Twiga Class ‘O’ Rated Flexible Duct

Twiga Class ‘O’ rated flexible duct, designed for HVAC systems is fire rated, strong, light weight, fully flexible, compressible yet dimensionally stable. Inner core made of aluminium/met foil is permanently bonded to a coated tough wire helix.

Thermal efficiency is achieved by wrapping with a blanket of glasswool insulation in various densities and thicknesses as per the required thermal resistance on the exterior of the inner core. Outer jacket, which acts as a vapor barrier, is tear and puncture resistant and is made of aluminium/met foil with glass yarn reinforcement.

Product Specification

  • Standard length: 3.048 m (10 ft.).
  • Diameter range: 100 mm to 500 mm (4 inch to 20 inch).
  • Maximum rated velocity: 20.32 m/s (4000 ft /min).
  • Temperature range: 0° C - 90° C (32° F - 194° F).
  • Maximum rated positive pressure: 253.99 mm w.g. (10 inch w.g.).
  • Maximum rated negative pressure: 25.39 mm w.g. (1 inch w.g.j).
  • Fire rating: certified as per BS 476 Part 6 and 7 (Class ‘O').
  • For insulated ducts
  • Standard insulation density: 16 Kg/m* (1 lb/ftp).
  • Standard insulation thickness: 25 mm (0.98 inch).
  • Insulation R value: 0.64 m 2K/W (3.63 Fft2hr/Btu).
  • NOTE: alternate insulation densities and thicknesses are available upon request for higher thermal resistance.

Application and Benefits

  • Ideal for all air-conditioning and ventilating systems in hospitals, hotels, industrial, residential, commercial and office buildings.
  • Available as both - with and without insulation.
  • Due to high degree of flexibility, it allows ducting around obstacles where prefabricated metal ducts would be difficult and costly to install.
  • A quick and economical means of correcting misalignment between system.

Products / Material of Construction


  • Insulated flexible ducts.
  • Uninsulated flexible ducts.

Material of Construction:

  • Inner core: aluminium/Met Foil.
  • Outer jacket: aluminium/Met Foil.

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