Single Wall Duct

The single-wall flue pipe is the connection solution for connecting heating appliances (stoves, boilers, gas air heaters) to the main flue or to the concentric flue. At Climatik, we offer black steel and stainless steel single-wall flue pipes for flue systems compliant with DTU 24.1.

Our range includes single-wall flue pipes Ø 80 to 200 mm: straight elements, 45°/90° elbows, connection tees, wall rosettes. Exclusive use in heated areas with strict safety distances.

Principle and use

Connection flue pipe only

The single-wall flue pipe is an uninsulated metal tube used exclusively for connecting the appliance to the main flue (twin-wall chimney or concentric flue outlet). External tube temperature: 200-300°C during operation. Strictly prohibited for passing through floors, walls, attics, or outdoor use.

Maximum regulatory length: 3 meters total with a maximum of 2 elbows. Beyond this, a twin-wall insulated flue pipe is mandatory.

Available materials

Matte black steel: Minimum 2 mm thick, black powder-coated finish. Economical: 15-40 €/element depending on diameter. Rustic aesthetic for wood/pellet stoves. Withstands 400-450°C. Brushed 304 stainless steel: 0.5-1 mm thick, modern appearance. Price: 25-60 €/element. Better corrosion resistance (acid condensation). Withstands 600-650°C. Ideal for condensing gas boilers.

Configuration and installation

Connection to twin-wall flue pipe

Classic configuration: appliance → single-wall flue pipe (1-3 m) → adapter connection → vertical insulated twin-wall flue pipe passing through floors and roof. The single-wall remains in the heated area, the twin-wall takes over for penetrations and outdoors.

Connection to concentric flue

For boilers and gas air heaters, the single-wall flue pipe can connect the appliance to a nearby concentric wall flue (0.5-2 m). The appliance often requires a short single-wall section before the concentric flue. Observe safety distances even over short lengths.

Mandatory safety distances

DTU 24.1 requires a minimum distance to combustible materials = 3 times the flue pipe diameter. Ø 150 mm flue pipe = 45 cm minimum from any combustible wall, beam, ceiling. Ø 200 mm flue pipe = 60 cm minimum. A thermal screen reduces the distance to 1.5 times the diameter.

Elements and accessories

Standard components

Straight elements: Lengths 25 cm, 50 cm, 1 m. Simple male-female connection. 45° and 90° elbows: Changes of direction, 2 maximum per installation. Connection tees: Junction for multiple appliances or a sweeping hatch. Wall/ceiling rosettes: Aesthetic finish for non-combustible partition penetrations.

Assembly and sealing

Assembly by simple interlocking: male element into female element for 5-8 cm. Stainless steel clamping collar every 1.5 meters and at each junction. Smoke sealing by high-temperature silicone cord (280°C minimum) on connections.

Compliance and limits

Authorized: Connection in heated areas only, length <3 m, maximum 2 elbows, safety distances respected.

Strictly prohibited: Passing through floors, walls, attics. Outdoor installation. Proximity <3× diameter to combustible materials without a screen. Length >3 m.

For installations requiring penetrations or long lengths, consult our collection of insulated twin-wall flue pipes compliant with regulatory requirements.

Climatik's expertise

At Climatik, we advise you on sizing (diameter according to appliance power), material choice (black steel or stainless steel), DTU 24.1 compliant configuration, and possible transition to a twin-wall flue pipe or concentric flue.

All our single-wall flue pipes are available in stock with fast delivery throughout France from our warehouse in Olivet.

Questions about Single Wall Duct?

Our experts answer your questions.

What is the difference between single-wall and double-wall ducting?

Single wall: Single black steel or stainless steel tube, non-insulated, external temperature 200-300°C, safety distance 3× diameter from combustibles. Use: connection only in heated areas, <3 m total, no penetrations allowed. Investment: 15-60 €/item. Applications: connecting stove/boiler to the main flue or a balanced flue.

Insulated double wall: Two concentric tubes separated by 25-50 mm insulation, external temperature <50°C, safety distance 8 cm only. Use: floor/wall/roof penetrations, outdoor installation, significant lengths. Investment: 80-200 €/meter. Mandatory outside heated areas.

Rule: Single wall connects the appliance for 1-3 m within the heated interior, double wall takes over for everything else.

Can a gas air heater be connected to a concentric flue in single-wall?

Yes, common configuration: Gas air heater → single-wall duct 0.5-2 m → adapter to concentric flue through wall. The single-wall remains in the heated indoor volume, the flue exhausts to the outside.

Mandatory conditions: Single-wall length <3 m. Distance 3× diameter from combustible materials (beam, insulation). Maximum 2 90° bends on the run. Downward slope 3-5 % towards the appliance (condensate drainage).

Example: 60 kW air heater with Ø 130 mm outlet → Ø 130 mm stainless steel single-wall duct over 1.5 m → adapter fitting → 80/125 mm flue through facade. Distance from wooden wall: 130 × 3 = 39 cm minimum.

Alternative: If flue/appliance distance >3 m, use a complete insulated double-wall duct up to the flue.

What are the safety distances for a single-wall flue?

No, our products are not tested on animals.

Black steel or stainless steel for my single-wall flue pipe?

Vous avez la possibilité d'échanger votre commande dans les 14 jours suivant sa réception. Pour cela, le produit ne doit pas avoir été porté et être renvoyé dans son emballage d'origine avec l'étiquette.