John H. Klote, D.Sc., PE, John H. Klote Inc., Leesburg, Va.

Prevent plugholing: Smoke control done right

Many engineers do not know that plugholing can result in occupants being exposed to smoke, but there is a method to prevent this. Plugholing is the pulling of “fresh” air into a smoke exhaust, which can happen when the smoke exhaust flow rate is relatively high, as shown in Figure 1. When fresh air is pulled into the smoke exhaust, the amount of smoke exhausted is reduced, the smoke...