As Featured in Pro Installer Magazine - 01/18
Phil Brown, European regulatory marketing manager at Pilkington United Kingdom Limited, part of the NSG Group, offers his top tips for installing self-cleaning glass.
It's been more than 15 years since Pilkington Activ™ became the first commercially available self-cleaning glass. Since then, over a million square metres of the product have been sold for a wide range of applications, from conservatory roofs to commercial facades. Despite this, it is still a new product to some in the industry and some are unsure of the best ways to install it.
Here are some pointers to bear in mind.
1. Be aware of lead.
Lead carbonate can leach from flashings in rainwater and be deposited as a white stain onto glass. This effect can occur on any glass, not just self-cleaning glass, but is one of the things it can’t remove by itself.
Inorganic contamination is not broken down by the self-cleaning coating and can be difficult to remove. It is recommended that lead used where there is a risk of rainwater run-off onto the glass be treated with patination oil (or similar) to reduce the risk of leaching.
Lead flashings should be treated on both sides, particularly if they lap directly onto the glass.
2. Dual action.
Not all self-cleaning glass is the same. Pilkington Activ™ is referred to as dual action, as there are two stages involved.
Stage one utilises a 'dirt eating' photocatalytic reaction to break down organic deposits such as mud, while stage two is based on the 'water loving' hydrophilic coating, which spreads water evenly over the surface of glass to form a thin film instead of forming into droplets.
This helps to wash dirt away, preventing the formation of drying spots and streaks. Make sure the self-cleaning glass you install is dual action.
3. Pick your angle.
The minimum recommended angle for a roof containing self-cleaning glass is 10 degrees from horizontal. Any less and the rainwater may not run off and wash dirt away effectively.
Sealants and gaskets that are lubricated with silicone oils can’t be used with Pilkington Activ™ as they can mask the hydrophilic and photoactive actions of the coating, the technologies that make the glass self-cleaning.
If silicone is used and left on the glass, the silicone contamination causes water beads to appear on the surface when it is raining or wet.
A number of alternative sealants, gaskets and cleaning agents can be used that are compatible with self-cleaning glass.
5. By the sea.
Wind-blown spray in coastal areas can cause salt crystals to adhere to the surface. As salt is an inorganic contaminant, it can’t be broken down by the photocatalytic action of Pilkington Activ™.
While this is worth considering, the technology will make the glass cleaner than ordinary glass after a light hosing or rainfall.
6. Tried and tested.
It is important to install self-cleaning glass that has been tested to the necessary standards.
A new European Standard, EN 1096-5, has been introduced that evaluates the self-cleaning performance of coated glass. This standard allows specifiers to differentiate between glass with a classified self-cleaning performance and without.
7. High and dry.
The amount of cleaning needed depends on how dirty the glass is and the amount of rain it is exposed to. During long, dry spells or if the windows are particularly dirty, some manual cleaning might be required, either by gentle hosing to replicate rainfall or by using a soft cloth and warm soapy water.
The activation of the glass occurs via a chemical reaction between UV rays from natural daylight, oxygen and the coating. It’s worth noting that when self-cleaning glass has been stored in a warehouse for a long period prior to installation, it may take up to seven days to become fully activated. After then, it will continue to work as long as it’s exposed to daylight, even in dull winter weather.
9. Hard water.
It’s rare that self-cleaning glass needs to be rinsed, but if the water is very hard, then it should be softened with a domestic softener or through adding a couple of drops of detergent.
10. Job done.
After self-cleaning glass has been installed in a building, care must be taken during any further construction work to avoid staining or damaging to the coating.
Rusty deposits, plaster products or adhesives can affect the coating. So, after building work is completed, the glass should be cleaned as soon as possible by rinsing with water to remove all traces of dust and abrasives which may have accumulated during construction.
Installers can go above and beyond by following this checklist, and their customers can save time, energy and money in the long term by choosing self-cleaning glass.
For more advice on self-cleaning glass, visit: www.pilkington.co.uk/activ