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Wagner Moisture Meters Ensure Proper Drying Kiln Dry Basics: What That Means for Wood and Moisture Content
Kiln Dry Basics: What That Means for Wood and Moisture Content.
Date Posted: 7/1/2014
Forestry, done well, is a combination of science and nature which results in strong, durable wood. However, all wood species are harvested in the "green" condition, which is a term for the property which characterizes wood in its natural growing state.
Wood producers usually kiln dry and sometimes air dry lumber to establish moisture content (MC) uniformity. Equilibrium moisture content (EMC) is a prime objective for any wood producer.
There's Green Wood
Many observers would be shocked at the high ("green") moisture content (MC) of some wood species. Since trees comprise an autonomous eco-system of water and nutrients, it stands to reason that sapwood (the layer next to the bark) is generally higher in MC than heartwood (inner wood which has died). Sapwood distributes water and nutrition through a tree. The heartwood, or inner wood, becomes infiltrated with gums, resins and other materials. This makes it more resistant to moisture flow; therefore the heartwood usually requires longer drying times than sapwood. Sapwood and heartwood will affect the drying curves for each wood species. For more information on the differences visit http://www.wagnermeters.com/sapwood-and-heartwood.php.
A wood’s MC is also a dynamic exchange between the wood itself and the surrounding air. When the relative humidity (RH) in the air rises, wood absorbs moisture from the air; when the RH falls, wood releases moisture into the air. This occurs naturally, and it occurs throughout a wood product’s life span even after it has been harvested and kiln-dried for human use. Wood producers, builders and consumers need not fret over such an organic, natural process, but a thorough knowledge of it will guarantee success with wood in all sorts of product applications.
The key to wood strength and performance over time is to dry the wood appropriately to its optimum MC depending upon the end product’s service conditions and the end product’s installation destination.
There's Kiln-Dried Wood
Wood in "green" condition must be kiln dried in order to be used as construction grade lumber for building purposes. Lumber production is a complex process in which green timber is sawn, dried and processed. The natural air drying of lumber can be a long process, so oftentimes lumber will be kiln dried to speed the process along.
Kiln drying is basically a process of placing sawn lumber into kilns where heated air is circulated and the temperature and RH of the kiln is controlled for the purpose of reaching the wood’s equilibrium moisture content (EMC): a balance between the MC of the wood, and the RH of its surrounding environment, depending upon the end wood products application specifications. Once the EMC is achieved, a wood's MC can vary with slight changes in the RH of the surrounding environment without jeopardizing the strength and structural integrity of the end wood product.
Lumber producers deploy expansive and expensive wood MC control systems at all phases of wood production. Kilns are an integral part of the wood’s MC measurement and management process, as the kiln-drying procedure is where the green lumber is dried to its optimum EMC.
There's a Moisture Meter to Measure It
A wood moisture meter is crucial in establishing and maintaining healthy wood MC levels at each stage of lumber production.
A wood moisture meter is a tool which measures the wood’s MC. As green wood circulates for processing in a mill, in-kiln and inline MC systems measure and document the wood’s MC and track the efficiency of the kiln drying process. Professionals carefully monitor and control the process to optimize the harvest. Kiln operators and quality control personnel deploy hand-held wood moisture meter products to conduct as many spot-checks as needed to verify the mill’s kiln-drying efficiency.
Ecology is merging with forestry in the modern era to make MC measurement and control an ongoing matter of wood maintenance. Wagner Meters, a family-run industry leader in MC measurement technology, has developed several wood moisture meter products to assist industry specialists, wood flooring installers and owners and hobbyists in protecting their investments.
As the world awakens to its own nature, wood moisture meter technology has advanced greatly. Wagner Meters features pocket size digital and analog styles of its wood moisture meter products. Now there's a cost-effective, reliable wood moisture meter to suit any wood measurement application goal.
Line of Wagner Moisture Meters
Wagner manufactures moisture meters for three general categories within the wooden products industry – flooring, woodworking, and forest products. The complete Wagner line of moisture meters includes in-line and in-kiln moisture measurement systems and hand-held meters, all made in the U.S.A. for notable accuracy. Wagner is known for its “sweet-spot” technology. Its IntelliSense™ technology allows accurate readings deep in the wood, unaffected by surface moisture
Wagner moisture measurement tools for flooring include the innovative Rapid RH and complete MMC line of products to accurately evaluate moisture content in wood, concrete and other building materials. The MMC line of moisture meters includes the MMC220 extended range moisture meter, the MMC205 digital shopline moisture meter, the MMl1100 data collection moisture meter, and the MMC210 digital proline moisture meter.
Wagner’s hand-held meters give accurate moisture reading without marring the surface of the wood. This makes them particularly useful for wood-working projects. You can scan even large boards from end to end in seconds, using the rugged L-600 series of hand-held moisture meters (L601-3, L620, and L622).
You can reach deep into stickered units of lumber with Wagner’s L-722 stack probe and take accurate moisture readings without the danger of broken pins. Wagner’s LDS200 green sort lumber system is a non-contact method of decreasing drying times, tightening moisture contents, and increasing lumber grade in your mill by sorting your lumber into groups that will dry more uniformly. The MC4000 in-kiln moisture measurement system utilizes state of the art electromagnetic wave technology for in-kiln moisture measurement. Whether your company is a primary lumber mill or a secondary wood products operation, the Omega in-line moisture measurement system can be your most important moisture measurement and analysis tool.
For more detailed information on the Wagner line of moisture meters and how they can meet your needs, contact Wagner by calling 800/581-2963 or see product information on www.wagnermeters.com.