Document gaGxVg9nX25BvyQKpkVpxOvNN

'/ ; rK v: 'S.i i ' i; '4 , r /` Hv i > ( 4& . + 1 m* i >j Report 52/68 f'*H* t ' VI ! tM Exposure to, Asbestos Dust" during Brake Maintenance Operations on Commercial!Vehicles Fleet Repair Garage. Dagenhan - ^ MV 1 '< f , "jis- V V i* -i 1 .i> . .ft i i iu f<L i m^Srnmmsm^ 'A?<\V ;inii:v 4 >1N1 < 5 i ' October 1968 tv 1 *. < 0';^ |Y,?s 1 -1 m r. i'fy'V. Dr D E Hiekish - 1/163 Industrial Hygiene Specialist. I *' i. INTHODUCTION - i;| '; Ikti itiiy wan odtrtaku to asseesthe; degree of : inoaara to fll>roaa daat .la brake maintenance prooedures : /.,"'> ;*!:S ' [j x-'/} X,` ] /,{ ' >: F,: ' ' 7 \ ':/'V./;: - ; / on commercial vehicles and to provide eo(pMtiT* data ': relating to a previous etudyonoperatore working on passenger ears* II INVESTIGATION u\ ' , . ' Air<sampllng,took plaea lnthe garaga on the X1* ( jX ^ , ' f/ 19th September 1968* Membranefilters,lii conjunction with .................................. ,................. M -h *;................................ Caaella personal samplers* suitably, modified to provide n'ii i! * 1N ^ x t^ia ,y;, t >*<>>. > -, a> flow < rata of 200 cms/ml.n. were need and the following /r 1 ,, <s, sampling procedure adopted* s "" f * i ! ' t| i 7 f *5, >? ". r '<< .If.,".,' 'fJlF 7'>;, . '>.)<:- 1 (a), Personal' samples were collected from the "brake <, v'>: ; blow off operator (Mr Crone) and the mechanio working in <, * V 1 r i';v`y*'V,,> '' the adjacent bay (Mr Hillman) during the blowing-off operation* The filters were then ohanged and replaced to run for the rest of the shift* (b) Static samplers were positioned at three points, A, B and C, about 20-25' from the source of dust generation and separate samples were collected for the morning and afternoon shifts* The sampling positions are shown in FlgFl* > ...................................,....., ' .................... . The collsoted samples were subsequently!removed to the laboratory and* after preparation* examined by projection mlorosbbpy for the presence of fibres greater than 5p* (A fibre is defined as haring:an aspect ratio equal to* or greater than, 3:1)* CCATES -2- III IV ' K,' . t ; i fOo*t.C<ooMK >f uuu* RESULTS y:;,:.; .. :: Table 1 shows the fibre counts per cb3 for each staple collected.:.;;,:1'/'';/Pp;:p;-;. i'i . DISCUSSION OF RESULTS ,P;! .ill Standards of dustiness !r H?' .P'-T: : >. ' . . :P/P ' 1 : In a previous Report (4l/68t Exposure to Asbestos during the servloing of brakes of passenger eare) reference was aedeto theHygiene Standard for Chrysotile Asbestos Dust proposed by the Britieb Occupational Hygiene Society. This standard suggested a Threshold Limit Value of 2 fibres/ca3 for an exposure period of SO years* Categories of dustiness were'proposed ae followa: : : Duet Category> , ' ' Concentration, fibrea/ca3 leveraged over 3 Booths) Negligible Low . ,t Medina 0 - 0.4 , 0.5 -1.9 : ' 2.0 - 10.0 P;P;I0- . Hi) Field Investigation Static Samples ,P~P j! F :P"; : , As the blowing-off operation took plaoe in the early part of the Borning shift, the Concentrations obtained at the static positions during the afternoonshift (staples 8. 9. 10) probably represent the background ! 1. ' contamination.: Thus it can be seen 'that the generation of' ' a dusteloudbyblowlng offduetfroB ooflBOTOial vehicle ' ' brakes results in increased background contaaination of 8 to 4 tiaes the background level at any point within a radius i of 20-?2S ft. P'PpPP;x'P pp -. 1' v-'P ''> ' ' ' The concentrations are all well below the TLV, and with one exception oone within the "Negligible* dust category. -PfP :'P ... Personal PRODUCED BY FORD IN -3 ) ."4: ,v,ti Personal sampler ^V;.-.!;:r!:;r, r`,-' : . . V The fibre concentrations for tlio nechanio engaged - ontheblowing-off task taken for the duration of the operation ahowe an exposure of nearly 4 tines the TLV, while the concentration measured In the breathing zone ; of the meehanlo working in the adjacent key daring the ease period just exoeeded the TLV. "i *< The personal saaplee froa the two aeehanies taken over the reaiaiiyier^f'jJtStai;';bbiit|jgiy^ ,When the sunples for the two aeehanies are calculated on ' the basis of tine-weighted concentrations, the exposures areibelow the TLV and leone within the "Low" dost category* CONCLUSIONS In the light of the environmental data, and of the irregular intervals at whioh brake-cleaning is carried out (it is not a daily procedure) it does not appear * .' that a significant hazard to health should occur in the , case studied* -f;-V. :., !? I .'v^, |;;;Neverthslese.! the conditions which obtain during the blowlng-out operatlon are extremely unpleasant,and alternative methods of cleaning should be investigated, ' br anasuree adopted to minimise personal exposure*'; ; e.g* looal ventilation,; or use of a suitable respirator* x. .. '. M` 'V PRODUCED BY COATES V FORD - 003 0 Table 1. 3asalt9 of Membrane Filter Counts Sapple No. .... ' Description 7v7y: y---; 7,7' Duration ' mins* ; Iflow Bate ml/min. Concentration fibreS/cn3 Dust Category i ; Personal-. lir Crone. drake maintenance. Front JirakM blown oat in thij period .v; ;C:pW:^ 193 -; 7-%:' 7. .-7 Medium V * Personal. Mr Hillman* Clutch repair y 7.-7 procedure at adjacent Tshicle bay .,7 207 2.25 7' ' Medium 7 3 ; Static. Position;A. 7777;/f,-y y, ' 190 232 ` 7* Static. Position B. 18S 133 . S . - " -mV ysiatleVyyPojsj&^ ' 180 . 206 Personal Mr Crone.One rear brake assembly ' I 317 blown off atbeginnifogofaampling period. . 180 . Personal. Mr Hillman. Clutch repair procedure at adjaoent vehicle bay. .1 278 148 0.17 0.49 0.28 0.08 Neg. 7 Neg/Low.y Neg. . Neg. 07*lyy7y\ Neg. V 8 Static. Position A. 9 Static. Position 2. 10 ; Statio. l'oeition C. ;;;y.:y--y : .,;y. V yy v y' 186 211 186 , 170 r-t-sp.--y /--yy. 185 172 0.07 0.11 0.07 Neg. -77 7 Neg. ;;y Neg. Tine-weighted average concentrations: V '~y - 7.; ' .. .7 - 7 .7 7' 1 Mr Crone '' " '-7. : : ''-7 . ^77/,\- ; Mr Hillman y 77yy Y;7 7 yV.'-j-..' y , '-''y- 7 .y-7--y.'ry -- 7/ .. -V-V-y ^7. ' :.....7 r* - 1" ' ' 1.75 y . ' Low 0.79 ' -- - , Low lCO - one* a . . S31V03 -W^'Sepm^pgg I1b6______________ ___ E;i 11 i g1 jui I , g i>S,i f ... i 1 , u.. S 'It r fr.- ,'4. - .,...W.>,x..... w... /vV ag<I ' `< i * i * '*% im Ok 1 > < ^f- J>i. * >, i * 58 <- >im;i-fe.:M!ii,i,,a<Hi^.:<l:f,H. *x * *{"- { * o * > 4* .....A,-.. |x `i * V 4 ....... i--,.t i' K , -I ..... 1 M ! 'liV . * * ^...if. <i t .:i,j.;...!.,ir:ir ^ ,, i!i-ii f i ' &I I w lU A Ito .St ifri