Smoke and toxic species analyses from controlled combustion of wood impregnated with guayule resin

Abstract

Dominant commercial treatments currently used for wood preservation are pentachlorophenols (PCP), creosote, and chromium copper arsenicals. These wood preservatives present many studied and documented environmental and toxicological problems with both use of the products themselves, and with the production of secondary reaction contaminants. Furthermore, several of these preservatives are considered priority pollutants according to the U. S. Environmental Protection Agency and are heavily regulated. The need for an environmentally benign combined fire/rot retardant treatment for wood that will effectively reduce both fire and decay is clearly evident. Guayule resin, a co-by-product during rubber extraction from the guayule shrub, is being explored by us as a natural, biodegradable wood rot and fire retardant with potential commercial applications. Wood impregnated with guayule resin has survived over eight years in tropical soils, free of rot, decay, and insect infestations. This study qualitatively analyzed the treated and untreated wood samples for ignitability, flame spread, toxic fumes, and smoke generation. Ignitability of the wood sample of fixed geometry was quantified by measuring the time required for ignition of treated samples vs. untreated samples. Flame spread was measured after ignition with a propane flame by a simple stopwatch-ruler technique. Smoke mass was determined in an Arapahoe Smoke Chamber as per ASTM D-4100. Analysis of the fumes involved continuous CO, C02, NOx, SOx, and 02 analyses using the Bacharach Instrument Model 300. Cascade impaction was used to determine the particle size distribution of the smoke and for smoke mass determination. Respirable particles were assessed by utilizing the Anderson 2000 Inc. 1 AFCM Ambient Particle Fractionating Sampler. Inflections of guayule-impregnated and untreated pine are indeed minor with respect to all aspects investigated. Ignition data indicated guayule-impregnated pine did not ignite as quickly as untreated pine. Evidence conveys favorable consideration for further research of wood preservation with guayule resin.