Document 5ZX7xw8dZwDD7qELE0YqkyBR

{' i i Report, on INDUSTRIAL HYGIENE SURVEY OF SELECTED PLANT OPERATIONS -PPG INDUSTRIES . Pittsburgh-Coming Corporation Port Allegany, Pennsylvania August 27-28, 1968 3y Morton Corn, Ph.D. #/ S'/ - ^ rJ , r i1 r i TAELE OF CONTENTS I. II. III. IV. V. INTRODUCTION SUMMARY AND RECOMMENDATIONS THRESHOLD LIMIT VALUES OF SUBSTANCESMEASURED IN THIS SURVEY DESCRIPTION OF SAMPLING ANDANALYTICAL METHODS RESULTS AND DISCUSSION /" 1 1 2 3 4 1 I. INTRODUCTION A survey of airoorne dust concentrations was performed in the Unicestos area of the Pittsburgh-Coming Port Allegany plant on August 27-28 by Dr. Morton Corn. The survey was performed at the request of Lee Grant, M.D. , Medical Director, PPG Industries. The survey was aimed specifically at assessing the degree of dust control achieved ifc the Unibestos facility with the improvements made since the former survey by the author in April, 1966. Also, recause a new assessment technique for asbestos fibers (Memorane filter) is now being used, the present survey was performed by simultaneously sampling at the same location with the traditional sampling instrument (midget iropinger) and the new instrument. During the period of the survey outdoor weather conditions were clear, cool, and sunny, with outdoor temperatures in the range 6 0-75F. It should be noted that the dust collection system in the Unibestos facility was thoroughly cleaned during the week prior to this survey. Therefore, it can be reasonably assumed that,dust concentrations measured in this survey are representative of the lowest concentrations which can be achieved with the present dust * control system. II. SUMMARY AND RECOMMENDATIONS This survey was performed by simultaneously sampling airborne dust in the Unibestos plant by two different techniques. Results of both methods of assessment suggest that dust concentrations in the plant are high when judged by the present U. S. Threshold Limit Value for asbestos dust, or by the recently proposed British guidelines for asbestos dust. Because the dust collection system was operating at, or close to the maximum efficiency achievable with present facilities modifications and additions to the present system would appear to be in order. It is beyond the scope of this report to present detailed recommendations for system modification, but certain obvious major sources of dust emission in the plant as cited in Section V of this report. . It is recommended that attention be focussed on major redesign c present system. It is obvious that additional air capacity for new local exhaust hoods will be necessary, and that this capacity probahl: cannot be found in the present system, which was not adequately handling existing hoods. III. THRESHOLD LIMIT VALUE OF ASBESTOS DUST ''The 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 wide variation in individual susceptibility exposures of an occasional individual at or even below the threshold limit may not prevent, discomfort, aggravation of a pre-existing condition, or occupational illness. "Threshold limits should be used as guides in the control of health hazards and should not be regarded as fine lines between safe and dangerous conditions."* The American Conference of Governmental Industrial Hygienists had, in 1967, a T.L.V, for asbestos of 5 million particles per cubic foot, as determined by impinger sampling and counting by light-field techniques. In a considered revision (1968), the Conference endorsed the retention of this T.L.V. for "most forms cf asbestos". However, for crocidolite, because of the production of mesotheliomas, it was recommended that workers be equipped with air-supplied helmets because "r.c safe limit can be established for this form of asbestos at this time." The British Occupational Hygiene society recently issued hygienic standards for chrysotile asbestos dust.** The standards are based on the objective that the risk of contracting asbestos be reduced to 1 per cent of those who have a lifetime's exposure to the dust. By "asbestosis" the committee meant the earliest demonstrable effects on the lung due to asbestos. These standards are cited here because they are more stringent than the U.S. guideline referred to above. The exposur guidelines are: - TABLE I BRITISH HYGIENIC GUIDELINES FOR ASBESTOS DUST DUST CATEGORY CONCENTRATION AVERAGED OVER 2 MONTHS Fibers/cm-1 MPPCF*** Negligible Low Medium Hi an 0 -0.4 0.5 - 1.9 2.0 - 10 over 10 0.011 0.014 - 0.054 0.057 - 0.28 aver 0.28 * Extracted from the Preface, Threshold Limit Values for 1968. American Conference of Governmental Industrial Hygienists, 1014 Broadway, Cincinnati, Ohio 45202. ' ** Ann. Occup. Hvg. 11, 47-69 (1968). _ *** Million particles per cubic foot(as fibers). The concentrations refer to fibers greater than 5 microns in length as determined by the memorane filter method. IV. DESCRIPTION OF SAMPLING AND ANALYTICAL METHODS Because of the current state of evaluation of the methods of assessing the potential hazard of asbestos dust, the standard impinger tecnnicue and the membrane filter technique were used in this survey. A. Impinger Method A midget impinger containing 10 ml of demineralized, distilled water was operated at 0.1 cfm air flow rate by means of a battery operated pump. Samples were agitated prior to withdrawing drops of suspension for examination in a Spencer Brightline Haemocytometer Cell. Particles were counted by viewing the sample with an objective lens of 0.25 Numerical Aperture (lOx) and a 15x Ocular. Approximately 200-300 particles were counted in each size class, except where frequency of occurrence in the viewing field was very-low, indicating concentrations in air far below the threshold limit value. The counting standard i /2 deviation was estimated to be , where N is the total count for the sample. A blank count was made on the distilled water. Dust concen tration in the air, expressed as millions of particles per cubic- foot (MFPCF), was calculated from the sample volume, liquid collection reservoir, and sample and blank dust counts. B. Membrane Filter Method A membrane filter (Type HA Millipore) was used to obtain samples for microscopic evaluation of fiber and dust particle concentrations. This paper is composed of pores 0.45 microns in size and has been shewn to retain, with 100% efficiency, particles down to 0.05 micron diameter^. The filter was first visually examined to detect any loose dust or uneven dust deposition. In the few cases where the filter deposit did not pass this examination it was necessary to resuspend the collected dust in distilled water and refilter this suspension on VF grade Millipore filter to assure an even dust distribution over the entire filter area. A pie shaped segment of the filter was then placed on a microscope slide and rendered completely transparent with Cargille certified index of refraction liquids. Cargille liquid of index of Megaw, W.j. and Wiffen, R.D.: Int. J. Air Wat. Poll. 1, 501 (1963). refraction 1.500 was usually most suitable. The counting of the dust particles and "the counting and sizing of asbestos fibers was performed with the aid of a Zeiss Photcmicroscope using Phase Contrast Illumination. The objective lens was a Zeiss Neofluor Ph 63x with a numerical aperture of 0.90. The eyepiece had a magnification of 20x and contained a calibrated Porton graticule. The optovar feature of the Zeiss scope contributed to the total magnification of 2Q16x. Resolution was approximately 0.25 microns. Particles and fibers of size 0.30 microns could be detected. In the evaluation procedure, all particles and fibers in the Fcrton field of view were counted and the fibers were grouped by fiber length into three categories (less than five microns, five to ten microns and large: than ten microns). This procedure was repeated for a number of randomly selected fields on the face cf the filter. Because only a portion of the total filter area was evaluated by this method, it was necessary to correct the count by the ratio of the total filter ar. to the evaluated area. The resultant particle or fiber number was divided by the volume of the air sample to obtain dust or fiber concentration, expressed as millions of particles per cubic foot (MFPCF). * The statistical reliability of the evaluation, was expressed as the standard deviation, calculated as where N is the particle or fiber count. The procedure outlined follows, in its essential points, that recommended by J. R. Lynch and H. E. Ayer in their article "Measurement of Asbestos Exposure" which appeared in the Journal of Occupational l* n n r wil n r Medicine, Volume 10, January, 1968. V. RESULTS AND DISCUSSION Measured concentrations of dust and asbestos fibers are summarized in Table 2. All samples were obtained in the breathing zone of men or "' W H W I an breathing level in areas where men were not at work at the time samples were obtained (in aisles, for instance). Impinaer and membran* filter samples were obtained simultaneously at the sites shown. Only at the last five sites were midget impingers used without simultaneous membrane filters operating.- . It is seldom that air sampling reveals a picture as consistent as the one depicted by the data in Table 2. With the exception of twc samples obtained with the impinger, all results indicate concentratio; in excess of the present U.S. Threshold Limit Value of 5 MPPCF. It loulu be noted that tne 'J.S.T.L.V. is in terms of total particles and not fibers alone. This approach stems from epidemiological methods initially used in surveying the asbestos industries. According to the ``ritish classification, three membrane filter samples were in the Medium dust category (0.057-0.28 million fibers (^5 um) per cubic foot) and the remaining six samples'were in the liich dust category ( 0.28 million fibers (}5 um) per cubic foot). These results suggest that with the present dust control facilities operating under optimum conditions of maintenance, dust concentrations are nigh in the Unibestos plant. . The highest concentrations of dust were measured at cutting stations and in the vicinity of the feed Stations.in the raw materials formulation area. The high results at the buildup station were due to dust from-the feed area backing up to the buildup area. /The high dust levels at the Uniclad area are surprising, but it was noted that the men use a special abrasive sponge to smooth the rolls and this may contribute to the dust. Exhaust hoods are not used in this area. , Possible major sources of the excessive dust are not hard to pinpoint and they will now be cited. A. Raw materials.formulation area. 1. Transfer of asbestos from bags to feed bins and recovered asbestos from the collection "houseM to bins are major sources cf dust emission. Present efforts directed at pneumatic pick-up cf scrap will reduce the latter source. 2. Line feed bin hoods are not effective based on measured face velocities. The new bin hood design is superior to the old design, bur tne need to open asbestos bags from the tops 'of bins results in low air velocities at the bases cf bin opening faces. The problem is the sloping face design of the bin entry. 3. Low room air velocities in the feed area indicates poor air turnover in this room. Velocities were 20-30 fpm. 4. Doors remain open in the scrap storage bin and dust enters the room as material drops to the base of the bin and "pulses" the dust laden air outward. 5. Floor sweeping and cleaning in this area generate a large amount'of dust. B. Unibestcs Cutting Area 1. Absence of hood at No. 3 Line Unloading Station. 2. Line No, 3 "push-pull" hood system at cutter is inefficient The "push" and "pull" areas are equal and the jet merely "splashes" off the "pull" hood after expansion in transit. 3. Line No. 3 exit hood ineffective. 4. Line No. 2 cutting hood is downdraft on tne left side, side draft on right side. The latter is ineffective. 5. The hood set-up for Line No. l,a canvas hood installed by the operator, appeared to work well and should be looked at for permanent design and use or. Lines 2 and 3. Thus, the problem in this area is really one of poor or non existent local exhaust hood design. It is beyond' the scope of-this report to present detailed hood designs." The designs required at these sites are not elaborate, but tne additional air capacity must be in the dust collection system. Information conveyed to the author ty Mr. Doiaway indicated that the present system does not have this capacit k_~- -6- :e and ne of imple tabu; DUST AND ASBESTOS FIBER CONCENTRATIONS AT SELECTED PLANT LOCATIONS Description of Sampling Site Du; ;l or Fiber Impingcr Sampling Particles Fibers Concentration, Fibers <T5 pm HPPcF t S t ai.dar.1 Deviation Membrane Filter Sampling Fibers Fibers 5 - 10 pm > 10 ,um Particles 1:05 PM- Loader BZ* Cutting 6.1 + 0.6 1:15 PM Unibestos (2* x 6") on Line No. 2 1:25 PM- Unloader BZ* Cut 1:35 PM ting Unibestos (2* x 6") on Line No. 2 6.2 +0.6 1:45 PM- Unloader BZ* Cut 1:55 PM ting Unibestos 12 1/2' x 16") Line No. 3 19.2 + 1.0 2:25 PM- Loader BZ* Cut 2:35 PM ting Unibestos (2 1/2' x 16") Line Ho. 3 28.3 + 1.7 ' 3:05 PM- General Back 3:15 PM ground in Aisles at breathing level. Opposite office adjacent to cutting area 2.9 + 0.4 1 4:20 PM- Raw Materials & 4:30 PM Line Formulation Area Line Feed Operator BZ* in vicinity of Lines 1A, IB, & 1C. Note: large amounts of visible dust. 10.0 + 0.7 Breathing Zone. 0.60 + 0.17 0.65 + 0.18 1.95 + 0.31 3.20 + 0.56 0.80 + 0.20 2.00 + 0.32 1.54 + 0.11 0.093 + 0.028 0.82 + 0. 11 0.077 + 0.034 2.17 + 0.19 0.14 + 0.05 1.62 + 0.15 0.23 A 0.06 0.93 + 0.11 0.49 + 0.08 4.74 + 0.28 0.51 ^ 0.09 0.051 + 0.021 2.40 + 0.1 0.015 + 0.015 2.34 + 0.1 0.017 + 0.017 3.62 + 0.2 0.071 + 0.032 2.44 + 0.1 0.44 + 0.08 6.69 + 0.3 0.22 + 0.06 5.72 + 0.3 TABLE 2 (con 'd) ime of Sample Description u Sampling Site !7 4:35 PM- Raw materials and 4:45 PM Line Formulation Area Background Sampling at breath ing level Dote: l.arge amounts of visible dust 28 8:30 AM- Breathing Level 8:40 AM Adjacent to Kiln (in aisle opposite control panel). 28 8:55 AM- Raw materials and 9:05 AM Line Formulation Area. Breathing Level in viciniLy of Lines 1 and 2 bins and adjacent to storage area. '28 9:35 AM- BZ* of builder 9:45 AM operator at Line No. 2 (2* x 6" rolls) /2B 9:50 AM- BZ* of builder 10:00 AM operator at Line No. 1 /28 10:05 AM Breathing level 10:15 AH. in storage areas behind Lines No. 1 and 2. Feed bins (Asbestos and Decalite bag storage) . Breathing Zone7 Dust or Fiber Concentration, MPPCF + Standard Deviation. . U.pin-jor Samplinj Mr-ml) ram* Filler Sampl i ng Fillers Fibers 1ibers Particles Fibers < 5 urn 5 - 10 urn >,10 urn Particles 44.3 + 2.1 6,40 + o!eo 4.43 + 0.29 1.88 + 0.19 0.72 + 0.11 7.07 + 0.36 2.3 + 0.3 0.40 + 0.14 1.40 + 0.16 0.15 + 0.05 0.074 + 0.037 7.38 + 0.37 5.2 + 0.5 0.50 + 0.16 4.75 + 0.29 0.57 + 0.10 0.31 + 0.07 6.98 + 0.35 32.0 + 1.8 9.20 + 0.96 9.7 + 0.7 0.50 .+ 0.16 26.3 + 1.1 2.10 + 6.32 i i i te and ne of ample Description of Samplinq Site TABLE 2 (continued) Dust or 1' 11 iOL ( Yjti t. ru( i on , V r M-i.i lai .1 Dovijiien Impinqer Sampling Membrane Filter Sampling Fibers Fibers Fibers Particles Fibers <5 um 5 - 10 um >-10 um Particles 28 10:25 AM- Cutting Area UZ* 10:35 AM of Line No. 1 Feed Operator (Cutting 16" x 2' rolls) 17.3 + 0.9 0.90 + 0.21 28 10:50 AM- Uniclad Area 11:00 AM DZ* operator 61.2 + 2.5 1.20 + 0.35 -- * _________ -- Breathing Zone. October 16, 1963 Dr. Lee Great Pittsburgh Plate Glees Corporation One Gateway Center ?ittsourgn, Pennsylvania Loar Lee; The Port Allegany Pleat survey report is enclosed. As you will see, my opinion based on the data obtained is that a dedasign oi the exhaust system is in order. I am fully aware of the future ei forts associated with this recommendation but cannot reach any otaer conclusion in view of the Measures tafcen to ensure ta&t tae system was .operating at high efficiency during ay survey. Thus, at best performance, it is just not good enough. In accordance with your request, the report does not dwell on d3sign aspects because our purpose was to determine where we stand at present* Sincerely yours. Morton Com, Ph.D. enclosure November 20, I?68 c-*riv a.54 X 3- o c-'TS* }'t. Byrl Stout "ice President - Manufacturing Pittsburgh Coming Corporation. (die Gateway Center Pittsburgh, Pennsylvania 15222 'r Tear Mr. Stout: Subject: Evaluation Of Oust Hazard Control In Hnibestos Operation - Port Allegany - August, 156b Attached for your information and appropriate action is a cover letter and report iron Or* Morton Corn and also a bill for professional services rendered. The subject evaluation indicates the need for a major redesign of the present dust collecting system to effect asbestos dust control within the plant to safe levels. Or. Corn has agreed to assist in the above redesign at such time as- you require. For this further assistance, you nay contact him directly. Sincerely, Lee 3. Grant, X.T. Medical Director LHGjIct Attachments cct ftr. L. 0. Griffith Or. Horton Com fe INDUSTRIAL HYGIENE AIR POLLUTION V. Morton Corn. pk. d., b. Ch CONSULTIN''. ENGINEER 3 10 EOWEFI HILL ROAD PITTSBURGH. PENNSYLVANIA 15223 e. BILLING telephone A 1 2 ESI.6233 PPG INDUSTRIES For services rendered in conjunction with Industrial Hygiene Survey of Dust Concentrations in Unibestos Facility, Port Allegany, Pennsylvania Plant, Pittsburgh-Corning Corporation. August 27-28, 1963 Consultation Fee four (4) days at $200 per day ................................................. $300.00 Travel and Maintenance Expenses Automobile travel: 459 miles at $0.10 per mile ......................................... Hotel (2 nights) .................................................................................. Meals ............................................................................ ................................ 45.90 19.40 18.50 TOTAL $883.30