Processes undertaken to prevent wood rot fall under the definition wood preservation or timber treatment. There are a number of different chemical preservatives and processes that can extend the life of wood, timber, wood structures or engineered wood. These generally increase the durability and resistance from being destroyed by insects or fungus and/or allow the use of wood structures in wet or underwater conditions (marine grade wood).
In CCA treatment, copper is the primary fungicide, arsenic is a secondary fungicide and an insecticide, and chromium is a fixative which also provides ultraviolet (UV) light resistance. Recognized for the greenish tint it imparts to timber, CCA is a preservative that was extremely common for many decades.
An organochlorine compound used as a pesticide and a disinfectant, pentachlorophenol is used in two general methods for preserving wood. The pressure process method involves placing wood in a pressure-treating vessel where it is immersed in PCP and then subjected to applied pressure. In the non-pressure process method, PCP is applied by spraying, brushing, dipping, and soaking.
Copper treatments (denoted as CA-B and CA-C under American Wood Protection Association/AWPA standards) are a major wood preservative class that has come into wide use in Canada, the USA, Europe, Japan and Australia following restrictions on CCA.
Ammonia Copper Zinc Arsenate (ACZA) is often used to treat wood species that do not easily retain other treatments, such as Douglas Fir. When treating wood, the proper balance of treatment solution must be monitored to ensure the highest quality while minimizing waste and excess cost due to treatment usage or product rejection. Cu, Zn and As levels are monitored in solution prior to treatment, and then in the wood to ensure proper retention. A quick, simple, reliable means of analysis is required throughout the quality control process. XRF is an ideal tool for such analysis.