Applied Research  Field Tests  Above Ground Exposure

Lap Joint Exposure

Test Method: AWPA E16-98

3.5 x 11.5 inch (89 x 292 mm) Lap-joints are exposed horizontally in above-ground racks and inspected twice yearly for decay and insect damage. This is intended to simulate a deck, or similar construction. Jointed specimens consist of two overlapping parts joined together with a nylon bolt-spring-nut assembly. This allows the two halves to be pulled apart for joint inspection without loosening the nut. Here is shown a lap-joint exposure rack full of specimens. Click here to view a detailed assembly drawing of a typical lap-joint.

Depletion Rate Specimens

Test Method: MTU Test Method

3.5 x 3.5 inch (89 x 89 mm) depletion rate specimens are exposed in above-ground racks. A number of specimens are pulled and analyzed for preservative content at specified intervals to determine the rate of preservative depletion.

Termite Exposure Field Test

Test Method: MTU Test Method

The MTU Termite Exposure Test Site located near Hilo, Hi USA provides a severe challenge because of its very high Coptotermes formosanus population. 1.875 x 3.5 inch (48 x 89 mm) wood (or composite) specimens are arranged on a 4 inch (102 mm) high platform so that they are in contact with aspen feeder stakes, which in turn contact aspen bait stakes driven into the ground to draw termites to the specimens. This test method is designed to mimic sill plates in contact with a concrete foundation. The specimens are examined and rated for termite damage at specified time intervals. The arranged termite specimens are covered with a treated wooden box to protect them from the weather. Click here to view a detailed drawing of a termite box.

Siding Exposure

Test Method: MTU Test

8x12 inch (203 x 305 mm) siding specimens are mounted unto a 4 x 4 foot (1.22 x 1.22 m) square exposure rack, which is positioned either vertically, or 45 to the ground. A 45-angle siding exposure rack is shown here. Maximum weathering is achieved using this orientation.
90 SIDING EXPOSURE RACK Here (left side) are shown siding exposure racks set up at a 90 angle to the ground (vertical). This simulates siding exposure as typically oriented.