Updated Lambda Values Declaration of the Kooltherm Range

29 October 2021 Kingspan Insulation Australia
WA NCC 2019-1

Kingspan Insulation takes compliance and performance declarations very seriously, and as one of the first insulation manufacturers to transition to the updated standard AS/NZS 4859.1:2018 ahead of the 1st May 2020 transition deadline, we have embraced the robust measures this updated standard has brought to the market. 

One of the most significant updates were amendments to the way in which ageing thermal performance of rigid foam insulation is determined providing a statistically adjusted mean aged thermal conductivity and R-values to represent thermal performance after 25 years of aging under normal in-service conditions.

This is referred to as λ50/90 and R50/90, respectively. Declared conductivity (λd) must not be any less than λ50/90 rounded up to the nearest 0.001, and the declared R-value (Rd) must not be any more than the R50/90 rounded down to the nearest 0.05.

AS/NZS 4859.1:2018 requires insulation manufacturers to declare thermal properties based on a statistical assessment of at least 10 test results (AS/NZS 4859.1:2018 –, and NCC 2019 requires these results to be determined by NATA (or equivalent) Accredited test laboratories for the relevant test method (NCC Vol. 1 – A5.2(d)).

As it is over 12 months since the new testing assessments have been implemented, in that time, we have continued to test and monitor via a NATA accredited lab to ensure that we are building our dataset and are within our performance claims. 

Ongoing testing and monitoring in accordance with Kingspan’s Product Compliance Management Policy has indicated a slight shift from our original λ50/90 and as such we need to adjust our R-values for Kooltherm Insulation 45mm and above downwards by between R0.05 & R0.20, depending on thickness and rounding (approx. 2.0 to 4.5% change)

In accordance with the thermal performance declaration of AS/NZS 4859.1:2018, this change will take effect from 1 November 2021 and does not impact performance declarations of products prior to this date. 

If you have any questions regarding the above or want to discuss Kingspan products, please don’t hesitate to contact us on 1300 247 235 or email our technical team on technical@kingspaninsulation.com.au.