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Arch Dust Suppression Handbook 2. Ventilation Systems: When control of respirable dust is required or the material handled cannot tolerate the addition of moisture, a well-designed ventilation system may be in order. These systems extract the dust as it is created and filters it through conventional collectors such as fabric filters or scrubbers. Ventilation systems are effective for certain types of materials and applications. They are generally more expensive and power consumptive than the alternatives though they often may be the only alternative because of their rated efficiency. 3. Garden Hose Technology: By far the most common instruments used in the control of fugitive dust are the garden hose \ hardware store nozzle variety. They're cheap, available anywhere, and will do the job if the source material can be thoroughly wetted without causing a problem. If, in handling the material, dry surfaces are created (such as by crushing) then dust will be released. If freezing conditions exist, the material will freeze. If the wet material is sticky, the abundance of water may cause clinging to conveyors or tires creating housekeeping and maintenance problems. Various unpublished studies have found that wear parts are significantly affected by the abundance of water. The idea of "more is better" is a mistake when considering the high cost of wear parts compared to the investment of an efficient fogger system for dust control. 4. Agglomerative Dust Control, the ARCH Fogger System: Agglomerative dust suppression is a cross between a ventilation / filtration system and the garden hose technology. It works on the principal that small particles of water will "come together" with small particles of solid matter (dust), forming larger and heavier particles that will settle by gravity. Like a garden hose spray because it uses water and no chemicals; similar to the ventilation system because it doesn't saturate the material; and it separates dust by the filtration process created from the fog. 5. Wind Fences: When the effect of wind is the cause of (or a contributing factor to) a fugitive dust emission problem, the only solution may be to isolate the dust source from the wind. Conventional design practice would utilize a building for this purpose. Using a woven polyester fabric mounted on support posts, the fence is extremely effective in reducing downwind velocity. This process reduces the amount of dust picked up and transported by the wind. EPA and other independent studies have used designed fence systems in conjunction with other fugitive emission technologies. BACKGROUND to Agglomerative Dust Control Agglomerative dust suppression technology was developed in the early 1970's with the commercial availability of atomizing nozzles that could produce liquid particles within 10 to 30 microns. The Royal Institute of Stockholm did most of the early work in Scandinavia. This was a direct result of the stringent dust control laws of Sweden. In the mid to late 1970's, the Page 4