Document em4Odpnwz98vEZXRE414p9G84

FEB-02-2005 08:40 SPE CUSTOMER SPILES 724 776 0002 P.ll 9 APPENDIX C DATA REDUCTION Table C-l contains the pertinent test data and calculated re- determination, the asbestos concentration in urban atmo- suits from the brake dynamometer tests. spheres from brake wear should be less than ESTIMATION OF BRAKE LINING ASBESTOS DILUTION IN URBAN ATMOSPHERE / 202g \ 2 /ig Fb/a? (15 mpg) . ^( . )10 (23 X 10~3) \10,000 miles/ 2 52gPb 0 75 Hie concentration of asbestos fiber from the brake lining wear debris is assumed to be the same as was found in the "normal usage" dynamometer test and to be dispersed and have the same residence times as the lead emitted from the engine. Assume an average mileage of 15 mpg from cars which emit 75% of the lead to the atmosphere. When gasoline averaged 2.52 gPb/gal, the typical Pb concen trations in urban atmospheres were about 2 pg/nv* (JAPCA, September 1969, Vol. 19, p. 684). Typical United States cars wear 202 g of lining/year and drive 10,000 miles/year. The "normal use" dynamometer tests provided asbestos fiber amounting to 0.0023% (2.3 X 10" 3) of the brake lining worn. Allowing a factor of ten to provide an upper bound in this or 0.07 ng/m^ Urban atmospheres vary in asbestos fiber concentration from city to city, within a city, and from one time to another. This variation does not correlate with expected automobile brake usage. The concentration has been reported to reach 100 ng/m^ (2). Thus, it appears that the wear of brake lining pro duces, at most, a small fraction of the asbestos fiber in urban air. This is not surprising when one considers that brake lining wear involves only 1.5% of United States asbestos usage and that brake usage converts over 99.95% of this to nonfibrous dust. Table C-l - Test Data and Calculated Results from Brake Dynamometer Tests Break-in Normal Use High Temp Use ___ _________ Test Sample 1. Filter airflow, m3 2. filter pickup, mg 3. Filter asbestos concentration, 2 ng/cm 4. "Blank" asbestos concentration, ng/cm^ 2 5. Filter area, cm 6. Filter asbestos, ng 7- Asbestos concentration in air, ng/m3 8. Lining asbestos in exhaust air, ng/m3 9. Lining asbestos on later, ng 10. Duct flow/filter flow 11. Lining asbestos released, mg 12. Lining worn, mg 13. Asbestos released as % of wear 14. Lining dust on fSter, mg 15. Lining dust in air, mg 16. % asbestos in wear dust 17. Lining dust as % of wear Test 2.22 0.36 15.32 0.33 9.62 144.2 64.95 61.8 137-2 1235 0.169 1100 0.015 0.26" 321 0.053 29* * Bkgrd 2.22 0.10 Test 23.00 1.56 Bkgrd 21.80 0.90 Test 0.564 0.27 1.06 7.98 4.64 S.37 0.33 0.33 0.33 0.33 9.62 9.62 9.62 9.62 7.02 73.59 41.46 48.48 3.16 3.19 1.90 85.96 1.29 29.7 1235 0.0367 1600 0.0023 OjSlt 754 0.0049 47 84.1 47.4 1235 0.0586 1070 0.0055 0.27* 333 0.018 31*" 'Value calculated based on "normal use" background, due to insufficient sample. 'Filter in one (central) location, and thus possibly nonrepreseutative, tConected for flow volume difference through test and background filters. Bkgrd 0.564 0.00 0.12* 0.33 9.62 1.07* 1-90* Calculation Baidft Measured Measured Measured Measured Measured [(3) "(4)] X (5) (6) + (l) A(7) (8)X(1) From measure (9) X (10) Measured (11)+(12) X100 A(2) (10) X (14) (11) * US) X 100 (IS)+(12) X100