What is autoclave treatment, or pressure impregnation?
The preservative (odourless and water-based) is injected into the wood under pressure (about 8 bar). The wood is thus protected durably against rot and attack by wood-boring insects.
When and why is autoclave treatment used?
This process is recommended for native softwoods (fir, spruce, pine, etc.), which are not sufficiently resistant to rot, fungi and wood-boring insects. It is used for wood in contact with the ground or moisture, such as posts, decks, avalanche barriers, stabilisation works, electricity poles, playgrounds, bridges, waterside constructions, balconies, etc. (Class 3: no ground contact, for example façades, noise barriers, privacy screens).
What are the advantages of autoclave treatment?
Autoclave-treated wood has a service life three times longer than that of untreated softwood.
What colour is autoclave-treated wood?
After oxidation and fixation, the wood takes on a slightly green to brown colour. The brown shade is obtained by adding a colouring paste. It is not a covering coat but a tint with limited penetration. The colour after impregnation depends on drying, surface structure, the penetration depth of the product and the quality of the wood.
Which products are used?
Tanalith C (Lonza Group Ltd.)
Korasit CX (Kurt Obermeier GmbH & Co. KG)
Wolmanit CX-10 (Dr. Wolman GmbH, BASF Group)
How should pressure-impregnated products be stored?
Impregnated wood must be stored protected from rain and dirt, and well ventilated.
What are the phases of the treatment cycle?
- Step 1:
Properly prepared and dried, the wood is loaded into the treatment cylinder. An initial vacuum is applied, emptying the wood cells of air. The vacuum is maintained. - Step 2:
The cylinder is filled under vacuum with the wood treatment product. A brown colour additive is added if required. - Step 3:
Hydraulic pressure is applied, forcing deep impregnation of the preservative into the wood cells. - Step 4:
The final vacuum extracts the excess solution, which is returned to the storage tank. - Step 5:
Air enters the cylinder to complete the treatment cycle.
