BlueScope Steel Colorbond Coolmax roofing material

In response to the growing worldwide issue of urban heat islands, BlueScope Steel has developed a roofing product named Colorbond Coolmax steel. It is a high solar reflectance material which, in moderate to hot climates, has a surface temperature that can be up to 6.5°C cooler than Colorbond steel in the colour Surfmist and up to 18°C cooler than Zincalume steel.

The term urban heat island refers to the fact that cities and urban areas are often significantly hotter than adjacent undeveloped areas. This is due to cities being comprised of predominantly non-reflective, high mass surfaces that absorb heat, as well as reduced vegetation cover. According to the US Environment Production Agency website, the hot, potentially uncomfortable conditions that result often lead to increased energy consumption for air conditioning, which in turn increases elevated emissions of air pollutants and greenhouse gases associated with power generation.

By creating cooler, more reflective roofs through the use of high solar reflectance products like the Coolmax steel, particularly in high-density areas such as business parks and industrial estates, the intensity of urban heat islands may be reduced locally.

Recent studies, conducted in Queensland by BlueScope Steel, show that compared to a standard roof made from Colorbond steel in the colour Surfmist, Colorbond Coolmax steel in the colour Whitehaven may reduce annual air-conditioning energy costs for cooling of a building by up to 7.5%. Therefore, pay back on the initial investment premium, compared to Colorbond steel in the colour Surfmist, could be within five years.

The study involved monitoring three nominally identical transportable buildings. The buildings were modified primarily for two reasons: to ensure that the differences indicated in the monitoring were only as a result of the different roofing products, and to make the influence of the roof heat flow into the building closer in nature to that of a typical, large commercial or industrial building.

The monitoring systems used in the study included: control equipment for the air conditioner, electrical consumption devices linked to a data logger and temperature measurement devices linked to a data logger. All monitoring equipment used in the study was independently designed and built.