E?A Applicability Of The Asbestos NESHAPToAsbestos Roofing Removal .

A variety of materials are used as vapor retarders,including one or two plies of asphalt-saturated felt adheredwith bitumen; vinyl or polyethylene film; polyvinyl chloride(PVC) sheets; aluminum foil; and laminated raft paper sheetswith a bitumen-sandwiched or bitumen-coated kraft paper.In temperate humid climates during much of the year,water vapor flows in the opposite direction, i.e., downthrough the roof to the interior. 5 In these climates, theroof membrane acts as the vapor retarder.3.3 THERMAL INSULATIONFour categories of insulation are used in low-slope roofsystems: Rigid board insulation Dual-purpose deck and insulating panels Poured-in-place insulating concrete fills Sprayed-in-place polyurethane foamIn addition, blanket or loose-filled insulation maybe used injoist cavities under the roof deck.Rigid board insulation includes wood and vegetable fiberboards, foamed plastics, rigid glass fibers, perlite, cellularglass, mineral fiberboard, and poured lightweight insulatingconcretes. Preformed structural wood-fiber decks made ofcement coated wood fibers (e.g., Tectum ) also serve as·insulation. ightweight insulating concretes contain perlite(siliceous volcanic glass), or vermiculite (expanded mica)aggregate and Portland cement. Polyurethane foam is theprincipal sprayed-in-place plastic foam.Insulation for steep-sloped roofs is often applied underthe deck. Insulation used in nonresidential, low-sloped roofsis summarized in Table 3-2. 63-3

TABLE 3-2.INSULATIONS USED IN NONRESIDENTIAL,LOW-SLOPED ROOFING PROJEC SInsulationPercent of projectsPolyisocyanuratePerliteExpanded polystyreneExtruded polystyreneGlass fiberCellular glassPhenolic foamCompositeOtherSource:43.321.39.84.36 .4·0.72.94.07.3National Roofing Contractors Association, 1991/1992NRCA Market Survey.3.4MEMBRANESRoofing contractors experiences with variouslow- loped membranes, are summarized in Table 3-3. 6Built-uproof and ethylene propylene diene monomer (EPDM) membranes arecurrently the most frequently used.3.4.1 Built-up RoofA diagram of a typical built-up roof is shown inFigure 3-1. 7 Built-up roof membranes consist of alternatinglayers of bitumen and roofing felt that may be surfaced withan aggregate. Bitumen is (1) a class of amorphous, black ordark colored (solid, semi-solid or viscous) cementitioussubstances, natural or manufactured, composed principally of·high-molecular-weight hydrocarbons, soluble in carbondisulfide, and found in asphalts, tars, pitches andasphaltites; (2) a generic term used to denote any materialcomposed principally of bitumen. 4Both petroleum asphalts and coal tar, the bitumens usedin built-up roofing, have the following desirable properties:. Good resistance to water penetration and low waterabsorptivity Good weather durability3-4

TABLE 3-3.MEMBRANES uSED IN NONRESI::::E:::.'":":.:u. i\OOFING ?ROJECTSMembranePercen Built-up roofingEthylene propylene dienemonomer (EPDM)Modified bitumen-APPModified bitumen-SBSAsphalt shinglesPolyvinyl chloride (PVC)Clorosulfonated polyethylene (CSPE)(e.g. Hypalon)TileOther rethane foamLiquid-appliedOtherSource:of 3.5National Roofing Contractors Association, 1991/1992NRCA Market Survey.3-5

a-Siooot1.- Ta.-red Cant StripC1989, R:D. Herbert Ill, Roofing: Design Criteria, Options. Selection, used bypermission of R.S. Means Co., Inc.Figure S-1. Typical built-up root.3-6

Good internal cohesion and adhesion Thermoplasticity5The bitumen is used as an adhesive as well as a waterproofinglayer. 4 The roofing felts stabilize and reinforce the system.The aggregate protects the membrane from the effects ofsunlight and weathering. Between the plies of roofing felt,bitumen is mopped, typically at 20 to 35 lb/square (a squareis 100 ft 2 ) 4 The top layer, or flood coat, of bitumen isapplied at 60 lb/square, allowing about half of the aggregateto become imbedded in it.The primary advantage of asphalt is that it comes in awide range of viscosities; hence, high viscosity (highresistance to flow) asphalts are available for slopes up to 6in./ft. In contrast, coal tar bitumen has viscosities aboutthe same as dead-level (Type I) asphalt and, thus, isgenerally only appropriate for slopes of 1/4 in./ft or less. 4The predominant reinforcing material used in roofing·felts is glass fiber. Asbestos was manufactured and used as areinforcing material in roofing felts until about the early1980s, after which its use and manufacture for that purposewere discontinued.3.4.2 Single Ply Membrane·Synthetic, single-ply membranes can be classified byapplication technique and design. They may be sheet- orfluid-applied and designed as fully or partially adhered,mechanically attached or loose-laid and ballasted membranes.They may also be classified as thermosetting, e.g., EPDM;thermoplastic, e.g., PVC, chlorinated polyethylene (CPE), andpolyisobutylene membranes (PIB); and modified bitumen.3.4.3 ShinglesA shingle is defined as a small unit of preparedroofing material designed for installation with similar unitsin overlapping rows on inclines normally exceeding 25percent. 43-7

3.4.3.1 Asphalt Shincrles. Asphalt shingles are made bytreating rolls of organic base mats (felts) or fiber glassbase mats with asphalt and cutting them to a desired size andshape. 8 The top surface of shingles is covered with ceramiccoated granules to protect the asphalt coat ng from theharmful effects of sunlight and to add some :ire resistance.3.4.3.2 A/C Shingles. A mixture of asbestos, cement andsilica is processed to form A/C sheet with an asbestos contentranging from 15 to 40 percent. In turn, A/C shingles (nolonger manufactured in the U.S.) were cut from flat A/C sheetin sizes ranging from 9 in. by 16 in. to 14 in. by 30 in. A/Cshingles were extremely durable, lasting from 30 to 50 years,and were produced in a variety of styles and colors. A/Cshingles were attached to the roof in the same way as asphaltshingles, i.e., with roofing nails. .Pilot holes forattachment were routinely predrilled or punched at the primarymanufacturing plant. 93.4.4 FlashingFlashing is the system used to seal membrane edges atwalls, expansion joints, drains, gravel stops, and otherplaces where the membrane s interrupted or terminated. Baseflashing covers the edge of the membrane, and cap flashing orcounterflashing shields the upper edges of the base flashing. 4An application of flashing is illustrated in Figure 3-2. 7Typically, base-flashing materials include .conventionalsaturated and coated felts, reinforced/laminated asbestos feltand scrim (a durable, plain-woven fabric), fiberglass orcotton wovens impregnated with bitumens, vinyls, neoprenes,and butyl rubber. Asbestos flashing have not beenmanufactured in the U.S. since about the early 1980s.Because they are exposed, counterflashings are usuallyrigid and durable; metals including copper, aluminum,galvanized steel, stainless steel, and lead have been used.However, bituminous materials similar to the base flashingalso may be used. 53-8

---Metal Counterflashing Composition.(Base Flashing -.,--WoodBloc:king'----RoofInsulation' - - - - Metal DeckC1989, A.D. Harbert Ill, Roofing: Design Criteria, Op1ions, Selection, used bypermission of R.S. Means Co., Inc.Figure 3-2. Base flashing.3-9

3.5 MEMBRANE SURFACING 53.5.1 Aggreaate for Built-uo RoofingAggregate, 3/16 to 3/4 in. in size, embedded in thebituminous flood coat is a common surfacing for built-uproofs. Common roof aggregates are river-washed gravel,crushed stone, and blast furnace slag. Gravel is typicallyapplied at a rate of 400 to 500 lb/square, and slag is appliedat a rate of about 300 to 400 lb/square. 4 Approximately 50percent of the aggregate is typically embedded in the floodcoat. 5An advantage of surfacing with a flood coat of bitumenand aggregate is that it results in a very durable surface.Other benefits of aggregate surfaces are Shields the membrane from solar radiation Resistance to bitumen erosion by wind and water, andto heat aging Impact resistance Fire resistance Wind uplift resistance Reduced membrane temperature3.5.2Smooth SurfaceA smooth-surfaced built-up roof membrane has a top coatof hot, steep asphalt. Some smooth-surfaced built-up roofsare also. coated with a reflective coating to reduce roofsurface temperature. Compared to aggregate-surfaced roofs,some advantages of smooth-surfaced membranes are: Easier inspection, maintenance, and repair Easier installation of new penetrations in the roof Easier reroofing or replacement Reduction in dead load (300 to 400 lb per square).3-10

3.5.3MineralMineral-surfaced roll roofing is made of felts oftencoated with granules of slate, ceramic, or ineralembedded inthe weathering grade asphalt on the surface to be exposed.3-115

II.I

4.0ASBESTOS ROOFING PRODUCTSThis section describes various roofing products and theiruses with particular emphasis on those that contain (orcontained) asbestos. Information on the time periods in whichasbestos-containing products were used is provided whereavailable.4.1 FELTS 54Asbestos roofing felts were no woven fabrics of organicand/or inorganic composition. Organic felts are made ofcellulose fibers--pulped wood and felted papers--saturated andcoated with coal tar bitumen or asphalt. Asbestos-reinforcedfelts were saturated and coated with asphalt and wererelatively low in cost and widely used.Asbestos felts conforming to the specifications of ASTM0250 were made of 85 percent chrysotile and 15 percent organicfibers saturated with asphalt though the ASTM standard waschanged frequently over the years. The addition of otherorganic fibers allowed the felt to absorb more of the asphaltsaturant, which asbestos fibers do not absorb. Asbestosfelts, like others, are quite thin. For example, dry asbestosfelts (before bitumen is added) weighed approximately 9 and 18lb/square and were 0.023 and 0.047 in. thick, respectively. 8Glass fiber mats saturated with asphalt were also used asroofing felts.The typical use, asbestos content, and time period soldfor asbestos felts are given in Table 4-1. 10 Virtually all4-1

TABLE 4-1. ASPHALT-SATURATED AND ASPHALT-COATED ASBESTOS ROOFING FELTSCommon trade na ·ASTM apedllcallonTypeProdud -ighlAsbestos weight(lb/10011')(lb/1 ootl')Typical useTime period sotdbAsphai.SaturaledNo. 15 asbestos, perforated, alsocalled asbestos "ffnishing left1 1502506-8Ply feK lor smooth andaggregate BURs, backerfeH in flashings, "5" course36-in. widlh: 1940 lo32-in. width: belorecold applied "Asbeslile.IIV\IVIIpresentflashings.No. 20 asbestos, perforat -&lueChip FeK"0250Ill17-209-10Ply felt for smooth andaggregate BURs1960s to 1980sNo. 25 asbeslos, unperforaled"Centurion" Base FeK0250IV21-2512-14Uncoated base sheet1960s to presentcNo. 30 asbestos, unperforated0250ll2! -2815-18Shingte undertay1930s to 1960s"Asbestosgard"None8-105-7Fire-rated vapor retarder1960s to 1980sAapb I:CMiedIN03378Ill37-3939-436-89-10Base aheet for asbestosBURs1960s to 1980sVenting base sheet03672I68-709-10Base sheet for reroofing1960s to 1980sAsbestos base flashing, also called"reinforced asbestos ftoshlng".or"composition base flashing"None5! -6015-18Hot mopped base flashinglor BURs1960s to presentAsbestos base flashing "AB--20"None528-8Hot or mastic eppltedbase ftashlng lor BURs1960s to 1963Asbestos base left, also called "No.45 asbestos base Source: The Roofing Industry EducationallnslRute. Englewood, CO., n.d.BUR: Built-up roofing. Some lehs have a number designation which refers to lhe weight ollhe lei, e.g., a No. 15 lei hal a weighl ol151b./100 ft' Refelll to period sold in both the UnRed Slates and Canida. 'LIHie, Wany, roofing feK II now uouid In the United Stales.cNo longer being sold.

U.S. production of asbestos roofing felts was discontinued,however, by the early 1980s, in part because of performancerelated problems with the product.4.2 CEMENTS, COAT:NGS, AND ADHESIVESCements, coatings, and adhesives are typically made ofasphalt cutback, i.e., solvent-thinned bitumens, and includecold-process roof primers, adhesives, roof and flashingcements, and roof coatings. Typical uses, asbestos contents,and time periods sold for asbestos-containing cements,coatings, and adhesives are shown in Table 4-2. 104. 3 SINGLE-PLY PRODUCTSAsbestos was used as a neoprene latex bonded asbestosbacking material in a few of the early single-ply roofingsystems such as TNA-200 (Tedlar-neoprene-asbestos) , PIBmembranes, and Hypalon sheets. The PIB membranes were soldbetween 1960 and 1966. 10 Other single-ply products (e.g. EPDM,PVC, modified bitumen, and CPE) are not and have not in thepast been made with asbestos.4 . 4 SHINGLESA/C roofing shingles and asphalt-asbestos roofingshingles have been in use in this country for more than 80years. Asphalt-asbestos roofing shingles were sold until1979, but were not used widely; A/C shingles were sold until1992.4.5 DECKINGSince the 1930s, corrugated A/C sheets and flat A/Csheets (Transite) have been used as wall cladding, andoccasionally as roofing panels; flexible and utility A/Cproducts have been used as decking. 11 However, unless damaged,decks are not repaired or removed even if other parts of theroof system are being replaced. 44.6 INSULATIONAsbestos is not and has not been employed in thermalinsulation used in roof systems.4-3

TABLE 4-2. ASBESTOS-CONTAINING CEMENTS, COATINGS, AND ADHESIVESProduct,.,.ASTMapecHicatlonTypeAsbestos Indry fDmUb/100fflTypical useTime period sold"1-2Coat smooth-surfaced roofing1930 to presentReflective coating for smooth·surfaced roofing and modifiedbitumens1930 to presentAsphalt roof coating(fibratedl02823Aluminum roof coating(asbestos fibrated)02824I or II2-3Asphalt emulsion(asbestos fibrated)01227Io.1-o.8Water-based coating forsmooth-surfaced roofing andmodified bitumens1930 to presentCold process cement03019II2-4Solvent-based adhesives forcoated felt systems (brushgrade), used with "splitsheet roll goods1930 to presentAsphalt cement(plastic cement, flashingcement)028226-16Solvent-based bodiedadhesivesTo present2-8Recoating old BURs, usuallyregravelledTo presentIRoofing resaturantsSource: The Roofing IJ1dustry Educational Institute. Englewood, CO., n.d. Refers to period sold in both the United States and Canada.

4.7OTHER ROOF COMPONENTSRoofing materials not covered in previcus sections ofChapter 4 (e.g., vapor retarders, thermal insulation, modifiedbitumen membranes) are not and have not in :he past been madewith asbestos.Roofing felts and single-ply membranespresently manufactured and used also do not contain asbestos.4-5

IIIIIIIIII

5.0ROOF REMOVALPRAC IC S5.1BUILT-UP ROOFSWhenever roofs become damaged or deteriorate to the pointthat leaks are likely, a decision must be made on how torestore the roof to its intended integrity. Usually thecourse of action requires, at a minimum, the repair of thedamaged or deteriorated areas and, in some cases, replacementof the entire roof may be necessary. Even when the decisionis to re-cover the existing roof, repairs are occasionallymade to the existing roof. Complete roof removal typicallyinvolves removal of the membrane, flashing, insulation, andvapor retarder (if present) in the affected area. In someinstances, the roof deck may need repair or replacement.The aspects of roof removal practices discussed here arelimited to the methods and equipment used in the removal ofthe roof membrane and flashing, the components of a roofsystem.where asbestos is most likely to be found. As.discussed above, other components of roof systems do notcontain asbestos or are not repaired or replaced using methodsthat trigger coverage under the asbestos NESHAP. Severalmethods of cutting the roof membrane are available and themethod chosen often depends on the nature of the job as wellas State and local asbestos regulations. Power roof cuttersare used predominantly to cut roof membranes into manageablesections that can be lifted and removed by workers. Manualmethods are sometimes used. Other mechanical methods may beused successfully to cut and slice roof membranes, althoughtheir use is not yet as well known or as widespread.5-l

Generally, for built-up roofs, the membrane is separated(e.g., by cutti g, sl:ci g, punching or shearing) intosections of approximately 2 ft by 2 ft, or 2 ft by 4 ft orother sizes that can be managed by one or :·,.,o workers and thatwill fit into a cart or wheel-barrow and a 2-ft diameterchute. The sections are pried up using power roof removers,shovels or tear-off bars, and lifted and stacked on a cart orwheelbarrow. Single-ply membranes may be sliced into longstrips and rolled up.Flashing is usually removed by slicing along the edge ofthe field of the membrane, next to the flashing, and pullingor prying the flashing loose. The roofing material is takenby cart or wheelbarrow to the roof's edge where it is conveyedby chute, hoist or crane into a container on the ground below.(Although it is not required by the NESHAP, even Category Imaterial should not be dropped to the ground without goingthrough a chute. I5.1.1 Surface PreparationLoose, surface gravel is often removed from theexisting roof membrane before removal begins. 5 This will helpto reduce the amount of du t generated during roof removal.Gravel can be removed by manual methods--raking, sweeping andshoveling--or by using a power vacuum. Gravel removal byvacuuming can be done dry or wet. 12 The removal of gravel byvacuuming is shown in Figure 5-1. Power brooms like the oneshown in Figure 5-2 are also used to remove gravel and consistof a rotating brush that pushes gravel forward and to theside.5.1.2 Manual MethodsRemoval by manual methods usually involves the use ofaxes, hatchets and utility knives to chop or slice the roofmembrane into sections that can be lifted by one or twoworkers with shovels, spud burs, etc. and loaded onto a cartor wheelbarrow. Manual methods are often used when repairingsmall areas of damaged membrane or when repairing small areasof flashing, although they can be and occasionally are used to5-2

.';. :"I. ·-··,.·-··, . · ···. ··· ·. ·,·· .:,.:.!. ··,:.; ."' I' Figure 5-1. Gravel removal by vacuuming.S-3,., .

remove roof membranes on larger removal jobs. On large,manual roof removal jobs, labor requirements usually increasefor the removal phase because it takes considerably moreworkers to chop or slice the same amount of membrane that canbe cut using powered cutting equipment in the same time.Manual removal was estimated by one roofing contractor toincrease labor re irements by about one and one-half times.: 35.1.3 Rotating Blade IRB) Roof CutterRB roof cutters, like the one in Figure 5-3, are usedextensively by roofing contractors to cut roof membranes forremoval. A gasoline-powered engine mounted on a three- orfour-wheeled deck turns a blade mounted near or toward thefront of the machine. Standard engines range in size from5 hp for cutters used for patch work and cutting around rooffixtures such as vents and heating, ventilation, and airconditioning (HVAC) components to 14 hp for cutters equippedwith double blades, with 8- and 9-hp engines being typical forthe RB roof cutters that do the bulk of the cutting. RB roofcutter blades typically

2.0 ROOFING INDUSTRY 2.1 NUMBER AND SIZE OF ESTABLISHMENTS Roofing contractors are classified in SIC 1761, Roofing, Siding, and Sheet Metal Work. Based on information from the Census of Construction Industries,1 and the National Roofing Contractors Association (NRCA) 2 there are about 15,000 firms