Gas and Oil heating
Gas and Oil heating
Wood heating
Wood Heating
FuranFlex® RWV
Ventilation ducts
Ventilation Ducts
VentilFlex and VentilFlex RKV
Rain water drains
Rain water drains
FuranFlex EN - FuranFlex composite liner - FuranFlex chimney lining official website
Gas and Oil heating
FuranFlex EN - FuranFlex composite liner - FuranFlex chimney lining official website
Wood heating
FuranFlex EN - FuranFlex composite liner - FuranFlex chimney lining official website
Ventilation ducts
FuranFlex EN - FuranFlex composite liner - FuranFlex chimney lining official website
Rain water drains
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What is FuranFlex?

FuranFlex® is the only method, by which chimneys of any shape, dimension and length can be lined with joint-free airtight liner of steel hardness composite material that is resistant to corrosion, flames and heat.

The FuranFlex® tube is lined in the chimney yet in its soft state, whereas being inflated by steam, it takes the shape of the chimney and by the effect of the heat it gets irreversibly hardened to form a heat and corrosion resistant composite liner of steel hardness.



Why composite material?

FuranFlex® is made of thermosetting resin material with fibre glass reinforcement (composite), the physical (steel hardness) and chemical (acid-proof, alkali-proof) features of which make it perfectly suitable for lining chimneys. Its special resin composition guarantees its high heat-resistant capacity.

FuranFlex® has 25 years guarantee.

FuranFlex® introduction

FuranFlex® technology demo - 1 min video

Advantages of FuranFlex®

  • no wall to be demolished, living spaces remain clean during the chimney lining works
  • lining the chimney only takes a few hours
  • it can be applied at all types of boilers and chimneys
  • chimneys up to 100 m height and 120 cm diameter can be lined without joints to be applied
  • its inner surface is smooth and its heat insulating capacity helps boilers operate economically
  • it does not corrode, 25 years of guarantee is provided for corrosion damages

For more information:

Application of FuranFlex®


Gas and oil heating

Perfectly resists to the aggressive corrosion generated in chimneys


Wood heating

A composite chimney liner of outstanding flame and heat resistance


Ventilation ducts

A flexible liner with excellent pressure- and air tightness feature


Rain water drains

For vertical rain water drain ducts with excellent water-resistance

FuranFlex® types


Maximum heat resistance: 500 °C
Certification temp: 200 °C
EU class (ETA-12/0346)
T200 P1 W 2 OXX

FuranFlex® RWV

Maximum heat resistance: 1000 °C
Certification temp: 450 °C
EN 1443
T450 N1 D 3 G


Maximum heat resistance: 500 °C
TG 1217, DIN EN 12237
Air tightness class: D
Fire classification: B-s1, d0


VenilFlex RKV

Maximum heat resistance: 1000 °C
TG 1216, DIN EN 12237
Air tightness class: D
Fire classification: A2-s1, d0

Newly developed liner in the product range of Kompozitor Kft.: FuranFlex® HHR


With the support of the National Research, Development and Innovation Office, Kompozitor Kft. has developed a new, highly fire-resistant chimney liner prototype for the use of solid fuels. The new product under the brand name of FuranFlex® HHR (High Heat Resistance) is suitable for lining chimneys exposed to higher heat loads and aggressive condensate condensation, for wood, pellet or coal-fired boilers. The development was necessary because the chimney lining systems available on the market are difficult to withstand the double effect that occurs during the burning of this type of fuel. Either they withstand the corrosive effect of the precipitation that condenses in the chimney during the operational load, but they are not adequately heat resistant, or they are adequately heat resistant, but they do not withstand aggressive moisture. Kompozitor Kft. also has a product, the FuranFlex® RWV composite synthetic resin chimney lining system, which has adequate heat resistance for wood burning in dry mode for the safe evacuation of flue gases, but for example the aggressive condensate produced by burning pellets (wet mode), it cannot sustain operating temperature maximums of up to 600 °C or higher. The development of the efficiency of the heat exchange elements that are part of modern boilers further increases the risk of the condensation phenomenon occurring on the chimney wall by reducing the temperature of the flue gases leaving the system. Thanks to this, the condensation phenomenon in the chimneys also increases when other solid fuels are used, which results in an increased corrosion effect of aggressive precipitation on the inner side walls of the chimney.

The newly developed FuranFlex® HHR chimney lining composite synthetic resin chimney liner for solid fuel combustion systems provides a solution to these problems. As a result, the objectives and expected technical parameters for its development were as follows:

- Higher heat and flame resistance. The permanent (lifetime) heat resistance of the lining pipe should be above 600 °C, but it should also be able to withstand the extremely high heat load of 1300 °C for 30 minutes, which is important due to fire safety regulations.

- Better moisture and corrosion resistance. The new product should resist the aggressive condensate that leaves the combustion chamber with the smoke when solid fuels are burned and settles on the side walls of the chimney.

- Long service life, which is unprecedented for solid fuel chimneys.

- Easy to install, which is a serious competitive advantage for the new product compared to competitors (steel, ceramic chimney lining systems).

- The new fireproof chimney lining pipe can only contain boron compounds as a flame retardant additive to a reduced extent in order to meet the strictest environmental protection requirements.

The new development of Kompozitor Kft. was based on the already successful FuranFlex® technology. The essence of this is the installation method, where the composite lining pipe is pulled into the existing chimneys in a soft, folded form and then placed under hot steam pressure. As a result of the steam pressure, the soft composite pipe is stretched over the inner side wall of the chimney, takes on its surface form, and then hardens irreversibly, thus lining it airtight from the inside, providing adequate surface protection for the masonry structure. The hardened chimney liner perfectly follows the changes in direction and pulls of the flight, taking its shape. A composite compound corresponding to this technology had to be developed, which fulfills the parameters defined at the beginning of the development.

The development of Kompozitor Kft. was successfully completed, resulting in a new product under the brand name FuranFlex® HHR (High Heat Resistance). The new chimney lining technology can sustainably and safely withstand the strong stresses resulting from the characteristics of solid combustion, the higher, in extreme cases, operational heat load reaching 600 °C and possible aggressive condensate condensation. At the same time, its installation is simple and the price is favorable.

By using the developed product, the chimneys can become suitable for the safe removal of flue gas produced when burning all kinds of solid fuels. The high corrosion, heat and flame resistance ensures that the product is durable in normal operating environments, but protects residential property and human life even under extreme stress, such as a chimney fire.

FuranFlex® sales information

The FuranFlex® technology is available through our partners in all countries of Europe and also in the USA. FuranFlex® chimney liner can be purchased through the installer partners of Kompozitor Ltd.

FuranFlex® international partners

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