Effect of Coating Systems on the Vaporization of Pentachlorophenol from Treated Wood

Specimens of southern pine treated with pentachlorophenol (penta) in mineral spirits (dip treatment), penta in P9 type A oil and penta in methylene chloride (pressure treatments) were used to evaluate the efficacy of different types of coatings in suppressing the vaporization of penta from treated wood. The clear film-forming coatings, such as polyurethane and alkyds, were typically greater than 90 percent effective for specimens dip treated with penta in mineral spirits. Two-component (epoxy type) pigmented coatings were effective on specimens treated with penta in P9 type A oil. Coatings that wre not compatable with P9 oil were the least effective in preventing penta vaporization. All coatings tested on specimens treated with penta in methylene chloride were greater than 90 percent effective in reducing vaporization