Insulating Glass
Insulating glass is made by joining two panes of glass with dry air or argon gas in between.
Benefits
- Greatly reduces cooling loads due to excellent solar heat insulation.
- Dry air keeps the surface free from misting.
- Using argon or other inert gases boosts efficiency further.
Applications
Applied in architecture, train windows, refrigerators, etc.
Specifications
- Air space: 6mm, 8mm, 10mm, 12mm, 16mm
- Max. size: 96″ X 138″ (2438mm X 3500mm)
Certifications
Meets EN-1279(Europe), IGCC(USA)
Overview of Insulated Glass
Often called double glazing, insulating glass combines two or more glass panes, spaced by a spacer bar and sealed with primary and secondary sealants. This forms air spaces, improving thermal performance, cutting heating and cooling costs, and reducing interior condensation in cold weather while enhancing comfort near windows.
By integrating Low-E coatings, tinted glasses, etc., diverse configurations meet various performance and aesthetic needs. IG units can be customized for energy codes, sound control, and resistance to impacts, bullets, hurricanes, and blasts, while minimizing light transmittance reduction.
IGU Surfaces
An IG unit has four surfaces. Surface 1 faces the building exterior, Surface 2 is its other side. Surface 4 faces the interior, and Surface 3 is the other side of Surface 4.
IGU: The Process
To make insulating glass, use washing, drying, spacer conveyor, butyl extruder, and vertical pressing units. Steps are:
- Bend a hollow aluminium spacer bar.
- Drill holes, fill with desiccant like silica gel or zeolite.
- Seal holes and apply butyl to spacer bar sides.
- Place two glass panes, press automatically.
- Apply secondary sealant like polysulphide or silicon.
Components of IGU
- Glass lites: At least two panes, can use coated or laminated glasses for enhanced performance.
- Frame: Aluminium spacer bar, filled with desiccant, holds panes, provides thickness and resistance. Bent frames (with one opinion) are better than corner-keyed ones (four joints) for heat retention.
- Desiccant: Silica, molecular sieve or zeolites absorb moisture. Must absorb water and hydrocarbons, not inert gases, and be nitrogen-free.
- Sealant: Primary (like butyl) fixes units; secondary (silicone, polysulfide) binds panes structurally. Protects gas-filled spaces from moisture, chemicals, and water.
- Filling: Three types – regular (dry air), inert gas-filled (better insulation, pricier), vacuum. Formula for gas amount: Height (cm) × Length (cm) × ID (mm) × 0.001 = Litres (x); Litres (X) × 1.5 = gas per window.
IGU Features
- Optical properties: Transmittance 7 – 80%, reflectance 13 – 48%.
- Theral Properties: Lowers U value, more with inert gases.
- Acoustical insulation: Reduces noise by ~ 30dB, further with inert gases and laminated glazing.
- Condensation: Dew point below – 65°C, prevents normal condensation.
- Sealing: Aluminium spacer, one joint, two seals, for good sealing and long life.
Benefits of IGU
- Energy Conservation: In hot climate, compared to single-pane glass, double glazing with sealed air space blocks sunlight, reduces temperature difference, and saves energy via air convection.
- Perfect Transparency: Reduces condensation on warm side, enables large glazed areas without extra energy use, like in retail chillers.
- Sound Insulation: Monolithic glass resonates with high-frequency sound. IG units block it, useful near noisy areas.
- Reduced Infiltration: In cold, stops cold air infiltration, cuts heating cost.
- Reduced Condensation: Prevents moisture damage by creating a thermal barrier.
Applications of IGU
Used in commercial/residential windows, curtain walls, storefronts, sloped/overhead glazing, non-vision areas.