XPS lambda: 0.031–0.036 W/mK — product example
XPS lambda depends on the exact board variant and thickness. The Polish URSA XPS ECO N-III-L page gives 0.031–0.036 W/(m·K). The accessible range does not assign a number to each thickness: check the current declaration. Do not use the lower endpoint for every board or substitute an older similarly named product.
URSA XPS ECO N-III-L — Poland. Product-specific or historical example; verify current conditions.
Document examples, not design defaults
| Product / source | λ [W/(m·K)] | Scope |
|---|---|---|
| URSA XPS ECO N-III-L — Poland | 0.031–0.036 | Product-specific or historical example; verify current conditions |
Check before using λ
- Record the exact product, market, density or thickness and document revision.
- Distinguish declared λD from the design value for the intended moisture and temperature. Unit conversion does not perform this correction.
- Confirm thickness in metres and use the same material conditions throughout the calculation.
From lambda to layer R
R [m²·K/W] = d [m] / λ [W/(m·K)]
At an illustrative 100 mm, the quoted endpoints give R = 0.10 / 0.036 ≈ 2.778 and 0.10 / 0.031 ≈ 3.226 m²·K/W. This sensitivity calculation does not assign either endpoint to a 100 mm ECO board. Use its thickness-specific declaration for an actual purchase.
| d [m] | λ [W/(m·K)] | R [m²·K/W] |
|---|---|---|
| 0.10 | 0.036 | ≈ 2.778 |
| 0.10 | 0.031 | ≈ 3.226 |
Interpretation and source limits
Low XPS conductivity does not select compressive strength or suitability for ground contact. Verify both the thickness-specific thermal declaration and the stated water and load conditions of the chosen variant.
Read declared and design thermal valuesMaterial lambda references
Sources and verification scope
URSA XPS ECO N-III-L, Polish product page checked on 14 October 2026: 0.031–0.036 W/(m·K). The accessible page lists a range without a thickness-to-value mapping; it is not a declaration for every board thickness.