NIKO STF RUND B is a single-walled system made of heat-resistant 0,8mm thick steel. It is used to remove fumes produced by wood, gas and oil-burning heating appliances working in underpressure. It can also be used as a ventilation duct. Generally, flue liners are used to protect brick chimney against harmful effect of condensates formed in the flue. NIKO STF RUND B systems are fully corrosion-proof. All components joints are bell-and-spigot joints (with female-ending always upwards). 

The lowest part is the condensate tray, removing condensate and rainwater out of the chimney. Access point is fitted directly on the condensate tray, and is used to clean the chimney. T-joint which connects flue terminal to the chimney is installed above the access point. Then pipes (standard length: 100cm, 50cm, 25cm) are installed. In case of chimney’s downcasts, bent pipes varying from 15 to 45 degrees can be used. At the brick chimney edge level the cover is installed and fixed with dowels to the existing chimney from the top. The top pipe should be cut to the brick chimney edge level, so it doesn’t stick out above it. All cuts should be made from spigot side (not bell side) as pipes can not be connected after the female-ending is cut out. Placing chimney components with female-ending upwards is crucial for correct condensate evacuation to the condensate tray inside the chimney. If the existing chimney duct is much bigger than flue liner diameter, stabilizers should be used to fix and to centre liner in the chimney duct.

Chimney liners are designed to be very high without the need of use of any support wall collar. For diameters of 80-150mm the maximum height is 60m, for diameters of 160-200mm – maximum height without additional support – 30m, diameters 300-400mm – 20m, diameter 500mm – 13m.

Chimney-sweep recommendations must be followed during assembly. Only plastic or stainless steel tolls must be used for chimney cleaning.