Ozone and Its Effect on Materials
Ozone is an oxidizing agent that is very powerful; its power comes from the free oxygen atom that results after atmospheric oxygen is converted into O3 . This is the result of electrical discharge from lightning and other atmospheric actions that produce electrical activity. This third atom of oxygen in ozone is not very stable and usually last very long, but it is constantly looking to link up with other atoms to achieve some stability. This is what causes the ill effects of ozone. It degrades material that it comes into contact with it and causes some sort of fading, as well as a loss in tensile strength, which accelerates aging and thus a reduction in the value.
Image Source: Wikimedia: Montage
Ozone causes substantial damage to rubber products, surface coatings, and polymers, all of which are used extensively in the building industry. While inorganic materials remain largely unaffected by ozone, its combination with sulfur dioxide and nitrogen dioxide present in the atmosphere has a deleterious effect on metals. For the same reason, the zinc that is contained in most paints causes it to be vulnerable to ozone. Of all the metals, copper and tin seem to be most vulnerable.
Building Materials That Need Ozone Protection
Ozone is formed as a result of electrical discharge combining with the atmospheric oxygen, and this is a situation that can be also largely prevalent in electrical equipment and installations. The ozone that does get formed can affect the insulation of wires and cause them to deteriorate, especially when the concentration of ozone exceeds 20 percent. For this reason, standards have been developed for insulation that will be resistant to such effects. This also includes the insulating compounds that are used to join wires and cables.
Rubber seals and sealing compounds used to weatherproof glazed windows are other building materials that are affected by ozone. Ozone in combination with ultraviolet rays cause such seals and compounds to become brittle and thus less effective in their function. Natural rubber and PVC are very vulnerable to ozone, and their use these days has become very limited in the building industry. Ozone gas attacks the polymers of which these materials consist, causing cracks in them to grow longer and deeper and, thus, complete degradation of the material. The application of waxes to protect the surface of these materials has been known to be effective, but these waxes are affected by heat and mechanical effects. This has led to the development of EPDM, which has a high resistance to heat, ozone, and UV rays, plus a resistance to color fading. This has led to architects specifying their use for weatherproofing of windows and around glass in glass facades.