ASTM_E_1435_-_98.pdf

Designation:E 1435 98Standard Practice forHandling Densified Articles of Aluminum Oxide Reinforcedwith Silicon Carbide Whiskers1This standard is issued under the fixed designation E 1435;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,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.1.Scope1.1 This practice covers recommended procedures to reducehealth and safety problems which may arise during thehandling of densified articles made from nonfibrous aluminumoxide reinforced with silicon carbide(SiC)whiskers.1.2 The information in this practice may be considered foruse in a manufacturers material safety data sheet(MSDS)fordensified articles of aluminum oxide reinforced with SiCwhiskers.1.3 This practice applies to finished articles where neitherSiC whiskers nor aluminum oxide are released during use inexcess of the limits of this practice.1.4 Other materials may be included in the article(forexample,sintering aids);information specific to these addi-tional materials should be included in each manufacturersMSDS.1.5 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 and determine the applica-bility of regulatory limitations prior to use.For specific hazardand precaution statements,see Sections 5,7,9 and 10.2.Referenced Documents2.1 ASTM Standards:E 1437 Practice for Handling Respirable Silicon CarbideWhiskers2E 1718 Guide for Administrative and Engineering Controlsfor Silicon Carbide Whisker Work Areas22.2American National Standards Institute(ANSI)Stan-dard:3ANSI Z9.21979 Fundamentals Governing the Design andOperation of Local Exhaust Systems2.3Occupational Safety and Health Administration(OSHA)Standard:4OSHA 8-hour Time Weighted Average(TWA)PermissibleExposure Limit(PEL)for alpha-Alumina from U.S.Codeof Federal Regulations(CFR)29 CFR 1910.1000,AirContaminants,Table Z-1,19943.Terminology3.1 Definitions:3.1.1 aspect ratio,nratio of whisker length to whiskerdiameter.3.1.2 respirable silicon carbide whiskers,na crystallinesilicon carbide fiber,approximately cylindrical in shape,with adiameter less than 3.0 m and an aspect ratio equal to or greaterthan 5:1.4.Significance and Use4.1 Handling or use of densified articles of aluminum oxidereinforced with SiC whiskers is not expected to be hazardousdue to the presence of SiC whiskers unless the whiskers arereleased through a material removal process,such as(re)grind-ing.4.2 This practice provides guidance,characteristics and datafor handling and use of densified articles of aluminum oxidereinforced with SiC whiskers.It also provides guidance fordetermining when(re)finishing or other processing of densifiedarticles of aluminum oxide reinforced with SiC whiskers willgenerate potentially hazardous conditions,and provides refer-ence to relevant standards.If SiC whiskers are released,theimplementation of Practice E 1437 may be required.4.3 This practice is intended for use by health and safetyprofessionals in determining whether an excessive exposureexists,in preparing procedures to establish a safe workenvironment,and in preparing relevant documentation.5.Hazardous Ingredients/Identity Information5.1 Densified ArticlesDensified articles of aluminum ox-ide reinforced with silicon carbide whiskers are not expected toproduce exposures which are hazardous to health.However1This practice is under the jurisdiction of ASTM Committee E34 on Occupa-tional Health and Safety and is the direct responsibility of Subcommittee E34.70 onSingle Crystal Ceramic Whiskers.Current edition approved April 10,1998.Published June 1998.Originallypublished as E 1435 91.Last previous edition E 1435 91.2Annual Book of ASTM Standards,Vol 11.03.3Available from American National Standards Institute,11 W.42nd St.,13thFloor,New York,NY 10036.4Available from the Superintendent of Documents,U.S.Government PrintingOffice,Washington,DC 20402.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.(re)finishing the article as discussed in Section 10 will producefine particles of potentially hazardous ingredients which can beinhaled,swallowed or come in contact with the skin or eyes.5.2 Hazardous Ingredients(specific chemical identitycommon name(s):5.2.1 Silicon Carbide(SiC)WhiskersAn acicular form ofsilicon carbide,which is Chemical Abstract Service(CAS)409-21-2.ACAS number specific to SiC whiskers has not beenassigned.OSHA PELs for SiC whiskers have not been estab-lished.American Conference of Governmental Hygienists(ACGIH)Threshold Limit Values(TLVs)have not beenestablished.Manufacturers currently use the following expo-sure limits for respirable SiC whiskers:5.2.1.1 A short term exposure limit(STEL)for respira