Moisture content is equal to what percentage of the equilibrium moisture content?

The correct choice indicates that moisture content is equal to 18% of the equilibrium moisture content, which aligns with typical values found in the woodworking and finish carpentry industry. The equilibrium moisture content (EMC) is the moisture level at which wood neither gains nor loses moisture to the surrounding environment. It varies depending on the temperature and relative humidity of the air.

A moisture content of 18% is often considered a standard for many wood species used in furniture and cabinetry. This level ensures that the wood is neither too dry, which can lead to cracks and splits, nor too moist, which can encourage fungal growth and warping.

Values like 10%, 15%, and 20% represent different scenarios, such as certain wood species or conditions that may not adhere to the average EMC typically used in the industry. Therefore, recognizing 18% as the industry standard reinforces the importance of maintaining appropriate moisture levels to ensure the durability and stability of wood products in various environmental conditions.