Colour Classification in Accordance with the BCA

Light coloured (low solar absorbance) roofing and wall materials remain cooler than darker coloured (high solar absorbance) materials. The cooler temperature has many benefits including the ability to reduce the energy costs for cooling a building.

In order to recognise the cooling benefit of lower solar absorbance roofs and walls building regulations have incorporated absorbance as an energy efficiency design parameter.

Lower solar absorbance materials typically qualify for a roof space and or insulation concession under the BCA and or BASIX. Alternatively, absorbance values are input to BCA (Building Code of Australia), Compliant Building Verification software, such as, Accurate, and Energy Plus during energy efficiency compliance work.

As a result of their low absorbance, insulation, roof space, glazing and or shading concessions are achieved resulting in reduced cost to construction. Moreover, the long term benefit to the building owner, of greatly reduced cooling loads and energy consumption.

In some parts of Australia reduced absorbance means real savings in the amount of insulation that is required to meet building regulations.

Example: Under deemed-to-satisfy rules.

Light colours under BCA.                     Drop of R0.5 for roof insulation.
Very light colours under BCA.           Drop of up to R1.0 for roof insulation.

Example: Under BCA alternate solution.

          In some climate zones, insulation to internal walls on tilt up concrete.
          Not required.
   
          The Building Code of Australia (BCA) has classified colour as light,   
                   medium and dark on the basis of their solar absorbance.

Light colour SA – < 0.35          Medium colour SA – 0.35 – 0.55          Dark colour SA - > 0.5