Document 446DeyRZ9NBkbBprNz006YM9e

FILE NAME: Flooring (FLR) DATE: 1979 DOC#: FLR002 DOCUMENT DESCRIPTION: Unpublished Report - Comparison Testing Monitoring Airborne Asbestos Fibers - Wet vs Dry Sheet Vinyl Flooring COMPARISON TESTING MONITORING FOR AIRBORNE ASBESTOS FIBERS: SHEET VINYL FLOOR COVERING, WET VERSUS DRY SCRAPING Report Prepared for: RESILIENT FLOOR COVERING INSTITUTE 1030 15th St., NW - Suite 350 Washington, DC 20005 Attention: Mr. Robert D. Maurer Managing Director Report Prepared by: Richard J. Walcott - Industrial Hygienist Janes C. Warrick - Industrial Hygienist Center for Occupational and Environmental Safety and Health SRI INTERNATIONAL 1611 N. Kent Street Arlington, VA 22209 SRI INTERNATIONAL SRI International is a problem-solving organization that provides consulting and research under contract for clients in business and government throughout the world. Since SRI was founded in 19*16, the problems confronting it's clients have so increased in complexity that few of them can be solved within the confines of a single discipline. The organization is uniquely qualified to deal with such intricate problems. Professionals representing more than 100 disciplines comprise nearly two-thirds of the 3.000'staff members. SRI performs consulting and research for the public sector in such areas as urban management; health, education, and welfare; environmental management, and national security. In addition to broad-ranging activities for the U.S. and other national governments, SRI serves city, state, and county governments in the U.S., and also their international equivalents. One of the most attractive aspects of life at SRI' for the staff is the opportunity to share in important work in the public interest. For private commercial and industrial clients, SRI engages in management consulting anil corporate strategy determination; technoeconomic, market, and operational studies;,new product, process, and equipment development; and the provision of information services. A significant percentage of SRI's professional staff have had a number of years of major responsibility in business prior to joining SRI. SRI is an independent, nonprofit corporation, using revenues in excess of operating costs to purchase advanced scientific equipment and to enhance its ability to continue to provide the highest quality consulting and research for its clients. SRI International has no shareholders and no endowment. SRI's annual revenues for consulting and research contracts exceed $125 million. SRI's headquarters are on a 70-acre site in Menlo Park, Californiaa suburban community about 20 miles south of the San Francisco International Airport and a few miles-from the campus of Stanford University. Other offices and laboratories are located in major centers in North America, Europe, East Asia, and.the Middle East. . STATEMENT OF OBJECTIVE The principal objective of this study was to monitor for airborne asbestos fibers, if any, that were generated during the complete removal of sheet vinyl floor covering when different methods of removal (wet versus dry scraping) were used. The effect of using different length handles on the scraping instrument Has also measured. c I c c TABLE OF CONTENTS I. II. III. IV. V. VI. VIII. Page Introduction,Sheet Vinyl Floor Covering .................. 1 Test Site L o c a t i o n ............ .......................... \ -(2 M e t h o d o l o g y .................... H Summary of Results ................ 5 C o n c l u s i o n .................... 6 Complete Removal ................... .. . . ............... 7 Attachments: A. RFCI Work Practices . .. B. NIOSH Analytical Method C. Representative Ambient Air Asbestos Concentrations in CitiesI I 1 0 ) ( I I. INTRODUCTION ''Sheet vinyl floor coverings are widely used in many residential, institutional and commercial locations. Asbestos is used as a constituent in the felt backing of many sheet vinyl floor coverings, but there is no asbestos in the various types of top or wear layers. Attention has recently been centered on the health effects resulting from certain exposures to asbestos. SRI was retained1to measure whether or not airborne asbestos fiber were produced under certain conditions of sheet vinyl floor covering removal, RFCI recommends that the felt backing of the sheet vinyl be removed from the' subflooring by a method known as "wet scraping". (See Attachment "A"). Wet scraping is- essentially a wetting of the felt remaining after the wear layer has been removed and a careful scraping of the moistened felt by a suitable instrument (wide-bladed putty knife). In the past, dry scraping, that is the scraping of the felt without prior wetting, has been done. In this test both methods were used and the/asbestospibers collected and counted. II. TEST SITE LOCATION The site for 'these evaluations was a six-year-old home located in a suburban Maryland community. The attic insulation material in this heme was, according to the occupant, a pink fiber glass material. This could not be confirmed since access to the attic was not feasible. The heating system in this house was forced air ventilation, and the air was filtered by the furnace unit. This operation was performed in the kitchen of the heme. The total floor surface area was approximately 350 square feet. The tests were done in the Spring (March 15 and 1'6) of 1979. A diagram of the test site is included as Figure 1. Refrigerator and Cabinets To Dinning Room Dry Scrape Section To Family Room -> Electric Range Wet Scrape Section I Sink and Dish Washer FIGURE 1. Site Plan III. METHODOLOGY 1. Complete Removal The operations were not done according to RFCI Recommended Work Practices (See Attachment "A") in that dry scraping was also done. 2. Determination of Airborne Asbestos Fibers The NIOSH method for'determining asbestos fibers in the air was employed (See Attachment "B", NIOSH Method ^o. P&CAM 239, "Asbestos Fibers in Air") . IV. SUMMARY OF RESULTS The following1Table lists the TWA concentrations of airborne asbestos fibers measured at the test site for the specified operations. TWA concentrations are stated assuming a full-days exposure to the conditions that existed during the test period. NOTE : The OSHA Standard for a safe workplace allows a concentration of 2 fibers per cc of air on an 8-hour time-weighted average (TWA). Table No. 1 ' Operation ... Wear Layer Removal Wet Scrape Dry Scrape Dry-Scrape 8 Hr. TWA (Asbestos Fibers/cc) Mechanic 1 Mechanic 2 0.1637 0.084M 0.U093 2.02M8 1.1207 0.8279 1.0583 V. CONCLUSION. Deviation from the recommended RFCI work practice (wet scraping) resulted in a 2-5 fold increase in asbestos exposure. These data reinforce the need to follow the recommended practice of wetting the felt backing prior to scraping. Dry scraping should never be done. VI. COMPLETE REMOVAL Discussion An existing sheet vinyl floor covering was removed by using both wet and dry scraping. First the wear layer was removed according to standard practice and thelpkrt of the floor was dry scraped and the rest was wet scraped. A water-detergent solution was used for the wetting. Two different length handles were also used in the scraping, Mechanic 1 used a regular handle on a stiff bladed putty knife while Mechanic 2 used a handle of 3-1! feet. Sampling Procedure: The sampling protocol was designed to: 1. Evaluate the background asbestos levels in the home and outside ambient air. This was accomplished using area samples taken several days before the test sampling. 2. Determine any increase above background concentrations of asbestos fibers. Personal samples were taken for each worker during the operation. Separate filters were used for each phase of the operation. Dry scraping was done in two phases so there are two samples for each worker for dry scraping. See Figure 1, for a diagram of the sampling area. Sampling Results: The result of the individual-filter analyses is shown below in Table 2. Table 2 Description Background Samples Outside Outside Kitchen Wear Layer Removal Mechanic 1 Mechanic 2 Filter No. Air Vol. Time (liters) (min) Fibers/ sq. mm* Total Asbestos* Fiber/ec Fiber/cc AB-9 760 380 0 0 0 C--1089- 766 383 / o 0 0 XX009 7^8 374 '' 0 0 0 AB-12 150 AB-2 140 75 39 0.218 0.1637 70 14 0.0844 0.0844 Wet Scrape Mechanic 1 Dry Scrape Mechanic 1 Mechanic 1 Mechanic 2 Mechanic 2 AB-14 no AB-13 126 AB-11 80 AB-10 126 I AB-15 90 55 96 63 327 40 * . 96 63 191 45 121 0.4837 2.168 1.0035 1.2669 1.1259 0.4093 2.0248 0.8279 1.1207 1.0583 Fibers/sq. mm of total filter surface area. **Analyst estimated that about 90S of the fibers were asbestos 8-!!r TW..', 0.16 0.08 0.4C 2 . 02 o .::: 1 . 12 1.05 The background samples obtained prior to and on the day of the test showed no asbestos fibers. Asbestos fiber concentrations found during the wear layer removal were very low (0.1637 and 0.0844 fibers/cc) . As sometimes happens when the wear layer is removed, a good deal of the felt was separated from the subfloor and removed with the wear.layer. The strips of wear layer were rolled and placed in trash bags for disposal. The higher concentration was from the worker who bagged the material-. Wet scraping, which took 55 minutes, resulted in a concentration of 0.4093 fibers/cc. Dry scraping samples, however, showed concentrations ranging from 0.82.79 to 2.0248 fibers/cc. Dry scraping was done with two different length handles. The results from the worker using the longer handle (1.1207 and 1.0583) are, on the average, a good deal lower than the results from the worker using the short handle (2.0248 and 0.8279).' The longer handle*does provide, as would be expected, seme protection from the asbestos concentration. Conclusion The contrast between the asbestos fiber concentration values found following wet versus dry scraping clearly indicate the need and desirability to follow the recommended RFCI work practice of wetting scraping. The comparison between long and short handles-, while not as great a difference as wet versus dry scraping, shows that longer handles are also more desirable if they can be practically used.