What is wood preservation?
Wood preservation is the process of treating commercial wood to prevent decay caused by fungi and the infestation of insects like termites, thereby extending the lifespan of the wood.

2. When did CCA treated wood begin to be used in the U.S., and when was this technology adopted in China for "CCA" and "ACQ"?
CCA wood preservative has been used in the U.S. for over seventy years, while "CCA" was only introduced and adopted in China in the 1980s. "ACQ" was only introduced, researched, and applied at the turn of the 21st century.

Why Does Wood Warp and Split?
Products made from wood processed with higher moisture content are prone to warping and cracking. While some water-seal coatings can temporarily delay these phenomena, they do not address the root cause of excessive internal moisture in the wood, and the moisture will eventually break through the protective layer of the coating, leading to more severe cracking. The most effective way to improve this situation is to use preservative materials with a moisture content below 20%, but secondary drying may require additional time and costs.

Why is wood warping and cracking related to moisture content?
Wood warping and cracking are caused by internal stresses. The fundamental reason for this change is the variation in moisture content of the wood. Since wood is composed of numerous annual rings, the age of the rings on the two surfaces of the sliced板材is unequal. To put it in a vivid way: the older side responds slower to moisture, while the younger side responds faster. Therefore, under the same conditions, the surface area change on the older side is not as significant as that on the younger side. Additionally, as wood lacks elasticity, the side with reduced area must increase its surface area through cracking to maintain balance. Hence, we say that cracking and warping are closely related to the moisture content of the wood.

How to collect samples during testing?
Samples should be taken from the center of the wood's lengthwise direction, avoiding knots, cracks, and stress wood when determining the specific location. Once the position is confirmed, cut a cross-section of the wood to obtain the middle block or drill out the core with a hollow drill.

How is the number of inspections determined?
The determination of the number of samples to be tested: batches are formed from wood of the same species and thickness from each can of preservation treatment. For batches with a treatment volume of <5m³, 5 samples are taken. For batches with a treatment volume of ≥5m³, 10 samples are drawn.

Why Does the CCA Preservative Work as a Biocide?
Arsenic CCA treatments prevent corrosion by being impregnated into the wood, forming insoluble compounds within the wood fibers, rendering the wood inedible to wood destroyers such as fungi, termites, and beetles, thereby making the wood less susceptible to decay and infestation.

What are the advantages of CCA preservative?
CCA wood preservative, a soluble double salt of Chromium-Copper-Arsenic oxide, stands out among other wood preservatives with the following advantages:
(1) Wide-ranging in application, it is suitable for both above and below ground, indoors and outdoors, as well as in both saltwater and freshwater environments. It not only combats common decay fungi but also pests such as termites.
(2) Excellent防腐 performance. Can extend the service life of wood by 5-10 times, and is widely recognized internationally as a wood preservative with the highest level of防腐 effectiveness.
(3) CCA-treated wood is odorless, tasteless, and easy to process and paint.
(4) Arsenic agents are cost-effective, do not cause secondary pollution, and the treated wood is non-toxic to humans and animals.

Why did we choose Siberian larch as the base material for our preservative wood?
Larch is a variant of the European red pine and falls within the genus Pinus sylvestris. This wood is moderately resistant to decay and is easy to treat for decay resistance. It has fine grain and straight grain, similar to red pine, and can be used as a substitute. It is an ideal wood for making wharf piles, though it must be treated for decay resistance. After treatment, it effectively prevents the infestation of mold, termites, and microorganisms, significantly reduces the moisture content variation of the treated wood, decreases the cracking, and extends the wood's lifespan to between 40 to 50 years. Russia is rich in larch resources, making it a primary source of raw wood imports for China's preservation industry. Larch preservation wood, imported raw wood from abroad and treated by Chinese preservation companies, offers a moderate price point and is currently popular in the Chinese preservation wood market. Therefore, we have chosen larch as our base material.

10. Preservative-treated Wood Processing Technique
The vacuum pump extracts air from the tank (approximately -0.09MPa) → injects preservative, filling the tank with the preservative liquid → expels the preservative and vacuum-pulls to remove excess preservative (approximately -0.09MPa) → applies pressure to ensure the preservative fully penetrates the wood interior (1.0-1.4MPa).

11. When the liquid on the surface of the treated wood dries completely, does it mean the preservative has set?
The liquid preservative on the surface of the treated wood will dry out, but this does not mean the preservative has set. For wood treated with CCA (copper, chrome, arsenic), the setting time for CCA in cold winter temperatures (below 5℃) is 4-6 weeks, while in hot summer temperatures (above 30℃), it typically only takes 1-2 days. The setting of the CCA preservative in the wood can also be artificially accelerated by placing it in a drying kiln for accelerated drying, also known as secondary drying. However, the drying speed should not be too fast, as this can cause some of the preservative to be released, leading to air pollution and corrosion of the fans in the drying kiln.

12. Properties of Wood Preservatives
Safety. (The toxicity to humans and animals, environmental pollution, and the likelihood of fire from wood preservatives and treated wood are low.)
Effectiveness. (Wood preservatives must effectively prevent biological attack on wood.)
Persistence. (1. Antioxidants are not easily chemically decomposed or precipitated at room temperature; 2. The anti-loss property of antioxidants or their inherent hydrophobic nature)
Economic viability: The cheaper the raw material for a preservative and the simpler and easier the formulation and manufacturing process, the lower the cost of the preservative, and the greater its competitiveness in the market.

What are the advantages of waterborne corrosion inhibitors?
(1) Low processing costs. Since these preservatives are water-soluble, and water is cheaper and more readily available than organic solvents, the processing costs are lower compared to organic solvent preservatives.
(2) The treated wood surface is clean, with minimal to no刺激性 odors, and does not affect the paint and adhesive properties of the wood, making it suitable for construction materials.
(3) It will not increase the flammability of wood.

Can spruce be treated for preservation?
Wood treated with preservative dipping requires a certain chemical carrier (resin) to transport the preservative from the surface to the core of the wood. Since spruce lacks such a substance, even after treatment, the preservative will only adhere to the surface and not penetrate the wood, affecting its preservative properties.