Canopy/Receiving Hoods

Canopy hoods, or exterior hoods, are those which are located above an emission source without enclosing it. Where the contaminant is a smoke, fume, or fine particulate and is not emitted with any significant velocity, the hood orientation is not critical. However, if the contaminant contains large particulates which are emitted with a significant velocity, the hood should be located in the path of the emission. As with welding, the process emits hot contaminated air and rises due to thermal buoyancy.