1、Designation: E 1132 06Standard Practice forHealth Requirements Relating to Occupational Exposure toRespirable Crystalline Silica1This standard is issued under the fixed designation E 1132; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONSilicon dioxide (silica, SiO2) is encountered in nature and industry in a wide variety of forms. Th
3、eserange from essentially anhydrous types with or without a very high degree of crystallinity, to highlyhydroxylated or hydrated types which are amorphous by x-ray diffraction examination. Crystallinesilica2exists in a number of forms or polymorphs. The three major forms, quartz, cristobalite, andtr
4、idymite, pertain to this practice. Quartz (or alpha quartz) is the more common form encountered asairborne particulates. Two of the polymorphs, cristobalite and tridymite, are formed at elevatedtemperatures and are much less common in nature, but might be encountered in several occupationswhere sili
5、cas are fired (calcined) at high temperatures.3These silica materials have a broad range ofphysical and chemical properties.1. Scope1.1 This practice covers a description of several actions thatshould be taken to reduce the risk of harmful occupationalexposures to humans in environments containing r
6、espirablecrystalline silica. This practice is intended for, but not limitedto, industries regulated by the U.S. Mine Safety and HealthAdministration (MSHA) and the U.S. Occupational Safety andHealth Administration (OSHA). A separate practice, designedfor the unique conditions of the construction ind
7、ustry is underdevelopment. While this practice was not designed specificallyfor construction, it can be applied and may be beneficial, to theextent feasible and practical, pending adoption of a construc-tion industry standard.1.2 Nothing in this practice shall be interpreted as requiringany action t
8、hat violates any statute or requirement of anyfederal, state, or other regulatory agency.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practice
9、s and determine the applica-bility of regulatory limitations prior to use. It is the responsi-bility of the user to consult all material safety data sheets andlabels pertaining to any hazardous materials used in thisstandard.2. Referenced Documents2.1 ASTM Standards:4D 4532 Test Method for Respirabl
10、e Dust in WorkplaceAtmospheres2.2 ANSI Standards:5ANSI/AIHA Z9.2 Fundamentals Governing the Design andOperation of Local Exhaust SystemsZ88.2 American National Standard Practice for RespiratoryProtection2.3 Code of Federal Regulations:629 CFR 1910.94, Ventilation29 CFR 1910.134, Respiratory Protecti
11、on29 CFR 1910.1000, Air Contaminants29 CFR 1910.1200, Hazard Communication30 CFR 47, Hazard Communication30 CFR 56, Title 30, Subpart D, Air Quality, Radiation, andPhysical Agents (MSHA)1This practice is under the jurisdiction of ASTM Committee E34 on Occupa-tional Health and Safety and is the direc
12、t responsibility of Subcommittee E34.16 onSilicas.Current edition approved Dec. 1, 2006. Published January 2007. Originallyapproved in 1999. Last previous edition approved in 1999 as E 1132 - 99a.2Smith, Deane K., Opal, cristobalite, and tridymite: Noncrystallinity versuscrystallinity, nomenclature
13、of the silica minerals and bibliography, Powder Diffrac-tion, Vol 13, 1998, pp. 118.3Miles, W. J., Crystalline silica analysis of Wyoming bentonite by X-raydiffraction after phosphoric acid digestion, Analytical Chemistry Acta, Vol 286,1994, pp. 97105.4For referenced ASTM standards, visit the ASTM w
14、ebsite, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, h
15、ttp:/www.ansi.org.6Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.42 C
16、FR 84 Title 42, Part 84, Approval of RespiratoryProtective Devices, Tests for Permissibility, Fees2.4 NIOSH Publications:7Manual of Analytical Methods, 4th Ed., DHHS (NIOSH),Publication No. 94-113, August 1994Method 7500 for Silica, Crystalline, Respirable (XRD)Method 7601 for Silica, Crystalline Vi
17、sible AbsorptionSpectrophotometryMethod 7602 for Silica, Crystalline (IR)Method 7603 for Coal Mine Dust by IR2000 Guidelines for the Use of ILO International Classifi-cation of Radiographs of Pneumoconioses2.5 Other References:National Industrial Sand Association, Occupational HealthProgram for Expo
18、sure to Crystalline Silica in the Indus-trial Sand Industry, March 1997American Thoracic Society, Standardization of Spirometry3. Significance and Use3.1 These practices and criteria were developed for occupa-tional exposures. They are intended to (a) protect againstclinical disease from exposure to
19、 respirable crystalline silica,(b) be measurable by techniques that are valid, reproducible,and readily available, and (c) be attainable with existingtechnology and protective practices.4. General Requirements4.1 Occupational Exposure Limits (OEL):4.1.1 Permissible Exposure Limit (PEL) established b
20、y U.S.Occupational Health and Safety Administration (OSHA) Gen-eral Industry (see 29 CFR 1910.1000)Workers shall not beexposed to respirable dust containing 1 % or more quartzexceeding 10/(% quartz + 2) mg/m3as an 8-h time weightedaverage in any 8-h work shift of a 40-h work week or, for totaldust (
21、respirable plus non-respirable), 30/(% quartz + 2) mg/m3.The PELfor respirable cristobalite and tridymite is one-half thevalue for quartz.4.1.1.1 PEL (mg/m3) (respirable fraction):10 4 % quartz 1 % cristobalite 3 2! 1 % tridymite 3 2! 1 24.1.1.2 PEL (mg/m3) (total dust):30 4 % quartz 1 % cristobalit
22、e 3 2! 1 % tridymite 3 2! 1 24.1.2 PEL established by U.S. Mine Safety and HealthAdministration (MSHA) (non-coal) (see 30 CFR 56.5001)Workers shall not be exposed to respirable dust containing 1 %or more quartz exceeding the PEL as determined for a timeweighted 8-h workday and 40-h workweek based on
23、 thefollowing formula: PEL = 10/(% quartz + 2) mg/m3. The PELfor respirable cristobalite and tridymite is one-half the value forquartz.4.1.3 Examples of other OELs are provided in AppendixX2.4.1.4 Employers shall determine the appropriate OEL fortheir operation, but in no case shall the OEL be less
24、stringentthan the applicable government limit.4.2 Exposure Assessment and Monitoring:4.2.1 Risk can be assessed qualitatively based on MaterialSafety Data Sheets (MSDS), prior information, likelihood ofdust generation, proximity of airborne dust to workers, natureof the industrial process (example:
25、wet worklow risk; dryworkhigher risk), and location of workers (example: controlroom). Note that the absence of visible dust is not a guaranteeof lack of risk.4.2.2 Initial sampling of representative workers exposuresshall be made to characterize the exposure and its variability, todetermine complia
26、nce with standards given in 4.1, and toestablish a baseline exposure level in all areas where workersare or may be exposed to silica. Initial task sampling would benot required for short duration or transient tasks, tasks wheretimely sampling results would not be available, representativeconcentrati
27、ons are already known, and proven task protectionis in place. Exposure sampling should be periodic, and shouldoccur frequently enough that a significant and deleteriouschange in the contaminant generation process or the exposurecontrols is not permitted to go undetected. This is particularlytrue for
28、 areas or operations where conditions can changedramatically within a short span of time.4.2.3 When sampling is conducted, workers with a highrelative risk of dust exposure should be sampled first. Samplingshould then progress toward those individuals with low expo-sure risk. High relative risk can
29、be assigned to any area wherethe process involved may generate respirable crystalline silicaparticles and persons are potentially exposed for most or all ofa work shift.4.2.4 Employers shall sample occupational exposures ofworkers exposed to respirable crystalline silica and maintainrecords of such
30、sampling.4.2.5 For workers with regular exposure to high silicaconcentrations that are placed inside of supplied air respiratorsor ventilated enclosures, such as in sandblasting, samplingshould be conducted inside of the control device to determineemployee exposure. The sampling line shall not inter
31、fere withthe fit of the respirator. Consultation with the respiratormanufacturer may be necessary to achieve the above require-ment.4.2.6 In areas where overexposures are persistent, a writtenExposure Control Plan shall be established to implementengineering, work practice, and administrative contro
32、ls toreduce silica exposures to below the OEL, or other electedlimit, whichever is lower, to the extent feasible. A root causeanalysis should be conducted for all exposures in excess of theOELthat cannot be accounted for. Root cause analysis involvesinvestigating cause(s) for the excessive exposure,
33、 providingremedies, and conducting follow-up sampling to document thatexposures are below the OEL.4.2.7 Sampling shall be done at a frequency that providesreliable information for determining an appropriate controlstrategy. Sampling information and recommended frequency issummarized in Table 1.4.2.8
34、 Because people have different work habits, samplingshould be rotated among different employees performing thesame task with a goal of sampling each individual at least onceevery three years or use statistical random sampling.7Available from National Institute for Occupational Safety and Health, Div
35、isionof Physical Sciences and Engineering, 4676 Columbia Parkway, Cincinnati, OH45226.E11320624.2.9 Measurement of worker occupational exposures shallbe within the workers breathing zone and shall meet thecriteria of this section. Such measurements should be repre-sentative of the workers customary
36、activity and should berepresentative of workshift exposure. Area sampling may beused to characterize exposures and identify effective controlswhen appropriate to the circumstances.4.2.10 Respirable dust samples are to be collected accordingto accepted methods. Refer to Test Method D 4532 and seeAppe
37、ndix X1 for an example.4.2.11 Sampling data records shall include employee iden-tification, a log of the date and time of sample collection,sampling time duration, volumetric flow rate of sampling,documentation of pump calibration, description of the sam-pling location, analytical methods, and other
38、 pertinent infor-mation. See Figs. X1.1-X1.3 for example sampling record,calibration forms, and employee notification of dust samplingresults.4.2.12 Samples for silica analysis should be analyzed by anAIHA-accredited laboratory.4.3 Observation of Exposure Monitoring:4.3.1 Employee ObservationThe emp
39、loyer shall provideaffected employees or their designated representatives anopportunity to observe any monitoring of employee exposureto silica and provide an explanation of the sampling procedure.4.3.2 Monitoring ProceduresWhenever observation ofthe monitoring of employee exposure to respirable cry
40、stallinesilica requires entry into an area where the use of respirators,protective clothing, or equipment is required, the employershall provide and ensure the use of such personal protectiveequipment and shall require compliance with all other appli-cable safety and health procedures.4.3.3 Monitori
41、ng ResultsObservers shall be entitled to:4.3.3.1 Receive an explanation of the measurement andanalytical procedures,4.3.3.2 Observe all steps related to the monitoring of respi-rable crystalline silica performed at the place of exposure, and4.3.3.3 Record the results obtained for any real-time instr
42、u-ments and/or obtain copies of printouts or downloadable datafiles from those instruments. They should also be entitled toreceive copies of the results when returned by the laboratoryand to obtain explanations if they have questions about thedata.4.4 Methods of Compliance:4.4.1 The methods listed b
43、elow are applicable where com-pliance is required because of personal exposures exceedingthe OEL or a company-adopted exposure limit.NOTE 1One half the exposure limit is frequently used by employersas a warning since excursions above the exposure limit are possible.4.4.2 Engineering Controls:4.4.2.1
44、 Use of properly designed engineering controls is themost desirable approach for controlling dust from crystallinesilica-containing materials.4.4.2.2 Adequate ventilation or other dust suppressionmethods shall be provided to reduce respirable crystalline silicaconcentrations to below the OEL, where
45、feasible.4.4.2.3 Enclosed workstations, such as control booths andequipment cabs, designed for protection against respirablecrystalline silica dust, shall be under positive pressure andprovided with clean make-up air. Re-circulation of air is notpreferred; however, properly designed and maintained r
46、e-circulation systems are acceptable. Re-circulated air insideenclosed workstations should be in accordance with NIOSHguidance.4.4.2.4 Engineering design of equipment shall include,where feasible, provisions to reduce exposure of workers torespirable crystalline silica dust to the OEL or below. Ifve
47、ntilation systems are used, they shall be designed andmaintained to prevent the accumulation and re-circulation ofrespirable crystalline silica dust in the working environment(see ANSI Z9.2). If wet suppression systems are used, spraynozzles and associated piping shall be maintained to ensurethat ad
48、equate wetting agent is applied where needed to controlrespirable crystalline silica dust. If hand-held or stationarytools are cut, grind or drill silica containing materials theyshould be designed and/or used in a manner to reduce dustexposures.TABLE 1 Sampling InformationCondition ActionQualitativ
49、e assessment Based on evaluation of process andmaterials used and visual review ofdust generation potential.Initial sampling Conducted at representative jobfunctions starting with assumed highestdust exposure levels. Results used toestablish sampling plan.Sampling results are below one halfthe OELNo periodic sampling necessary butadditional samples may be required dueto process changes.No OEL overexposures were found,but exposures exceed one half theOELThese noted locations are to beincluded in a sampling plan. Noted jobfunctions should be sampled at leastannually
