1、Designation: E1132 131Standard Practice forHealth Requirements Relating to Occupational Exposure toRespirable Crystalline Silica1This standard is issued under the fixed designation E1132; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revis
2、ion, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEAppendix X1 editorially corrected in August 2013.INTRODUCTIONSilicon dioxide (silica, SiO2) is encountered i
3、n nature and industry in a wide variety of forms. Theserange 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
4、. The three major forms, quartz, cristobalite, andtridymite, 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 m
5、ight be encountered in several occupationswhere silicas 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 occupati
6、onalexposures to humans in environments containing respirablecrystalline 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, desig
7、nedfor the unique conditions of the construction industry has beendesignated Practice E2625.1.2 Nothing in this practice shall be interpreted as requiringany action that violates any statute or requirement of anyfederal, state, or other regulatory agency.1.3 UnitsThe values stated in SI units are to
8、 be regardedas the standard. No other units of measurement are included inthis standard.1.4 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 practices
9、 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:4D4532 Test Method for Respirable
10、Dust in Workplace At-mospheres Using Cyclone SamplersE2625 Practice for Controlling Occupational Exposure toRespirable Crystalline Silica for Construction and Demo-lition Activities2.2 ANSI Standards:5ANSI/AIHA Z9.2 Fundamentals Governing the Design andOperation of Local Exhaust SystemsANSI Z9.7Z88.
11、2 American National Standard Practice for RespiratoryProtection1This practice is under the jurisdiction of ASTM Committee E34 on Occupa-tional Health and Safetyand is the direct responsibility of Subcommittee E34.16 onSilicas.Current edition approved July 1, 2013. Published July 2013. Originally app
12、rovedin 1999. Last previous edition approved in 2006 as E1132 - 06. DOI: 10.1520/E1132-13E01.2Smith, Deane K., Opal, cristobalite, and tridymite: Noncrystallinity versuscrystallinity, nomenclature of the silica minerals and bibliography, PowderDiffraction, Vol 13, 1998, pp. 118.3Miles, W. J., Crysta
13、lline 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 website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
14、s 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, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
15、 19428-2959. United States12.3 Code of Federal Regulations:629 CFR 1910.94, Ventilation29 CFR 1910.134, Respiratory Protection29 CFR 1910.1000, Air Contaminants29 CFR 1910.1200, Hazard Communication29 CFR 1926.57 Ventilation29 CFR 1926.103 Respiratory Protection30 CFR 47, Hazard Communication30 CFR
16、56, Title 30, Subpart D, Air Quality, Radiation, andPhysical Agents (MSHA)42 CFR 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 f
17、or Silica, Crystalline, Respirable (XRD)Method 7601 for Silica, Crystalline Visible AbsorptionSpectrophotometryMethod 7602 for Silica, Crystalline (IR)Method 7603 for Coal Mine Dust by IRGuidelines for the Use of the ILO International Classifica-tion of Radiographs2.5 Other References:American Thora
18、cic 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 respirable crystalline silica,(b) be measurable by techniques that are valid, reprod
19、ucible,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 by U.S.Occupational Health and Safety Administration (OSHA) Gen-eral Industry (see 29
20、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 (respirable plus non-respirable), 30/(% quartz + 2) mg/m3.The PELfor respirable cristo
21、balite and tridymite is one-half thevalue for quartz.4.1.1.1 PEL (mg/m3) (respirable fraction):10% quartz1% cristobalite 32!1% tridymite 32!12#4.1.1.2 PEL (mg/m3) (total dust):30% quartz1% cristobalite 32!1% tridymite 32!12#NOTE 1Federal OSHA PEL is approximately equivalent to a quartzlevel of 100 g
22、/m3.4.1.2 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 thefollowing formula: PE
23、L = 10/(% quartz + 2) mg/m3. The PELfor respirable cristobalite and tridymite is one-half the value forquartz.4.1.3 Occupational Exposure Limits may vary country bycountry. Please consult the authority in the country, where theoperation exists. Examples of other OELs are provided inAppendix X2.4.1.4
24、 Employers shall determine the appropriate OEL fortheir operation, but in no case shall the OEL be less stringentthan the applicable government limit.4.2 Exposure Assessment and Monitoring:4.2.1 Risk can be assessed qualitatively based on SafetyData Sheets (SDS), prior information, likelihood of dus
25、tgeneration, proximity of airborne dust to workers, nature of theindustrial process (example: wet worklow risk; dry workhigher risk), and location of workers (example: control room).Note that the absence of visible dust is not a guarantee of lackof risk.4.2.2 Where qualitative risk assessment indica
26、tes that apotential risk is present, initial sampling of tasks or represen-tative workers exposures shall be made to characterize theexposure and its variability, to determine compliance withstandards given in 4.1, and to establish a baseline exposurelevel in all areas where workers are or have the
27、potential to beexposed to silica. Initial task sampling would be not requiredfor short duration or transient tasks, tasks where samplingresults would not be timely, representative concentrations arealready known or proved task protection is in place. Conductexposure sampling when needed to detect ov
28、erexposures due tosignificant and deleterious change in the contaminant genera-tion process or the exposure controls. This is particularly truefor areas or operations where conditions can change dramati-cally within a short span of time.4.2.3 Sampling strategy should follow good industrial hy-giene
29、practice.4.2.4 Recordkeeping required under this practice shall bemaintained and made available for review by employees andconsistent with federal or state requirements.4.2.5 For workers with regular exposure to high silicaconcentrations that are placed inside of supplied air respiratorsor ventilate
30、d enclosures, such as in sandblasting, samplingshould be conducted inside of the control device to determineemployee exposure. The sampling line shall not interfere withthe fit of the respirator. Consultation with the respiratormanufacturer may be necessary to achieve the above require-ment.4.2.6 In
31、 areas where overexposures are persistent, a writtenExposure Control Plan shall be established to implementengineering, work practice, and administrative controls toreduce silica exposures to below the OEL, or other electedlimit, whichever is lower, to the extent feasible. A root causeanalysis shoul
32、d be conducted for all exposures in excess of theOELthat cannot be accounted for. Root cause analysis involves6Available 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.7Available from National In
33、stitute for Occupational Safety and Health, Divisionof Physical Sciences and Engineering, 4676 Columbia Parkway, Cincinnati, OH45226.E1132 1312investigating cause(s) for the excessive exposure, providingremedies, and conducting follow-up sampling to document thatexposures are below the OEL.4.2.7 Sam
34、pling 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 Because people have different work habits, samplingshould be rotated among different employees performing
35、thesame task with a goal of sampling each individual at least onceevery three years or use statistical random sampling.4.2.9 Measurement of worker occupational exposures shallbe within the workers breathing zone and shall meet thecriteria of this section. Such measurements should be repre-sentative
36、of the workers customary 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
37、Method D4532 and seeAppendix X1 for an example.4.2.11 Sampling data records shall include employeeidentification, 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, analyti
38、cal methods, and other 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 Exposure Monitoring:4.3.1 The employer shall p
39、rovide employees with an expla-nation of the sampling procedure.4.3.2 Whenever exposure monitoring activities require en-try into an area where the use of respirators, protectiveclothing, or equipment is required, the employer shall provideand ensure the use of such personal protective equipment and
40、shall require compliance with all other applicable safety andhealth procedures.4.3.3 Sampled employees shall be provided with copies oftheir sampling results when returned by the laboratory andexplanations of their data.4.4 Methods of Compliance:4.4.1 The methods listed below are applicable where co
41、m-pliance is required because of personal exposures exceedingthe OEL.NOTE 2One 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 Use of properly designed engineering controls is themost desira
42、ble 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 feasible.4.4.2.3 Enclosed workstations, such as control booths a
43、ndequipment 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 re-circulation systems are acceptable. Re-circulated air insideen
44、closed workstations should be in accordance withANSI Z9.7or federal and state requirements and consensus guidelines.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. Ifventilation s
45、ystems 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 ensureTABLE 1 Sampling I
46、nformationCondition ActionQualitative 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 or based onrepresentative sampling data fordefin
47、ed tasks. Results used to establishsampling or protection plan, or both.Sampling results are below OEL No periodic sampling necessary butadditional samples may be required dueto process changes or new qualitativeassessments.No OEL overexposure found, butexposures exceed one-half the OEL.These locati
48、ons are to be included in asampling plan. Sampling strategy maybe determined by a qualitativeassessment or statistical analysis thatfacilitates determination of the likelihoodthat exposures may sometimes exceedthe OEL. If qualitative assessment orstatistical analysis indicates exposuresmay sometimes
49、 exceed the OEL,see below.OEL was exceeded and engineering,work practice, and administrativecontrols, or all three, are being appliedto the work area to reduceexposures to below the OEL(see 4.2.6)Sampling to be conducted before andafter the remedy to assess the resultsof silica reduction efforts. If high levelspersist institute workplace controls andinclude in sampling plan until levels arebelow the OEL.Process materials, process equipment,engineering controls, or any otherchanges that occur which would tendto increase worker exposuresSampling to be conducte
