Accoya A1 quality is classified as C22 strength grade and Accoya A2 quality is classified as C16
The Accoya acetylation process improves hardness and compression strength significantly. Accoya is approved for a general building approval by the German Institute for Building Technology (DIBt) for load bearing structural applications. This DIBt approval qualifies the strength class of A1 and A2 solid Accoya timber based on the European strength class system of C classes (EN338).
Accoya A1 quality is classified as C22 strength grade and Accoya A2 quality is classified as C16. The approval applies to Accoya wood in the widths 100 mm to 250 mm with a thickness of 25mm to 100mm, and can be used both flat and upright use. The standard wood design safety factors (kdef, kmod) as given in EN 1995-1 were determined in the DIBt test program to be appropriate and may be used. Accoya wood may be fastened to a timber sub-frame with nails, clamps, wood screws, dowels and bolts. For non pre-drilled holes, the minimum spacing distance and edge/end clearance (EN 1995-1-1, table 8.2) should be in line with wood with a density between 420 and 500 kg/m³.