Document 7MRoagnGX18rqdg6wQR4zB1xo

Kilos -m-?4-s) n.^leidel / USPHS/NIOSH MEMBRANE FILTER METHOD FOR EVALUATING AIRBORNE ASBESTOS FIBERS I SCOPE A This method describes the equipment and procedures for collecting, mounting, sizing, and counting asbestos fibers on membrane filters in the evaluation of breathing zone samples of airborne asbestos fibers. B The method has been successfully applied using 37 mm Millipore AA filters and small battery operated personal sampling pumps at a flow rate of 1.0 to 2.5 liters per minute for time periods of IS to ISO minutes at concentrations of 1 to 20 fibers (longer than 5 micrometers)/cubic centimeter. Large deviations from these conditions may result in filters with either too few or too many fibers, which will yield air concentration estimates of low statistical precision and accuracy. C This method considers only fibers with a length to width ratio of 3 to 1 or greater and a length greater than 5 micrometers. II SUMMARY OF METHOD A The sample is collected by drawing air through a membrane filter by means of a battery powered personal sampling pump. The filter is transformed from an opaque solid membrane to a trans parent, optically homogeneous gel. The fibers are sized and counted by phase-contrast microscope at 400-4S0X magnification. Ill SIGNIFICANCE A This method was first used by the Asbestosia Research Council in Great Britain^) and later was slightly modi fied by the U. S. Public Health Service for asbestos dust studies in the United State s^ 2). It has been specified as the . method of test^3) for the Federal Standard Prepared by Nelson A. Leldel, Stephen G. Bayer, and Ralph D. Zumwalde, NIOSH, 11/73. for asbestos in industrial air (29 C. F. R. Part 1910. 93a), in the U.S. Public Health Service Criteria Document on occupational exposure to asbestos^4), and in sampling procedures of the Occupa tional Safety and Health Administration, Department of Labor/5) IV DEFINITIONS A For definitions of terms used in this method, refer to ASTM Definitions D 1336, Terms Relating to Atmospheric Sampling and Analysis. V INTERFERENCES All particulates with a length to width ratio of 3 to 1 or greater and a length greater than 5 micrometers should, in the absence of other information, be considered to be asbestos fibers and counted as such. VI APPARATUS A Sampling Equipment . The personal sampling equipment train consists of l) personal sampling pump, 2) tubing, 3) clothing spring clip, 4) tubing-to-field monitor metal adaptor, and S) field monitor (collecting filter and holder). 1 . Personal sampler pump. The pump must be battery powered and weigh less than 2 pounds (0.91 kg). The pump must be capable of sampling at 1.0 to 2.5 1pm against a flow resis tance of 7.5 inches H2O (1.4 cm Hg) for 8 continuous hours on a fully charged battery. See Note A for sources of pumps that have been found satisfactory for this method. 2 Tubing. Laboratory tubing such as rubber or plastic with 6 mm bore (l/4 inch) and about 90 cm length (3 feet). PLAINTIFF'S EXHIBIT AL-997 J USFHS/NIOSH Membrail* Filter Method .....'** i 3 Clothing spring clip. This clip attaches the rubber tubing to the.lapel or shirt of the Individual being moni tored. See Note B for the source of a clip that has been found satisfactory for this method. Large spring paper clips will also work. 4 Tubing-to-field monitor adaptor. See See Note C for a source of an adaptor that has been found satisfactory. 5 Field monitor (collecting filter and holder!. The only field monitor currently approved by the National Institute for Occupational Safety and Health is manufactured by the Millipore Corporation. The unit consists of: l) A three-section styrene plastic case designated Millipore Aerosol Monitor Case. 2) a 37 mm diameter plain white cellulose ester membrane filter designated Millipore AA (nominal pore size of 0.8 micro meter) , 3) a support pad, and 4) two plastic sealing caps. . If a large num ber of samples are to be taken, it will be less expensive to reuse the plastic cases. Great care must be taken in the cleaning and reassembly process. The outside mating surfaces of the field monitors should be covered with 'shrink-fit" sealing bands to seal the units and provide a writing surface for filter identification. See Notes D and E. B Optical Equipment For general guidance on microscopes consult Needham(6) and Clark*" under phase contrast microscopes and accessories. - 1 Microscope body with binocular head. 2 10X Huygenian eyepieces are recom mended. Other eyepieces can be substituted if necessary.3 3 Koehler illumination (preferably built in and having provisions for adjusting light intensity). 4 A Porton reticle is recommended. Others such as the Patterson Globe and Circle can be substituted, if necessary. 5 Mechanical stage. 6 Abbe or Zeraike condenser fitted with phase ring (or Heine) with a numerical aperture (N. A.) equal to or greater than the N. A. of the objective. 7 40-45X (N. A. 0. 65 to 0. 75) positive phase contrast achromatic objective. 8 Phase-ring centering telescope or Bertrand lens. 9 Green filter, if recommended by microscope manufacturer. 10 Stage 'micrometer with 0.01 mm subdivisions. C Filter Mounting Equipment Experience has shown that certain equip ment is useful for efficient sample mount ing. The following items are recommended for extracting and mounting a portion'of' the filter onto the microscope. 1 Microscope slides: 2.5 by 7.5 cm (one inch by three inches) glass slides are most commonly used. Sample . number, data, initials, etc., can be conveniently written on a frosted end slide. 2 Cover slips: Cover slips are a neces sary part of the slide mount and optical system. The shape should be appro priate for the size of the filter wedge. The appropriate cover slip depends upon the objective to be used. Ordi narily objectives are optically cor-, rected for all 1/2 (0.17 millimeter) thickness cover slip. Improper cover glase thickness will detract from the final image quality. 3 Scalpel: A scalpel is needed to re move a portion of the filter to be ) ) 2 J I t USPHS/NIOSH Membrane Filter Method examined. A number-ten curved blade scalpel works very well. 4 Tweeters: A pair of fine-tipped tweeters is used to remove the membrane filter slice from the field monitor and place it upon the slide. 5 Lens tissue: To insure cleanliness, use of a lint-free lens tissue is recommended. This tissue should also be used for wiping mounting tools and for cleaning slides and cover slips. 6 Glass rod or spatula: A spatula or fire-polished glass rod is needed to spread the mounting solution on the slide. 7 Wheaton Balsam bottle; This special glass container has a glass top which prevents contamination of the mounting solution. A glass rod is included for dispensing the solution. Vn REAGENTS Chemicals should be reagent grade, free from particles and color, conforming to the specifications of the Committee on Analytical Reagents, at the American Chem ical Society, where such specifications are available. A Dimethyl Phthalate B Diethyl Oxalate Vm SAFETY PRECAUTIONS A Avoid getting the mounting solution on the skin. Wash skin with soap and water if contact occurs. DC SAMPLING A General Information Refer to the Recommended Practice D 1357, for Planning the Sampling of the' Atmosphere and Recommended Practice D 2009, for Collecting by Filtration and Determination of Mass, Number, and Optical Sizing of Atmospheric Particu lates. These guides are cited only for general principles, as they are intended primarily for air pollution measurements at fixed sampling stations. B Calibration The personal sampling pump should be recharged prior to calibration and then calibrated^) against a bubble meter, wet test meter, spirometer, or similar device at 1.0 to 2. 5 1pm. The sampling train used in the calibration (pump, hose, filter) should be the same as the one used in the field. The calibration should be of sufficient accuracy that the 98% con fidence limits on the flowrate are + 10% (two standard deviations). C Mounting the Sampler Fasten the sampling pump to the worker1 s belt and fasten the field monitor to the lapel or shirt front (as close to the face as is practical). Remove the cover of the plastic monitor making certain the exposed filter is facing downward. Turn on the pump and adjust to the previously calibrated flowrate (1.0 to 2.5 1pm). Immediately record the following informa tion in a logbook: 1 Filter number 2 Pump start time and date 3 Flow rate 4 Subject1 s name 5 Type of operation 6 Ventilation controls and/or if worker is wearing a respirator approved for asbestos. The pump should be checked periodically during the sampling period for proper operation and flowrate. D Optimum Sampling Times Leidel(9) has described the requirements for optimum sampling times for airborne 3 HSrilS/NlOSH Membrane Filter Method iishfstos fibers. A nomogram to aid in the calculation of these times is shown as Figure 1. For typical microscope field areas and pump flow rates the optimum collection times are about SO to RO minutes. The nomogram is in tended an a guide to be used where no prior knowledge of the air concentration is uvailable. If. after sampling for the times recommended by Figure 1, the sample is very heavily loaded (greater Ilian 10 fibers/field), then the air con centration probably greatly exceeded the ceiling standard of 10 fihers/cm^. Conversely if the filter fiber density is very low (less than 1 fiber/field) then the air concentration probably was less than the 1976 TWA Standard of 2 fibers/cm3. The nomogram gives the the sampling times which produce optimum fiber densities on the filter (I to 5 fibers/field) for air concentrations <>f 1 to 10 fibers/cm^. If the air concentrations are very high or verv low, then graphs given by l.eidc)i9} would aid in the calculation of the proper sampling times. If there is . a dense-visible cloud, short (5-IS min utes) sampling times should probably be used. To sample for the ceiling standard of 10 fibers/cm3, a 15-minute period should be used. K Knd of Sampling Period llrmove the field monitor, replace the plastic top cover and the small end caps, and store the monitor. Always shut off th<* pump when changing monitors to avoid contaminating or damaging the pump. Record the pump shutoff time in the logbook. F Blanks With each batch (25 to 50 filters) of samples aubmit two unopened filters which have been subjected to the same handling as the samples except that no air has been drawn through them. Label these as blanks. If the blanks yield fiber counts greater than about 5 fibers/ 100 fields, then the entire sampling 4 procedure should be examined carefully for the cause of contamination. G Shipping The field monitors in which the samplers are collected should be shipped (n a rigid container with sufficient packing material to prevent crushing. H Numbers of Samples When sampling for the ceiling standard only one sample (15-minute minimum duration) is theoretically necessary. How ever, several 15-minute samples should be taken during expected periods of peak air concentrations to allow for detection of gross sampling or counting errors. When sampling for determination of noncompliance with the 8-hour TWA Standard one ahould continuously sample as large a portion of the work day as la feasible. Normally this would mean 6 to 10 con secutive samples on the same man. How ever, if this is not feasible the 8-hour TWA air concentration can be estimated from fewer than 6-10 samples. Leidel and BuschOO) have shown an optimum number would be 4 to 7. Refer to (10) for treatment of the data for the determination on noncompliance. See Jones and Br^ierfU) for how to treat data taken for an environ mental monitoring program. X CALIBRATION AND STANDARDIZATION A Porton Reticle The asbestos fiber count procedure con sists of comparing fiber length by com parison with calibrated circles, and counting all fibers greater than 5 micro meters in length within a given counting field area. It la recommended that a Porton reticle be used for this purpose. . The Porton reticle is s glass plate in scribed with a series of circles and rectangles. The square on the left, divided into six rectangles, is defined as the counting field. DSPHS/NIOSH Membrane Kilter Method B Placement in Eyepiece The Porton reticle is placed inside the Huygenian eyepiece where it rests on the field-limiting diaphragm. The reticle should be kept clean, since dirt . on the reticle is in focus and will com plicate the counting and sizing process. For mounting in other eyepieces such as a Ramsden, a counting collar must be used. C Stage Miorometer The Porton reticle cannot be used for counting until it has been properly calibrated with a stage micrometer. Most stage micrometer scales are approximately two millimeters long and are divided into units of one-hundredth of a millimeter or ten micrometers. D Microscope Adjustment Follow the manufacturer's instructions while observing the following guidelines. 1 The light source image must be in focus and centered on the condenser iris or annular diaphragm. With a 10X objective in place, place the stage micrometer on the mechanical stage, focus, and center the image. Change to the 40-4SX objective and adjust the first scale division to coincide with the left boundary of the Porton rectangle. Count the number of divisions between the left and right boundaries of the long horizontal dimension of the largest rectangle, estimating any portion of the final division. This measurement repre sents 200 L units and one divides the measurement by 200 to find "L". The large rectangle is 100 L. units long on the short vertical dimension. The calculated "L" is inserted into the formula D = L (2N)I where "N" is the circle number (indicated on the reticle) and "D" is the circle diameter. Since the circle diameters vary logarithmically, every other circle doubles in diameter. For example, number three is twice the diameter of number one; number four is twice the diameter of number two. When the circle sizes have been determined, the counting field area consisting of the left six smaller rectangles can be calcu lated from the relation iO.OOO L2. This completes the reticle calibration for this specific objective - eyepiece - recticle combination. 2 The object for examination must be in focus. XI PROCEDURE 3 The illuminator field iris must be A Mounting in focus, centered on the sample, and opened only to the point where the field of view is illuminated. A very important part of the sample eval uation is the mounting process. This process involves a special mounting 4 The phase rings (annular diaphragm and phase-shifting elements) must be concentric. medium of prescribed viscosity. The mixture must be stirred periodically until the filters have dissolved and a homogeneous mixture is formed. The normal shelf life of the mounting solution E Porton Reticle Calibration Procedure is about six months. Twenty milliliters of mounting solution will prepare approxi Each eyepiece-objective-reticle combina mately 300 samples. tion on the microscope must be calibrated. Should any of the three be changed (dis assembly, replacement, zoom adjustment, B Sample Mounting etc.) the combination must be re-calibrated. Calibration may change if interpupillary distance is changed. For proper calibra tion, the following procedure should be followed closely. Cleanliness is important! A dirty work ing area may result in sample contamina tion and erroneous counts. The following steps should be followed when mounting a sample. 5 USPHS/NIOSH Membrane Filter Method 1 Clean the slides and cover slips with lens tissue. Lay the slide down on a clean surface with the frosted end up. It is a good practice to rest one edge of the cover slip on the slide and the other edge on the working surface. By doing this, you keep the bottom surface (the one which contacts the filter) from becoming contaminated. 8 Label the slide with the sample num ber and current date before proceed ing to the next filter. 9 The sample should become transparent after about fifteen minutes. If the filter appears cloud/, it may be nec essary to press very lightly on the cover slip. This is rarely necessary. 2 Wipe all the mounting tools clean with lens tissue and place them on a clean surface (i.e., lens tissue). When mounting a series of filters the scalpel should be wiped clean before cutting each sample. 3 Using a glass rod which is supplied with the Wheaton balsam bottom, apply a small drop of mounting solu tion onto the center of the slide. It may be necessary to adjust the quanti ty of solution used or the size of the wedge. The correct amount will re sult in the solution extending only slightly beyond the filter boundary. If the quantity is greater than this, adverse particle migration will occur. 4 With the spatula or a supplemental glass rod, spread the mounting media into a triangular .shape. The size of this triangle should coincide with the dimension of the filter wedge. 5 Separate the middle and bottom sec tions of the field monitor case to ex pose the fragile filter. Cut a triangu lar wedge from the center to the edge of the filter using the scalpel. The size of the wedge should approximate oner-eighth of the filter surface. 10 Discard the sample mount after three days if it has not been counted. Crys tals which appear similar to asbestos fibers may begin to grow at the mount ing media/air interfaces. They sel dom present any problems if the slide is examined before three days. In any case, stay away from the filter's edges when counting and sizing. C Counting and Sizing 1 Finding and inspecting counting fields. Place the slide on the mechanical stage and position the center of the wedge under the objective lens and focus upon the sample. Nearly all of the particulates {particles and fibers) will be found in the upper ten to fifteen micrometers of the filter surface. When counting and sizing, continual use of the fine focus control is required to insure that nothing is missed. Start counting from one end of the wedge and progress along a radial line to the other end (count in either direction from circumference to wedge tip). Random fields are selected, without looking into the eyepieces, by slightly advancing the slide in one direction with the mechanical stage control. 6 Grasp the filter wedge with the tweezers in the outer area of the filter which was clamped between the monitor case sections. Do not touch the filter with your fingers. Place the wedge, sampled side up, upon the mounting medium. 7 Pick up the cover slip with the tweezers and carefully place it on the filter wedge. Once this contact has been made, jdo not reposition the cover silo. D Achieving Comparable Results 1 Size only fibers with a length to width ratio greater than or equal to 3:1. 2 Count only fibers greater than S micro meters in length. (Be as accurate as possible in accepting or rejecting fibers near this length). Measure curved fibers along the curve to estimate the total length. )" J t % USPHS/NIOSH Membrane Filter Method 3 Count as many fields as necessary to yield a total count of at least 100 fibers. Exceptions: a) count at least 20 fields even if you count more than 100 fibers and b) stop at 100 fields even if you haven't reached 100 fibers. 4 Select the field of view without look ing through the microscope1 s eye piece s to eliminate unconsciously selecting "heavy" or "light" areas. Reject and do not count all other fibers. Refer to Figures 2 through 7. XU CALCULATIONS A Calculation of Airborne Concentration Asbestos fiber airborne concentration may be calculated from the following formula: (F - BXW) (A)( V) 5 The fields are selected along the entire length of a radial line running between the outside perimeter and the tip of the wedge. Where: C = Airborne fiber concentration in fibers >5 Mm/cm^ 6 When an agglomerate (mass of mate rial) covers a significant portion of the field of view (approx. l/6 or greater) reject the field and select another. (Do not include it in the number of fields counted). However, report the fact as it may have mean ing to sampling or medical personnel. F * Average fiber count in fibers >5 Mm/field. B* Average fiber count of blank( s) or control filterfs) in fibers >5 /*m/ field. (It is subtracted to elimi nate the error or background con tamination). 7 Bundles of fibers are counted as one fiber unless both ends of a fiber crossing another can be clearly re solved. 8 For fibers that cross either one or two 8ides of the counting field, the following procedure is used to Ob tain a representative count. First, arbitrarily select a) the left and bottom sides and b) the upper and lower left corners or vertical di rection as "decision aids. " W" 855 mm^ for 37 mm diameter filter (the portion of the Millipore filter which is exposed when mounted in the field monitor case, i.e., the effective filter area). A The area of the counting field of a calibrated reticle expressed in mm^/field. V Total air volume collected through filter expressed in milliliters. Then count any fiber greater than 5 micrometers in length, but only if the fiber: a lies entirely within the counting area or, b crosses the left or bottom sides, or c crosses the upper or lower left corners, or XIII PRECISION AND ACCURACY A An accuracy and precision study of the membrane filter counting procedure for asbestos has been conducted by Conway and Holland. (12) They conducted an intralaboratory study involving six counters. Three of the counters were experienced while the other three had only a short familiarization with the rules for fiber counting. The conclusions of the study included: d crosses both the top and bottom sides. 1 The precision of the procedure for filters not containing an abundance of 7 USPHS/NIOBH Membrane Filter Method fine fibers can be estimated by a standard deviation of 16.2%. This value includes variation among counters and observed interaction effects. 2 The accuracy of the procedure for similar filters may be estimated for a 100-fiber cotun by a standard deviation of 21.4%. This assumes that the contribution of the overall variance from the nonuniform fiber distribution is additive. 3 The fiber concentration varies significantly between angular sectors on a given filter. Where approximately 100 fibers are counted, the standard deviation of the fiber count distribution for the whole filter appears to be. represented by 1,6 * <n)l. rather than (n)J which is a property of the Poisson distribu tion. where (n) is the total number of fibers counted. 4 A high percentage of very fine fibers on the filter can significantly affect the standard deviations and confi dence limits for counts by different counters. After combining variations in fiber concentrations over the entire filter with those for different counters it was concluded: a For filters with a low concentra tion of fine fibers, the standard deviation is estimated at 21% and the 95% confidence interval is 43%. b For filters with a high concentra tion of fine fibers, the standard deviation is estimated at 25% and the 95% confidence interval is 50%. B Lynch, Kronoveter, and Leidel^1^ have also reported on the precision of the method. Their intralaboratory study utilized the data from a large number of dust counts made by different methods by experienced counters over a period of years in an epidemiologic study of the asbestos products Industry. They concluded that the standard deviation of counts of fibers longer than 5 micrometers on membrane filters could be estimated from the relation * (n)0*591. Thus for counts of about 100 fibers, the stan dard deviation could be estimated at about 15. 2% and the 95% confidence limits at + 30.4%. These values are lower than the precision values reported by Conway and Holland. (12) REFERENCES 1 Asbestos Research Council: "The Measurement of Airborne Asbestos Dust by the Membrane Filter Method: Technical Note," Dr. S. Holmes (Secretary) P.O. Box 40, Rockdale Lancashire. Great Britain (1969). 2 Edwards, G. H. , and J. R. Lynch: "The Method Used by the U. S. Public Health Service for Enumeration of Asbestos Dust on Membrane Filters," Annals of Occupational Hygiene. 11. 1-6 (1968). 3 Federal Register. 37. 22142-22144 (18 Oct. 1972). 4 U. S. Department of Health, Education, and Welfare, Public Health Service, National Institute for Occupational Safety and Health: "Criteria for a Recommended Standard-Occupational Exposure to Asbestos," HSM-72-10267 (1972). 5 U.S. Department of Labor, Occupational Safety and Health Administration, "OSHA Sampling Data Sheet No. 2-Asbestos," (Unpublished - Jan. 1972). 6 Needham. G. H.: "The Practical Use of the Microscope," Charles C. Thomas Publishing Corp. Springfield, Illinois (1958). 7 Clark, G. L.: "The Encyclopedia of Microscopy," Rhelnhold Publishing Corp. N.Y. (1961). 8 American Conference of Governmental Industrial Hygienists: "Air Sampling Instruments for Evaluation of Atmospheric 8 USPHS/NIOSH Membrane Filter Method 1 Contaminants," Fourth Edition, Section Kj Air Movers and Samplers, pp K-28K-31, P.O. Box 1937, Cincinnati. Ohio <1972). 9 Leidel, N. A.: "Optimum Sampling Times for Airborne Asbestos Fibers," USPHS, NIOSHTH-82. (1972). 10 Leidel, N. A., and K. A. Busch: "Statistical Methods for the Determina tion of Noncompliance with Occupational Health Standards." USPHS. NIOSH TR-76, (To be published 1973). 11 Jones, A. R., and R. S. Brief: "Eval uating Benzene Exposures," AIHA J. 32. 610-613 (1971). 12 Conway, R. E., and Holland, W. D.: "Statistical Evaluation of the Procedure for Counting Asbestos Fibers on Mem brane Filters," LFE Corporation Richmond, CA. Prepared for Asbestos Information Assoc/North America, New York, N.Y. (1973). 13 Lynch, J. R., K. J. Kronoveter, and N. A. Leidel: "Validity of the Poisson Distribution in Dust Counting," USPHS, NIOSH. TR-83, (To be published 1973). ACKNOWLEDGEMENTS: The authors gratefully acknowledge the suggestions and assistance of the following individuals: Philip J. Bierbaum, George A. Carson, R. Earle Conway, John M. Dement, Lorice Ede, Harry Ettinger, Geoff Knight, William H. Krebs, Kay Kumler, Jeremiah R. Lynch, Robert Magor, and Milton Sheinbaum. Special thanks are due John F. Vlning, in for assembling the initial version of this report. Finally very special thanks are due Myra D. Brooks, Mary K. Geimeler, and Pauline J. Elliott for typing the many versions of this report* NOTES A Sources of personal sampler pumps 1 Mine Safety Appliance Company 201 North Braddock Avenue Pittsburgh, PA 15208 2 National Environmental Instruments, Inc. P. O. Box 590 Warwick. RI 02888 3 Willson Products Division P. O. Box 622 Reading, PA 19603 B Source of clothing soring clip Catalog number 1140 John F. McGuire Company 120 Bacon Street Pawtucket , RI 02860 C Source of tubing-to-field monitor adaptor Catalog number LH/L Bection, Dickinson, & Company Rutherford, NJ d gQHrss. of-fte.te .inflaAiac. 1 Complete monitor (plastic case, filter, pad, and caps), catalog number MAWP 037AO (50/box). 2 Filters and pads only, catalog number AAWP 03700 (100/box). 3 Monitors only, catalog number M0000 37AO (50/box), from the Millipore Corporation Ashby Road Bedford, MA 01730 e Sonrse. 9t.gtrilngJaag Cellulose bands, white, opaque, 41 X 25, #28 (minimum order 2500) Walter H. Jelly & Company 2822 Birch Street Franklin Park, 1L 60131 9 - Ie w |r * a foe o p tim a sampling times fo r airborne aebestoe fib e rs . USPHS/N10SH Membrane Filter Method 2>U<U * V3UV (D3U 3dCOSOWDIW - V s3 s oo e o cf o It. .ill.II . I i. .1 I . . . . I . l . . I i i l 11 . I I . t II I t I 1 8 M UJ sE El *I- CM * j ^ O 2* : sjs y oi! > z </ O I " * S bl uj < oc T r~r i l i l i | l I ll| s .s mu|Ui *3WI1 9NHdWVS /NriflllrfO 2 * 31Vd MO*U dWfld-MJ 10 KySlualWC Airborne Asbestos Dust........... i i * r f oooOOOO I....tw II I) Figure'2. COUNT, fiber crocees both top ad bottom sides. S> 4 I a f O o.oowOOOO Ilews w i Figure 3. COUNT as one fiber. NlS4r t oooooQO O am? ? ? 4 Figure 4. COUNT, fiber crosses left side. Figure 5. COUNT, fiber crosses bottoe side. 6n<i i ) t t r o O o O__ O OO 144te W 4 Figure 7. COUNT, fiber crosses upper left corner. \7s . N I I 4 t ( t | * N*l 1 1 4 O o O o 41 oO "in I OO n PRE-SELECTED ADJACENT SIDES MoK |0obWt* S' \b * ^ {.|^ Ifr^X I * M+Ch **.7/< ^ 'lOjA. **SoX I 00 b *wjb ^ 0?C W<*f ~ IP b -W* * TSVfl *(* ofS/m**), - >o7 ixs~ / CiA-*7 A* ) I % Evaluating Airborne Asbestos l)iim If Part No. T113, Model BC Personal Air Sampler complete with pump, rechargable battery, and sampling head (Including cyclone and pre-welghcd cassette $213.00 Part No. T16124, Battery Charger with charging leads lor above $ 50.00 Part No. T121, pre-weighed cassettes, 10 cassettes/package $ 13.00 Willson Products Division, ESB Inc. P. O. Box 622 Reading, Pa. 19603 Milllpore Field Monitors, Cat.No. MAWP 037 A0, 50/carton Millipore field monitor refills, Cat.No. AAWP 037 00, 100/box Forceps Millipore Corporation Bedford, Mass. 01730 Dispensing Buret, 1000 ml or 2000 ml (any chemical supply house) Diethyl Oxalate (Ethyl Oxalate) Dimethyl Phthalate (Methyl Phthalate) (any chemical supply house) A/v\ $ 30.00 ' - 1) N51MP Series 50 Phase Teaching Microscope wil^i 4x scanning objective, lOx phase 45x phase object Ives^0^4. 2) Case for above, Cat.No. A01650 (optional) 3) Spare bulb. Cat.No. A0611 4) Burrell Cat.No. 58-492, AO-400 microscope stage micrometer, 2 mm scale in 200 parts on 75 x 25 nun slide 5) Huygenian eyepiece lOx, AO-C1142 (must accept 21 mm dia. eyepiece reticle) 6) Part No. 30,084 porton reticle 7) Cat.No. 12-552 microscope slides, 75 x 25 mm, one frosted end 8) Cat.No. 12-520B micro cover glass, square, size 22 mm sq 9) Lens tissue 10) Luer Slip adapter. Cat.No. LH/L 1/4" I.o. hose connector Burrell Corporation 2223 Fifth Avenue Pittsburgh, Pa. 15219 1-2-3-4-5 Edmund Scientific Co. 300 Edscorp Bldg. Barrington, N.Ji 08007 6 Fisher Scientific Co. 7-8-9 585 Alpha Drive Pittsburgh, Pa. 15238 (or any chemical supply house) Environmental Compliance Corp 400 Greentree Rd. Pittsburgh, Pa. 15220 10 $448.00 $ 38.00 $ .50 $ 30.00 $ 30.00 $ 17.50 $ 5.40/ gross $ 3.06/< $ %.75 ASBESTOS COUNT RECORD SHEET / SAMPLE OPERATION FLOW TIME VOLUME DATE___________________________________________ FILTER AREA (bus2) __________ FIELD AREA (a2 ) __________ K AV .COUNT__ CONCENTRATION COMMENTS SUB-TOTALS FIBERS/ FIELDS AVERAGE NET COUNT X X AIR VOLUME SAMPLED (ITT FIBERS/al