As of 1 May 2009 the Building Code of Australia requires all calculation reports for demonstrating the performance of insulation products to be carried out according to the 2006 amendment of AS/NZS 4859.1:2002. This means any product labeling and promotional materials showing calculated system R-values should be updated to meet the changes in the 2006 amendment.

See the Australian Building Codes Board for more information.

The amendment includes adjustments to a product’s tested emissivity, in Section K3.2. These adjustments are summarised as follows:

-For vertical and downward facing surfaces, emissivity of 0.03 or as tested, whichever is greater

-For upward facing surfaces in non-vented cavities where the cavity is fully sealed, emissivity of 0.03 or as tested, whichever is greater

-For upward facing surfaces in non-vented cavities where no special precautions for the prevention of air ingress have been included, assume slight dust cover and add 0.05 to the tested emissivity

-For upward facing surfaces in naturally ventilated space, assume moderate dust cover and add 0.25 to the tested emissivity.

Section K4.2 of the amendment addresses the ventilation of roofs, walls and floors. The implication of this section is that tile roofs are assumed to be naturally ventilated; whereas metal roofs are assumed to be non-vented. This means that any reflective foil insulation installed directly under a tiled roof will be penalised with an additional 0.25 added to the tested emissivity for moderate dust cover.

Section 3.12.1 in volume two of the Building Code of Australia gives the requirements for building thermal insulation. Table 3.12.1.1 gives the minimum total R-Value for different climate zones, with the minimum being 2.7 downwards for zone 1 and the maximum 4.8 upwards for zone 8.

The effect of the amendment will mean that some systems, particularly tiled roofs with the insulation installed parallel to a roof, and including an anti-glare upper surface, and without any sarking, will not achieve an R-Value of 2.7.

One solution to this problem is to use reflective foil and bubble cell insulations in new installations in a similar manner to the retrofit case. This would mean specifying systems for new installations with a reflective sarking (with an upward facing anti-glare surface and a downward facing low emissivity silver surface) under tile roofs, (metal roofs may not need the sarking) and install reflective insulation parallel to the ceiling with both upper and lower surfaces being low emissivity silver.

By Jodie Kemp

The Australian Government seeks to improve the energy efficiency rating of Australian homes through its $4 billion Energy Efficient Homes Package. This is the largest measure of this kind ever to be undertaken in Australia and represents a significant opportunity for the insulation industry.

Ceiling insulation is one area being particularly targeted. As part of the package, assistance may be granted:

Up to the value of $1,600 through the Homeowner Insulation Program, and
Up to the value of $1,000 through the Low Emission Assistance Plan for Renters.

These programs will remain in effect until 30 June 2011 for renters and landlords, and 31 December 2011 for owner-occupiers.

Since 2004, e3k has been working with industry leaders to calculate and identify the “total R-Value” of various building structures, that is, a structure’s overall resistance to heat transfer. This is an essential quantity for compliance with the relevant standard*, the Building Code of Australia, and to qualify for the grants.

Comparing different products in various installation configurations can be challenging. The total R-Value provides a benchmark against which to measure, and is required for effective comparison.

With the knowledgeable and experienced help available through e3k, insulation suppliers can position themselves to benefit to the fullest from this environmentally friendly initiative.

For further information on the Energy Efficient Homes Package, click here

Download the Homeowner Insulation Program Guidelines as a PDF here

* Australian and New Zealand Standard, AS/NZS 4859.1:2002/Amdt 1:2006 Material for the thermal insulation of buildings