Twiga Flexible Ducts

Twiga Flexible Duct designed for HVAC systems is light weight, strong, fully flexible and compressible yet dimensionally stable.

Twiga Flexible Duct is made of double lamination of films permanently bonded to a coated spring tough steel wire helix. Thermal efficiency is provided by wrapping the exterior with a blanket of fiberglass wool insulation in various densities & thicknesses for required thermal resistance. The outer jacket is made of double laminated film with fiberglass yarn reinforcement, which acts as a vapour barrier surface as well.

Twiga Flexible Duct can widely be used in all Air Conditioning / Ventilating Systems including commercial & office buildings, hotels, hospitals and many other industrial and residential applications.

Twiga Flexible Ducts come in a variety of styles and constructions and provide the most economical solution to your air handling needs.

Features and Benefits

  • Air tight – No air leakage, No fiber erosion
  • Insulation – “Twiga Insul” – Class O rated Glasswool
  • Core material – Low friction loss, strong and flame resistant
  • Vapour barrier – Reinforced for maximum toughness and tear resistance
  • Wire – Strong and non corrosive
  • Modular and economical air distribution system with maintenance free life - high degree of flexibility which allows it to be connected to any desired position
  • A quick and economical means of correcting misalignment between system components.
  • Available as bare and preinsulated
  • Reduces total installed cost – Fast and easy to install
  • Allows ducting around obstacles where fabricated and fitted ducts would be difficult and costly to install.

Properties

Insulated Flexible Ducts

Standard Length :25 ft. / 7.5 M Diameter Range :100 mm to 500 mm (4” to 20”) Maximum Rated Velocity : 4000 ft /min Temperature Range : 0-90ºC Maximum Rated Positive Pressure : 10 inch Water Maximum Rated Negative Pressure : 1 inch Water Standard Insulation density :16 Kg/m3 Standard Insulation Thickness : 25mm Insulation R Value : 0.64 Sq.mK/W Fire Rating : certified as per BS 476 Part 5, 6 & 7

Note : Alternate insulation densities and thicknesses are available upon request.

Standard Length : 25 ft. / 7.5 M Diameter Range : 100 mm to 500 mm (4” to 20”) Maximum Rated Velocity : 4000 ft /min Temperature Range : 0-90ºC Maximum Rated Positive Pressure : 10 inch Water Maximum Rated Negative Pressure : 1 inch Water

Installation

All the flexible duct shall be installed in a fully extruded position and bends made with adequate radius.

The maximum allowable sag, between any two adjacent suspension points, should not exceed 50 mm per meter.

The distance between any two adjacent suspension points may vary from 1.50 to 3.00 meter, depending upon the type of flexible duct in use.

Flexible ducts mounted above suspended ceiling should always be independently supported.

All bends should be made as large as possible and should have a radius of not less than the diameter of the duct in use. Double bends should be avoided, however if un-avoidable, ensure that each radius is not less than R = 2 x D.

Ideally the hanging straps should supports the flexible duct with a minimum of half the circumference surface in contact, and without reducing the effective inside diameter of the duct. It is also recommended that the minimum width of material to be used for the hanging straps should be at least 25 mm.

Extra care should be taken when making connection to fixed conventional ducts, etc., and ensure that they do not become too stressed. An additional support is recommended to overcome the potential problem.

Light railing is a good alternative hanging support when using long length of flexible duct.

Specification

Uninsulated flexible duct shall be made of double lamination of metalised polyester film permanently bonded to a coated spring steel wire helix. Duct shall be in tear and puncture resistant construction.

Insulated flexible duct - Inner core should be made of double lamination of polyester film permanently bonded to a coated spring steel wire helix. Blanket of fibreglass insulation of R 4.2 (RSI - 0.76 m2K/W) having density of 24 kg/cu.meter and thickness of 25 mm shall be wrapped over the inner core & covered with tear and abuse resistant outer jacket cum vapour barrier made of fibre glass reinforced double layer of metalized polyester film laminate.