Glass Futures, 2005

Coating is now an integral part of glass manufacturing, not simply an “offline” process applied by end users. Consequently, coating places demands on the entire manufacturing process. Glass temperature and speed are closely linked to the deposition efficiency achieved by online coating methods in the float glass industry. Offline deposition methods, such as sputtering, rely on a high degree of cleanliness and reproducibility in the glass surface, which is tightly linked to initial manufacturing conditions. Similarly, float line speeds must be compatible with the speed of the deposition chemistry, and container temperatures must be carefully controlled to achieve the appropriate coating properties.
In the glass-fibre industry, water-based coating solutions also serve to cool the fibre to a temperature at which it can be wound.
Sheet glass coating processes require very large amounts of energy and have major waste and environmental issues.
Consider the fact that the best-case yield for chemical vapor deposition (CVD), also known as pyrolytic coating, is around 70% on float glass using online methods (which are the most economical. Other coating processes are only at 50%. Uncoated float line glass achieves about 80% production quality. This means up to an additional 30% is wasted, and the glass has to be recycled and impurities removed again.
This is a huge energy bill to the industry and for us all. The industry recognizes that there is much Coatings R&D to be done and which has to cover a diverse set of issues which include: Data bases of film – optical, mechanical, electrical properties
Pilot-scale facilities and fast prototyping methods for evaluating coating processes
Deposition chemistries
Computer simulation of potential coating materials
Improved understanding of glass surfaces and interfaces
Low-cost deposition methods

Environmental issues, particularly recycling implications as mentioned above are already a major issue for the glass industry. In addition, the development of higher performing glass may be hindered because of insurmountable environmental issues – for example, multi-functional coated glass incorporating encapsulated material creating an expensive separation and recycling procedure.

Safety issues have become paramount throughout all industries, including construction. Glass in architecture has always been seen as vulnerable to breakage and more recently to shattering (toughened) because of its innate molecular structure. Many techniques have been developed to attempt to overcome this flaw. Some are successful, such as lamination and more recently standardising heat soaking of toughened glass. Nevertheless, more still needs to be done to economise in manufacture and assembly to ensure that the products remain competitive in the market. Losses due to transport and handling is a still an economic issue.

Conclusion
Our use of glass is fundamentally concerned with light. There is a long way to go to understand light as a material, and this research “mirrors” the atomic bonding research of glass and of the glass surface with other materials (coatings) aimed at improving and opening up new horizons for this ubiquitous material.
If humanity and intelligence have as much to do with the process of decision-making as with the tangible artifacts which result from our application of science, technology and economics then we can envisage an environment with improved buildings.

There are many new products that suggest we are learning to behave better on this planet. For example, microbes that take toxic substances in contaminated soil and convert them into harmless by-products, `stay-white’ concrete and self-cleaning glass (Pilkington Activ™) using Titanium dioxide as a base. Biogenetic and environmentally sensitive coatings, and mixes within materials, are increasingly being used to try to produce products and buildings for a better biosphere. Our concern for recycling has value when the materials we produce become easier to reuse. For example, foamed glass can be made very strong and lightweight. As and when society places more value on humanity and relationships and less on those material objects of desire that use vast amounts of materials, less resources will be needed, and less will need to be recycled. The search for long lasting, stable and high performance materials for building our habitats is essential ­ and new glass products will continue to be essential ­ for we are optical animals with phototropic tendencies!

The need to make evident metaphorical intelligence and humanity in what we design should be indisputable. It is this which drives my investigations of materials, design approach, and the spaces within and outside the architecture which I help create.

© Ian Ritchie 2005