1、Designation: E2625 09 (Reapproved 2017)Standard Practice forControlling Occupational Exposure to Respirable CrystallineSilica for Construction and Demolition Activities1This standard is issued under the fixed designation E2625; the number immediately following the designation indicates the year ofor
2、iginal adoption 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 i
3、ndustry 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. The three ma
4、jor 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 might be encoun
5、tered 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 describes several actions to reduce the riskof harmful occupational exposures in environments containingrespirab
6、le crystalline 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 E1132.1.3 Nothing in
7、this practice 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 st
8、andard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision
9、 on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:4D4532 Test Method for Respirable Dust in Workplace At-mospheres Using Cyclone Sampler
10、sE1132 Practice for Health Requirements Relating to Occu-pational Exposure to Respirable Crystalline Silica2.2 ANSI Standards:5Z88.2 1992 American National Standard Practice for Respi-ratory ProtectionANSI/AIHAZ9.2 2001 Fundamentals Governing the Designand Operation of Local Exhaust Systems2.3 U.S.
11、Code of Federal Regulations:629 CFR 1910.134 Respiratory Protection29 CFR 1910.1000 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
12、 on Occupa-tional Health and Safety and is the direct responsibility of Subcommittee E34.80 onIndustrial Heath.Current edition approved Nov. 1, 2017. Published November 1, 2017. Originallyapproved in 2009. Last previous edition approved in 2009 as E2625 09. DOI:10.1520/E2625-09R17.2Smith, Deane K.,
13、“Opal, Cristobalite, and Tridymite: Noncrystallinity VersusCrystallinity, Nomenclature of the Silica Minerals and Bibliography,” PowderDiffraction, Vol 13, 1998, pp 118.3Miles, W. J., “Crystalline Silica Analysis of Wyoming Bentonite by X-rayDiffraction After Phosphoric Acid Digestion,” Analytical C
14、hemistry 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 ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.5Available from America
15、n 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 of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.Copyright ASTM International, 100
16、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Re
17、commendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.130 CFR 56, Title 30, Subpart D Air Quality, Radiation, andPhysical Agents (MSHA)2.4 NIOSH Publications:7Manual of Analytical Methods, 4th Ed., DHHS (NIOSH),Publication No. 94-113 August 1994.Method 7500
18、 for Silica, Crystalline, Respirable (XRD)Method 7601 for Silica, Crystalline Visible AbsorptionSpectrophotometryMethod 7602 for Silica, Crystalline (IR)2000 Guidelines for the Use of ILO International Classifi-cation of Radiographs of Pneumoconioses2.5 Other References:American Thoracic Society, St
19、andardization ofSpirometry1994 Update3. Significance and Use3.1 These practices and criteria were developed for occu-pational exposures during construction and demolition activi-ties. They are intended to (a) protect against clinically signifi-cant disease from exposure to respirable crystalline sil
20、ica, (b)be measurable by techniques that are valid, reproducible, andreadily available, and (c) be attainable with existing technologyand protective practices.4. General Requirements4.1 Occupational Exposure Limit:4.1.1 Permissible Exposure Limit (PEL)U.S. Occupa-tional Health and Safety Administrat
21、ion (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 weightedaverage in any 8-h work shift of a 40-h work week or, for totaldust (respirable plus non-respirable), 30/(% quartz + 2)
22、 mg/m3.The PELfor respirable cristobalite and tridymite is one-half thevalue for quartz.PEL mg/m3!respirable fraction! 5 10% quartz1% cristobalite32!1% tridymite 32!12#PEL mg/m3!total dust! 5 30% quartz1% cristobalite 32!1% tridymite 32!12#4.1.2 Federal OSHA PEL is approximately equivalent to aquart
23、z 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 government limit.4.2 Exposure Assessment and Monitoring:4.2.1 Risk can be assessed qualitatively based on materialsafety data sheets (MSDS), his
24、torical data, likelihood of dustgeneration, proximity of airborne dust to workers, nature of theconstruction process (for example, wet worklow risk; dryworkhigher risk), and location of workers (for example,closed equipment cab). Note that the absence of visible dust isnot a guarantee of lack of ris
25、k.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 to characterize theexposure and its variability, to determine compliance withstandards given in 4.1, and to establish a baseline exposurel
26、evel 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, tasks where samplingresults would not be timely, representative concentrations arealready known or proven task protection is in place. C
27、onductexposure sampling when needed to prevent a significant anddeleterious change in the contaminant generation process or theexposure controls so that overexposures do not go undetected.This is particularly true for areas or operations where condi-tions can change dramatically within a short span
28、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 high silicaconcentrations who are placed inside of supplied air respiratorsor ventilated enclosures, such as in sandblasting, conductsampl
29、ing inside of the control device to determine employeeexposure. The sampling line shall not interfere with the fit ofthe respirator. It is possible that consultation with the respiratormanufacturer will be necessary to achieve the above require-ment.4.2.5 In areas where overexposures are persistent,
30、 a writtenexposure control plan shall be established to implementengineering, work practice, and administrative controls toreduce silica exposures to below the PEL, or other electedlimit, whichever is lower, to the extent feasible. Conduct a rootcause analysis for all exposures in excess of the PEL
31、thatcannot be accounted for. Root cause analysis involves investi-gating cause(s) for the excessive exposure, providing remedies,and conducting follow-up sampling to document that expo-sures are below the PEL.4.2.6 The employer shall re-assess exposures when therehas been a change in the process, eq
32、uipment, work practices orcontrol methods that have the potential to result in new oradditional exposures to crystalline silica or when the employerhas any reason to believe that new or additional exposures haveoccurred.4.2.7 Measurement of worker occupational exposures shallbe within the workers br
33、eathing 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 work shift exposure. Use area sampling to character-ize exposures and identify effective controls when appropriateto the circumstances.4.2
34、.8 Respirable dust samples are to be collected in accor-dance with accepted methods. Refer to Test Method D4532.4.2.9 Sample 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 pu
35、mp calibration, and description of thesampling location, analytical methods, and other pertinentinformation.4.2.10 Analyze samples for silica content analysis by anAIHA-accredited laboratory.7Available from CDC/NIOSH, 4676 Columbia Pkwy, Cincinnati, OH 45226-1998.E2625 09 (2017)24.3 Exposure Monitor
36、ing:4.3.1 The employer shall provide 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 per
37、sonal 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 returned by the laboratory andexplanations of the data.4.4 Methods of Compliance:4.4.1 Task-Based Control
38、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 Abrasive BlastingOSHA has already establishedstandards for abrasive blasting work requiring ventilation
39、 (29CFR 1926.57) and respiratory protection (29 CFR 1926.103).In the case of abrasive blasting operations, it is recommendedthat the employer provide a Type CE, pressure demand orpositive-pressure, abrasive blasting respirator (APF of 1000 or2000).4.4.1.2 Other engineering controls with the potentia
40、l to limitexposure are:(1) Using alternative materials,(2) Wet suppression systems, and(3) Exhaust ventilation.4.4.1.3 Cutting Clay and Concrete Masonry UnitsThecontrols found in Tables 1-5 apply to employees cuttingmasonry units during a full work shift and does not apply tooccasional cutting limit
41、ed to 90 min total time4.4.2 Exposure-Based Control StrategiesWhere exposurelevels are measured and known to exceed the PEL, anexposure-based control strategy shall be applied that uses theappropriate controls to lower exposure.4.4.2.1 Engineering Controls:(1) Use of properly designed engineering co
42、ntrols is themost desirable approach for controlling dust from crystallinesilica-containing materials.(2) Adequate ventilation or other dust suppression methodsshall be provided to minimize respirable crystalline silicaconcentrations to below the PEL, where feasible.(3) Enclosed workstations, such a
43、s 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 equipment shallinclude, where feasible, provisions to minimize exposure ofworkers to respirable crystallin
44、e 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 the working environment(see ANSI Z9.2). If wet suppression systems are used, spraynozzles and associated pipi
45、ng 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 periodically evaluated and brought up to specifications,when needed.4.4.3 Work Practices and Administrative Co
46、ntrols: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 ofrespiratory protection, unless proven task protection is in use orair sampling shows exposures less than the PEL.4.4
47、.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 agency.4.4.3.3 Employers shall instruct workers about specificwork practices that minimize exposure to respira
48、ble 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 reduceexposure to dust, including the use of respirators, rest areas,ventilation systems, high efficiency particulate ai
49、r (HEPA)vacuum cleaners or water spray, wet floor sweepers, androtation of personnel to minimize individual exposure.4.5 Respiratory Protection:TABLE 1 Cutting Masonry UnitsOperation/Task Control Measures Respiratory ProtectionCutting masonry units(Using stationary or portable saws)Wet Method: Continuously apply 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 a
