With the air-exhaust system (LAS), fireplaces are operated in a room-air-independent manner. In one of the lines toxic fumes are discharged into the air, while in the other line fresh air is supplied to the fireplace. The LAS system can be used for chimney renovation in masonry chimney and also in concentric systems. In concentric systems, the annular gap between the pipes is used as a supply air guide. In the brick chimney, a pipe is drawn in, which dissipates the exhaust gases and uses the cavity between the shaft and pipe as supply air.
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