Document qmdBJqLr98eG5mE0JrOGg3vv5

i Alexander & Alexander tne. 201 Nth Cht'tes $t'eet fijitimste. Maryiantf 2)20) T<c?Ko^ 301 83M930 Jexander Alexander February 6, 1973 Mr. F. L. Gardener Assistant Secretary A C 3, Inc. 120 North Lime Street Lancaster, Pennsylvania Dear Freds 17602 INDUSTRIAL HYGIENE SURVEY A C & S, INC. COLUMBIA, MARYLAND I have just had an opportunity to review a very good Industrial Hygiene Survey prepared by Mr. D. B. Troup, Industrial Hygienist, Aetna Life & Casualty Company. It appears that your efforts to reduce the amount of air contaminants at your Columbia, Maryland location have been very successful. I would like to take this opportunity to again offer our services to you. If we can be of assistance at any time, please feel free to contact us. Sincerely yours ALEXANDER & ALEXANDER, INC Chris McGee Loss Control Department eet Mr. Wayne Ssibold Tele. 87974 Cable ALEXSLUE 100G93 WV-05537 r.-ro*:v G" na WJC.AL S5WICE5 STUDV PftL?ARK> ?on. AC AND S, DfC. COLUMBIA, MARYLAND INDUSTRIAL HYGIENE SURVEY D. B. TROUP TNDLT.IB.IAL HYGIENIST " r D*"' " DEC. 1', 1972 ALEXANDER & ALEXANDER ;; -*v, <; :*. 'Wi-r <;*fw /<;/.*;*<j/.. /, <-- * r '<c<j; ?.* .% -V.W' htlmflUfl it*1* t` ** 4 fItI.I. -i- *f/*^r?*;v?i . --i-j- tlfi KCASC^rtV 100G94 ACandS, 2KC, December 15, 1972 PURPOSE: On August 16, 1972, I made- a survey of this asbestos operation, which included operators' breathing zone samples, as veil as samples taken in the general area outside of the asbestos operations, as veil as operators* breathing zone samples taken in adjacent rooms. At that tine, ve found sane relatively high levels of asbestos and made scot recommendations for improvement of the control of the asbestos dust, as veil as the calcium silicate to control the hazard to the operator and those working in adjacent roorw. The recosmendaticas were com plied viand this survey vas made to check the levels now in exis tence after the installation of new localized exhaust ventilation equipment, CONTACT: A. Stokley, District Manager; 1. McKabb, Branch Manager. CONCLUSIONS: The localized exhaust ventilation installed at the calcium silicate, asbestos operation has been brought almost completely under control by the use of the manufacturer's recommended localized exhaust ven tilation. The air movement at the savblaae, vhere the actual cutting takes place is at a velocity of approximately 6h,CXX> feet per minute. All areas of the plant are veil below acceptable limits for calcium silicate dust and asbestos fibers. There Is a slight exposure to the operator at the actual cutting operation itself; however, some minor changes can bring this well within tolerable limits, RECOMMENDATIONS A. The bandsaw should be more completely enclosed. This enclosure should be designed In accordance with good industrial ventilatfcn principle* and should .be in-accordance with *** -AaftyiaaB Standards Institute Z 9,2-1971. (OSHA 1910.95 a) Industrial l^gieniat 100695 PROCEDURES: Standard procedures upon vhich the Threshold Limit Values for asbestos is based was followed in air sampling entirely. The air samples vere collected on open membrane AA filters at a sailing rate of two liters per minute for periods of 13 minutes, where possible. These filters were returned to our laboratory, where the number of fibers vere counted at *00 X Phase Contrast Identification in accordance with the National Institute of Occupational Safety end Health published methods. Air flew measurements were made with an Ainor St, Velometer. Air sailing for dust at the operations was done by drawing air through midget icroingers with ethanol as the collecting medium. Dust counts vere made in a microscopic light field, following the procedure outlined by the United States Public Health Service. Free silica in the dust vas found to be belov 1$ and was determined by careful selection of sajroles and-with the use of dispersion staining in our laboratory. RESULTS: The results are found in the Appendix at the end of this report. DISCUSSION: r.r. evaiua'-i:: the results of our air sampling, ve used as a guide the Threshold Limit Values (ILV's), which have been adopted by the American Conference of Governmental Industrial Hygienists (ACGIH). These limits, for the most part, have been incorporated in the regulations of the Federal Occupational Safety and Health Act (OSHA), Threshold Limit Values refer to airborne concentrations of substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed, day after day, without adverse effect, because of a vide variation in individual susceptibility, however, a small percentage of -workers may experience discomfort from the substance at concentrations at or below the Threshold Limit, a smaller percent age nay be affected more seriously by aggravation of preexisting condi tion or "by development of an occupational TUnesa, Threshold Limit Values refer to time-weighted concentrations for an eight-hour vorkday and a *i8-hour work week. They should be used as guides in the control of health hazards and should not be used as fine lines between safe and dangerous concentrations. Time-weighted averages permit excursions above the limit provided they are compensated by equivalent excursions below the limit during the vork day. In some instances, given a permissible to calculate the average concentration for a vork week rather than for a vork day. The degree 10Q696 of permissible excursion is related to the magnitude of the Sireshold IdJdt Value of a particular substance, as given in the Occupational Safety and Health Act* She relationship between these threshold Halts and permissible excursion is a rule of thumb and in certain case# say not apply* AH factors must be taken into consideration in arriving at a decision as to whether a hazardous condition exists* "For the purpose of this discussion, asbestos includes chrysotile, aaosite, crocidolite, tremoldte, anthophyllite, and actinolite. Asbestos fibers mean asbestos fibers longer than five micrometers. Permissible exposure to airborne concentration of asbestos fiber#, which was the standard effective July 7, 1972, on an eight-hour, time-weighted average airborne concentration to which any employee may be exposed shall not exceed five fibers longer than five mdrcuneters per cubic centimeter of air, as determined by theaethod prescribed in the determination of airborne concentrations by the membrane filter method# at 400-1*50 X magnification {four millimeter objective, with phase contrast illumination). It should be pointed out here that it is expected that as of July 1, 1976, the eight-hour, time-weighted average airborne concentrations of asbestos fibers to which any employee may be exposed shall not exceed two fibers longer than five micrometers, per cubic centimeter of air* a So eeployee shall be exposed at any time to ceiling concentrations* of asbestos fibers in excess of 10 fibers per cubic centimeter of air* Since the lest visit to this location, when relatively high asbestos counts were found, localized exhaust ventilation and dust-collection system# have been used and by and large constructed and installed in accordance with the American National Standards Fundamentals govern ing the design and operation of local exhaust systems, ANSI Z 9-2-1971. Once these localized exhaust ventilations recommendations are completely eoaplied with, 2 feel that the fibers to Which all employees are ex posed will be well within the five fiber limit. I have enclosed a drawing at the end of this report Which shows a more cora- plete enclosure of the bandsaw to bring the asbestos fiber concentre-- tions, as veil as the calcium silicate dust concentration well below limits. Asbestos fiber concentrations throughout the rest of the plant were found to be far belcw acceptable standards and I suggest that it is not necessary any longer for the men working the room adjacent to the saving operation to wear face flasks. Furthermore, anyone working in iO06S7 the warehouse area as veil as those individuals exposed in the office ares axe veil under acceptable asbestos concentrations. I ran a qualitative analysis on the arterial being handled in this factory and found approximately 15? asbestos and approximately 85? calcium silicate. I found that the new installations have brought these chemicals castletely under control. In addition to the above-mentioned evidence, I would say that since in the fitting and fab shop, the silica is only worked with from three to six hours per day, this cuts the concentration e^osure to an even lower limit. I made a measurement of the veloc% of the air, traveling at the point of source, where the ban&aav cuts the asbestos chunks and found it to be &,000 feet per minute. I also took samples in flange pad shop and found the asbestos count to be very low. In addition, concentrations of asbestos in the warehouse were also very low and as long as adequate maintenance is continue on the collec tion systems, I expect this case to be the same in the future. t I must continue to insist that to insure that exhaust hoods are opera ting properly, there should be adequate supply of outdoor air into the room to replace air removed by the exhaust ventilation. Industrial hygienist DISTRIBUTION* 2 - P. Gardner, Contract Office, ACandS 1 - 0. Dekowafci, Alexander & Alexander 1 - Reading Eng. Dept. 1 - Baltimore Eng. Dept. 1 - H.O, National Accounts Dept. 1 - H.O. Eng. Dept., National Accts. Sect. 100698 AC&ndS, Inc. COLUMBIA, MARYLAND Leeeaber 15, 1972 Air sample resalts for asbestos. Number Location Percent Asbestos 1. Fitting and Fabrication Shop, Operators* Breathing Zone. 15$ 2. Flange Pad Shop next to the Fitting and Fabrication Shop at the breathing height of the second operator. 15$ 5# Warehouse area on the other side of the vail from the Fitting and Fabrication Shop near the Flange Pad Shop token at,the exhaust of the bag-tjrpe collector. 15$ Results (Fibers/cnr :leaa than Sjji in Lergh) 6.5 .5 .8 Results of the air sampling for the calcium silicate. Percent Humber Location Calcium Silicate 4. Fitting and Fabrication Shop, Operators' Breathing Zone. 85? .5- Flange Pad Shop next to the Fitting and Fabrication Shop at the breathing height of the Second Operator. *8S5 .6 Warehouse area on the other side of the vail frem the Fittingand Fabrication Shop near the Flange Pad Shop taken at the exhaust of the bag-type collector. Results 11.5 nppcf .15 fflppcf 1.8 nppcf nppcf * million particles per cubic feet of air. The TTAT for asbestos is five fibers per eubie centimeter of air. She TUf far calcium silicate is 50 nppcf. 5-76 WDUSTIUAL VENTILATION Blade Hood slotted to enclose bbdt + i NJjV* Sbt/ed wood block ) Hinged doer for cleanout Top hood TOP HOOD DETAIL Sot/re base enclosed on oilsIdas Blade mdtht Exhaust volume, cfm inches Bottom Top Total Up to 2 over 2 to 3 over 3 to 4 over 4 toB over 6 to 8 350 350 550 550 550 350 550 800 ' 1100 1400 700 900 1350 1650 ' 1950 UUGI velocity - s/'-'w'*' fyu* Entry toss - / 75 VP in duct riser (Point AJ AMERICAN CONFERENCE OF . GOVERNMENTAL INDUSTRIAL HYGIENISTS DATS BAND SAW !-S6 VS-706 100700