Document ppMxjyOVMaavXj25z3b0wvqdB

SaiqpUqg for Air Omtamirartis P. A. Huggins The primary purpose of monitoring airborne contaminants is to determine if employee exposures are in cnrpliance with appropriate Occupational Safety and Health Administration (OSHA) exposure limits. OSHA apasure limits brittle right (9) hour Permissible Exposure limits (PEL), eight (S) hour Actios Levels (AL), cefftng Emits and peak expaure eascestraticns. Dcfinitkaa of these exposure Emit terms and expcsje Emits tor potential Bril System air cmtaminants am attached. In each case the espcaure Emit is given b terms d an amount d contaminant pa unit vdume d air. Tfan expressan comvemly used to daiote exposure Emita are given b metric units. They include the following: m^tri* Milligrams d a contaminmt per unit vdume ef air (cubic meters). igfm? - Mtaqgrama cf a contaminant per unit vdume cf air (cufab meters). - fibcrVcm* Note d ttbm pa unit voirana of air (enfab oentimetas). This expression is used almost exdosivdy for aabesta. The tcaa tatfa? on ha convexted (Erectly into the expiation parts per mflEoa (pm) but only when the bumii'mih is a gu <r vapor* can then be convoted into a percent b air value if w f In order to cbtxm results that can be used to assess compliance, we mot select a sampling method which wiD reflect an naiplryina axpaure aver the time period specified by the eyrie Emit. Usually tins b anrampEshed by using e pmraal sampler, wfcfcb vdl mafia b the operator t (GHZ) our a 7-8 hour period. The p----* nmpi /amity --fa* d a ab Ufqg tbb iatnimagation allows am to <*-- the kI a want miwvfm* device. d a wiamhiun hi a given mat vdomerf ab. Tl wmrvtm tt .mwiime tm. ttapitmA ftnm gnatytirnt wmllt n b inipnrtam that the results are in the units specified b the apprqniatc espowae Emit (eg^mgo ig <r fibers, etc.}. The vdane ef ab sampbd cm bn olndated flow rate bom the pomp fine rate and the taal time the poop kb qpnated as shown bdoae VfcfaneAb Sampled * Pump Flow Rale x Time Sampled The pnqi flow rate b determined by prior pmqp caEfamion and b generally expresed b Stem pa rrnrmtm pwj TV ti'lM mmylwi fw hf moly (WwmiiwH in minima, Multiplying ttCK VUlUS giva the taal vdume cf ab sampled in Etas. fhpi Uni wnwia (f uiiituiilmt mfllwtwl amt the vcfasne (f ab is iM^minwi, the wpmiiii concentration can ba calculated rearSIy as shown on the attached sample problems. An 8*hanr integrated ampi which can be wed to detennbe compEanea with OSHA S*honr PEL) may he **< by sampling, using one cnEectian devise over the fidl writ shift. However, it b necessary or desirable to break up the sampling period wbg several coDaetion devices over the full wtrk period. In tbs case the average 8-hcur espenue may be drrcniiimxi by raimtaring a time weighted average cm-oiaatian (TWA). An aample cf a TWA calculation fer three sample collected during pw^ai nsautoring far lead b also attached. LLA 002006