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11.2 Asphalt Roofing11.2.1 General1-2The asphalt roofing industry manufactures asphalt-saturated felt rolls, fiberglass and organic(felt-based) shingles, and surfaced and smooth roll roofing. Most of these products are used in roofconstruction, but small quantities are used in walls and other building applications.11.2.2 Process Description1-4The production of asphalt roofing products consists of six major operations: (1) felt saturation,(2) coating, (3) mineral surfacing (top and bottom), (4) cooling and drying, (5) product finishing(seal-down strip application, cutting and trimming, and laminating of laminated shingles), and(6) packaging. There are six major production support operations: (1) asphalt storage, (2) asphaltblowing, (3) back surfacing and granule storage, (4) filler storage, (5) filler heating, and (6) filler andcoating asphalt mixing. There are two primary roofing substrates: organic (paper felt) and fiberglass.Production of roofing products from the two substrates differ mainly in the elimination of thesaturation process when using fiberglass.Preparation of the asphalt is an integral part of the production of asphalt roofing. Thispreparation, called "blowing," involves the oxidation of asphalt flux by bubbling air through liquidasphalt flux at 260 C (500 F) for 1 to 10 hours. The amount of time depends on the desiredcharacteristics of the roofing asphalt, such as softening point and penetration rate. Blowing results inan exothermic reaction that requires cooling. Water sprays are applied either internally or externally tothe shell of the blowing vessel. A typical plant blows four to six batches per 24-hour day. Blowingmay be done in either vertical vessels or in horizontal chambers (both are frequently referred to as"blowing stills"). Inorganic salts such as ferric chloride (FeCl3) may be used as catalysts to achievedesired properties and to increase the rate of reaction in the blowing still, decreasing the time requiredfor each blow. Blowing operations may be located at oil refineries, asphalt processing plants, orasphalt roofing plants. Figure 11.2-1 illustrates an asphalt blowing operation.The most basic asphalt roofing product is asphalt-saturated felt. Figure 11.2-2 shows a typicalline for the manufacture of asphalt-saturated felt. It consists of a dry felt feed roll, a dry loopersection, a saturator spray section (seldom used today), a saturator dipping section, heated drying-indrums, a wet looper, cooling drums, a finish floating looper, and a roll winder.Organic felt may weigh from approximately 20 to 55 pounds (lb) per 480 square feet (ft2) (acommon unit in the paper industry), depending upon the intended product. The felt is unrolled fromthe unwind stand onto the dry looper, which maintains a constant tension on the material. From thedry looper, the felt may pass into the spray section of the saturator (not used in all plants), whereasphalt at 205 to 250 C (400 to 480 F) is sprayed onto one side of the felt through several nozzles. Inthe saturator dip section, the saturated felt is drawn over a series of rollers, with the bottom rollerssubmerged in hot asphalt at 205 to 250 C (400 to 480 F). During the next step, heated drying-indrums and the wet looper provide the heat and time, respectively, for the asphalt to penetrate the felt.The saturated felt then passes through water-cooled rolls onto the finish floating looper, and then isrolled and cut to product size on the roll winder. Three common weights of asphalt felt areapproximately 12, 15, and 30 lb per 108 ft2 (108 ft2 of felt covers exactly 100 ft2 of roof).1/95Mineral Products Industry11.2-1

Figure 11.2-1. Asphalt blowing process flow diagram.1,4(SCC Source Classification Code)11.2-2EMISSION FACTORS1/95

Figure 11.2-2. Asphalt-saturated felt manufacturing process.1,2(SCC Source Classification Code)1/95Mineral Products Industry11.2-3

The typical process arrangement for manufacturing asphalt shingles, mineral-surfaced rolls, andsmooth rolls is illustrated in Figure 11.2-3. For organic products, the initial production steps aresimilar to the asphalt-saturated felt line. For fiberglass (polyester) products, the initial saturationoperation is eliminated although the dry looper is utilized. A process flow diagram for fiberglassshingle and roll manufacturing is presented in Figure 11.2-4. After the saturation process, bothorganic and fiberglass (polyester) products follow essentially the same production steps, which includea coater, a granule and sand or backing surface applicator, a press section, water-cooled rollers and/orwater spray cooling, finish floating looper, and a roll winder (for roll products), or a seal-downapplicator and a shingle cutter (for shingles), or a laminating applicator and laminating operation (forlaminated shingles), a shingle stacker, and a packaging station.Saturated felt (from the saturator) or base fiberglass (polyester) substrate enters the coater.Filled asphalt coating at 180 to 205 C (355 to 425 F) is released through a valve onto the top of themat just as it passes into the coater. Squeeze rollers in the coater apply filled coating to the backsideand distribute it evenly to form a thick base coating to which surfacing materials will adhere. Filledasphalt coating is prepared by mixing coating asphalt or modified asphalt at approximately 250 C(480 F) and a mineral stabilizer (filler) in approximately equal proportions. Typically, the filler isdried and preheated at about 120 C (250 F) in a filler heater before mixing with the coating asphalt.Asphalt modifiers can include rubber polymers or olefin polymers. When modified asphalt is used toproduce fiberglass roll roofing, the process is similar to the process depicted in Figure 11.2-4 with thefollowing exception: instead of a coater, an impregnation vat is used, and preceding this vat, asphalt,polymers, and mineral stabilizers are combined in mixing tanks.After leaving the coater, the coated sheet to be made into shingles or mineral-surfaced rollspasses through the granule applicator where granules are fed onto the hot, coated surface. Thegranules are pressed into the coating as the mat passes around a press roll where it is reversed,exposing the bottom side. Sand, talc, or mica is applied to the back surface and is also pressed intothe coating.After application of the mineral surfacing, the mat is cooled rapidly by water-cooled rollsand/or water sprays and is passed through air pressure-operated press rolls used to embed the granulesfirmly into the filled coating. The mat then passes through a drying section where it is air dried.After drying, a strip of adhesive (normally asphalt) is applied to the roofing surface. The strip will actto seal the loose edge of the roofing after application to a roof. A finish looper in the line allowscontinuous movement of the sheet through the preceding operations and serves to further cool and drythe roofing sheet. Roll roofing is completed at this point is and moves to a winder where rolls areformed. Shingles are passed through a cutter, which cuts the sheet into individual shingles. (Someshingles are formed into laminated products by layering the shingle pieces and binding them togetherwith a laminating material, normally a modified asphalt. The laminant is applied in narrow strips tothe backside of the sheet.) The finished shingles are stacked and packaged for shipment.There are several operations that support the asphalt roofing production line. Asphalt (coatingand saturant) is normally delivered to the facility by truck and rail and stored in heated storage tanks.Filler (finely divided mineral) is delivered by truck and normally is pneumatically conveyed to storagebins that supply the filler heater. Granules and back surfacing material are brought in by truck or railand mechanically or pneumatically conveyed to storage bins.11.2.3 Emissions And ControlsEmissions from the asphalt roofing industry consist primarily of particulate matter (PM) andvolatile organic compounds (VOC). Both are emitted from asphalt storage tanks, blowing stills,11.2-4EMISSION FACTORS1/95

Figure 11.2-3. Organic shingle and roll manufacturing process flow diagram.1,2(SCC Source Classification Code)1/95Mineral Products Industry11.2-5

Figure 11.2-4. Fiberglass shingle and roll manufacturing process flow diagram.1,2(SCC Source Classification Code)11.2-6EMISSION FACTORS1/95

saturators, coater-mixer tanks, and coaters. The PM from these operations is primarily recondensedasphalt fume. Sealant strip and laminant applicators are also sources of small amounts of PM andVOCs. Mineral surfacing operations and materials handling are additional sources of PM. Smallamounts of polycyclic organic matter (POM) are also emitted from blowing stills and saturators.Asphalt and filler heaters are sources of typical products of combustion from natural gas or the fuel inuse.A common method for controlling emissions from the saturator, including the wet looper, is toenclose them completely and vent the enclosure to a control device. The coater may be partiallyenclosed, normally with a canopy-type hood that is vented to a control device. Full enclosure is notalways practical due to operating constraints. Fugitive emissions from the saturator or coater may passthrough roof vents and other building openings if not captured by enclosures or hoods. Controldevices for saturator/coater emissions include low-voltage electrostatic precipitators (ESP), high-energyair filters (HEAF), coalescing filters (mist eliminators), afterburners (thermal oxidation), fabric filters,and wet scrubbers. Blowing operations are controlled by thermal oxidation (afterburners).Emission factors for filterable PM from the blowing and saturation processes are summarizedin Tables 11.2-1 and 11.2-2. Emission factors for total organic compounds (TOC) and carbonmonoxide (CO) are shown in Tables 11.2-3 and 11.2-4.Particulate matter associated with mineral handling and storage operations is captured byenclosures, hoods, or pickup pipes and controlled by fabric filtration (baghouses) with removalefficiencies of approximately 95 to 99 percent. Other control devices that may be used with mineralhandling and storage operations are wet scrubbers and cyclones.In the industry, closed silos and bins are used for mineral storage, so open storage piles are notan emission source. To protect the minerals from moisture pickup, all conveyors that are outside thebuildings are covered or enclosed. Fugitive mineral emissions may occur at unloading pointsdepending on the type of equipment used and the mineral handled. The discharge from the conveyorto the silos and bins is normally controlled by a fabric filter (baghouse).1/95Mineral Products Industry11.2-7

Table 11.2-1 (Metric Units). EMISSION FACTORS FOR ASPHALT ROOFINGaProcessAsphalt blowing: saturant asphaltc(SCC 3-05-001-01)Asphalt blowing: coating asphaltd(SCC ING3.3E12EAsphalt blowing: saturant asphalt with afterburnerc(SCC 3-05-001-01)0.14DAsphalt blowing: coating asphalt with afterburnerd(SCC 3-05-001-02)0.41DShingle saturation: dip saturator, drying-in drum section,wet looper, and coatere(SCC 3-05-001-16)0.60DShingle saturation: dip saturator, drying-in drum section, wetlooper, and coater with ESPf(SCC 3-05-001-16)0.016DShingle saturation: dip saturator, drying-in drum section, andwet looper with HEAFg(SCC 3-05-001-18)0.035DShingle saturation: spray/dip saturator, drying-in drumsection, wet looper, coater, and storage tanksh(SCC 3-05-001-19)1.6DShingle saturation: spray/dip saturator, drying-in drumsection, wet looper, coater, and storage tanks with HEAFh(SCC 3-05-001-19)0.027DFactors represent uncontrolled emissions unless noted. Emission factors in kg/Mg of shinglesproduced unless noted. Polycyclic organic matter emissions comprise approximately 0.03% ofPM for blowing stills and 1.1% of PM for saturators. SCC Source Classification Code. ESP electrostatic precipitator. HEAF high-energy air filter.As measured using EPA Method 5A. Filterable PM is that PM collected on or prior to thefilter, which is heated to 42.2 C (108 F).Reference 10. Saturant blow of 1.5 hours. Expressed as kg/Mg of asphalt processed.Reference 10. Coating blow of 4.5 hours. Expressed as kg/Mg of asphalt processed.References 6-7,9.Reference 6.Reference 9.Reference 8.11.2-8EMISSION FACTORS1/95

Table 11.2-2 (English Units). EMISSION FACTORS FOR ASPHALT ROOFINGaProcessAsphalt blowing: saturant asphaltc(SCC 3-05-001-01)Asphalt blowing: coating asphaltd(SCC 4EAsphalt blowing: saturant asphalt with afterburnerc(SCC 3-05-001-01)0.27DAsphalt blowing: coating asphalt with afterburnerd(SCC 3-05-001-02)0.81DShingle saturation: dip saturator, drying-in drum section, wetlooper, and coatere(SCC 3-05-001-16)1.2DShingle saturation: dip saturator, drying-in drum section, wetlooper, and coater with ESPf(SCC 3-05-001-16)0.032DShingle saturation: dip saturator, drying-in drum section, andwet looper with HEAFg(SCC 3-05-001-18)0.071DShingle saturation: spray/dip saturator, drying-in drumsection, wet looper, coater, and storage tanksh(SCC 3-05-001-19)3.2DShingle saturation: spray/dip saturator, drying-in drumsection, wet looper, coater, and storage tanks with HEAFh(SCC 3-05-001-19)0.053Dabcdefgh1/95Factors represent uncontrolled emissions unless noted. Emission factors in lb/ton of shinglesproduced unless noted. Polycyclic organic matter emissions comprise approximately 0.03% ofPM for blowing stills and 1.1% of PM for saturators. SCC Source Classification Code. ESP electrostatic precipitator. HEAF high-energy air filter.As measured using EPA Method 5A. Filterable PM is that PM collected on or prior to thefilter, which is heated to 42.2 C (108 F).Reference 10. Saturant blow of 1.5 hours. Expressed as lb/ton of asphalt processed.Reference 10. Coating blow of 4.5 hours. Expressed as lb/ton of asphalt processed.References 6-7,9.Reference 6.Reference 9.Reference 8.Mineral Products Industry11.2-9

Table 11.2-3 (Metric Units). EMISSION FACTORS FOR ASPHALT ROOFINGaTOCbEMISSIONFACTORRATINGCO0.66ENDAsphalt blowing: coating asphaltd(SCC 3-05-001-02)1.7ENDAsphalt blowing: saturant asphalt withafterburnerc(SCC 3-05-001-01)0.0022DNDAsphalt blowing: coating asphalt with afterburnerd(SCC 3-05-001-02)0.085DNDShingle saturation: dip saturator, drying-in drumsection, wet looper, and coatere(SCC 3-05-001-16)0.046DNDShingle saturation: dip saturator, drying-in drumsection, wet looper, and coater with ESPf(SCC 3-05-001-16)0.049DNDShingle saturation: dip saturator, drying-in drumsection, and coaterg(SCC 3-05-001-17)NDShingle saturation: dip saturator, drying-in drumsection, and wet looper with HEAFh(SCC 3-05-001-18)0.047DND0.13DND0.16DNDProcessAsphalt blowing: saturant asphalt(SCC 3-05-001-01)dShingle saturation: spray/dip saturator, drying-indrum section, wet looper, coater, and storagetanksj(SCC 3-05-001-19)Shingle saturation: spray/dip saturator, drying-indrum section, wet looper, coater, and storagetanks with HEAFj(SCC sphalt blowingk(SCC 3-05-001-10)ND0.14EAsphalt blowing with afterburnerk(SCC 3-05-001-10)ND1.9EFactors represent uncontrolled emissions unless otherwise noted. Emission factors in kg/Mg ofshingles produced unless noted. SCC Source Classification Code. ND no data. ESP electrostatic precipitator. HEAF high-energy air filter.Total organic compounds as measured with an EPA Method 25A (or equivalent) samplingtrain.Reference 10. Saturant blow of 1.5 hours. Expressed as kg/Mg of asphalt processed.Reference 10. Coating blow of 4.5 hours. Expressed as kg/Mg of asphalt processed.References 6-7.Reference 6.Reference 7.Reference 9.Reference 8.Reference 3. Emission factors in kg/Mg of saturated felt produced.11.2-10EMISSION FACTORS1/95

Table 11.2-4 (English Units). EMISSION FACTORS FOR ASPHALT phalt blowing: coating asphaltd(SCC 3-05-001-02)3.4ENDAsphalt blowing: saturant asphalt withafterburnerd(SCC 3-05-001-01)0.0043DNDAsphalt blowing: coating asphalt with afterburnerd(SCC 3-05-001-02)0.017DNDShingle saturation: dip saturator, drying-in drumsection, wet looper, and coatere(SCC 3-05-001-16)0.091DNDShingle saturation: dip saturator, drying-in drumsection, wet looper, and coater with ESPf(SCC 3-05-001-16)0.098DNDShingle saturation: dip saturator, drying-in drumsection, and coaterg(SCC 3-05-001-17)NDShingle saturation: dip saturator, drying-in drumsection, and wet looper with HEAFh(SCC 3-05-001-18)0.094DND0.26DND0.32DNDAsphalt blowing: saturant asphalt(SCC 3-05-001-01)Shingle saturation: spray/dip saturator, drying-indrum section, wet looper, coater, and storagetanksj(SCC 3-05-001-19)Shingle saturation: spray/dip saturator, drying-indrum section, wet looper, coater, and storagetanks with HEAFj(SCC 3-05-001-19)0.0019EMISSIONFACTORRATINGDAsphalt blowingk(SCC 3-05-001-10)ND0.27EAsphalt blowing with afterburnerk(SCC 3-05-001-10)ND3.7Eabcdefghjk1/95Factors represent uncontrolled emissions unless otherwise noted. Emission factors in lb/ton ofshingles produced unless noted. SCC Source Classification Code. ND no data.ESP electrostatic precipitator. HEAF high-energy air filter.Total organic compounds as measured with an EPA Method 25A (or equivalent) samplingtrain.Reference 10. Saturant blow of 1.5 hours. Expressed as lb/ton of asphalt processed.Reference 10. Coating blow of 4.5 hours. Expressed as lb/ton of asphalt processed.References 6-7.Reference 6.Reference 7.Reference 9.Reference 8.Reference 3. Emission factors in lb/ton of saturated felt produced.Mineral Products Industry11.2-11

References For Section 11.21.Written communication from Russel Snyder, Asphalt Roofing Manufacturers Association,Rockville, MD, to Richard Marinshaw, Midwest Research Institute, Cary, NC, May 2, 1994.2.J. A. Danielson, Air Pollution Engineering Manual (2nd Ed.), AP-40, U. S. EnvironmentalProtection Agency, Research Triangle Park, NC, May 1973. Out of print.3.Atmospheric Emissions from Asphalt Roofing Processes, EPA Contract No. 68-02-1321, PedcoEnvironmental, Cincinnati, OH, October 1974.4.L. W. Corbett, "Manufacture of Petroleum Asphalt," Bituminous Materials: Asphalts, Tars,and Pitches, 2(I), Interscience Publishers, New York, 1965.5.Background Information for Proposed Standards Asphalt Roofing Manufacturing Industry,EPA 450/3-80-021a, U. S. Environmental Protection Agency, Research Triangle Park, NC,June 1980.6.Air Pollution Emission Test, Celotex Corporation, Fairfield, Alabama, EMB ReportNo. 76-ARM-13, U. S. Environmental Protection Agency, Research Triangle Park, NC,October 1976.7.Air Pollution Emission Test, Certain-Teed Products, Shakopee, Minnesota, EMB ReportNo. 76-ARM-12, U. S. Environmental Protection Agency, Research Triangle Park, NC, May1977.8.Air Pollution Emission Test, Celotex Corporation, Los Angeles, California, EMB ReportNo. 75-ARM-8, U. S. Environmental Protection Agency, Research Triangle Park, NC, August1976.9.Air Pollution Emission Test, Johns Manville Corporation, Waukegan, Illinois, EMB ReportNo. 76-ARM-13, U. S. Environmental Protection Agency, Research Triangle Park, NC, August1976.10.Air Pollution Emission Test, Elk Roofing Company, Stephens, Arkansas, EMB ReportNo. 76-ARM-11, U. S. Environmental Protection Agency, Research Triangle Park, NC, May1977.11.2-12EMISSION FACTORS1/95

11.2 Asphalt Roofing 11.2.1 General1-2 The asphalt roofing industry manufactures asphalt-saturated felt rolls, fiberglass and organic (felt-based) shingles, and surfaced and smooth roll roofing. Most of these products are used in roof construction, but small quantities are used in walls and other building applications. 11.2.2 Process Description1-4