Applied Research   Laboratory Testing   Biological

Soil Bed Decay

Test Method: AWPA Standard, E14-94 -Standard Method Of Evaluating Wood Preservatives In A Soil Bed.

Soil bed stake decay testing is an effective means for relatively quickly evaluating the efficacy of wood preservatives in wood under severe ground contact conditions. Wood foundations, utility poles, building poles, and land or fresh water pilings may undergo similar, if less severe exposures. Treated (and untreated) wood stakes are inserted half-way into the soil bed. At specified time intervals the stakes are removed and rated for severity of decay and insect damage. They are placed back into the soil bed after each rating until a light bending force causes them to fail.
Decay stakes in a soilbed. Also shown is water-spraying apparatus.

Soil Block Decay

Test Method: AWPA Standard, E10-91, Standard Method of Testing Wood Preservatives by Laboratory Soil-Block Cultures, 1999. Also, ASTM D1413 and WDMA TM-1.

The soil block decay test is a highly standardized means for evaluating wood preservatives under tightly controlled laboratory conditions, including control over the type and number of decay fungi species to which the specimens will be exposed. Small soil block specimens are dried, weighed and inoculated with decay fungi in a jar containing soil, which is then maintained at approximately 80F (27C) and 80% RH. After a specified time period the soil block specimens are removed, dried and weighed to determine the weight loss due to decay.

Mold Resistance

Test Method 1: MTU developed (Click link for detailed test method)

This test evaluates the resistance or susceptibility of wood materials to surface mold-stain fungi. Treated (and untreated) specimens are sprayed with inoculum and placed horizontally on a screen, which is enclosed inside a container and maintained at 80F (27C). The bottom of the container is covered with water to achieve ~100% RH. At specified time intervals the top surface of each specimen is rated for degree of mold coverage.

Test Method 2:Proposed Standard; AWPA EXX-XX Standard Method of Evaluating Resistance to Growth of Mold on the Surface of Wood Products.

This test evaluates the resistance or susceptibility of wood-based materials to surface mold-stain fungi. Test samples are suspended above potting soil in a chamber. The soil is above 3 inches of heated water, which keeps the air temperature at 25 degrees C and the relative humidity at 90%. Specimens are not directly inoculated with fungi, but two weeks prior to introducing the samples an inoculum suspension is added to the soil. Samples are kept in the chamber and are rated weekly for a total of eight weeks.