Natural Smoke Ventilation

Natural smoke ventilation systems (NRA) work by the thermal lift of the fire gases. The fire gases are discharged into the open air by automatically or manually opening ventilation systems. In case of fire, the fire heats up the room air. This creates the thermal lift, which in turn creates a pressure difference within the room, resulting in negative pressure at the floor and positive pressure under the roof.

This pressure difference causes outside air to flow in through the supply air downstream openings in the lower area of a hall and air to flow out through NRGW (Natural Smoke and Heat Exhaust Ventilators) in the upper roof area.

Compared to mechanical ventilation, natural smoke ventilation has the advantage that the possible volume flow to be discharged through the ventilation openings increases as the flue gas temperature rises. The NRA is therefore ideally suited for large building sections with high fire loads. If the fire continues to develop, an automatic readjustment effect can result in greater effectiveness.