Document nN98kDgkxqpRz0o2p6VKE4d08

FILE NAME Brakes BRK DATE 1973 Feb DOC BRK042 DOCUMENT DESCRIPTION EPA Report - Control Techniques for Asbestos Air Pollutants OFeE Nemeeslns reMeroe, awe ioMerman, e Sugtems OK cabaKlyeme he reN,epean aee,ae CeamaNeyn rn ComerNoren: i OK Com onspoen Oe cmoan I omar (aan NOEframes a,rene oeCpa Me PEN +) ae +, be gy, a NeeMe CUeee eR te pow TECHNIQUES TECHNIQUES CONTROL TECHNIQUESPOLLUTANTS . re oo i ) _ oy e CONTROL TECHNIQUES | - FOR ASBESTOS AIR POLLUTANTS { 1 | ENVIRONMENTAL PROTECTION AGENCY Office of Air and Water Programs Office of Air Quality Planning and Standards : Research Triangle Park North Carolina 27711 February 1973 of Documents U.S. Government Printing Office Washington D.C. 20402 For sale by the Superintendent average of 3 pounds of asbestos per set.35 The yearly number of sets of replacement brake linings can be gauged by considering that | trillion vehicle were traveled in 1968 in the United States and that an average lifetime for brake linings is 27.500 miles Further it is estimated that between one and two sets of containing clutch facings are consumed during the average vehicle equipped clutch the lifetime of with a manual Figure 3-29 Dust capture device fitted to portable drill.33 Courtesy of Manville readily supplied by an industrial vacuum cleaning system The prompt cleanup of trimmed wastes broken material fragments and spillage from containers minimizes further disintegration airborne entrainment and creation of secondary emission sources such as dispersion from workers clothing Tightly sealing waste containers should be conveniently accessible vacuum cleaning devices are recommended for the removal of The principal types of asbestos containing friction products are molded woven or extruded Chrysotile asbestos 30 to 60 percent of product is mixed or asbestos cloth is impregnated with asphalt drying oil synthetic resin or rubber Chrysotile is preferred over crocidolite because of better resistance and heat metal surfaces less severe wear against Friction materials materials containing asbestos are also used in the pads of disk brakes for clutch facings in automatic transmissions and for small particles and dust In the absence of brake blocks for heavy trucks Se vacuum cleaners the watering of wastes prior moving equipment elevators and other mn to sweeping and shoveling can be an effective industrial applications The percentage of gn control measure The disposal of domestically produced motor vehicles tiem rte containing wastes is discussed in equipped with disk brakes has increased from Ramee weber Section 3.5 2.9 percent in 1966 to 11.2 percent in In an effort to control emissions from the 1968. Additional increases in the fraction epntram opening and dumping of bags of asbestos of vehicles equipped with disk brakes will insulating cement or loose dry insulating affect the types of operations carried out materials and also from the subsequent during replacement of motor vehicle brake mixing of those materials with water to form linings a a slurry it has been proposed that mixing 3.4.3.1 Emissions take place within the shipping bag.34 Water is injected into a polyethylene bag through a narrow sleeve and the contents are kneaded into a wet mixture prior to removal from the During the brake linings on and trimming replacement of drum motor vehicles the grinding operations required for container 3.4.3 Friction Products The automotive and heavy equipment industries are the major users of asbestos friction products.19 In 1968 new passenger and commercial motor vehicles manufactured individual fitting are potential emission sources assumed asbestos of asbestos loss of 0.05 content to fibers Based on an percent of brake lining the atmosphere during grinding and fitting asbestos emissions from the fitting of brake linings were estimated to total 190 tons in 1968.23 The analogous in the United States accounted for 9,913,000 grinding operations that are performed in sets of brake linings which contained an friction product manufacturing plants are 3-48 known to yield asbestos physical form to those associated with adverse fibers of similar that have been health effects.36 Since disk brake pads are not contour ground as drum brake linings are the current trend to disk brakes should reduce asbestos emissions As brake linings and clutch facings rub against their mating bearing surfaces in the course of usage particles of the lining material are abraded These particles can be partially trapped in the housings of manual clutches and in brake drums the remainder can be emitted directly into the atmosphere The latter emissions are treated as a problem in mobile source air pollution control and are outside the scope of this study Because extremely high temperatures can result from the sliding of brake linings and clutch facings against the corresponding mating surfaces the question arises as to whether the asbestos that would otherwise be contained in the particles released from the friction materials has been thermally degraded One set of tests of automobile bus and truck drum brakes and clutches has shown that except under conditions ofvery severe usage the majority of the freed asbestos has been thermally degraded.36degrade.36 For example most of these samples of released material from automotive brakes contained less than 1 percent asbestos as compared with 50 percent in formulation 36. the This original lining residual amount however is not inconsequential relative to air pollution control Further tests are needed to evaluate emissions from type brakes In the course of servicing and overhauling motor vehicle brakes and manual clutches the accumulated containing dust is frequently dislodged from drums and housings by directing a compressed air jet against the deposits.37 Depending upon the servicing location this results in airborne asbestos emissions either to the work space or directly to the atmosphere 3.4.3.2 Control Techniques Asbestos emissions accompanying the grinding and trimming of replacement brake installation linings at the site of and fitting are presently uncontrolled at most sites The incorporation of volume velocity capture hoods see Section 3.3.2 into grinding equipment is feasible and can provide an effective method for controlling these emisions.18 emissions.18 The removal of asbestos dust from brake drums and from housings of manual clutches by the compressed method produces uncontrolled emissions The dislodging and collection of this waste material at the source by operating a brush connected to an industrial vacuum cleaner as- a volume velocity dust capturing and collecting device has been evaluated.37 evaluated.37 This control technique reduced personal exposure to fibers larger than 1 micrometer in diameter by approximately 75 percent 3.5 DISPOSAL OF ASBESTOS WASTE MATERIALS Potential waste materials containing asbestos are produced during the mining and milling of asbestos ores and in the manufacture and use of containing products The wastes ranges form of asbestos in these from asbestos bound in relatively large rock masses or in such manufactured products as asbestos pipe and reinforced plastics to diameter readily dispersed asbestos fibers that are removed by cleaning devices or are produced in the milling of asbestos ores In mining operations large quantities of asbestos ore are sometimes rejected at the mine site because either the concentration or the form of dispersal of the asbestos renders recovery uneconomical The lower limit for profitable recovery of chrysotile asbestos from massive deposits of serpentine rock is a concentration of approximately 3 percent 3-49