flue(redirected from flues)
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a smoke conduit, a passage for discharge of flue gases from space-heating furnaces, stoves, water heaters, and the like. In brick buildings flues are generally placed inside the inner main walls (the thickness of the flue wall must be at least half the width of a brick). Flues are frequently constructed with asbestos-cement pipes or ceramic or concrete blocks. The flue cross section may be rectangular, round, or oval. The flue is extended beyond the roof of a building for discharge of smoke into the atmosphere. It is topped by a chimney, which frequently joins together several flues. Exhaust ventilation conduits operating through natural drafts should be installed alongside the flue.