Non-Toxic Preservative Treated Wood

Summary

Details

A non-toxic preservative chemical, Ammoniacal Copper Quat (ACQ) combines the effectiveness of copper with a low-toxicity co-biocide to achieve a high degree of preservation and durability in various softwoods. Tests of ACQ-treated wood have shown retention levels equivalent to traditional copper-based preservatives. Similar to traditional pressure-treated woods, NTPT wood has a service life of 30 to 40 years or more. Its color can vary from light tan to a deep olive and it weathers to a brown rather than gray. The non-toxic compound does not have any impact on the mechanical properties of wood.

NTPT wood is as easy to work with as untreated wood of the same species, but when sawing and machining, eye protection and a dust mask is advised to protect against flying particles. Because NTPT wood will probably be used in environments where corrosion is likely to occur, corrosion-resistant, hot-dipped, galvanized and stainless steel fasteners are recommended. When finishing, wood should be dry, oil-based semi-transparent stains should be used, and low-quality latex products should be avoided. Different retention rates of NTPT wood are specified for applications above ground and with ground contact, as well as for permanent wood foundations, poles, and pilings.

Installation

Installation is the same as conventional preservative treated wood. Take the normal precautions, such as wearing a dust mask and gloves while sawing and cutting. Because it's not an environmentally toxic material, it can be disposed of with normal garbage.

Benefits/Costs

NTPT has the same preservative benefits as conventional preservative-treated wood, and has low leaching and depletion rates that compare favorably with other copper-based preservatives. The biodegradable co-biocide is easier to dispose than the potentially hazardous arsenic and chromium metals in conventional pressure-treated woods. Wood scraps and sawdust from ACQ-treated wood are not considered hazardous. It is available in a variety of wood species.

The cost of ACQ-treated lumber is typically about 10 percent higher than conventional CCA-treated lumber.

Limitations

ACQ-treated lumber is more expensive than conventional CCA-treated lumber.

Code/Regulatory

Although arsenic and chromium are toxic in certain forms, the EPA does not consider treated lumber harmful or hazardous because the chemicals fix well to the wood, though they do suggest wearing masks and goggles when cutting and sawing it. This practice is also recommended for NTPT wood, but other EPA recommendations may not apply to NTPT. For example, the EPA recommends disposing of conventional treated wood waste through burial or discarding it with regular trash, but advises against incineration because of harmful toxins in the smoke and ash. The EPA also recommends cutting outdoors, washing hands, and laundering clothes separately after use.

The chemical components of the non-toxic, preservative compound are EPA-registered, general-use pesticides that are less toxic than chemicals in conventional wood preservative systems. Unlike traditional preservative systems, none of its components are listed under toxicity characteristics of rule 40 C.F.R. 261.24 (55 Federal register 11862). NTPT is accepted by the American Wood Preserver's Association (AWPA) and the International Conference of Building Officials (ICBO).

Availability

The non-toxic preservative compound is sold by one manufacturer under the trade name "ACQ Preserve." Wood treated with ACQ is not available in all states.

Contact(s)

Do you have a specific question about this technology and/or its 'real life' applications? Try the contacts listed below:

American Wood-Preservers Association
3426 Fall Creek Highway, Suite 190
Granbury TX 76049-7979
Phone: 817-326-6300

B. B. & S. of New England
PO Box 982
Davisville, RI 02854
401/295-3200

Chemical Specialties, Inc.
One Woodlawn Green, Suite 250
Charlotte, NC 28217
800/421-8661

Chicago Flameproof
PO Box 318
Montgomery, IL 60538
630/859-0009

Conrad Wood Preserving
3998 Wildwood Drive
North Bend, OR 97459
541/756-2595

J. H. Baxter & Co.
P. O. Box 5902
San Mateo, CA 94402
650/349-0201

McArthur Lumber and Post
313140 State Route 93
McArthur, OH 45651
740/596-2551

National Pesticide Telecommunications Network
Agricultural Chemistry Extension
Oregon State University
333 Weneger Hall
Corvallis, OR 97331-6502
800/858-7378

Northern Crossarm Co., Inc
PO Box 34
Chippewa Falls, WI 54729
715/723-0861

Quality Forest Products
Route 1 Box 406 QF
Enfield, NC 27823
252/445-2113

Superior Wood Treating
13702 8th Street East
Sumner, WA 98390
253/863-4495