- Author
- Holmes, C. A.
- Title
- Correlation of ASTM Exposure Tests for Evaluating Durability of Fire-Retardant Treatment of Wood.
- Coporate
- Forest Products Lab., Madison, WI
- Report
- FSRP-FPL-194, 1973, 12 p.
- Distribution
- Available from National Technical Information Service
- Keywords
- wood | fire retardant treatments | exposure | durability | plywood | test methods | flame spread
- Abstract
- A cooperative study was carried out to determine the equivalency of two alternate methods of exposure testing described in ASTM Standard D 2989-70T, "Tentative Methods of Test for Durability of Fire-Retardant Treatment of Wood." Matched specimens of 5/8-inch Douglas-fir plywood, pressure treated with leach-resistant and nonleach-resistant fire-retardant chemical systems, were exposed by methods A and B of the standard and fire tested in the 25-foot and 8-foot tunnel furnaces. Method A is the 12-week "rain test" exposure in use at Underwriters' Laboratories, Inc., and method B is the 1,000-hour accelerated weathering chamber apparatus in use at the Forest Products Laboratory. The two methods differ in the cycling time of water-spray and drying. However, the percent water pick up by treated specimens during the water-spray periods of the exposure cycle was approximately the same for both methods, 20 to 24 percent of initial weight. During the drying periods, specimens under method A were brought back to initial weight or below, while speciments under method B retained about an additional 6 to 8 percent water. The flame-spread results on the treated specimens by both fire test furnaces did not show any significant difference in the leaching effect between the two exposure methods. Thus overall exposure by either method can provide conditions that differentiate between leach-resistant and nonleach-resistant treatments.