The transition period for the National Construction Code (NCC) introduced in 2019 came to an end on May 1st 2020 in most states. This updated version of the NCC has a more stringent Section J, which sets the standards for energy efficiency of buildings.

Part J1 details the requirements of the Building Fabric, specifically its thermal, roof and ceiling, wall and glazing and floor construction. These elements form the building envelope and as such have a big impact on the thermal performance and energy efficiency of the finished building.

In the section Thermal construction – general; an update of the current AS/NZS 4859.1 has been called upon stating that: “Where required, insulation must comply with AS/NZS 4859.1:2018”.

What is AS/NZS 4859.1?

AS/NZS 4859.1 is a standard that outlines the general criteria and technical provisions of thermal insulation materials for buildings.  

What are the changes?

The updated AS/NZS4859.1:2018 standard will see changes introduced to the way the product is tested and how thermal performance (R-value) is calculated and declared, affecting bulk, reflective foil and rigid foam insulations.

The biggest changes within the amended standard AS/NZS 4859.1:2018 are to do with thermal testing and formal declarations of performance labelling:

Thermal Testing:

  • A statistical assessment of at least 10 test results is required for each material assessed under the standard.
  • This statistical assessment shall determine the R-value and thermal conductivity for the products tested from the statistically adjusted mean values representing a 50% fractile with 90% confidence for a one-sided tolerance interval. To be expressed as R50/90 or λ50/90.
  • The same statistical assessment is applicable for all insulation materials, except for vacuum insulation panels.
  • The adopted heat aging methods required for determination of long-term thermal values for rigid foam insulation materials are now aligned with European standards and are more stringent than before to more accurately represent long term in-situ performance:
    • Phenolic foam (PF) insulation is now included with an accelerated aging requirement for aging for 14 days at 110°C, or for 175 days at 70°C, or aged using a prescribed slicing method.
    • Polyisocyanurate (PIR) and Polyurethane (PUR) insulations are now required to be heat aged for 175 days at 70°C, or aged using a fixed increment slicing method.
    • Extruded Polystyrene (XPS) insulation is now required to be aged for up to 90 days, either sliced or unsliced, at 23°C, depending on product thickness and composition, i.e. whether faced or unfaced with foil.
    • Expanded Polystyrene (EPS) is not required to be aged before testing.  
  • Manufacturers shall prepare a thermal value summary report, which includes the product label details, including statement of conformance with the standard, and the statistical calculation of R50/90.

Thermal Declarations and Labelling:

  • The ‘Declared R-value’ or ‘Declared λ-Value’ shall not be higher or lower than the R50/90 or λ50/90 respectively.
  • Additional requirements for labelling are:
    • Location of the manufacturing plant
    • The relevant temperature for the declared thermal values (23°C for Australia and 15°C for New Zealand) must be consistently applied across the relevant markets.
  • It should be noted that Total R-values are no longer acceptable for product labelling

Impact on the insulation industry

With the AS/NZS 4859.1:2018 introducing significant changes to product testing and labelling, the insulation market in Australia will see a change to product R-Values being declared and advertised in data sheets. The new thermal testing requirements are more stringent, meaning that the declared product R-Values will decrease across the insulation product offering.

Specifiers and builders need to be vigilant and make sure that products they are specifying, and buying, comply with the newly amended standard.

If manufacturers and suppliers aren’t following the new standard it might mean that the advertised thermal values are not matching the actual values of the product in the market. This will affect the thermal performance of the finished building and, in some cases, might make it fall short of the minimal required thermal performance under the NCC.