Penetration class according to EN 351-1
Use classes UC1-UC5 according to EN 335 and their relation to the wood protection classes NTR M, NTR A, NTR A pole, NTR AB, NTR B, NTR GRAN and NTR GW
Relation between Wood protection class according to NWPC and Use class according to EN 335-1
| Penetration class according to EN 351-1 | Penetration requirement | Use Class 1 | Use Class 2 | Use Class 3 | Use Class 4 | Use Class 5 |
|---|---|---|---|---|---|---|
| NP1 | None | NTR GRAN** NTR GW** | ||||
| NP 2 | Min 3 mm lateral into sapwood | |||||
| NP 3 | Min 6 mm lateral into sapwood | NTR B | ||||
| NP 4* | Min 25 mm | |||||
| NP 5 | Full sapwood | NTR AB | NTR A NTR A pole | NTR M | ||
| NP 6 | Full sapwood + 6 mm into heartwood |
