A clay flue pipe (Dutch: kannebuis) is a fired clay pipe (ceramic/terracotta) used to carry off water, smoke, or gases. The Dutch term derives from the French boisseau. Clay pipes belong to the older, traditional building materials and were widely used before modern plastic and metal pipes became common.
Application
Clay flue pipes are used, among other things, for:
- Flue gas removal — as an inner pipe (liner) inside a chimney flue, for example with wood-burning and pellet stoves
- Carrying off water — as a rainwater or drainage pipe
- Ventilation and gas ducts — for removing gases
For flue applications, clay pipes are sometimes made double-walled, which improves insulation and durability and limits condensation in the flue.
Properties
- Heat-resistant — fired clay copes well with the heat of flue gases
- Resistant to aggressive substances — ceramic is unaffected by the acidic condensates that can form during combustion
- Durable — the material hardly ages, but it is brittle and can crack under stress or impact
Points to note
When (re)using a chimney with clay pipes, it is important that the flue is gas-tight, clean, and free of cracks. Old or cracked pipes can let flue gas escape. Have a chimney inspected and swept regularly, and if in doubt, have the flue checked or fitted with a modern liner.
Related terms
- Chimney
- Stoneware pipe
- Flue
- Ceramic
- Old building materials
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