The surface coating has two important chemical properties which, when combined, make the glass "self cleaning".

• It is Hydrophilic - it attracts water and causes it to "sheet" on the surface of the glass, preventing the formation of separate droplets and ensuring that loose particles of dust and dirt can be washed naturally from the surface during normal rainy weather.
• It is Photocatalytic - ultra violet (UV) radiation causes it to react chemically with unwanted deposits of organic dirt, oxidising them and breaking their adherence to the surface of the glass.

As this chemical activity is continuous, even heavy soiling will eventually be broken down sufficiently to wash naturally off the glass during showers of rain. Regular cleaning should not normally be necessary, but for unusually heavy or tenacious soiling, or in periods of little or no rainfall, hosing or washing down with clean water can help the cleaning process along.

For more information visit Pilkington Activ™ self-cleaning glass page.