rates in garage exhaust ducts. In the United States, these products are manufactured and classified according to the UL555s standard which is categorized in 1 to 3 leakage classes based on leakage rate in different pressure, and also the airflow rate measurement. Additionally, this standard includes structural requirements, operational performance tests, temperature degradation, salt spray test, and cycling tests. Operational performance tests include 20 thousand disconnections for on/off dampers and 10 thousand disconnections for modulating dampers. In projects that decreased amount of leakage does not affect the control system’s performance smoke damper with leakage class of 2 or 3 can be utilized but in places where gas leakage such as acid gases is significant to use dampers with 1 class or zero leakage or bubble-tight dampers.

Moreover, special damper actuators are used for these smoke and fire dampers which are produced by various companies. For instance, Belimo BLE, Belimo BEN, Belimo BFL/BFN/BF, Siemens GGA/GCA, and others with 230 or 24 volts.

Application

These products are part of a “passive smoke control system” that is mounted upon deflection to detect and intercept the transmission of smoke in air ducts. In addition, as part of an “engineered smoke control system” designed to restrain the amount of smoke by using walls and floors as barriers and create pressure differences. Moreover, these products are mounted as exhaust dampers to eliminate or control the entrance of smoke contaminated airflow to exhaust risers and are also used to separate the sensitive environments containing specific gases which in particular times need to be evacuated or trapped like fire suppression systems (FM200).

Installation

The following should be considered when installing smoke dampers:

  • Installation position:

These dampers are mounted on or inside the smoke separation walls or smoke barriers. The mounted smoke damper must not distance more than 24 inches from smoke barriers. Especially, dampers installed as air handling unit isolators are exceptions to this rule. Furthermore, NFPA 90A states that smoke dampers must be used to isolate air handling units with a capacity of 15000 CFM.

  • Damper sleeves:

Smoke dampers usually do not require additional sleeves and can directly connect to ducts.

  • Sealing:

The attachment between smoke and fire dampers, ducts, and installation positions must be sealed completely. In addition, the smoke dampers are classified based on the leakage rate between the frame and blades so the leakage rate must be equivalent to zero.

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