What is Low Iron Glass and when is it needed?

What is Low Iron Glass?

Low iron glass is glass that is specially manufactured to have a lower iron oxide content. Standard ‘clear’ glass is not completely clear, it has a slight green tint due to the presence of iron oxide.

The tint is not usually noticeable, however it can become noticeable in thicker panes of glass, when multiple panes are layered together or on an exposed glass edge. Projects that require these kinds of glazing units would benefit from low iron glass to avoid discoloration.

When glass is manufactured there are a variety of materials and impurities that are present. The natural presence of iron oxide in glass comes from elements such as sand or from the container in which the glass was melted.

Low iron glass is also useful when two different glass specifications are being used in the same installation. If a thicker glass pane is next to a thinner one there will be a slight difference in colour.

A solution for this issue is to use low iron glass for the thicker glass elements but not the thinner ones, giving them the same level of clarity for a consistent look.

Just like float glass, low iron glass can be toughened, laminated and designed with different finishes such as sandblasting.

low iron glass used in roof glazing for glass beams

Low Iron Glass for glass floors

Glass floors need thick, toughened and laminated glass to be able to provide the structural support needed to allow people to walk on it. This means they tend to have at least three pieces of toughened glass laminated together, possibly more depending on the desired insulation.

Sieger’s Thermally Broken Floorlight is engineered for heavy pedestrian traffic, using three pieces of toughened glass laminated together for the external pane and two for the internal pane.

If the glass is going to be sandblasted for a slip-resistant finish, then low iron may be the better choice. When normal glass is sandblasted the green tint becomes more obvious but when Low Iron Glass is sandblasted it becomes a white frosted surface.

There are other ways to make a glass floorlight slip-resistant, such as ceramic frit or specialist anti-slip glass if you do not want low iron glass or a green tint.


Low Iron Glass for balustrades

Balustrades used in balcony settings are made from at least two layers of toughened glass laminated together to be able to withstand the required line load.

Although this may not be as thick as other pieces of structural glass such as glass walls, when using units such as The Sieger Balustrade System the edges are visible.

The green tint in standard glass is more noticeable on exposed edges, if the balustrade or balcony is frameless some may want to opt for low iron glass in their design.

low iron glass used for a door
a standard and low iron piece of glass next to each other for comparison
low iron glass used for an internal glass balustrade

Low Iron Glass for beams and fins

For support on horizontal glass units, glass beams can be used, and for support on vertical glass units, glass fins can be used for support.

These beams and fins are usually the thickest glass element in the installation, made using multiple layers of toughened and laminated glass to ensure they can withstand the required load.

Glass beams may be used to support The Sieger Rooflight System if multiple panes are being used next to each other.  The multi-laminated pane sits below the glass joint to support the inner side.


When using decorative interlayers such as a coloured interlayer, low iron glass may be chosen to produce a truer representation of the chosen colour. This applies particularly if the colour is light, neutral or pastel coloured, where a very slight green tint could skew the colour.

From an internal perspective, low iron glass can achieve light transmission values of up to 91% making it the clearest building material available.

Changing a glass specification from clear glass to low iron glass will increase the cost. This increase is due to the additional processes that are needed during the manufacturing process.


For more information contact our technical team or book a showroom visit where you can discuss your project in person and see the Sieger systems.

To talk to the team, call 01494 722 882 or email

[email protected]

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