The cross section
The cross section of the pipes can be oval, round or even polygonal. For their manufacture, non -combustible materials are used, such as natural stone, asbestos -cement, brick, ceramics, concrete or metal.
The cross section of the pipes can be oval, round or even polygonal. For their manufacture, non -combustible materials are used, such as natural stone, asbestos -cement, brick, ceramics, concrete or metal.