Document vVXQqOxYVM7XJ8ZVm7j67GnLb

FILE NAME Roofing ROOF DATE 1982 Dec DOC ROOF002 DOCUMENT DESCRIPTION Report Prepared for the EPA - Analysis of Fiber Release from Certain Asbestos Products 4 uuuuuuuuu~-~-~-~- uuuuuuuuu~-~-~-~- u u u ~- ~- uuuuu~-~-~-~- u u u u u~-~-~-~- u u u u u~-~-~-~- u u u u u~-~-~-~- uuuuu~-~-~-~- u u u u u~-~-~-~- u u u u u~-~-~-~- Prepared for U.S. Environmental Protection Agency Office of Pesticides and Toxic Substances Chemical Control Division Washington D.C. 82-53 Contract No. 68-01-5960 Technical Directive No. 15 EPA Project Officer James P. Bulman ANALYSIS OF FIBER RELEASE FROM CERTAIN ASBESTOS PRODUCTS Draft Final Report December 1982 Prepared by Peter H. Anderson Marc A. Grant Robert G. McInnes William J. Farino GCA CORPORATION CORPORATION TECHNOLOGY DIVISION Bedford Massachusetts SECTION 7 ASBESTOS PAPER PRODUCTS OVERVIEW Products within this category include those that contain asbestos fibers and are Several manufactured on a fourdrinier or cylinder papermaking machine subcategories have been identified for Paper Product1,s2 For this report the following subcategories were investigated roofing felt flooring felt millboard and rollboard beater paper used for gaskets and electrical insulating paper Paper product subcategories not profiled include commercial paper specialty paper and pipeline wrap The manufacture of all containing paper products is similar Raw materials are blended together with water in a pulp beater or hollander This base stock is then processed through a series of material build and dewatering steps followed by drying Product addition of a manufacturing step such as the differentiation results from the saturation of paper with asphalt to produce roofing felts or millboard production Paper asbestos content and grades from using different forming equipment as with products are also differentiated by varying as well as binders and fillers ROOFING FELT Introduction Asbestos roofing felt is a paper product that is converted to a weather resistant roofing material by saturation of the paper with asphalt or tar Asbestos fibers are used in the manufacture of roofing felts because they provide dimensional stability and resistance to rot fire and heat buildup Rot resistance is particularly important due to roofing felt's use on flat or nearly flat surfaces having poor drainage Asbestos roofing felts are asbestos primarily chrysotile typically composed of 85 to 87 percent with differing amounts of cellulose fibers and starch binders Sheets multilayered grades and of roofing paper are made in either single or may have fiberglass filaments or wire strands embedded between the felt layers for reinforcement Following formation on the papermaking machines the paper product is either drawn through a bath of hot asphalt or coal tar to provide a weather resistant coating or wound into rolls for future processing The process of 85 * applies the felt In order to achieve a uniform membrane referring to the total built layer thickness along the edges of the roof deck a single felt is ordinarily cut lengthwise to obtain two felt strips of the required widths to build up the perimeter thickness These strips are generally 30 46 and 61 cm 12 18 and 24 inches wide When the felt is used as underlayment for a shingle or sheet roof the felt is generally nailed to the deck and no asphalt coatings are used Asbestos roofing felts have been in use for over 100 years Built roofs of at comprised of these felts are reported to have an yearxspected least 20 years with some lasting up to 40 9,10 service life Product deterioration results principally from climatic exposure During weathering asphalt coatings and asphaltic felts become brittle and crack Where isolated leaks occur due to excessive wear the roof may be repaired simply by application of heated asphalt or a apply roof coating to the affected area If the deterioration is widespread the entire roof must be recovered or replaced Since the roof membrane derives much of its integrity from the structure of overlapping felts a number localized repairs is much less effective than total recovering or replacement 7 Industry representatives report that more than percent of the asbestos roofing felt produced is applied during reroofing with the remainder used in new construction Manville representatives report that the surface type of roof is the easiest to recover and replace owing to the smooth surface and overall light weight 4,8 A surface roof requires at least brooming to prepare the surface for recovering and top frequently the a smooth surface layer of asphalt must be removed entirely to provide 4,8 Additionally the surface roof is the heaviest of the three built roof types and careful attention must be paid to the structural capacity of the underlying roof deck if the existing asphalt flood coat and gravel are to be left intact Recovering tends to be preferred over reroofing because of lower costs Roof removal generally requires chopping or sawing the existing roof membrane into pieces which can be pried or scraped off the roof deck Any number of roof layers may be removed depending on the scope of the roofing job from the top layer of asphalt down to the insulation or the roof deck itself Cutting tools commonly used are an axe or circular saw mounted on wheels the latter being faster and generally used on large jobs The circular saw is preferred for removal of top layers of a membrane because it cuts to a pried off controlled depth After cutting the of the deck or underlying layers with cut blocks of a shovel or crow roof are bar 4,11 In large job operations the waste material is carted to the edge of the roof in wheelbarrows and is dropped down enclosed chutes leading to a ground dumpster Less sophisticated disposal methods are used for smaller jobs A series of several scraping routines and a final sweep of the roof area may be necessary to prepare the deck for application of a new roof A Manville representative stated that it is impossible to characterize 187 vt ; } the number of workers and time required for a reroofing job as the work and even the tools used vary widely with the roof type Removal of a 10.5 x 18 meter 35 x 60 foot section of fiberglass asphalt roofing membrane which was monitored by Technology Division personnel in December 1979 required about 2 hours 11 Built roof installation is estimated to take a similar length of time or longer to apply the multilayered membrane Airborne asbestos fiber release during roofing felt installation is expected to be low containing roofing felts which are coated with asphalt are quite pliable and normally carefully handled during built roof construction to ensure the integrity of the finished membrane during During installation the only mechanical disruption applied to the felt is cutting with a sharp bladed tool Liberation of asbestos fibers from such a low energy activity is expected to be minimal In use containing felt is isolated from the atmosphere by layers of asphalt and other roof coating materials Although these coatings may eventually wear off wind and water erosion is believed to very gradual process whereby minimal fiber release is expected By the be a time the felt becomes exposed a membrane leak is likely and repairs would be performed therefore on the affected the felt is not area likely Roofing materials tend to be exposed over the to wear nonuniformly whole roof at one time Of all the roofing felt end use activities felt removal poses the greatest potential for fiber release During this operation the top membrane coating and the During removal asphalt in the felt when surface layers have weathered to a hard stiff are sawed and scraped the felt material matrix is likely to be physically altered releasing form asbestos fibers The membrane top coat and asphalt coats between the felt layers however do tend to bind the cut felts together minimizing felt fracture during prying and waste disposal Airborne Fiber Monitoring Data Several monitoring studies have been asbestos fiber concentrations encountered conducted to determine airborne during roofing felt installation and removal Results of these studies conducted by the Manville Corporation and Technology Division are presented in Table 19. Airborne fiber concentrations in and around the work sites were generally found to be equal to or less than 0.6 cm The Manville studies were initiated through requests by internal marketing staff or roofing representatives and spanned a period from October 1972 to August 1976. Air samples collected were analyzed in Waukegan IL Manville NJ and Denver CO by Manville technicians using the PCM analytical method The GCA samples were obtained on December 11 1979 and were analyzed by Eastern Analytical Laboratories of Burlington MA using SEM 5000x and EDXR techniques The data presented in Table 19 do not indicate any trends as to which roofing operation has the greatest potential for airborne asbestos fiber release Although reported fiber concentrations for any given study 88 STUDIES al 11,13 TABLE 19. FIBER MONITORING DATA FROM ASBESTOS ROOFING FELT fit Test conditions Sample No. woe Man Area Specific operation -- 3rea sped Tools materials Fiber level 1/3 5 10-10-72 5-10 mph 1 Univ of Wisconsin ED by Nelson Roofing Co. Manville 2 Mankegan 3 Majority of cutting felt Centurian base No. 15 0.3 also spread asphalt finishing felts Assisted cutting and Same as above 0.2 laying felt Carried fells to operation Same as above 0.2 some cutting _ 333333333 I Upwind of operation - 333333333 Z Along side operation 333333333 3 Downwind of operation b Six ft above operation ... 333333333 5-18-73 ND I Mopping hot asphalt ... 333333333 School at Hobart IN 333333333 ND by Maris Roofing Co. 2 Laying and cutting felt Manville 333333333 Waukegan 3 Hot asphalt tank operator 1 Dovewind of operation ... 0.1 2 Downwind of operation near 0.4 89 en shoveling scrap off roof to truck 0.1 7 3 Downwind of operation 3-14-74 9-10 apb at Racine WI 1 Ground level 500 ft from school aaied 0.4 building 75 ft below roof 2,000 sq ft by oH 0.4 unidentified contractor 2 15 ft upwind of operation Manville Denver 4 Et above roof 3 Same as No. 2 arra --- 0.2 - 0.3 4 15 ft downwind of opera- tion 2 ft above roof S 30-15 ft downwind of _ 0.0 operation 2 ft above . roof 6 Mopping hot asphalt some Knife to cut felt Centurian 0.6 felt cutting and laying base perforated finishing felts 7 Cutting and laying felt Same as above 0-5 continued TABLE 19 continued Ieat conditions Sample No. Sample Mao Area Specific operation or area sampled -11-74 10 mph School at Indianapolis 1x 1,350 1,350 q ft by Sink & Edwards Roofing 0 -Manville Waukegan 1 525 ft upwind of building at ground level z 18-25 ft downwind of operation 4-5 Et above roof 3 Same as No. 2 area 4 40 it upwind of operation 4-5 Et above roof Tools materials _ Fiber Level f c) 0.3 0.2 0.4 5 All phases of roof removal Are cutting pry bars and 0. abovels to remove surface sweep clean with broom 6 Same a0 No. 5 m Same as above 0.3 5-21-74 moderate 1 Dept. Store at Allentown PA 1,500 sq ft by Hill Metal and Roofing Co. 1 1 ManvillMaenvil e Manville Manville 2 Power zawing and removing Power sav pry bar 0.1 sections of old roofing Tacking down new felt Nailing Centurian base felt 0.0 Prying off old roofing Pry bar 0.0 90 Laying new felt unrolling Centurian base felt 0.1 3 Removing old roofing Wheelbarrow 0.1 Tacking down new felt Nailing Centurian base felt 0.2 _ 4 Upwind corner of work 0.1 removal - Installation S 25 ft downwind of work TROVE _ 0.1 0.1 - Installation 0.1 6 15 Et downwind of ground- 1 0.2 level truck receiving waste removal ~ Installation Installation 0.1 7 150 ft downwind of work 0.1 area and at ground level- removal ~ Installation 0.1 continued TABLE 19 continued Test conditions,, Specific operation -- ares sampled matemals Piber level 8/0370 8/0370 5-21-74 continued continued 7-25-74 0-2 mph 3 School at Cary IN 3,500 sq ft by Mar Roofing Co. R Jobs- Manville Waukegan 2 25 t upwind of ground nen 0.0 track receiving waste roofing removal - Installation _ 0.0 Roof removal by saving Power saw shovel wheel- 0.2 prying installation by barrow broom nailing ailing base frit and hot felts mopping hot asphalt mopping other layers Same as Bo 1 man Same as above 0.3 15 ft downwind of work area _ 0.1 15 ft upwind of work are 0.2 11-20-74 18-8 pb School at Cherry Creek Upwind edge of work area _ 0.1 no state given 5,800 sq ft Downwind edge of work area _ 0.1 by United Materials Roofing Co. 1 Manville 3 Felt laying machine operator Machine lays felt in bot tar 0.2 . Waukegan 91 4 Broom felt into hot asphalt Push broom 2 S Bot asphalt tank operator Pouring hot asphalt 0.1 6 Felt fitting probable MHJ 3 cutting 12-15-75 variable 1 Industrial building no location given 7,700 aq ft 2 by unknown contractor -Manville Waukegan Felt laying machine operator Machine laya felt in hot tar 0.1 Replace felt rolla on laying Push broom 3 machine broom felt into tar North edge of work area oe 0.1 generally upwind South edge of work area - 0.0 generally downwind East edge of work are 0.1 8-76 ND School at Anderson DN 1,500 sq ft by Adams Roofing R ) JolmaManville Waukegan _ 2 ft downwind of work area 0.0 5 ft above removal - installation mee 0.0 Same as No. 1 removal _ 0.0 continued continued TABLE 19 continued Test conditions le No.b Specific operation or area sampled Tools materials Fiber level cmc 5-76 continued continued ) + 0.0 - Installation contimed Opwind edge of work area _ 0.0 5 ft above removal - Installation ane 0_0 Tear an probably 30 0.0 cutting and prying off old roofing Scrap removal man ND 0.0 probably shoveling and wheelbarrowing old roof material 0.0 Asphalt applicator probably mopping hot tar 0.0 Asbestos paper application probably cutting and laying felt 8-76 ND _ 0.0 2 ft downwind of work area School at Chesterfield IN 5 ft above roof 92 1,500 sq ft by Adams 0.0 _ Roofing --Johns Manville Same as No. 1 are Waukegan - 0.0 Upwind edge of work area 5 ft above roof 12-11-79 15 mph Office building at Bedford MA 31,000 sq ft by unidentified contractor R ) Technology Technology Division Eastern Analytical Asphalt applicator probably mopping bot tar Asbestos paper applicator probably cutting and laying felt Corner of roof 25 ft downwind of work area Edge of roof 25 ft downwind of work area Edge of roof 25 ft downwind of work area NO ND - _ 0.0 0.0 0.00 NA 0.03 100 ft upwind of work area 0.95 continued continued TABLE 19 continued Test conditions 12-11-79 continued Sample No. aa--- Man Specific operation --area smpled materials 5 Same as No. 4 area 3 Catting scraping and Removal circular saw aboveling old roof off of shovels wheelbarrows deck sweeping laying brooms fiberglass insulation and Installation : NO roofing felts layered with hot asphalt Fiber level 07 ) 0.01 0.00 Test conditions include date of sampling reported wind speed location area of work site roofer type of operation > oval I - installation sampling personnel analysis lab Sample No. generally corresponds to sampler'a reported data and two columns indicate whether sampling was performed on a worker moving or in a general area stationary Manville data based on PO GCA data based on EDXR analysis ND No data NA > Nor analyzed 93 generally follow a logical pattern with highest concentrations reported for cutting scraping and sawing operations as compared to spreading asphalt or unrolling felts the differences in fiber levels within a given study are less than the differences between studies generally less than 0.2 cm The variations in reported concentrations between studies in which similar materials and operations were used seem to suggest some contribution from the work practices of individual roofers or from background fiber concentrations A confusing factor in 4 of the 11 studies was that upwind fiber concentrations were higher than downwind concentrations and in 3 of the 4 studies they were higher than work site levels No explanation is given for these unexpected results Summary of Findings There is no secondary processing of containing roofing felt manufactured material is sold directly or through distributors to the The roofing contractor containing felts are used predominantly in built roof systems which combine the felts between layers of asphalt asphalt or other coatings These systems are rarely used for residential roofing The flat or gently sloping built roof widely employed on commercial and industrial buildings containing felts are occasionally used as an underlay for shingle or sheet roofing materials on inclined surfaces . Felt handling practices employed by roofing contractors tend to be fairly standardized although a wide range of combinations with asphalt roof deck insulation and other felts occur Felt installation is generally a low brooming removal energy intensity process requiring only felt unrolling with hot asphalt Only a minor amount of underlying air pockets and mopping of cutting with a bladed hand tool is required Removal of existing roof material requires greater energy input Power saws or axes are used to cut the substrate into 0.6 meter two foot square or larger blocks which are then pried off and scraped from the underlying deck using crow bars and shovels 20 Despite the variety of cutting and scraping operations that are fiber release potential This performed roofing felts appear to have a low results from the encapsulation of the fibers during the asphalt probably saturation step of manufacturing Also during installation as the felts are successively layered with hot asphalt and cold coatings the asbestos weathering is very gradual and fibers are further isolated In addition roof wind or rain erosion is expected to be minimal fiber release resulting from The greatest potential for fiber release exists during roof removal sections of when felt from energy mechanical disruption is required to remove the roof deck Fiber monitoring studies indicate that asbestos roofing felt installation and removal operations result in airborne fiber concentrations that are equal to or less than 0.6 cm Table provides a summary of the data presented on asbestos roofing felts and identifies the principal activity of concern with respect to airborne asbestos fiber release 94 TABLE 20. FELT SECONDARY PROCESSING AND END USE ACTIVITIES SUMMARY OF ASBESTOS ROOFING Product Roofing Felt Activity Duration incident Daily total Secondary processing No secondary processing performed End use Installation service use and removal specific Installation and removal highly variable with roof size and number of felt layers Actual felt cutting time is estimated to last less than one hour Fiber releasability Chemical composition Physical composition Disruptive energy 95 Control measure Measured fiber concentrations cm LowBefore asphalt saturation 85 to 87 asbestos fiber content remainder filler and binder Pliable with a tacky surface Knife or slitting machine during installation axes power saws and scraping tools during removal hand None 0.0 to 0.6 ranging from installation to removal Environmental setting Outdoors Activity of Concern brittle felts from roof deck Removal power sawing and scraping of wornout