AS 4859.1:2018 is a standard that outlines the general criteria and technical provisions of thermal insulation materials for buildings, 

2018 update 

The 2018 update has introduced changes in the calculation of R Value. Changes have been made to testing and declaration of R value. The changes affect bulk, reflective foil and Rigid foam insulation. 

Thermal Testing 

• A statistical assessment of at least 10 results is required for each material assessed under the standard.
• This statistical assessment shall determine the R value and thermal conductivity, of the product tested, based on the statistical mean values representing a 50%  fractile with 90% confidence for a one sided tolerance interval. To be expressed as R_50/90 or λ_50/90.
• The same statistical assessment is applicable for all insulation materials except for vacuum insulation panels.

The adapted heat aging methods required for determination of long term thermal values are now aligned with European standards and are more stringent than previous standards. These values will more accurately represent long term performance in the building.

Thermal Declarations and Labelling  

The Declared R-Value or λ-value shall not be higher or lower than the R_{50/90 or λ50/90.}

The labelling must include the

• Location of the manufacturing plant 
• Relevant Temperature for the declared thermal values (23⁰ C for Australia and 15⁰C for New Zealand) must consistently be applied across the relevant markets. 

It should be noted that Total R values are no longer acceptable for product labelling. 

Effective Date 

May 1 st 2020