NTR-systemet gör det enkelt att välja rätt produkt för den avsedda användningen, vilket stödjer en ekonomisk och hållbar användning av trä i byggprojektet.
Tabellen nedan beskriver användningsklassen enligt europeisk standard EN 335 och hur denna förhåller sig till NTR-träskyddsklasserna.
Användningsklass EN 335
Den europeiska standarden EN 335 beskriver hur beständig träprodukter kan användas och relaterar detta till NTR-träskyddsklasserna.
Use class EN 335
| Use class | Service conditions | Example | Recommended wood protection class |
|---|---|---|---|
| UC 1 | Interior timbers in dry conditions | Furniture, interior cladding | Not specified in NTR |
| UC 2 | Wood above ground and under cover and fully protected from the weather but where high environmental humidity can lead to occasional but not persistent wetting. | Roof trusses, exterior timbers under cover | Not specified in NTR |
| UC 3 | Wood above ground and either continually exposed to the weather or subject to frequent wetting; where there is relatively easy to replace damaged components and where the consequences of failure will be moderate. | 3.1 Windows and doors etc.
3.2 External cladding, decking, garden timbers | 3.1 NTR B
3.2 NTR AB |
| UC 4 | Wood in contact with the ground or fresh water or severely exposed to the weather; or if wood component is inaccessible or where the consequences of failure will be particularly serious. | 4.1 Transmission poles
4.2 Railway sleepers, fence posts, bridges | 4.1 NTR A pole
4.2 NTR A |
| UC 5 | Wood constructions in sea water and constructions subject to extreme conditions or where there are special durability and strength requirements. (Sea water. Salinity > 0,6%) | Wharf timbers, jetties, piles | NTR M |
