Supafil 90:90

Labmda 90-90-banner

As of 1st July 2012, the BBA require all BBA certified in-situ formed insulation solutions to have thermal performance declared to Lambda 90/90.

Products which do not have thermal performance declared to Lambda 90/90 risk having their BBA certificate withdrawn, or a penalty applied to the declared thermal performance.

Supafil -34-wall

Understand the requirements and ensure you comply


What is the requirement as from 1st July?

The BBA have decided that in order to maintain a fair market, all materials which declare a thermal performance should have thermal conductivity declared to Lambda 90/90 rather than Lambda mean.

An area of initial focus is in-situ formed insulation products in masonry cavity walls.

The deadline for this task is 30th June 2012.

BBA certificate holders must have provided both independent and in-house conductivity data, have had their Lambda 90/90 calculated, and the Agrement certificate updated by the 1st July 2012.


What is an in-situ formed insulation product?

In-situ formed insulation products are those which are installed by being blown or pumped into lofts, masonry cavity walls or framed constructions; as opposed to products supplied pre-formed in the shape of slabs, rolls or boards.


How is thermal performance currently declared?

Thermal performance of in-situ formed insulation products has previously been calculated using a Lambda mean convention. In order to declare thermal performance to Lambda mean, a range of production samples are tested and the mean, or average, thermal conductivity of that range is declared.


What is Lambda 90/90?

Lambda 90/90 refers to the value that can be obtained for 90% of production within a 90% confidence level, thus increasing confidence in the declared thermal performance value. This method has been in use for over 10 years for factory formed insulation products.


Why is Lambda 90/90 being used?

The purpose of using Lambda 90/90 is twofold; to ensure a level playing field across different insulation materials, and to also increase confidence in actual performance of insulation products.

By using the same declaration method across differing insulation materials, the BBA are ensuring that specifiers can carry out like-for-like comparisons when assessing potential solutions.

In addition, Lambda 90/90 is providing increased levels of confidence in the thermal performance of in-situ formed insulation products.


What is the likely impact of Lambda 90/90 on declared thermal performance?

It is expected that products which have not been adapted or re-engineered to meet the changes will face an increase (worsening) in the declared thermal conductivity value when moving from a Lambda mean declaration to a Lambda 90/90 declaration.


What if insulation solutions aren't Lambda 90/90 compliant from 1st July?

For products which are not re-tested to declare thermal performance to Lambda 90/90 within the required timescale, there is a chance that either thermal performance penalties will be applied, or BBA Certification may be withdrawn altogether.


Are Knauf Insulation solutions Lambda 90/90 compliant?


We have tested and declared the thermal conductivity of all of our in-situ formed products to Lambda 90/90 as required.

Not only are our solutions compliant, our products have been further developed to ensure no worsening of thermal performance when switching from Lambda mean to Lambda 90/90.


The products we have tested and declared to Lambda 90/90 are as follows:

ProductApplicationThermal performance
declared to Lambda 90/90
Supafil 40 Masonry cavity walls 0.040 W/mK
Supafil 34 Masonry cavity walls 0.034 W/mK
Supafil Frame Timber frame walls 0.033 W/mK

Lambda 90/90 and the Green Deal

Under the Green Deal there will be a clear advantage to using products declared to Lambda 90/90 as they give a higher level of confidence into the actual thermal performance of insulation products.

Contact us

For more information regarding our Lambda 90/90 compliant solutions contact:

Knauf Insulation Technical Support Team (TST)