BUILDING: Case For Steel In Green Buildings
Recent Western Cape Business News
AMONG its many important priorities for 2012 and beyond there is none more important to the Southern African Institute of Steel Construction (SAISC) than the promotion of steel as a green product.
“It is perhaps a truism that one of the most pressing challenges facing global industry is to make its processes less harmful to the environment or, in the current parlance, more ‘green’. The institute is committed to helping the local industry to be more energy efficient while also demonstrating that significant strides have been made in making steel more green with a reduction in its carbon footprint of more than 40% in the last 50 years,” says Southern African Institute of Steel Construction executive director Hennie de Clercq.
“The fact is that steel is one of the greener construction materials but there is a perception, because steel factories have large chimneys spewing smoke into the air, that steel must be bad for the environment. But in relation to the environment, with steel ‘what you see’ is not necessarily ‘what you get’,” says de Clercq.
According to de Clercq the carbon footprint has generally been accepted as the criterion by which to measure the environmental impact of construction products and materials. He says the advantage of this criterion is that it deals both with the global warming impact as well as the use of energy. The key is to take into account the whole life-cycle of a construction project and not only the impact of producing the material.
“In order to ascertain a fair measurement of the impact of a construction material on the environment one has to take a holistic view,” he says.
De Clercq says unfortunately for most materials, the information that is available deals only with the ‘cradle-to-gate’ process, which means measuring only what happens up to the moment the product leaves the factory.
“With construction projects there is also the transport, the activities on the construction site, maintenance during the life of the project and, importantly, what happens at the end of the life-cycle of the project that must be taken into account.”
“For example, with structural steel there is often the possibility of re-using the steel structure at the end of the life-cycle of the project, either where it stands or by taking it to another site. If the steel cannot be re-used virtually every scrap of it can be recycled by melting it and then producing new products using less energy than if they were made of steel from iron ore. If measured in this way, the ‘cradle to grave’ carbon footprint becomes relatively small.”
De Clercq points out that with respect to concrete, steel’s main construction material competitor, while the production process may seem at first sight to be more environmentally benign than steel’s, the life-cycle story is quite different.
The options for re-use are minimal, salvaging the reinforcing steel bars is difficult and, whereas you can grind and re-use the stone and sand, the cement, which is the item with a large carbon footprint, is totally lost.
“The bottom line can be summarised by a recent study done in the United Kingdom, which showed that the carbon footprint of a concrete structure for a building can be some 22% more than that of a steel structure.”
“The truth is that steel, when taking a holistic approach to energy, is an extremely environmentally-friendly, green product and often more so than products that may appear more ‘natural and earthy’,” de Clercq says.
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