b'Incompatibility ofCoal Tar Asphalt and By Bob Lacosse, GAE Both asphaltcoalare clas guidelines are provided for andtar sified as roofing bitumens. Athe types indicated: bitumen is aamorphous, blackTypeI- Includes class of ordark-colored(solid,semi-solidasphalts thatare relatively or viscous) cementitious substance,susceptib to flow at roof le natural or manufactured, composedtemperatureswithgood principallyhigh molecularightadhesiveandself-hofwe ealing hydrocarbons,solublein carbonproperties. T are generhey disulfide, andfoundinasphalts,ally u in slag- or gravelsed asphaltites, tars and pitches.is asurfacedroofson inclines It generictermusedtodenoteanyupto4.17percent(materialcomposedprincipallyofinch/foot) slope. bitumen.TypeII- Includes D te ar of significantasphalts th are moderately espi numbe at ph landchemicalchanges,susceptibletoflow atroof ysicaboth asphalt and coal tar have thetemperatures., they are forTypeI - Su a for u in Generally it blese following properties:use in built-upconstruction onbuilt-up roofing systems with felts roofExcel entresistancetoweatherin s fromapproximately 4.17conforming to therequirements of l clinepenetrationandextremely lowpercent (-inch/foot) slope to 1 Specification0227 or asspecifie~ water absorptivitypercent (1 -inch/foot) slope.2.5by then urer.J ma ufact GoodinternalcohesionandTypeIll - Inclu asphaltsTypeII - Suitable for usein des adhesion to the roofing felts andthat are re tive non-susceptible todamp-proofingandinmembrane la ly withrimeroof insulationflow at roof temperatures for use inwaterproofing systems,p rsDurabilityexpo the constructionof buiroofc tothe requirementsof under prolongedIt-uponforming sure to the elementsconstructiononinclinesfromSpecification 043, felts conformingThermoplasticity (i.e.reversible,approximately 8.3 percent (1-inch/to the requirements of Specification temperature-producedchangesfoot) s to 25percent (3-inch/0227, andrics with coal-tar satulopefabtorequiremenfromsemi-elasticsolidtovis foot) slope.rant conformingthets cous fluid)TypeIV- Inclu asphaltsofSpecification01 , 01 , or des73 327Themost basic,functionaldis that are generallyible to01666, in s using any combinonsuscept ystems tinctionbetweenthe t typesofflow at roof temperatures for use innation of componen specified by wots roof bitumens is th asphalt comesthe construction of built-up roofingthe manufacturer. at in agreater range of viscosi on inclines from approximately 16.7Type Ill - Suitabler use in muchfobu haties,whichmakesit suitableforpercent (2-inch/foot)slopeto50built-up roofing systems,tving slopesupto6 inches.Coaltarpercent {6-inch/foot)slope.Theseless volatilethan Type I. components comes inroofing grades and atypes of asphalts may be useful in0227 referred to insectwothe above water grade, withareaswhererelativelyhighyear tionsknownasASTM"proofingmaximumStandard viscosity about the same as that ofroundtemperaturesareexperi SpecificationforCoal-Tar-Satudead-level (ASTM t 1)Itenced.rated Organic Felt Used in Rooypeasphalt.fing generallylimited to 1/2-inch max and Waterproofing " is imum slope.Coal Tar Types In0460, "Standard Spec Two Don\'t l\\lix ASTM Asphalt Typesification for Coal Tar Pitch Used inMixing asphaltcoal tar panditch Asdescribedin ASTM0312,Roofing,Damp-proofingandviolatesa well-publicizedroofink "Standard Specification for AsphaltWaterproofing,"al tar isindustrytaboo,becausethetv, - j co classified UsedinRoofing,"thefollowingas follows:Co page 7 ntinued on 6'