Air-cooled

From Drummond House Plans Wiki

An air-cooled is a chimney which uses a flow of air between inner and outer layers to keep the outer surface cool. Air-cooled chimneys are approved for use in some factory-built fireplaces that are used for decorative purpoes. Air-cooled chimneys are not suitable for cold climates or well sealed houses. Wood-burning appliances should never be connected to air-cooled chimneys.