The 6(C)) change in treated wood

Copper azole has become common and its most udvancedformulotion is Type C

Over the past 10 years, lumber dealers have been introduced to wood protected by several preservatives in differing variations. Out of this competitive mix, Copper Azole has emerged as the most common preservative for residential treated wood. It provides wood products with long-term resistance to termites and decay fungi.

The effectiveness of CA-C is recognized by the American Wood Protection Association (AWPA), the organization that sets standards for the wood treating industry. Before AWPA lists a preservative in its standards, the candidate must satisff a knowledgeable membership that encompasses treated wood users, academic experts, wood scientists, and manufacturers

Because of the intensive process involved, AWPA standards are accepted by the Intemational Code Congress for its model code, the International Building Code (rBC).

In January 2009, cA-c preservative made with dissolved copper was accepted for listing by AWPA, as were its treating requirements. This variation incorporates two carbon-based azoles. Their use together has been granted a patent because of synergistic efficacy.

Because of its effectiveness, the retention levels required of CA-C are quite low. In preserved wood, chemical retention is defined as the amount of preservative retained in the wood after treafment. lt is measured in pounds of preservative per cubic foot of wood, or pcf. For different preservatives, different retention levels may be necessary for particular applications. Preservatives do not have the same degree of effectiveness.

As can be seen in the comparison below, derived from AWPA standards, it takes far less CA-C to protect wood than ACQ-Dless than half the amount for above ground use and ground contact. This means less chemical exists in the wood.

Contributing to the lower retention levels is the synergistic effect of the two co-biocides, tebuconazole and propiconazole. These two azoles, when used together, are more effective than the sum of them used separately. The combination has been patented.

The workhorse ingredient in CA-C is copper, a very effective fungicide. Some fungi can tolerate copper, however, so a cobiocide is needed to control them. The azoles provide protection against coPPertolerant fungi.

Wood treated with ICA-C preservative is sold I as Wolmanizedu Residential iOutdoore wood. The lWolmanized name is a respected trademark that has i symbolized properly treated wood for decades. :*2'44*

Over these decades, the developers of Wolman ized* pressure-treated wood have introduced numerous innovationsfrom new preservatives and advanced treatment procedures to built-in water repellent and promotional support.

As did previous tYPes of Wolmanized@ wood, wood treated with CA-C carries a lifetime limited warranty against termite damage and fungal decaY. For warranty details, visit www.wolmanizedwood.com. It is also backed by the Good Housekeeping Seal.

In addition to the treatment that extends service life, and in addition to construction convenience, aesthetic value, and often lower cost, this product has the environmental advantages of wood. Its base is a renewable resource using plentiful, rapidly replenished species typically grown on managed timberlands and requiring less energy to produce than alternative building materials. Growing forests absorb carbon dioxide and wood products sequester carbon, thus reducing greenhouse gases. Wood offers greater thermal, electrical, and acoustic insulation than alternatives, and, because of its lighter weight, can often be installed with equipment having less environmental imPact.

Wolmanizede wood treated with CA-C preservative is Produced bY leading wood treating comPanies including:

Conrad Forest Products, 800-356-7 146

Exterior Wood, 800-83 3-083 8

McFarland Cascade, 800-426-8430

Nevada Wood Preserv ing, 1 7 5 -57 7 -2000

TrueGuard, 800-777 -07 49

Utah Wood Preserving, 80 | -29 5 -9449

A brief look at chemistrY

Copper azole combines copper with a small amount of azole, a carbonbased fungicide. Although copper is an effective pesticide against nearly all organisms, there are some fungi that can tolerate it. The azole is a co-biocide that protects wood against copper-tolerant fungi. Copper azole evolved from its original Type A formulation to Type B wiih borate removed, and is now available in its advanced dual-azole formulation, Type C. It can be made using dispersed copper or, as is done in western states, with dissolved copper.