Highly Reflective Dark Films are a “No No” on Laminated Glass

Klingshield Technical Department
Johannesburg South Africa July 2011

Dark Grey 15 reflective and Dark Bronze reflective 15 are very good performers when it comes to total solar energy rejected. These films have approximately 74% total solar energy rejection.

Laminated glass being two pieces of glass laminated together, is a problem when applying these dark reflective films. The reason for this is that dark colours absorb high amounts of the sun’s energy. The total solar energy absorbed with these films is about 61%. When installing these films on the inside, the inner glass of the laminated glass absorbs this heat and starts to expand. This expansion in some cases is a problem because there is no room in frames for the glass to expand. Hence, once experiences cracking.

Please note it is clear from our Conditions of Sale that no responsibility will be accepted by the company for glass breakage after installations due to any circumstances.

In some cases very large panes of glass are also at risk as the glass may be installed with putty which has hardened like rock and therefore does not allow for any movement within the glass.

This can also allow glass to crack : Another reason for glass cracking is bad edges on the installation of the glazing, which is normally hidden behind the frame and not accessible to the naked eye. In some cases this glass has not been treated at the edges and has raw “shark like teeth” finish. As these jagged edges touch the frames due to expansion of glass, hairline cracks start appearing from the edge.

The best film for laminated glass in areas where consumers are suffering with overheating in offices, is the Silver 20 reflective film. This Silver 20 reflective film has the highest total solar energy rejection of all films, being 79% and also Silver 20 has the highest reflection of sunlight of all our films available. This film also stops 80% of the glare, creating glare-free areas.

This Silver film has a low total absorption of only 33% which is half the amount the dark bronze and grey film has. Therefore Klingshield only recommends a film with a low absorption factor to be installed on laminated glass.

Should you require to know further information on the reason glass cracks please contact our Research and Development Department who will be able to provide you with documentation explaining all reasons why glass cracks under normal wear and tear.

Please view our website for any other technical information required.

For further information, please contact us.

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