b'MRCA ONVENTION REPORT Cullen, at the MRCA meeting, madefresh product"We a progress report on the status of theis always added.feel research.that this is the safe field limit and we "There isastrongpossibilitythatshouldnotexceedtheselimits regardless of mopping conditions,"he performanceoftheBURmaybesaid. improved by overheating procedures",He cautioned that before increasing he said. "With further laboratory andany kettle temperatures,contractors, field research, I hope toproperfirst of all, determine the flash point of obtain a mix of the factorsinvolved to insurethat particular asphalt. good performance."Tothe Johns-Manville Corpora date, Cullenrecommendedthatforthetion has approved temperatures up to THE "ROARING SEVENTIES"interim period, the industry seriously500F and the Corp of Engineers has predictedatthebeginningofthisconsider an increased kettle tempera raised their requirements up to 490F. decade,has resolved unwittingly intoture to amaximum of 500F,limitingEdPorter,roofingcontractor, the "Raging Seventies"instead,as ahowever the time at which the asphaltdescribed the various field tests made strongpublicoutcryhasarisenoniskeptatthistemperaturebybycontractors and in particular the the everysubjecttouchingthelivesofconstantly adding more material to thetestinKansasCity,citinga American citizens.kettle. He called on roofing contractorstemperature drop of 200F in a period TherecentMidwestRoofingtodeterminethebestpossibleof 40 seconds from kettle to mopping ContractorsAssociationconventionminimum mopping temperature and tosurface.Inthistest,underideal heldinOmaha,Nebraskawasnomeasureandcontrolthekettleconditions,nowindandasummer exception,withcontractors"raging"temperature at the lowest level whichtemperature of 70F, the asphalt was aboutmaterialshortages,aboutwillprovide this mopping viscosity.heated to approximately 550Fin the inflation, about price increases, about"YouCANcontrolyourkettlekettle, drawn off into a 5-gallon bucket inequities, about roof deck Master spectemperaturesto holdthis range",heand transported 25-30feet througha problems,aboutlabordemands,andsaid.windowopening intothe building.It about difficulties with OSHA.Indeed,"Also, lets shoot for aminimum aswas carried an additional 25-30 feet and it was difficult to find a subject whichwell as a maximum thickness betweendumped into mop buckets. At this time wasnot controversial.the plies. I contend that 15 to 25# perthetemperaturewascheckedandit The onlyarea of agreement onthesquarearereasonableeffortsrighthadalreadydroppedapproximately subject of "ApplicationTemperaturesnow."40-50.When mopping was begun the vs.KettleTemperatures"wasthatOthers on the panel included Robertmop bucket temperature was at450. furtherknowledgeandresearchwasWiskus,SiouxCity,Iowa,EdwardThemechanicmoppedanarea neededbeforethe problem wouldbePorter, Greenley, Colorado,and Johnapproximately 3 feet wide and nine feet resolved to the satisfaction of roofingHopkins,TrumbullAsphaltCo.,longinonecontinuousswab.Ashe contractors,suppliersandmanufac Summit, Illinois.mopped, the temperature was checked turers.Robert Wiscus described the resultson the surface just behind him. At this. Gradually, through field research byoffieldtestsheldinKansasCity,point the temperature of the surface of both the National Roofing ContractorsChicago,DenverandPhiladelphia,the asphalt was 250, a drop of 200 in Association and the Midwest Roofingduringpastmonths,wherethey40 seconds. When using a mop bucket ContractorsAssociationsaswellasattemptedtoduplicateactualjobtemperature of 400,using the same local groups, and the National Bureauconditions as closely as possible and toproceduresasdescribedabove,the of Standards, much new data is beingdocument the results. ABC will have asurface temperature was reduced in 20 compiledregardingapplicationvisfull story on these studies in the nextseconds. cosity of bitumens as related to kettleissue alongwithachartof thedataRelatingthesetimelag figuresto temperatures.compiled so far.manufacturersspecificationrequireWilliam C. Cullen, National BureauJohnHopkinsapplaudedtheworkments, the mechanic applying the felt of Standards, Gaithersburg, Maryland,being done by the industry, saying thathas less than 10-12 secondsapply the to hasastudyunderwaytoevaluatethese laboratory and field tests repre felt in order to get proper penetration performance of the Built-Up Roof,assent the first step towards resolving aof the asphalt. This of course, refers to related to the temperatures at whichserious problem. Most manufacturers,theapplicationtemperature,notthe the bitumen was heated, as well as thehe said, recommend 450 toas thekettletemperature.Ontheroof, 475F effectoftheply-thicknessofthemaximumkettletemperature.How however, the contractor must also take applicationonthedurabilityoftheever,TrumbullAsphaltisnowinto consideration other factors such as installation.approving 490 to 500F, provided thatthedecktemperature,theair 6NOV. - DEC., 1973'