A ventilation device for use in protective hoods. The ventilation device is formed with facing plates, each plate having a plurality of slots therethrough, the slots in one plate being in offset registration with the slots in the other plate, thereby creating a semi-tortuous path for air flow through the ventilation device. Alternatively, the ventilation device may be a single, integral element, or each plate may be made in two or more segments. The ventilation device may be mounted in an opening in a hood, and several ventilation devices may be mounted in several openings in the hood.
