Stainless steel smoke flue BIOMASS

double wall

Product overview
This 125mm (5") vertical conventional twin‑wall insulated stainless steel flue system is designed for use with Spira biomass pellet boilers. It is engineered for continuous operating temperatures up to 200℃, while typical flue gas temperatures from Spira boilers are under 80℃. The stainless steel outer case is load‑bearing and the stainless steel inner liner is free to expand independently to accommodate thermal movement.

Features & benefits

• Twist‑lock bayonet jointing system with seals, secured by locking bands
• Laser‑welded stainless steel inner liner and outer case for enhanced corrosion resistance
• 25mm Superwool high‑efficiency blanket insulation to maintain flue gas temperature, improve draft at start‑up and minimise condensation
• Low external case temperature for safer adjacent clearances
• Inner liner retained by male locking collar and free to expand/contract by up to 18mm via the female collar
• Inward bead at female end acts as a capillary break to prevent moisture being drawn through joints
• CE certified (compliant with regulations in force from 1 July 2013)
• Internal components available in white or black powder paint finish; external components in black powder paint only

Installation
The system is available with extension pieces and bends to suit a wide variety of installations. Components are joined by placing the female collar of one section over the male collar of the preceding section and locking by rotating the upper section clockwise. All components must be installed with the male collar pointing upwards; an arrow on the label indicates flue gas direction. The male end is enlarged so the female end of the next section overlaps, allowing any condensation to run back to the boiler without escaping from joints.

Flue Runs
The flue should remain as straight as possible through its vertical run. If angling is necessary, offsets must not exceed 45° from vertical and the run between bends should not exceed 20% of the overall chimney height. Allow a vertical rise of 600mm immediately above the appliance before any offsets. Installations must comply with Building Regulations Document J (England, Wales, Northern Ireland & Republic of Ireland) and building standards (Part F) in Scotland. Maintain a minimum clearance of 60mm from any combustible material.

Technical specifications

• Commercial name: Biomass Flue System for Spira Boilers
• Nominal diameter: 125mm (5")
• Type: Vertical conventional twin‑wall insulated flue system
• Materials: Stainless steel inner liner and stainless steel outer case (laser welded)
• Insulation: 25mm Superwool high efficiency blanket
• Continuous operating temperature rating: up to 200℃
• Typical flue gas temperature from Spira biomass boilers: less than 80℃
• Inner liner expansion allowance: up to 18mm via female collar movement
• Jointing: Twist‑lock bayonet joint with seals and locking bands
• Inner liner feature: inward bead at female end acting as capillary break
• Outer case: load‑bearing design
• Finishes: internal components available in white or black powder paint; external components in black powder paint only
• Certification: CE certified (compliant with regulations from 1 July 2013)
• Installation constraints: minimum 600mm vertical rise above appliance before offsets; offsets ≤45° and inter‑bend run ≤20% of overall chimney height; minimum 60mm clearance from combustible material