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Frequently Asked Questions – CCA


1. What is CCA and how does it work?
The chemical used to preserve DuraPine® Heavy Duty pressure-treated wood is a mixture of the oxides of copper, chromium, and arsenate known as CCA. The preservative has been formulated to render wood useless as a food substance for termites and fungi while keeping the wood attractive, clean, odorless, non-staining, and safe to handle when used as recommended.

2. For what applications can DuraPine® Heavy Duty wood be used?
DuraPine® Heavy Duty wood can be used for industrial applications.

3. What are AWPA retention requirements & Use Categories?
DuraPine® Heavy Duty pressure-treated wood is treated to various retention levels that are intended to protect the wood for particular applications. Retention levels indicate the amount of preservative retained in the wood in a specific assay zone.

4. What hardware is recommended for DuraPine® Heavy Duty wood?
Corrosion-resistant fasteners should be used with DuraPine® Heavy Duty wood.

5. What are the design values for CCA-treated wood?
Since pressure treatment with DuraPine® CCA preservative does not alter the natural characteristics of wood, the design values for untreated lumber and plywood should be used in accordance with the National Design Specification for Wood Construction (2001 edition), issued by the American Forest and Paper Association.

Wood products which have been preservative-treated are referenced in Section 4.3.14 and 6.1.4. If lumber is not dried after treatment, or if the end use will result in a moisture content exceeding 19%, wet service factors shall be applied (see 4.1.4 and 4.3.3).

In addition, load duration factors greater that 1.6 shall not apply to structural members. The design values for all acceptable species and grades of lumber are given in the Supplement to the National Design Specification.

6. Is CCA-treated wood safe?
The fixation which occurs subsequent to the treating process makes DuraPine® Heavy Duty wood safe for the environment and for the individual user when this wood is handled as recommended. Once the Wolman CCA is fixed in the wood cells, it is highly leach-resistant. With seven decades of usage, its harmlessness to people, plants, pets and the environment has been documented by academic and governmental researchers and agencies.

As a federally registered pesticide, DuraPine® CCA preservative undergoes a formal investigation and evaluation by the Environmental Protection Agency periodically. Based on an abundance of documentary evidence, the EPA deems DuraPine® wood to be suitable for uses described on this site (see Consumer Safety Information Sheet). Other agencies also oversee aspects of the production, transportation, and use of CCA and CCA-treated wood. Material Safety Data Sheets are available.

7. What are the environmental benefits of DuraPine® Heavy Duty wood?
Unlike plastics, steel, and concrete, DuraPine® wood is made from a renewable resource grown on managed timberlands. It requires less energy to produce than plastics and offers greater insulation value; and, because of its lighter weight, preserved wood can often be installed with lighter equipment which has less environmental impact. DuraPine® Heavy Duty wood also contains copper derived from recycled sources.

8. How is DuraPine® Heavy Duty wood produced?
The basic treating process is simple and highly controlled.

  1. Lumber, timbers, or plywood is loaded onto small rail or tram cars. The trams are moved into a large, horizontal treating cylinder.
  2. The cylinder door is sealed and a vacuum is applied to remove air from the cylinder and the wood cells.
  3. Preservative solution is then pumped into the cylinder.
  4. The pressure is raised to about 150 pounds per square inch, forcing CCA into the wood. Treating time varies depending on species of wood, commodity being treated, and the amount of preservative to be impregnated.
  5. At the end of the process, excess treating solution is pumped out of the cylinder and back to a storage tank for later re-use.
  6. A final vacuum removes excess preservative from wood cells. The cylinder door is opened and the trams are pulled out. The wood is wet, so it is kept on a concrete pad until any dripping ceases.