Applications of smoke control methods
Figure 4: Sample HVAC operation during smoke control
Note:
For simplicity, Figure 4 does not show the ducts on each floor or the penthouse equipment.
When an HVAC system serves only one smoke control zone, the following sequence provides smoke control:
1.In the smoke control zone, the return/exhaust fan activates, the supply fan deactivates.
2.The return air damper closes, and the exhaust damper opens (optionally, the outside air damper closes).
3.In the
4.The return air damper closes, and the outside air damper opens (optionally, the exhaust air damper closes).
Stairwell smoke control
Stairwell smoke control uses pressurization to prevent smoke migration through stairwells to floors remote from the source of the smoke. Secondarily, it provides a staging area for fire fighters.
In the smoke control zone, a pressurized stairwell maintains a positive pressure difference across closed stairwell doors to limit smoke infiltration to the stairwell. Stairwell smoke control employs one or more of these design techniques: compensated pressurization, non- compensated pressurization, single injection pressurization, and multiple injection pressurization.
Compensated pressurization technique
The compensated stairwell pressurization technique adjusts air pressure to compensate for various combinations of open and closed stairwell access doors. The technique maintains constant positive pressure differences across openings. To compensate for pressure changes, it either employs modulated supply airflow or
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