Trane BAS-APG001-EN Manuel D’Utilisation

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Chapter 1 Smoke control overview
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BAS-APG001-EN
Design considerations for smoke 
control
Two occurrences will hinder smoke control: 
Plugholing
Smoke feedback
Smoke control systems should be designed to address the problems that 
are caused by plugholing and smoke feedback. 
Plugholing
Plugholing occurs when an exhaust fan pulls fresh air into the smoke 
exhaust (Figure 10). Plugholing decreases the smoke exhaust and 
increases the smoke layer depth. It has the potential of exposing 
occupants to smoke.
The maximum flow of smoke (Q
max
) exhausted without plugholing 
depends on the depth of the smoke layer and the temperature of the 
smoke. If the required total smoke exhaust is greater than Q
max
additional exhaust vents will eliminate plugholing. The distance between 
vents must be great enough that the air and smoke flow near one vent 
does not affect the air and smoke flow near another vent.
Figure 10:  Sample plugholing