Document jmkvVML61gyNdpdg2qp8kjwep

FILE NAME: Flooring (FLR) DATE: 1985 DOC#: FLR024 DOCUMENT DESCRIPTION: Journal Article - Asbestos Fibers Release from VA Tile I1 ^ L crer^ u^j WV_ x^JL_ T /A ca]L{Ks Asbestos Fibers Release from VA Tile How much asbestos is released into the air during standard dry removal of vinyl asbestos floor tile? This question has been debated by flooring contrac tors, asbestos consultants and school building officials for some time. A re cent test conducted by the DeKalb County, Georgia School System pro duced interesting results. Floor cover ing replacement for a 15-year old elementary school was scheduled and offered an excellent opportunity to investigate the release of asbestos fibers during the process of removing old vinyl asbestos tile. A classroom in the school was selected as a test area and a flooring contractor was authorized to remove the old floor and install a new Type IV Vinyl Com position floor covering in the room using standard floor removal and re placement procedures. Prior to beginning the removal, a test procedure was developed for determin ing fiber release1. The procedure called for pre-removal and post-removal monitoring using both phase contrast procedures and transmission electron m icroscopy procedures2. Samples were to be taken at a flow rate of 16 liters per minute and at a total volume of 2,400 liters. Filters for phase con trast analysis were standard Millipore filters while those for electron micro scopy were Nucleopore. All filters were 37 mm diameter filters. All sampling was done using aggressive techniques. Pre-removal sampling in the room produced a level of 0.01 fibers/cc usng phase contrast test (P&CM 239) and 10 asbestos fibers were detected in the 'EM test. Since no asbestos fibers were resent in the classroom, no outside mbient air test was conducted. The 2" x 12" x 1/8" floor tile was then moved using spud hoes and an elcclcal powered vibrating lltxir tile spud, emoval was accomplished in approxi- ately three hours. Air samples were en collected before the new tile was stalled. The phase contrast test con- by: John Jenkins showed a fiber level of 0.08 fibers/cc. The TEM test showed a level of .0838 fibers/cc with a weight of 0.5695 nanograms per cubic meter. Analysis of the fiber size showed that all fibers were less than 5 microns in length and that 60 % of the fibers were approximately .05 microns in diameter with approximately 40% being 0.1 microns in diameter. All asbestos fibers were' chrysotile. The classroom was closed off to per mit settling in the room and then cleaned to remove residual fibers. TEM testing confirmed that the room was clean. A sample of the removed tile was subjected to analysis by optical microscope using polarized light and dispersion staining techniques. This analysis indicated an asbestos content of less than 1%. This percentage was not consistent with the tile manufac turer's reported mixtures and not con sistent with the post-removal fiber count. Tile manufacturers report'that mixtures normally contain ten to fifteen percent chrysotile asbestos. A recheck of the sample using an optical micro scope and polarized light did not con firm the reported content so additional procedures were used for testing the bulk sample. A portion of the same was crushed to a powder and dispersed in distilled water-1. The large particles were allowed to settle and a drop of the suspension was placed on a TEM grid and dried. Analysis of this grid verified that the tile probably contained at least 10% asbestos, which is consistent with the manufacturer's statements and also supports the measured levels in the air after removal. The DeKalb County School System is aware that air monitoring is not an exact science and for this reason deter mined to repeat the test on a second classroom in the same school. The pro cedures utilized in the second test were the same as those employed for the first test. The pre-removal test confirmed that no asbestos fibers were present and therefore no outside ambient test was conducted. Floor tile removal procedures were the same as those used in the first test. It was noted that during this removal the classroom windows were open and that the classroom door to the corridor was also open. The phase contrast reading for the post-removal air monitoring was 0.009 fibers/cc. The TEM reading was .2384 fibers/cc with a mass of 26109.3 nanograms per cubic meter. The micrograph below illustrates the wide dispersion of fiber sizes in the sample analyzed by TEM methods. CONDENSED DATA 1. Number of Asbestos Fibers analyzed 40 2. Number of Nonasbestos Fibers analyzed 50 3. Number of Ambiguous Fibers analyzed 0 4. Asbestos type: Chrysotile 5. Concentration of Asbestos Fibers (fibers/cc) or (million/m3) 0.2382 6. Percentage of concentration due to Asbestos Fibers >5 ;tm (microns) in length 27.500% 7. Mass of Asbestos Fibers (nanograms/m1) 26109.3 8. Percentage of mass due to Asbestos fibers equal to or greater than 5 /m in length 99.6626% Comments' Nonasbestos fibers nresem u-ere r.unu.m n i .... __1 - - CONTINUATION OF ASBESTOS RELEASE FROM VA TILE CHRYSOTILE Fibers Less Than 5 microns in Length 100. P 90. E 80_ 76 R 70. C 60. E 50. N 40. T 30. 20. 10. 0 0 7 0 3 0 7 _0_ 0 0.025 0.05 0.075 0.1. 0.25 0.5 0.75 1.0 1.5 Fibers Greater Than or Equal To 5 microns in Length Because o f the air circulation from the classroom to the corridor during the second removal, a decision was made to test the air in the corridor outside o f the classroom. This test using TEM procedures indicated a fiber count of 0.0558 fibers/cc of chrysotile asbestos. The mass o f the fibers in this sample was only 0.0854 nanograms per cubic meter. All o f the fibers collected in this sample were less than 5 microns in length with 50 percent of the fibers having a diameter of 0.025 microns and the remaining 50 percent having a dia meter o f 0.5 microns. No phase con trast test was conducted in this area. Both the classroom and the adjoin ing areas were thoroughly cleaned and checked to confirm that they were suitable for occupancy prior to being released to the school system for use. The tests conducted arc obviously not fully laboratory controlled tests, but are certainly indicative of the problems relating to tile removal. The following conclusions were reached based on the results o f the test: 1. A significant amount of asbestos fiber is released during removal of vinyl asbestos tile using con ventional tile removal methods. 2. Fiber control methods such as damp removal or isolation of areas by plasticizing and use of appropriate respirators should be used for tile removal. 3. Areas subjected to contamina tion by tile removal using un controlled methods should be thoroughly cleaned and tested prior to being returned to use. The DeKalb School System expects to do additional investigative work in order to determine the most cconom- ical method of removing tile safel; Investigations will probably be coi ducted on damp removal methods ar area isolation and cleaning procedure 'Test procedures developed by Southern Engineering Cui pan> Sampling performed by Southern Company IS Peachtree Street. N W . Atlanta. Georgia 30367-8301. Jo M. Jenkins. Vice President 'Laboratory testing by Electron-Microscopy S em e Laboratories. Inc . 108 Haden Avenue. Westmont. Ne Jersey 0810S. Dr Peter Frasca. Ph D . Director `Sample test procedure by Georgia Tech Research Instnui Georgia Institute of Technology. Atlanta. Georglj 3033 James L Hubbard. Senior Scientist John M. Jenkins Southern Engineering Company 1800 Peachtree Street. N W. Atlanta. GA 30367-8301 404/352-9200