Sustainable design – a protective coatings perspective

In today’s society it is crucial that organisations not only consider the economic bottom line but also the environmental and social impacts of their activities. This so-called ‘triple bottom line’ approach is becoming an increasingly important factor in the selection of materials for the construction industry.

Architects and engineers routinely consider the sustainable design credentials of their plans. In doing so, they must also understand how protective coatings can impact on the environment over the complete lifetime of the structure – from construction right through to decommissioning.

Unlike decorative coatings, which are applied onsite, protective coatings are routinely applied remotely at specialised fabrication shops. Their role is to provide anticorrosive protection, coupled with an aesthetically pleasing finish.

The protective coatings element of the overall sustainable design credentials for a project is affected by:
• Coating design life
• Volatile organic compounds (solvent) emissions
• Cradle-to-grave coatings care
• Coating supplier credentials

Coating design life

One of the most significant effects that the coatings can have is on their design life. If this is considerably lower than the design life of the structure, the coatings will inevitably need to be replaced – sometimes on more than one occasion. This may become a major refurbishment project involving re-blasting the surface, as well as recoating the steel. This clearly has a potentially negative impact on the environment, and can also prove very costly. Coating specifications to ISO 12944 (www.infrastructure-coatings.com) will help in specifying the correct systems from the start, minimising the need for maintenance over the lifetime of the structure.

Volatile organic compounds (VOC)

A VOC is the solvent component of a coating, which is released into the environment when the coating is applied. VOCs, in combination with nitrous oxides and sunlight, can contribute to smog. A coating VOC content is typically quoted in grams per litre (or lbs/gal), and legislation in some countries limits the VOCs of coatings. This legislation often only sets a minimum standard. On large infrastructure projects, the protective coatings used can be responsible for over 60,000 litres of solvents emitted directly into the atmosphere. By utilising low VOC coating systems it is possible to reduce VOC emissions by over 60 percent.
(see the VOC calculator at: www.international-pc.com).

Cradle-to-grave coatings care

International Protective Coatings is part of a business unit of global chemical group Akzo Nobel and a signatory of the industry-wide Coatings Care initiative. As such, the company takes a responsible and proactive approach to both developing new coatings and re-engineering existing products to ensure their impact on health and the environment, now and in the future, is minimal – a ‘cradle to grave’ approach.

Our regulatory affairs personnel continually work with industry bodies and governmental institutions to identify materials that may cause concern when used in coatings. These substances are examined and tested, not just for their immediate health and environmental effect, but also for their potential impact at the end of their service life – for example, what impact will the coating have if the building is subsequently demolished and the steel recycled? Our chemists work with research institutes to identify alternative materials that will have a minimal health and environmental impact.

Coating supplier credentials

Large infrastructure projects often source some, if not all, of the pre-coated structural steel from outside the country, where it will finally be used. This probably means that the coating will be manufactured and supplied by an overseas affiliate of the specified coating supplier. Different business practices and legislative requirements in the supplying country can result in environmentally sensitive materials being applied to the steel. To prevent this occurring, International Protective Coatings rigorously adheres to the same formulations for all of its worldwide core range products in all of its manufacturing facilities, ensuring that no project is unintentionally saddled with an environmental issue.

In summary

Protective coatings affect the overall sustainable design credentials of a project. Therefore, by understanding the issues and selecting the correct coating systems at the design stage it is possible to significantly reduce their environmental impact.