Applications of smoke control methods
Single and multiple injection pressurization techniques
The single injection and multiple injection techniques provide pressurization air to a stairwell (Figure 6). Both techniques use one or more pressurization fans located at ground level, roof level, or any location in between.
The single injection technique supplies pressurization air to the stairwell from one location.
IMPORTANT
The single injection technique can fail when stairwell access doors are open near the air supply injection point. Pressurization air will escape and the fan will fail to maintain a positive pressure difference across access doors farther from the injection point.
The multiple injection technique supplies pressurization air to the stairwell from more than one location. When access doors are open near one injection point, pressurization air escapes. However, other injection points maintain positive pressure differences across the remaining access doors.
Figure 6: Sample single and multiple injection methods
Elevator shaft smoke control
Elevator shaft smoke control uses pressurization to prevent smoke migration through elevator shafts to floors remote from the source of the smoke. Elevator shaft smoke control is similar to stairwell smoke control. The stairwell pressurization techniques described previously are applicable to elevator shaft pressurization.
Designating an elevator as a fire exit route is an acceptable, though not typical, practice. NFPA 101 (NFPA 2003, Life Safety Code) allows elevators to be second fire exit routes from air traffic control towers. For
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