What is balancing moisture content and why is it important?
Define EMC
The term 'EMC' is an acronym for Equilibrium Moisture Content. This term is commonly used for "hygroscopic" materials, such as wood. The term 'hygroscopicity' refers to a material that absorbs or releases moisture from the atmosphere until it reaches equilibrium with the surrounding environment.
For the woodworking industry, balancing moisture content is defined as the point at which wood stops absorbing moisture or releases it into the surrounding air. At this point, it is said that the material has reached equilibrium with the atmosphere.
So, why is EMC important for carpenters, flooring contractors, and repair professionals?
Why EMC is Important
For those who frequently use wood products, there are several reasons why it is important to know that wood meets its EMC, which will be affected by the average moisture content of the area where the wood is located. Used.
Firstly, when wood absorbs or releases moisture, it expands or contracts. The more water absorbed or released, the more severe the expansion/contraction of wood products.
For example, suppose you are installing a set of wooden flooring boards on a construction site, with an average moisture content of 11%, indicating a humid environment. However, the initial adaptation of wooden boards to areas with an average moisture content of 6% indicates a drier environment.
When exposed to a "humid" environment, the wooden board will begin to absorb moisture from the air and expand slightly. This may cause the installed wooden boards to start cupping or warping, as their expanding mass pushes other wooden boards - causing damage to the floor and damaging its appearance.
Check the average moisture content of EMC and structure/area in the wood
So, how do you check the EMC of wood? A good method is to check the% MC of wood multiple times within a few days in the installation environment. Using a wood moisture meter, read the moisture content of the wood every few hours until the% MC reading stops changing.
Based on the original moisture content of the wood, the temperature of the new environment, and the relative humidity of the area, it may take several days for the wood to fully adapt to the specific environment. Generally speaking, the more significant the difference between the moisture content of wood and its EMC point, the longer it takes to fully adapt to the environment.
Now, you may want to know how to determine the average water content of the area. If you look at the map of the United States here, you can see that the average water content in most parts of the United States is 8%, while the average water content in some coastal areas is 11%, while the drier desert areas are close to 6%.
Although this can give you a rough idea of what will happen, it may be necessary to obtain more detailed information by conducting RH measurements on the area where you installed the wood.
To obtain a relative humidity (RH) reading, you need a temperature and humidity meter that can measure the temperature and humidity conditions in a large workplace. The RH reading you obtain from the hygrometer can help you understand what EMC should be for on-site wood products.
For example, if your RH reading is between 58% and 63% RH, then your average moisture content is approximately 11%.
Detailed humidity information (such as RH and EMC) can help you with carpentry, floor installation, and repair work
