SOME OF OUR FREQUENTLY ASKED QUESTIONS...

We receive dozens of calls a day regarding Conrad Forest Products services and products. Below are a small sampling of the most frequently asked questions. IF you need further explanation on any of these topics or we don't address your particular question here, please call us at 800-356-7146 or fill in your question using our online form at the end of this page.

Questions Menu

Q: What do we do?
Q: What are the benefits?
Q: What are CCA and ACZA preservatives?
Q: Is Treated Wood environmentally safe?
Q: What about safety at the plant? How safe is a wood treating plant?
Q: What's involved in treating wood?
Q: How do we ensure health and safety?

A: A reasonable question in a world that has become more concerned about our fragile environment. It's a question we welcome, because of the pride we take in what we do:

• the contribution we make to conserving our natural resources
• our dedication to protecting the environment
• the care we take to ensure the health and safety of our own people
• our good faith commitment to the welfare of the communities in which we and our families work and live

To the uninitiated, a wood treating plant presents a confusing scene of tanks, pipelines and large cylinders. So let's begin our introduction to the plant with a little background information.

We pressure-treat lumber and plywood with wood preservatives to significantly increase their useful life by protecting them against termite attack and decay caused by fungi and microorganisms-- and we do this without impairing the natural characteristics of the wood.

Just as an example without treatment, Southern pine or Western hemlock, which are commonly used in construction, have an average life in ground contact, according to U.S. Forest Products Laboratory tests, of 1.8 to 3.6 years. In contrast, wood treated with ACZA and CCA preservatives have remained in service for over 50 years! It is for this reason that most building codes actually require preservative treated wood for applications that involve contact with the ground or unprotected exposure to weather.

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A: The benefits are obvious, for while wood is a replenishable natural resource, our forests must be carefully managed. By extending the useful service life of wood in exterior uses, preservative treatments contribute significantly to the maintenance of precious forest reserves.

Some species of wood do have natural resistance to termites and fungi. But these species are increasingly rare and must be harvested very conservatively. And they are expensive. Other wood species are vulnerable to termites and fungi and must be protected.

Termites, the most common type of wood-eating insect, subsist on the cellulose content of wood. And certain strains of fungi use wood fiber as their food supply. As a fungus feeds on the wood fibers, the wood decays and loses strength. Therefore, since Biblical times, any number of preservative treatments have been applied to wood-- even to Noah's ark-- to increase its durability and longevity, especially wood in contact with soil or exposed to weather.

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A: The CCA preservative is a formulation of chromated copper arsenate, a formulation found to be highly effective as a wood preservative.

Each of the three elements in CCA and ACZAare important to the overall performance.

Copper and Zinc are normally associated with piping, metal roofs and perhaps coined money. However, in certain forms, it is an effective fungicide. It is the copper that lends CCA and ACZA treated wood its unique greenish cast -- which, over time, weathers to a driftwood gray (CCA), dark to light brown and dark brown to black (ACZA).

Chromium,(not contained in ACZA), which also helps to protect against certain fungi, plays an important part in the fixation of preservative to the wood fiber in CCA.

The arsenic in ACZA and CCA preservatives is pentavalent arsenate, a naturally-occurring trace element in the soil, water, air, plants, and in the tissues of most living creatures, including man. When it is fixed in the wood cells as copper arsenate and chrome arsenate, it is toxic to wood-destroying termites and fungi, but, when used properly in the concentrations found in pressure-treated wood, it is not harmful to people or to animals.

When the solutions are pressure-impregnated into wood cells, (CCA and ACZA), the mixture of stable metallic oxides is reduced by the wood sugars to form insoluble precipitates. What this means is that the preservative ingredients actually become locked in the cells of the wood - they will not vaporize or evaporate. And unlike wood that has merely been coated with paint or stain, pressure-treated wood treated to AWPA standards forces the treating solutions deep into the wood structure.

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A: An impact Assessment Report of the United States Department of Agriculture, prepared in cooperation with the Environmental Protection Agency, concludes that "the environmental effects of As [arsenic] in air, water, or soil at concentrations normally found from arsenical pesticides as currently used are insignificant," and that "no problems have been found in the literature relative to the environment from wood preservative use."

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A: We know that, improperly handled, chromated copper arsenate can be nasty stuff --just as virtually any chemical, man-made or naturally occurring, can be nasty. We all know that even a life-preserving medication, improperly used, can adversely affect health. For example, even aspirin can be unsafe when improperly administered. But without such chemicals, the quality of our lives would be diminished.

The long and the short of it is this: experience with the ACZA and CCA has shown no adverse effects on employees working with the preservative on a daily basis. And we have 50 years of testing and use to prove it!

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A: The basic treating process is simple and highly controlled.

The lumber, timbers and plywood to be treated are loaded onto small rail or tram cars. Using a vehicle such as a forklift, the trams are pushed into a large horizontal treating cylinder. The cylinder door is sealed, and a vacuum is applied to remove most of the air from the cylinder and the wood cells. Preservative solution is then pumped into the cylinder and the pressure raised to about 150 pounds per square inch, forcing preservative into the wood.

The total treating time will vary, depending on the species of wood, the commodity being treated, and the amount of preservative to be impregnated but, in all instances, the treating process is a "closed system".

At the end of the process, excess treating solution is pumped out of the cylinder and back to a work tank for reuse. The cylinder door is opened and the trams are pulled out.

The wood is wet at that time, so it is kept on a concrete pad, which meets EPA requirements. Any drips trickle onto the pad containment area, then to a sump where it is pumped to a work tank where it is reused.

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A: Our treating process and our work practices ensure the health and safety of our employees and the community in a number of ways:

• Our wood treating process is accomplished in a closed system. When the chemical concentrate arrives in a special tanker at our treating plant, it is unloaded directly into a concentrate receiving tank. No one comes in contact with the solution.
  
  
• The concentrate is then diluted with water in an automated mix system to produce the work solution we use in the wood treating process.
  
  
• At the cylinder, wood is loaded onto small cars which are pushed into the treating cylinder. There, in a sealed and locked cylinder, by vacuum and pressure under precisely controlled conditions, the wood is injected with the diluted solution of the chemical preservative.
  
  
• When the wood is removed from the treating cylinder, no fumes or vapors are released to the environment except ammonia, which is used as a carrier for ACZA. All areas are monitored to comply with PEL monitoring requirements for the EPA.
  
  
• The treated wood comes out of the cylinder with approximately 80% of the preservative locked into the wood cells. While it cures, it remains on a drip pad, which is designed to collect excess preservative for reuse. Within a few days, all the preservative becomes fully fixed in the wood cells, and is moved to storage or loaded for delivery.
  
  
• The drip pad is made of impervious material including high- strength reinforced concrete, using special water-tight construction joints, and is coated with an impermeable sealer per 40 CFR, part 264 Subpart W.
  
  
• Our operation is considered a zero discharge plant. That means that we do not discharge any process water. The portion of the plant where we handle the liquid preservative is totally contained through the use of concrete diking around our tanks and cylinders. The floors of these areas are also impermeable and sloped toward collection points where liquids are sumped and piped to work tanks for reuse. All rainwater, cleaning water, etc. that contact these chemical processing areas are collected for reuse in the preservative treatment.
  
  
• When cylinders are cleaned, loaded or unloaded, or when freshly-treated wood is handled, employees wear appropriate personal protective equipment.
  
  
• All collected process waste is properly shipped off-site.
  
  
• Ongoing air monitoring ensures that employees breathe healthful air.
  
  
• Employees are provided with ongoing training to make sure they understand how to work safely.
  
  
• Everyone at our plant knows our spill prevention and emergency plans - and these plans, as well as the nature of the materials with which we work, have been shared with local hospital, fire department and emergency response personnel.
  
  
• The process of pressure treating wood with CCA and ACZA preservative is regulated throughout North America by the United States Environmental Protection Agency as well as state authorities, and in Canada, by Environment Canada and the Code of Good Practice.
  
  
• We comply fully with both the letter and the spirit of all applicable regulatory compliance requirements.

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Wood is our only renewable building material, and it saves energy when compared with other building materials. But wood is not ours for the wasting. The longer it lasts, the less the drain on our exhaustible metals and minerals -- and the more we reduce the pressure on our forests.

Nature returns wood to the soil through the action of decay fungi, bacteria, and insects. To deal with such biological degraders, we must deal with them biologically -- which is precisely what wood preservative has proved itself so capable of doing. By proper treatment, we not only make wood an economical material, we make one tree last as long as many untreated trees.