Technical documentation
Performance values
The thermal resistances of Isoflect build-ups, with the source of every value. For specifiers, distributors and for anyone who wants to check before buying.
The complete build-up, tested in an accredited laboratory
Breather membrane, insulation fibre and the complete reflective membrane assembly, with a sealed air layer.
INCD URBAN-INCERC, Bucharest Branch · Test report no. 7039 / 18.10.2023 · guarded hot plate method, SR EN 12667 · laboratory accredited by RENAR, certificate LI 320. The fibre was compressed in the specimen in order to fit within the limits of the apparatus; at installed thickness, the value is higher.
The two-layer reflective pack, measured
Gold, sealed air layer and Multistrat, without insulation between the rafters.
Measurement on a Lambda-Meter EP500e, at 10 °C and a difference of 15 K: λ = 0,0358 W/mK.
The result, by thickness of the insulation between the rafters
The values below are for the complete build-up: breather membrane, insulation fibre and the reflective membrane assembly. The resistance of the membrane assembly is the one derived from the test report; to it is added the fibre, at installed thickness.
| Insulation fibre between the rafters | Total R, m²K/W | U, W/m²K |
|---|---|---|
| 5 cm | 4,62 | 0,216 |
| 10 cm | 5,94 – 6,16 | 0,168 – 0,162 |
| 15 cm | 7,25 – 7,48 | 0,138 – 0,134 |
| 20 cm | 8,57 – 9,02 | 0,117 – 0,111 |
| 25 cm | 10,34 | 0,097 |
| 30 cm | 11,88 | 0,084 |
Ranges appear where the thickness can be achieved from two different fibre densities. The values refer to the build-up, not to a single product.
What each part adds
For anyone calculating the build-up themselves, or adapting it to an existing situation.
| Part of the build-up | R, m²K/W | Source |
|---|---|---|
| Reflective pack, two layers | 2,09 | measured |
| Reflective pack, four layers | 3,01 | derived from report 7039 |
| Breather membrane, above | 0,30 | design value |
The membrane assembly works together with the air layer between the layers. The values are not added to those of another membrane system installed in addition.
Why we publish the source too, not just the figure
Most of the values on the market are calculated. A calculation is done on paper and starts from assumptions chosen by whoever makes it. A test is carried out on a real specimen, in an accredited laboratory, and has a report number that can be requested.
That is why every table above states where each value comes from: what was measured, what was derived from a measurement and what is a design value. If you need the full report for a project, we will send it to you.
For projects
Do you need the full report, or a build-up calculated for your project?
We send the test report, the technical data sheets and the declarations, and we calculate the build-up for the situation in your project.