Saturday, 19 May 2012
A chance remark about the self cleaning glass in the roof of St Pancras station during the visit to London on Wednesday (see article on Aurasma visit) came back to me. I was chatting to Jamie Bartlett of My Little Cleaning Company, who takes on the window cleaning side of the business.
It turns out that self cleaning glass exists in several forms – it still does need the occasional clean but not as frequently as normal glass. A bit of internet research this evening revealed the principles.
I was already familiar with one form of treatment, silanisation, which makes glass non-stick and therefore water and dirt repellent. This was in the days when we made our own DNA sequencing gels in the lab (nowadays things are very different! See article on DNA sequencing). This method can be used to coat windows and even car windscreens.
The glass used for St Pancras is the opposite, it is water loving. An ultra-thin layer of titanium oxide is bonded with the glass surface during manufacture using a patented process. Small particles of organic dirt initially bind to the glass. Natural UV light and a catalytic action of the coating break down the organic dirt. Mineral dirt still sticks – until it rains. When rain hits the glass it spreads over it due to the water loving nature of the glass. The excess water then flows down the glass, taking the remaining dirt with it, off the glass.
Yet at some point, the windows will still need to be cleaned, even if at a much lower frequency per year – preferably by an equally hi-tech window cleaner.
What surprised me further was that Jamie uses the purest water possible, and no detergents, to clean the glass. In his van, the water for washing is first filtered, passed over activated charcoal, pushed though a reverse osmosis column and then de-ionised – very pure water indeed. When used with soft mono-filament brushes, the dirt is removed and the window rinsed, it can be left to dry without leaving any trace.
Furthermore, by using carbon fibre poles, it is possible to clean windows to a height of up to 20m, safely from the ground! No ladders or scaffolding required. This is crucial as ladder based accidents are serious – often fatal or debilitating – and are subject to financial penalties for both the window cleaner and the client.
All this technology is a far cry from the conventional image of window cleaners and I left the conversation with Jamie suitably impressed and better informed.
Jamie Bartlett of My Little Cleaning Company is based in the beautiful market town of St Ives, Cambridgeshire. Visit http://www.mylittlecleaningcompany.co.uk for more information.