What are D1, D2, D3 & D4 Adhesives?
One question we are commonly asked is what the ‘D’ stands for when it comes to adhesives. Many people online find adhesives that look similar but then they see a ‘D2′ or a ‘D4′ next to them. This can seem like jargon but it is a quick way of noting different properties of an adhesive.
The D grading stands for durability.
These gradings are part of the European standard BS EN 204 governing the classification of wood glues for non-structural applications.
There are 4 main types of durability grading, running from D1 to D4. The differences between these are listed below:
- D1 = Interior areas, where the temperature only occasionally exceeds 50°C for a short time and the moisture content of the wood is 15% maximum
- D2 = Interior areas, with occasional short term exposure to running or condensed water and/or to occasional high humidity, provided the moisture content of the wood does not exceed 18%
- D3 = Interior areas, with frequent short-term exposure to running or condensed water and/or heavy exposure to high humidity. Exterior areas not exposed to weather
- D4 = Interior areas with frequent long-term exposure to running or condensed water. Exterior areas exposed to weather
For those interested in the classifications, the bond strength requirement for the different classes is listed below: