Glass Duct Board for HVAC Application

Introduction:

Fiberglass duct board is a rigid board of insulation material manufactured from resin bonded inorganic glass fibers. The exterior surface of the board is a factory-applied reinforced aluminium foil-air barrier and water vapour retarder. The edges of the board are formed by machine to create a ship lapped edge or grooves, to allow the grooves to be joined to build straight ducts of any size or length. Duct system components such as tees, offsets, elbows and transitions may be fabricated from flat duct board. Fibrous glass duct boards are fabricated into ducts to make a fibrous glass duct system.

Features & Benefits

  • Fire Safe - Made from rigid glasswool boards which provides thermal and acoustic insulation
  • Faster installation - Easy to install and light weight
  • Lower installed cost - Minimal material waste, higher productivity
  • Flexibility of site fabrication and assembly – Adaptable to job site changes
  • Precision of factory made ducts – Low leakage rates
  • Improved performance and energy savings
  • Excellent aesthetics - Cleaner look
  • Outer facing provides resistance, stiffness and a vapour barrier and inner facing provides a smooth and cleanable surface

Specification

Glass wool duct for thermal application

Pre-insulated duct board shall be made of high density of rigid resin bonded fire safe glass wool with both side factory laminated aluminum foil, outer facing foil is having - Reinforced aluminum + Kraft+ glass veil and inner facing - Black glass textile.

Density of glass wool duct board shall be 75-80Kg/m3 and at the edge of panels shall have density of 150Kg/m3 .Size of panels for duct construction as below.

Thickness(mm) Length(m) Width(m) 25 3 1.19

The thermal conductivity of duct board shall not be exceeding 0.033 W/m K at 10 deg C means temperature and thermal resistance should be more than 0.6 m2.K/W.

Glass wool duct panels shall be tested as per EN 13403 Vapour permeance of duct panels should be approximate value: 0.013 g/m2. day mm Hg (outer facing)

Mechanical stiffness: R5 rigidity, according to EN 13403 (European Standard for non metallic ducts) this rigidity is the maximum level of the ones established by this standard.

Duct board should withstand pressure under 800 Pa with no evidence of fissures or swelling (test according to EN 13403)

Fire test: Panels shall be tested as Euroclass: Euro class C-s1, d0

  • s1: null smoke emission
  • d0: non flaming droplets / particles.

Joint System: Duct boards should have exclusive design with male / female edges, in order to provide greater strength for joints, easy installation and shall reduce the number of cutting operation & exceptional inside finish.

Tools and Accessories for Installation of Duct Boards shall be followed as per recommendation of manufacturer’s manual.

Duct Support: Duct board shall be installed, using support as described in installation manual of manufacturers. Maximum distance between hangers / support shall not exceed for horizontal ducts as

  • 900 mm inner dimension maximum distance of hanger 2.4 m
  • 900-1500 mm inner dimension maximum distance of hanger 1.8mm
  • Above 1500 mm inner dimension maximum distance of hanger 1.2 m

Inspection and Testing

Duct dimensions shall be checked based on the duct dimension / layout drawings duly approved by the Architects/ Consultants.

The ducts, branches elbows etc. shall be inspected and the joints and connection shall be checked properly before these are assembled in position. After assembly the system shall be checked for tightness of male/ female joints to avoid the leakage

Climaver Al. tape of 75mm thickness shall be applied on each male / female joint to avoid the leakage of air

Full sized standard dimension sheet as specified are to be used and any patched or made-up pieces of duct work are liable to be rejected. Joints between male/ female connections shall be fitted properly and Al. tape of 75 mm thickness shall be applied on joints.

Test points shall be provide at the discharge of each air handling unit and at each individual zone of the duct work system. Test points shall consist of 25mm diameter sockets fitted with sealing plugs which can be removed for the fitting of measuring devices. Test points shall be insulated as for the duct work and shall be provided with identification labels.

Rectangular risers should be free supported by angles or channels secured to the sides of the duct flanges with bolts or sheet metal screws or blind rivets. The supporting angle or channel should be freely resting over the slab cut-out. Riser support intervals should be limited to one storey height.

To ensure the air tightness, all ducts shall be checked with Leak Test after completion of duct fabrication but before installation of duct system.