1、Designation: E 2625 09Standard Practice forControlling Occupational Exposure to Respirable CrystallineSilica for Construction and Demolition Activities1This standard is issued under the fixed designation E 2625; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, 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.INTRODUCTIONSilicon dioxide (silica, SiO2) is encountered in nature and industry in a wid
3、e 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. The three major forms, quart
4、z, 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 might be encountered in several
5、 occupationswhere silicas are fired (calcined) at high temperatures3. These silica materials have a broad range ofphysical and chemical properties.1. Scope1.1 This practice describes several actions to reduce the riskof harmful occupational exposures in environments containingrespirable crystalline
6、silica. This practice is intended for theunique conditions during construction and demolition activi-ties.1.2 Health requirements relating to occupational exposureto respirable crystalline silica not covered in this practice fallunder the jurisdiction of Practice E 1132.1.3 Nothing in this practice
7、shall be interpreted as requiringany action that violates any statute or requirement of anyfederal, state, or other regulatory agency.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 esta
8、blish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:4D 4532 Test Method for Respirable Dust in WorkplaceAtmospheresE 1132 Practice for Health Requirements Relating to Occu-pational Exposure t
9、o Respirable Crystalline Silica2.2 ANSI Standards:5Z88.2 1992 American National Standard Practice for Res-piratory ProtectionANSI/AIHA Z9.2 2001 Fundamentals Governing the De-sign and Operation of Local Exhaust Systems2.3 Code of Federal Regulations:629 CFR 1910.134 Respiratory Protection29 CFR 1910
10、.1000 Air Contaminants29 CFR 1910.1200 Hazard Communication42 CFR 84 Title 42, Part 84 Approval of RespiratoryProtective Devices, Tests for Permissibility, Fees1This practice is under the jurisdiction of ASTM Committee E34 on Occupa-tional Health and Safety and is the direct responsibility of Subcom
11、mittee E34.30 onOccupational Health and Safety in Construction.Current edition approved May 1, 2009. Published May 2009.2Smith, Deane K., Opal, cristobalite, and tridymite: Noncrystallinity versuscrystallinity, nomenclature of the silica minerals and bibliography, PowderDiffraction, Vol 13, 1998, pp
12、 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 website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Ann
13、ual 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, http:/www.ansi.org.6Available from U.S. Government Printing Office Superintendent
14、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.30 CFR 56, Title 30, Subpart D Air Quality, Radiation, andPhysical Agents (MSHA)2.4 N
15、IOSH Publications:7Manual of Analytical Methods, 4th Ed., DHHS (NIOSH),Publication No. 94-113 August 1994.Method 7500 for Silica, Crystalline, Respirable (XRD)Method 7601 for Silica, Crystalline Visible AbsorptionSpectrophotometryMethod 7602 for Silica, Crystalline (IR)2000 Guidelines for the Use of
16、 ILO International Classifi-cation of Radiographs of Pneumoconioses2.5 Other References:American Thoracic Society, Standardization ofSpirometry1994 Update3. Significance and Use3.1 These practices and criteria were developed for occu-pational exposures during construction and demolition activi-ties.
17、 They are intended to (a) protect against clinically signifi-cant disease from exposure to respirable crystalline silica, (b)be measurable by techniques that are valid, reproducible, andreadily available, and (c) be attainable with existing technologyand protective practices.4. General Requirements4
18、.1 Occupational Exposure Limit:4.1.1 Permissible Exposure Limit (PEL)U.S. Occupa-tional Health and Safety Administration (OSHA) GeneralIndustry (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 weightedav
19、erage 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 cristobalite and tridymite is one-half thevalue for quartz.PEL mg/m3! respirable fraction! 5 10 4 % quartz 1 % cristobalite3 2! 1 % tridymite 3 2! 1 2PEL
20、mg/m3! total dust! 5 30 4 % quartz 1 % cristobalite 3 2!1 % tridymite 3 2! 1 24.1.2 Federal OSHA PEL is approximately equivalent to aquartz level of 100g/m3.4.1.3 Employer shall determine the appropriate PEL fortheir operation, but in no case shall the PEL be less stringentthan the applicable govern
21、ment limit.4.2 Exposure Assessment and Monitoring:4.2.1 Risk can be assessed qualitatively based on materialsafety data sheets (MSDS), historical data, likelihood of dustgeneration, proximity of airborne dust to workers, nature of theconstruction process (for example, wet worklow risk; dryworkhigher
22、 risk), and location of workers (for example,closed equipment cab). Note that the absence of visible dust isnot a guarantee of lack of risk.4.2.2 Where qualitative risk assessment indicates that apotential risk is present, initial sampling of tasks or represen-tative workers exposures shall be made
23、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 potential to beexposed to silica. Initial task sampling would be not requiredfor short duration or transient tasks
24、, tasks where samplingresults would not be timely, representative concentrations arealready known or proven task protection is in place. Conductexposure sampling when needed to prevent a significant anddeleterious change in the contaminant generation process or theexposure controls so that overexpos
25、ures do not go undetected.This is particularly true for areas or operations where condi-tions can change dramatically within a short span of time.4.2.3 Recordkeeping required under this practice shall bemaintained and made available for review by employees.4.2.4 For workers with regular exposure to
26、high silicaconcentrations who are placed inside of supplied air respiratorsor ventilated enclosures, such as in sandblasting, conductsampling inside of the control device to determine employeeexposure. The sampling line shall not interfere with the fit ofthe respirator. It is possible that consultat
27、ion with the respiratormanufacturer will be necessary to achieve the above require-ment.4.2.5 In areas where overexposures are persistent, a writtenexposure control plan shall be established to implement engi-neering, work practice, and administrative controls to reducesilica exposures to below the
28、PEL, or other elected limit,whichever is lower, to the extent feasible. Conduct a root causeanalysis for all exposures in excess of the PEL that cannot beaccounted for. Root cause analysis involves investigatingcause(s) for the excessive exposure, providing remedies, andconducting follow-up sampling
29、 to document that exposures arebelow the PEL.4.2.6 The employer shall re-assess exposures when therehas been a change in the process, equipment, work practices orcontrol methods that have the potential to result in new oradditional exposures to crystalline silica or when the employerhas any reason t
30、o believe that new or additional exposures haveoccurred.4.2.7 Measurement of worker occupational exposures shallbe within the workers breathing zone and shall meet thecriteria of this section. Such measurements need to be repre-sentative of the workers customary activity and be represen-tative of wo
31、rk shift exposure. Use area sampling to character-ize exposures and identify effective controls when appropriateto the circumstances.4.2.8 Respirable dust samples are to be collected in accor-dance with accepted methods. Refer to D 4532.4.2.9 Sample data records shall include employee identifi-catio
32、n, a log of the date and time of sample collection,sampling time duration, volumetric flow rate of sampling,documentation of pump calibration, and description of thesampling location, analytical methods, and other pertinentinformation.4.2.10 Analyze samples for silica content analysis by anAIHA-accr
33、edited laboratory.4.3 Exposure Monitoring:4.3.1 The employer shall provide employees with an expla-nation of the sampling procedure.7CDC/NIOSH, 4676 Columbia Pkwy, Cincinnati, OH 45226-1998.E26250924.3.2 Whenever exposure monitoring activities require en-try into an area where the use of respirators
34、, protectiveclothing, or equipment is required, the employer shall provideand ensure the use of such personal protective equipment andshall require compliance with all other applicable safety andhealth procedures.4.3.3 Affected employees shall be provided with copies oftheir sampling results when re
35、turned by the laboratory andexplanations of the data.4.4 Methods of Compliance:4.4.1 Task-based Control StrategiesWhere exposure lev-els are known from empirical data, a task based controlstrategy shall be applied that matches tasks with controls. Thefollowing lists examples of this approach.4.4.1.1
36、 Abrasive BlastingOSHA has already establishedstandards for abrasive blasting work requiring ventilation (29C.F.R. 1926.57) and respiratory protection (29 C.F.R.1926.103). In the case of abrasive blasting operations, it isrecommended that the employer provide a Type CE, pressuredemand or positive-pr
37、essure, abrasive blasting respirator (APFof 1000 or 2000).4.4.1.2 Other engineering controls with the potential to limitexposure are:(1) Using alternative materials(2) Wet suppression systems(3) Exhaust ventilation4.4.1.3 Cutting Clay and Concrete Masonry UnitsThecontrols found in Tables 1-5 apply t
38、o employees cuttingmasonry units during a full work shift and does not apply tooccasional cutting limited to 90 minutes total time4.4.2 Exposure-based Control StrategiesWhere exposurelevels are measured and known to exceed the PEL, an exposurebased control strategy shall be applied that uses the app
39、ropriatecontrols to lower exposure.4.4.2.1 Engineering Controls:(1) Use of properly designed engineering controls is themost desirable approach for controlling dust from crystallinesilica-containing materials.(2) Adequate ventilation or other dust suppression methodsshall be provided to minimize res
40、pirable crystalline silicaconcentrations to below the PEL, where feasible.(3) Enclosed workstations, such as control booths andequipment cabs, designed for protection against respirablecrystalline silica dust, shall be provided with filtered air toreduce exposures.(4) Engineering design of tools and
41、 equipment shallinclude, where feasible, provisions to minimize exposure ofworkers to respirable crystalline silica dust to the PEL orbelow. If ventilation systems are used, they shall be designedand maintained to prevent the accumulation and re-circulationof respirable crystalline silica dust in th
42、e working environment(see ANSI Z9.2). If wet suppression systems are used, spraynozzles and associated piping shall be maintained to ensurethat adequate wetting agent is applied where needed to controlrespirable crystalline silica dust.(5) All engineering controls shall be properly maintainedand per
43、iodically evaluated and brought up to specifications,when needed.4.4.3 Work Practices and Administrative Controls:4.4.3.1 Ensure that workers do not work in areas of visibledust generated from materials known to contain a significantpercentage of respirable crystalline silica without use ofrespirato
44、ry protection, unless proven task protection is in use orair sampling shows exposures less than the PEL.4.4.3.2 Workers shall not use compressed air to blowrespirable crystalline silica-containing materials from surfacesor clothing, unless the method has been approved by anappropriate Regulatory age
45、ncy.4.4.3.3 Employers shall instruct workers about specificwork practices that minimize exposure to respirable crystallinesilica.4.4.3.4 Workers shall utilize good housekeeping practices tominimize the generation and accumulation of dust.4.4.3.5 Workers shall utilize available means to reduceexposur
46、e to dust, including the use of respirators, rest areas,ventilation systems, high efficiency particulate air (HEPA)vacuum cleaners or water spray, wet floor sweepers, androtation of personnel to minimize individual exposure.4.5 Respiratory Protection:4.5.1 Respirators shall be required in work situa
47、tions inwhich engineering and work practice controls are not sufficientto reduce exposures of employees to or below the applicableTABLE 1 Cutting Masonry UnitsOperation/Task Control Measures Respiratory ProtectionCutting masonry units(Using stationary or portable saws)Wet Method: Continuously apply
48、stream orspray at the cutting point.Not RequiredORDry Method: Enclose saw within aventilated enclosure operated with aminimum face velocity of 250 feet-per-minute.Saw blade must be contained entirelywithin the booth and exhaust must bedirected away from other workersor fed to a dust collector with a
49、 HEPAfiltration system.100 series filtering face piece(disposable dust mask)OR12 facerespirator with 100 series filters* Additional control measures for consideration: Ventilation (naturaland mechanical), dust collection methods, architectural design, usespecial-shaped products, job rotation and demarcation of specificcutting areas.E2625093PEL or company adopted level. Where the use of personalrespiratory protection is required under this practice, theemployer shall establish and enforce a program.4.5.2 The employer shall institute a respiratory protecti
