United States Environmental Protection Agency Water Engineering Research Laboratory Cincinnati OH 45268 Research and Development EPA/600/S2-87/091 Jan. 1988 AEPA Project Summary Evaluation of Encapsulants for Sprayed-On Asbestos- Containing Materials in Buildings W. Mirick, E. W. Schmidt, C. W. Melton, S. J. Anderson, L J. Nowacki, and R. Clark About 150 water-based liquid coat- ings sprayable by conventional airless paint-spraying equipment were applied to 2-in.-thick sprayed, mineral wool test matrices mounted overhead. After curing, specimens of the encapsulated test matrix were tested for fire resist- ance, flame spreading index, smoke generation, and toxic gas release. Cohesive and adhesive strengths were measured as well as impact resistance. All of the criteria established for satisfactory performance were met by 11 coatings and 19 others met most of the criteria. Special circumstances explained in the report text caused two more to be rated ''acceptable" and another two to be rated ' 'marginally acceptable." This Project Summary was devel- oped by EPA's Water Engineering Research Laboratory, Cincinnati. OH. to announce key findings of the research project that is fully docu- mented in a separate report of the same title (see Project Report ordering information at back). Introduction There is an increasing awareness of the carcinogenic properties of asbestos fibers. One possible source of exposure of the general population to this contam- ination is from deteriorated, friable, sprayed-on, asbestos-containing mate- rials These materials were used in the construction industry until banned by the U.S. Environmental Protection Agency in 1978. Much of this asbestos-containing material is in a loosely bonded form. It was applied to ceilings and structural steel columns in public buildings for thermal insulation, fireproofing, acous- tical insulation, and even as decorative finishes. It is presently found in such buildings as schools, apartments, night clubs, hotels, office complexes, and industrial plants. The research program described herein was undertaken to: 1. determine what commercial pro- ducts, if any, are available that could be used as encapsulants to either contain, prevent, or restrict the release of asbestos fibers from friable asbestos-containing mate- rials; 2. determine methods of evaluating these commercial products for their efficiency as encapsulants; 3. determine the effectiveness of the methods used to evaluate a group of commercial products; and 4. evaluate fiber release during field trials. Methods Initially, 74 commercially available candidate encapsulants were identified using standard communication methods, such as telephone, contacts, direct mailings, and an insert in the February 1 0, 1 978, issue of Commerce Business Daily. Later, in Phase II, an additional 84 ------- commercial products were identified giving a total of 158 candidate encapsulants. Desired Encapsulant Properties The researchers developed the follow- ing list of properties an effective encap- sulant should exhibit. The encapsulant should: 1. Seal or lock in the asbestos fibers by either bridging over the surface or penetrating into the matrix (asbestos-containing materials), 2. Not add any toxic substance to the insulation and also not break down under direct flame impingement to release any toxic gases or an undue amount of smoke, 3. Not reduce significantly the fire- retardant properties of the insulation, 4. Be applied with a minimum of effort and technical skill, 5. Have sufficient impact resistance, flexibility, and resistance to pene- tration to withstand some moder- ate physical contact, 6. Be water insoluble when cured, 7 Be nontoxic and without noxious fumes during application, and 8. Have sufficient aging characteris- tics to withstand normal atmos- pheric changes for a minimum of 6 years and still have sufficient surface integrity to allow recoating. Encapsulant Classifications Each encapsulant was classified by type of resin used for the binder and whether or not the encapsulant was pigmented. Further screening consisted of determining the percent solids and viscosity of each encapsulant and its degree of penetration into the test matrix. The test matrix consisted of a dry- blended, non-asbestos-containing insu- lation (United States Mineral's Cafco Blaze Shield D C/F)* that was spray applied approximately 5.1 -cm (2-in.) thick on a foam insulation board. This test matrix exhibited key properties such as high friability, poor cohesive strength, and high water absorption. These are similar to the properties of the spray- applied, asbestos-containing insulation that had been removed from an existing site for use as the control matrix. From the results of the screening program, it was possible to divide the initial 74 encapsulants into 2 distinct groups. The first group (43 encapsulants) was classified as bridging encapsulants, and the second group (31 encapsulants) as penetrating encapsulants. The bridging encapsulants were defined as those that formed a contin- uous surface membrane over the test matrix. These encapsulants also exhibit minimal penetration into the test matrix (0.6 cm [0.25 in.] maximum) even when reduced up to one-third with water. The bridging encapsulants, in general, were above 35% solids (maximum 50%) and had high viscosities (greater than 1,000 centipoise). The penetrating encapsulants were defined as those that penetrated 0.5 to 3 cm (0.25 to 1.25 in.) into the test matrix and thus improved the cohesive strength of the friable matrix to the depth of penetration. The adhesion of the matrix to the underlying substrate can also be improved when the encapsulant pene- trates all the way through the asbestos- containing material to the substrate. In general, the penetrating type encapsu- lants were low in solids (minimum 15% to 35%), nonpigmented, and had low viscosities (water thin). After initial screening evaluation, division of the encapsulants into 2 groups (bridging and penetrating), and classifi- cation by resin binder, the following 10 encapsulants were selected for more extensive evaluation in Phase I (Table 1). This selection was based on the following factors: 1. Inclusion of as many types of resin binders as possible, 2. Inclusion of both encapsul' groups, i.e., bridging and penetr ing, and 3. Meeting the properties desired for an effective encapsulant. The 10 encapsulants selected for an effective encapsulant evaluation in- cluded 3 bridging and 7 penetrating encapsulants. The predominance of the penetrating encapsulants was because they appeared to exhibit more of the desired properties for an effective encapsulant, e.g., improving the cohesive strength of the matrix and improving the adhesion of the asbestos-containing materials to the substrate when complete penetration was achieved. Extensive Evaluation The 10 encapsulants selected for extensive evaluation and those encapsu- lants with similar resin binders included 64 of the 74 encapsulants received. The remaining 10 encapsulants included 7 other classes of resin binders. Although several of these encapsulants exhibited promise, no further work was done with them in Phase I of the study because the limit of 10 encapsulants for extens. evaluation and because the 10 encap- sulants selected for this evaluation included a greater representation of the commercial encapsulants submitted as classified by type of resin binder. The selection of these encapsulants did not mean that the other encapsulants were considered unsatisfactory. The extensive evaluation included determination of flexibility (bend), impact strength, and abrasion properties. In most cases, these physical properties were determined with the encapsulants applied by airless spray onto metal panels. Table 1. Encapsulants Evaluated in Phase I "Mention of trade names or commercial products does not constitute endorsement or recommenda- tion for use. Class of Type of Binder Vinyl acrylic Butyl rubber Epoxy. two-component Acrylic Acrylic Acrylic Polyester Polyvinyl acetate copolymer Acrylic vinyl acetate copolymer Polyester, acrylic-modified Group Penetrating Bridging Bridging Penetrating Bridging Penetrating Penetrating Penetrating Penetrating Penetrating Battelle Code 3377 5 -3 B " 4A " -4B " -12B " -13B " -15B " -15C " -19A " -21 A " -21! ------- The encapsulants were also examined _jr smoke generation and toxic gas release. For these evaluations in Phase I, the encapsulant was applied to three substrates: (1) asbestos board, (2) non- asbestos friable test matrix, and (3) plywood. The criteria for evaluation were the performance levels given in the "National Bureau of Standards Technical Note 808." Both the smoke generation and toxic gas release data from the 10 encapsulants were below the value classified as "potential problems." Therefore, the encapsulants were con- sidered satisfactory in these perfor- mance areas. One main concern was whether the encapsulants, when applied by airless spray, would penetrate into an asbestos- containing matrix and thus improve the cohesive strength. In Phase II, to evaluate the degree of penetration and possible increase in cohesive strength, test panels were mounted on a rack in an overhead position to simulate a ceiling and then a measured amount of encapsulant was applied using airless spray equipment. After drying, the sealed test matrix was evaluated for adhesion to the substrate and cohesion using a modification of the -inspection method recommended by the ternational Association of Wall and "Ceiling Contractors. This inspection method gives an indication of the ability of spray-applied, fire-resistant materials to remain in place and resist separation during anticipated service conditions. The method measures the adhesive force required to either separate the material from the base substrate or overcome the cohesive force within the material. Field Application of Selected Encapsulants There were 4 encapsulants selected for field evaluation from the 10 that underwent the extensive evaluation in Phase I. The selection process for field application consisted of (1) attempts to achieve a good mix of bridging and penetrating encapsulants, (2) selection of representative products based on the evaluation, and (3) the availability of sufficient amounts of the encapsulants. The four encapsulants selected for field evaluation were: 1. 13B, a bridging acrylic-based material; 2. 19A, a penetrating polyvinyl ace- „.- tate copolymer-based material; 3. 21 A, a penetrating acrylic-vinyl acetate copolymer; and 4. 21 B, a penetrating acrylic-modified polyester. These encapsulants were then evaluated for fire resistance using a modification of ASTM Method E-162. The encapsu- lants were applied to three substrates: (1) asbestos board, (2) the test matrix, and (3) plywood. The coated panels were evaluated using a modification of ASTM Test Method E-162. The asbestos board substrate was used as a control. The bridging encapsulant, 13B, had a Class C flame spread index when evaluated on the test matrix using the Department of Housing and Urban Development Min- imum Property Standards. Class C mate- rials have a limited application. The three penetrating encapsulants, 19A, 21 A, and 21 B, were rated as Class A on the same substrate. The field trials were conducted during two different time periods. How- ever, both trials were conducted at the same location and on the same asbestos- containing substrate in different rooms. Description of Field Substrate The field trial matrix was a friable, asbestos-containing material (30%-35% chrysotile) applied approximately 5.1 -cm (2-in.) thick over the underside of a precast cement floor and also on steel, support I-beams. The material, although highly friable (released visible fibers when brushed), was in good condition (no loose material hanging down). First Field Trial The bridging encapsulant, 13B, and penetrating encapsulant, 19A, were applied to the asbestos-containing mate- rial with an airless spray gun. The pump pressure was kept as low as possible to minimize asbestos fiber release, but sufficient to get a good, uniform, spray pattern. The pump pressure resulted in a nozzle pressure of 1,050 to 1,200 psi. The bridging encapsulant, 13B, was applied in two coats. The first coat was applied as a mist coat with the encap- sulant reduced approximately 10% with water. The second coat of encapsulant was applied without reduction approxi- mately 4 hours after the first coat. The combination of the two coats formed a very tough elastic film about 0.3-cm (0.13-in.) thick over the surface of the asbestos. Penetration of the two coats including the mist coat was approxi- mately 1 -cm (0.38-in.) deep. The penetrating encapsulant, 19A, was also applied in two coats. However, the first coat was actually applied as a "double coat." The encapsulant pene- trated into the asbestos-coated material very quickly. Therefore, after coating approximately a 1.1 -m2 (12-ft2) area, the same area was recoated immediately. The application of the second coat was made after allowing the first "double" coat to cure for a minimum of 12 hours. The second coat application was done in one pass. This method of application resulted in penetration by the encapsu- lant up to 1.9-cm (0.75-in.) into the 9.1- cm-thick (2-in.-thick), asbestos- containing material. Second Field Trial The second field trial application of two additional penetrating encapsulants was conducted following the same procedure used for the penetrating encapsulant in the first trial. Similar airless spray nozzles and pump pressures were used. Also, the first coat application was applied as a "double coat" and the second application as a single coat. Penetrating encapsulant 21A pene- trated approximately 0.6-cm (0.25-in.). Observations from a core sample indi- cated that the resin binder did not carry nor penetrate as deeply into the asbestos material as water in the encapsulant system. This resulted in an apparent resin-rich, top layer that sealed the surface, preventing the release of asbes- tos fibers. However, the surface did not exhibit the impact resistance desired. Encapsulant 21 B foamed during the airless spray application of the first coat. This problem was solved during the application of the second coat by reduc- ing the encapsulant with water. The foaming apparently restricted the pene- tration of the encapsulant, because a core sample indicated that the maximum penetration achieved was 1 cm (0.38 in.). Although the foaming was overcome during the second coat application, no further penetration was achieved, pos- sibly because the surface of the asbestos material was partially sealed by the first coat. Even though the encapsulant did not penetrate as desired, it did form a sealed surface over the asbestos material that could restrict asbestos fiber release. Air Sampling and Analysis Description of Test Area The original ceiling with asbestos insulation had been concealed by a drop ceiling that was removed before appli- ------- cation of the encapsulant. The test rooms were actually two large rooms at opposite ends of the building, divided into three rooms by flexible partitioning. Two of these three rooms at each site were used for encapsulant application rooms and the third room was a work/control room. Although the rooms were divided by the flexible partitioning up to the level of the drop ceiling, the area above the drop ceiling was continuous throughout the entire building. The test rooms were sealed and isolated from each other using polyethylene sheet both over and extending above the flexible partitioning. However, complete isolation was not achieved in the area extending through- out the building. This allowed some cross contamination of the two test rooms and the work/control room, as indicated by air sampling data, thus demonstrating the need for careful sealing of the isolated work area. Air Sampling A series of air samples was taken during the field evaluations. The samples were collected during the following periods: 1. Before any work was initiated, 2. During removal of drop ceiling, 3. Immediately after drop ceiling removal, 4. 3 to 5 hours after drop ceiling removal, 5. During application of first coat of encapsulant, 6. During cure of first coat, 7. During application of second coat, 8. During cure of second coat, 9. During clean up procedure, 10. 18 hours after clean up, and 11. 7 weeks after application of sealant. Analysis of Air Samples The analysis was performed using transmission electron microscopy (TEM) at 20,OOOX magnification. Also, selected area diffraction patterns were obtained to confirm identification of fibers as chrysotile asbestos. No fiber counts were made using the Occupational Safety and Health Administration (OSHA) method. The data were processed by a computer program designed to provide the follow- ing information: 1. ' Calculate mass of chrysotile per m3 of air based on length and width measurement, 2. Calculate number of chrysotile fibers per m3 of air, 3. Calculate the mean length versus length, width, and length/width aspect ratios of chrysotile. The results of the air sampling analysis demonstrated the strong direct dependence of airborne asbestos fiber concentration on activity in the work room. Also shown was the increase in airborne fiber concentration during active periods. For example, in the room where encapsulant 1 3B was applied, the initial ambient level was 8.5 x 1 0" fibers/ m3 as measured using TEM. When the ceiling tile was removed, the level of fibers increased to 1.3 x 1 O6 fibers/m3 After a settling period the count decreased to 9.7 x 10" fibers/m3. How- ever, during airless spray application of the first coat, the count increased to 6.4 x 107 fibers/m3. Between coats the level dropped to 4.3 x 106 fibers/m3. Appli- cation of the second coat of encapsulant again increased the fiber count (6.8 x 106 fibers/m3), but the level was much lower than during application of the first coat. This demonstrates that even one coat of sealant is effective in reducing the release of fibers during strong air currents and on slight impact. An increase in fiber count was also shown during clean-up procedures; however, after clean up the count was very near ambient levels. An air sample taken after 7 weeks showed the level of fibers to be at the initial mean outdoor level. In all cases of encapsulant application in the field trials, peaks in airborne fiber concentrations were shown during periods of activity (ceiling removal, encapsulant application by airless spray- ing, and clean up). Without exception, the highest levels of airborne asbestos fiber were observed during the application of the first coat of encapsulant, as would be anticipated. This occurs because loose surface fibers are released by the spray disturbance of adjacent areas of the matrix. The second phase of the resear program was undertaken to determi, the effectiveness of the test methods by evaluating additional commercial pro- ducts. These were restricted to water- borne systems because of the fiber- containment procedures recommended during application. Methods Used to Evaluate Candidate Encapsulants This study evaluated lOOcommerically available candidate encapsulants. Each was applied by airless spray to a specially designed, 1.5-m2 (16-ft2) test matrix. Application rates, pump pressure, and spray nozzle size data were recorded. After the encapsulant cured for a min- imum of 7 days, core samples were taken to determine the degree of penetration when a penetrating encapsulant was applied, or the thickness when a bridging encapsulant was spray applied. The test matrix with the encapsulant applied and cured was then sectioned into a series of test blocks and evaluated for the following: 1. Impact resistance, 2. Smoke generation, 3. Toxic gas release, 4. Fire resistance, and 5. Surface rub test, Each encapsulant evaluated was dis- cussed separately. The 33 acceptable and marginal encapsulants are described in the full report and unacceptable encapsulants are described in Appendix D of the full report. Most of the unac- ceptable encapsulants failed in one or more of three modes: 1. Flame Spread Index greater than Class A limit, 2. Smoke generation greater than 50%, and 3. Poor adhesion to test matrix. Results and Discussion A total of 158 candidate encapsulants were evaluated. Phase I evaluated 74 encapsulants and many of them were more extensively tested in Phase II, where about 100 evaluations were performed. All materials evaluated wf applicable by standard airless spr^. ------- equipment and were water base so that they could be applied in an unventilated work area without hazard to the workers The evaluation included tests for flexibility, abrasion resistance, penetra- tion, cohesive strength, flame spreading properties, emissions of smoke and toxic gas in a fire, viscosity, percent solids, impact resistance, and a subjective judgment of ability to retain asbestos fibers based on dusting when rubbed with the hand. Based on test results and criteria established for desired performance, 13 encapsulants met all criteria for satisfac- tory performance and 21 met most of the criteria and were judged to be "margi- nally satisfactory" by the principal investigator (see Table 2) Conclusions and Recommendations From the results of the screening study, the field trials, and the second- phase program, several conclusions were reached 1. Encapsulants should not be employed when friable, asbestos- containing materials show evi- dence of poor cohesive strength and extensive damage such as material hanging loose. 2. The use of an encapsulant, either bridging or penetrating, should not be considered where there \s extensive water damage to the asbestos-containing material. 3. When applied correctly, penetrat- ing encapsulants, improve the cohesive strength of the asbestos- containing matrix, and if the encap- sulant penetrates to the substrate it will improve the adhesion between the asbestos-containing matrix and the substrate. 4. Selection of appropriate applica- tion techniques, such as airless spray and multiple coats, is impor- tant to the achievement of uniform, impervious membranes and the desired depths of penetration. 5. Application of encapsulants to friable asbestos thicker than 3.2 cm (1.25 in.) is not recommended because the penetration of the water from the encapsulant into the thicker, friable material can increase the probability of delamination. 6. The air sampling data indicated that complete barrier systems to contain the released asbestos fibers within the work area were not obtained. 7. Worker activity increases the level of airborne asbestos in the work area during the work period. 8. Following periods of activity, the airborne concentrations return to background levels in approximately one-half day. Therefore, after work activities, several thorough wet cleanings followed by waiting periods are necessary before allowing occupancy of the work area. 9. Evaluation of asbestos settling (supported by analytical observa- tions) indicates that the airborne asbestos is most likely predomi- nantly present as clusters and not individual fibers. 10. The 1.4-mz (16-ft2) test matrix is an adequate method for screening encapsulants in the laboratory. However, because of the wide variations of spray-applied, friable material experienced in the field, it is recommended that a test area be encapsulated and evaluated before complete encapsulant of the building is begun. 11. Screening test of an encapsulant performed on any material other than a friable matrix may not give reliable indication of the perfor- mance of the encapsulant when applied to a friable, asbestos- containing material. The full report was submitted in fulfillment of Contract No. 68-03-2552 by Battelle Columbus Laboratories under the sponsorship of the U.S. Environmen- tal Protection Agency. Table 2. Sealants Rated Satisfactory Battelle Code Company Designation Company Address and Phone Rating 33775-4A 33775-12B Decadex Firecheck Chemex Ultra 33775-15C Water-based Polyester "Acceptable ^Marginally Acceptable \Not recommended where impact is expected " "Same Material. Pentagon Plastics U.S.A. Ltd. Chemex Chemical & Coating Co Western Coating Co 905 North RailroadAve. West Palm Beach, FL William F. Russek (305)655-2111 P.O. Box 5072 Tampa. FL 33675 Herbert F. Ross 1813)248-6104 P.O. Box598 Oak Ridge Station Royal Oak, Ml 48073 Jack Sheets (313)588-3311 M ------- Table 2. Continued Batte/le Code Company Designation Company Address and Phone Rating 33775-19 A Cafco-Bond-Seal United States Mineral Products Co. 33775-21A 554-21-1 "Protector" 2 Part System H. B. Fuller Co. 33775-21B Water-based XD-DG 33775-27A, #207 Special Sealer 33775-28A Pyrokote-Mx 33775-29C 29-C Aqualoid 15-10 Western Coating Co. Makus Development Corporation Development Services International Essex Chemical Corporation 33775-30B Asbestop BW225 Two Component McGeddy International, Inc. 33775-42-A Ocean Fire Retardant #666 33775-52-A FRC-AES 33775-52-B FRC-REPC 33775-42-B Metro Shield 33775-41-C C-1019 33775-43-A 1583 33775-45-A 95-CO-104 33775-45-C 95-W-100 33775-47-A L 241-43 Part A & B 'Acceptable. ^Marginally Acceptable. |/Vo/ recommended where impact is expected. "Same Material. Ocean Fire Retardant Co FRC Composite Ltd. FRC Composite Ltd. Bertelson Assoc., Inc. California Products Corp. H. B Fuller Co. M. A. Bruder & Sons, Inc. M. A. Bruder & Sons, Inc. Carboline Co. Stanhope, NJ 07874 A Frank Meuwirth (201)347-2100 Foster Products Div. . P.O. Box 6255 Springhouse. PA 19477 Gene Secor (212)628-2600 or Toll Free (800)523-601 7 P. O. Box 598 M Oak Ridge Station Royal Oak, Ml 48073 Jack Sheets (313)588-3311 P.O. Box 31 M Mercer Island, WA 98040 Dan S. Makus (206)621-8594 2021 K St.. NW Ml Suite 305 Washington. DC 20000 (202)331-7373 125 B/ackstone A ve. M Jamestown, NY 14701 (716)665-6313 1043 Broadway A W. Longbranch. NJ 07764 (201)229-5580 1072 Cyrville Road A Ottawa, Ontario KIJ 7S5 Canada (613)741-4248 FTS: 950-5111 1993 Leslie St. A\ Don Mills, Ontario M3B2MC Canada 1613)741-4243 (Same as above) A 8 DelwoodLane M Tinton Falls, NJ 07724 (201)542-6393 169 Waverly St. M Cambridge, MAO2139 Foster Division M P.O. Box 625 Springhouse. PA 19477 Toll Free (800) 523-6017 600 Reed Road M P.O. Box 600 Broomall, PA 19008 (215)353-5100 (Same as above) M 350 Hanley Industrial Ct M St. Louis, MO 63144 ------- Table 2. Continued Battelle Code Company Designation Company Address and Phone Rating 33775-47-C Super Chemseal 33775-48-A Hygienscote 33775-50-A TCI-750 33775-51 -A 25-2355 33775-53-A Thermatek 33775-13B-3 EX 64-3 OX-LINE-ABC 33775-31A Ultra Lok 40-871 33775-33C Penqua 200 33775-34C" Product # HI-6625-583-9 33775-35A 350-A-1 Asbestight 2000 33775 35B Cable Coating 2-B 33775-36B Dust-set 33775 37A" 662-583 33775-37C Mono-Therm F-100 33775 42C SK-J3 Emulsion 360-0017 Chemray Coatings Corp. 150 Lincoln Blvd. Middlesex, NJ 08846 Ac a/or Chemical Construction 33 Kenhar Dr. Weston. Ontario M9L 1M9 Canada (416)749-2265 Therma-Coustics National Starch & Chemical Corp. Protek Manufacturing Lehman Brothers Corp. Cellin Manufacturing. Inc. United Coatings Habersham Industries, Inc. Arpin Engineering, Inc. American Coatings Corp. Mateson Chemical Corp. Findley Adhesives, Inc. Mono-Therm Industries, Inc. National Cellulose Corp. P.O. Box 190 Colton. CA 92324 (714) 783-0462 1164 N. Great Southwest Parkway Grand Prairie, TX 75050 (214)647-9222 520 South Muskego Ave. Milwaukee, Wl 53208 (414)643-7689 22 Halladay St. Jersey City. NJ 07304 Carmine Spatola (201)434-1882 P.O. Box 688 Springfield. VA 22150 (703)550-7277 E. 1130 Sprague Ave. Spokane. WA 99202 (509)535-4131 5212 Industrial Ct. Smyrna, GA 30080 (404)351-7173 1716 Melv/IISt. Oakhurst. NJ 97755 (201)280-0400 5235 N. Elston Chicago, IL 60630 (312)286-6610 1025 Montgomery A ve. Philadelphia, PA 19125 (215)423-3200 P. 0. Box 3000 Elm Grove. W153122 (414)782-2250 Mono-Therm International 645 £. 60th St. Los Angeles, CA 90001 Toll Free (800) 426-8080 12315 Robin Blvd. Houston. TX 77045 Dan Kelly (713)433-6701 M M M M M M M M M "Acceptable ^Marginally A cceptable \Not recommended where impact is expected ' "Same Material. ------- W. Mirick, E. W. Schmidt, C. W. Melton, S. J. Anderson, L. J. Nowacki, and R. Clark are with Battelle Columbus Laboratories, Columbus, OH 43201. William Cain is the EPA Project Officer (see belowj. The complete report, entitled "Evaluation of Encapsulants for Sprayed-On Asbestos-Containing Materials in Buildings," (Order No. PB 88-113 329/ AS; Cost: $19.95, subject to change! will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Water Engineering Research Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 Official Business Penalty for Private Use 5300 EPA/600/S2-87/091 ------- |