What is an advantage of aspirating nozzles compared to nonaspirating nozzles?

Aspirating nozzles are specifically designed to mix air with liquid foam concentrate to produce a foam that forms a thick blanket over the burning surface. This foam serves several critical functions, one of which is to restrict reignition and burnback. The ability of the foam to create a barrier between the fuel and the air not only suppresses flames during the initial application but also prevents the re-ignition of flammable materials. This characteristic is particularly valuable in fire situations where there is a risk of the fire restarting after being initially extinguished.

In contrast, nonaspirating nozzles do not mix air with the foam agent in the same way; as a result, they do not provide the same level of flame suppression or protection against reignition. While other potential advantages of aspirating nozzles, such as lighter weight or ease of operation, may exist, the primary and most pertinent advantage in fire suppression contexts lies in their superior ability to control moisture and prevent re-ignition.