Applied Research   Laboratory Testing   Physical

Thickness Swell and Water Absorption

Test Method: Modified ASTM Standards, D 1037 - Standard Methods Of Evaluating the Properties of Wood-Base Fiber and Particle Panel Material, 1989, pp. 167-196.
3 x 3 inch x board thickness (76 x 76 mm) specimens are measured, weighed and placed under a grid one-inch below the water-line in a water bath maintained at approximately 64F (18C). After two hours and 24 hours the specimens are removed from the water, weighed, and the thickness is measured. The percent change from the original thickness represents the thickness swell, and the percent weight change from the original weight represents the water absorption. Specimens are air-dried for at least two weeks, and measured again to determine non-recoverable thickness swell.

Specific Gravity, Density, and Moisture Content Definitions

Test Method: ASTM Standard: D 2395 - 93, Standard Test Methods for Specific Gravity of Wood and Wood-Base Materials.
Specific gravity and moisture content are two factors having a great affect on the physical and mechanical properties of wood. As such, these variables must always be considered when wood is tested, or used to evaluate the efficacy of an experimental preservative. Wood selection for preservative testing is often determined by the number of growth rings per inch, or by a specific weight range to minimize specific gravity (and density) as a variable. Moisture content is also controlled, either by ovendrying the specimens, or by conditioning them in a climate-controlled room for a specified period of time.

Specific Gravity:The weight of any given volume of a substance divided by the weight of an equal volume of water.

Density:The weight of a substance divided by its volume.

Moisture Content:The weight of water contained in a substance expressed as a percentage of the mass of the dry weight of the substance.