FAQ PA 08 - Use of wood preservation agents in a multi-layer system

Wood preservations may be used in so-called systems like combinations with decorative coatings and/or with transparent finishings to protect the preservative against physical effects such as UV radiation, precipitation, mechanical abrasion etc. In practice a system is already present, if the wood preservation priming is simply covered with a finish coating. Systems arise with industrial manufacture of wood or wood based products (e.g. windows, doors, fence fields etc.) when repetitive layers of product and coatings are applied.d.

1 | Has an applicant to prove the effectiveness of a wood preservation system as a system?

Yes, if the label of the system claims “Wood protected against…” or “Product against wood-destroying … organisms” or likewise. An examination of the system is redundant, if effectiveness of the wood preservative without the system is shown and when the loading of the wood preservation in the system is equal to the loading of the wood preservative in the test without the system.ht.

2 | Has an applicant to demonstrate the non-effectiveness of a coating without bioactive ingredients?

No, the non-effectiveness of the inactive substances in the wood preservation or a system may be justified by structural effectiveness relationships, literature data etc.

3 | Which tests on biological effectiveness has the applicant to carry out, if wood preservatives and film preservatives are combined in a product?

If the claim of the wood preservative product is singly wood preservation, then film preservation actives remain formally unconsidered. A possible contribution to the entire effectiveness in the wood preservation is included integrally with the examination of the system. However, if the non- wood preservation active substances are bio-available, corresponding data for the biological effectiveness for the evaluation of the toxicological and eco-toxicological characteristics may be expected..

4 | Has an applicant to carry out new tests in accordance with EN 73 (evaporation) and/or EN 84 (leaching) when the wood preservative is changed but the system otherwise remains unchanged?

With industrial manufacture of well fitted products (e.g. windows and doors) thick layer lasures are mostly used. In the case of the comparable quality of laminating and with comparable chemical-physical characteristics of the wood preservative main components (e.g. viscosity, wettability/liability of the layer with the wood preservative etc.) - after individual case examination - one can waive renewed pre demands. In the case of not well fitted products (e.g. fence fields) thin layer lasures are often used. Compared with thick layer lasures, thin layer lasures still evaporative active. That means incoming and outgasing of humidity is possible which may result in evaporation or leaching of active compounds. In the case of such open systems the applicant cannot waive pre demands before biological tests. New tests will be required in any case when bioactive ingredients in the wood preservative have been changed.

2010-04-16

FAQ PA 08 - FAQ PA 08 - Control of lyctid powder post beetles

1 | Is a control of lyctid powder post beetles useful?
When yes? When no?

Infestations of lyctid powder post beetles occur on starchy sapwood parts of hardwoods, often locally limited, however very aggressively. Once an infestation is detected, destroyed wooden parts should be removed and replaced rather than treated with wood preservatives. Only very slight infestations by lycid powder post beetles can be curatively treated by applying heat or microwave radiation.Note: Most lyctid powder post beetles originate from subtropical to tropical regions. Their development is independent from seasonal changes, so that they constantly reproduce in large numbers under warm environmental conditions like inside houses where they may breed in furniture, window frames or parquet floors. The brown powder post beetle Lyctus brunneus was introduced most likely with tropical woods whereas Lyctus linearis is meanwhile native to central Europe.

More information

ECHA EUROPE - European Chemicals Agency

The Federal Institute for Occupational Safety and Health (BAuA)

OECD guidance document for flammability testing of plant protection and biocidal products

further information