Exhaust fans are the workhorses of exhaust ventilation systems. They must be the appropriate size and type to make the ventilation system work effectively to provide enough air pressure difference ("suction") to capture contaminants, draw them through the building, and exhaust them outdoors.
Great for greenhouse applications requiring a quiet, quick air exchange. Industrial ventilation typically removes welding fumes, solvent vapors, oil mists, or dusts from a work location and exhaust these contaminants outdoors. While dairy ventilation creates air flow through the barn for a "wind chill" effect, removing heat produced by cows at a faster rate than simply radiating heat into still air.