Low-Iron Glass Explained

What Is Low-Iron Glass?

Low-iron glass is a type of glass specially produced to contain less iron oxide than standard "clear" glass. The presence of iron oxide in the glass results in a slight greenish tint, which is not always noticeable but can become more apparent in thicker or multi-layered glass constructions.

Due to the reduction of impurities, low-iron glass has a clarity and transparency that ordinary glass cannot achieve. For this reason, low-iron glass is especially popular for architecturally designed buildings to provide a clear view and a neutral appearance that blends seamlessly with the existing surroundings.

The architectural classic Fallingwater by Frank Lloyd Wright was one of the first houses to incorporate low-iron glass in its windows.

The clarity of low-iron glass allows maximum light transmittance and solar gain to benefit from natural energy and is widely used in solar panels.

How Is Low-Iron Glass Made?

During the production of regular float glass, impurities are inherent in the raw materials, such as silica and can be contaminated from the container in which the glass was melted.

Low-iron glass uses carefully selected higher-grade raw materials with naturally low iron content.

The melting process is more precise and tightly controlled to ensure that the product properties remain consistent.

The result is a glass with fewer inherent impurities and a reduced iron oxide content, which gives it a clearer and more neutral appearance.

What Are the Benefits of Low-Iron Glass?

Optimum Transparency and Unfiltered Light

Standard float glass has a green tinge which is more obvious in thicker panes of glass. A reduced iron content offers a pure and light glass colour.

Because low-iron glass has more clarity, it allows unfiltered light to pass through and is favoured by architects, especially for thicker large walls of glass.

The unfiltered natural light allows decor and objects to be seen in optimum light and is preferred where undistorted colours are desired.

Because of its perfect clarity low iron glass is used for display cases where items are seen through the glass and an unrestricted view and true colour are required - e.g. museums and jewellers.

Energy and Solar Heat Transmittance

The clarity of low-iron glass allows more light transmittance than standard glass. The higher solar gain allows more solar energy to be transmitted through the glass and more warmth from the sun.

For this reason, low-iron glass is used in solar panels. However, the trade-off is that low-iron glass does not retain heat efficiently.

Increasing the number of glass panes in a window can reduce the amount of solar energy transmitted. For instance, triple glazing has a lower G-value than double glazing due to the reduction in solar energy transmittance.

To optimise energy efficiency, a combination of low-iron glass and low-emissivity (Low-e) glass is used for maximum light transmission while reflecting heat back into the room, providing a comfortable living environment.

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Design Versatility

Low-iron glass can be used in a wide range of applications, including structural glass, decorative glass, and architectural glass. It can also be toughened, laminated, and finished with different textures and coatings, providing designers with a high degree of flexibility in their designs.

What Is Low-Iron Glass Used For?

Due to its clarity, low-iron glass is mostly used for its display qualities. As the edging on low-iron glass has a reduced green colour, low-iron glass is especially popular for furniture such as table tops and shelving in cabinets.

• Aquariums
• Museum display cases
• Jewellery display cases
• Shop windows
• Skylights
• Architectural glazing
• Internal partitions and glass walls
• Balconies and balustrades
• Furniture and shelving

Do I Need Low-Iron Glass?

Before using low-iron glass, there are several factors that you should consider to ensure that it is the right choice for your application:

• Cost - Low-iron glass is typically more expensive than standard clear glass due to the additional manufacturing process required to reduce the iron oxide content. You should consider whether the benefits of using low-iron glass justify the additional cost for your specific application.
  
  
• Performance - While low-iron glass is known for its clarity and transparency, it may not provide the same level of insulation or energy efficiency as other types of glass, such as low-e glass. You should consider the performance requirements of your application and whether low-iron glass is the best choice for meeting those requirements.

For the reasons above, some double and triple-glazed units use a pane of low-iron glass in combination with low-e glass. The Low-iron glass allows more UV light and solar energy into the room, while the Low-e glass acts as insulation keeping the heat energy in the room.