A series - National Roofing Contractors Association

1 ,A seriesof articlesas theyappeared inthe Roofing specofficial publicationof the National RoofingContractors Association ~TABLE OF ..12-14.. '"'Fibrous Glass Roof Insulation by Edward Mirra, Jr. ,Cellular Glass Roof Insulation by Carl Olm ~..Rigid Urethane Foam Roof Insulation by Donald M. Durdan Perlitic Roof Insulation by A. E. Bernardi Extruded Expanded Polystrene Roof Insulation by James P. Sheahan..Composite Insulation by Paul E. Burgess, Jr.. National AnoFlNG Contractors ASsoaATIONOne O'Hare Centre6250 River RoadRosemont, Illinois 60018(312) 318-NRCA official publication of the National Roofing Edward Mirra, ~r glass is presumed to have beendiscovered some Yt'an agowhen nomadic tribesmen built a hotfire in a bed of sand. The fire meltedthe sand. and presumably atribesman poked a stick -into themolten puddle that appeared. Whenhe pullecd the stick away the meltedsand formcd a long stringy typcEditor', Note: Edward MirT4, fro iscurrently Section MarketingManager, Roof Insulation, forOwens-Corning Fiberglas Cor-poration.

2 He received his Bachelor ofScience Degree in ElectricalEngineering from Lehigh Unlwrsity,and a Masters Degree in BusinessAdmim:stration from the Universityof has been associated with Owens-Corning Fiberglass since 1962,during which time he has obtainedexperience in many diverse areas ofthe corporation, includingProduction Management, Sales,Market Research, and Finance inaddition to Marketing. Mr. Mirra isa member of the AmericanMarketing Association , AmericanSoa'ety of Heating, Refrigeratingand Air Conditioning Engineers the Societyfor the Admncementof are grateful to him for this. ourfirst in a series of articles on roofl' INSULATION fiber. The further he pulled. thethinner it became until suddenly ithardened. Little did he realize thathe had formed the first glass centuries later. there arenumerous products and applicationsderived from the discovery of theglass fiber.

3 One such product isfibrous glass roof insulation. owners and contractorsare benefiting from the uniqueproperties of glass fibers used toproduce fibrous glass roof thickness with thecorresponding maximum flute since alm~t all metal decks haveflute spans of 21,i" or less. fibrousroof insulation can meet practicallyall of the metal deck flute :MAXIMUM flute SPANPRODUCT glass roof insulation boardsare composed of glass fibers. Theglass fiber reinforced asphalt andkraft top surface provides the rough,impact. resistant mopping surface forthe built-up Roofing insulation boards producedfrom fibrous glass are available in"'x4'sizes, as well as4'x 8' sizes, whichresult in fewer joints in the roofsystem. Fewer joints are purported bymany to provide additional ad-vantages not available with smallersized boards, such as less heat leak-The thickness is varied from ~.

4 To2 v." to achieve the insulation ef-ficiency required as shown in TableI. Double layer application is alsocommonly used to achieve evengreater insulation GLASSROOF INSULATIONMax FluteThicknesa SpanInches Inches5/4"15/16"1-1/16" "1-5/8" "TABLE 1:GLASS nBER. SELECTION GUIDECA nductantt 2-1/4".Ig 1-7/8".15 ".19 1-~/16".24 1-1/16".27 15/16".56 5/4"WIDE FLUTEROOF INSULATIONMax FluteThicknea SpanInchea Inchea2-1/2"2-7/8"5-1/4"4-1/4"GENERAL DESCIlIPTIONAND USEF iber glass roof insulation has twoprimary uses today. First andforemost is its we as a thermal to retard the flow of , it's used as a base for built-up Roofing in the construction ofroofing systems for non.~ the energy crisis continues toincrease in severity, the insulationquality of fibrous glass roof is becoming increasinglyimponant in its role of conservingthe nation's vital energy resources, aswell as reducing the operating costsof businesses and institutionsthroughout the United fine glass fibers from whichroof insulation is manufacturedprovide the very efficient insulatingpropenies of the product.

5 Roof insulation product mustexhibit additional properties becauseof the complex forces present in aroofing unique combination ofproperties of fiber glass, not found inany other material, provides thecharacteristics to meet the stringentrequirements of Roofing such as strength: weightfor weight, fiber glass has six timesthe breaking strength of steel. Glassfibers are dimensionally stable andwill not expand with heat or swellwith addition, glass fibers arf::flexible, inert and fire resistant,which adds up to an imponant arrayof propenies that are panicularlyhelpful for the long-range of roof insulation and theentire Roofing glass roof insulation willvent vapor through the can be vented or free waterpumped out in the event of damageto the built-up roof, eliminating th~need to remove the insulation shouldit become wet for anyone of manypossible causes.

6 Once the roof in-sulation has been dried, the originalthermal value is glass roof insulation isacceptable and approved by FactoryMutual in accordance with theirpublished requirements. Similarly, itis approved by UnderwritersLaboratories, Inc. for many specificconstruction majority of decks beingconstructed p~ntly are metal;therefore, flute span capability ofroof insulation is important. Table 2provides the fiber glass roof in-I."12"18"12"5/4"15/16"1-1/16"1-5/16"H OW FIBROUS -- -GLASS ROOF INSULATIONIS MANUFACTUREDThe first step in the manufacturingprocess of gla~ fiber insulation is tomelt sand. li~one. soda ash andother ingredients at temperatures of25000 Fahrenheit. While the glass isa molten liquid. it flows through tinyholes that shape it into fi~n finerthan human hair. Once the fibergla~ is formed it is spun into lightfluffy material which is than into a rigid insulation.

7 Th~insulation then has the reinforcedcover applied. after which it is cut tosize and schematic description of theprocess is shown. but only personalobservation of this manufacturingoperation can vividly depict how farglass fiber technology has progressedsince the tribesmen first discoveredthe phenomenon years OF FIBROUSGLASS ROOF INSULATIONF ibrous glass roof insulation can beinstalled using hot steep asphalt. coldadhesive or mechanical fastenersdepending upon the specific job andits requirements. For metal decksthat are Factory Mutual Class I orclassified as an UnderwritersLaboratories roof deck respective specific requirementsfJ:~~~~~ ."'WEIGHMIXq IGLASS MELTIN88 REFINING TANK~~CENTRIFUGEFORMING~'COMPRESSAND CURE~=bcrPACK OR CURING OVENFABRICATEMANUFACTURING PROCESS\03must be followed as they relate toacceptable materials and how theyare installed. One aspect of thelisting of materials for FactoryMutual Class I requires they pass a 60 PSF (Pounds per Square Foot) uplifttest.

8 Although Factory Mutual maylist materials for use with fibrousglass roof insulation. themanufacturer's manual should bechecked to see if there are glass roof insulation canbe installed over the commonly usedvapor retarder systems. For metaldecks. Factory Mutual and Un-'--"'L'--"'. ~dl .'dl III I dIIII-lATCH INGREDIENTS H II IIIderwriters Laboratories guidelinesshould be followed as required. Themost common roof insulation ap-plication is over a metal deck withoutvapor retarder systems. Glass fiberroof insulation is applied to metaldecks with a 12-15 lbs. per squaremopping of hot steep asphalt. or .7gallons/square of cold adhesive. orby the use of mechanical fastenersbeing applied one fastener for each 2sq. ft. of roof insulation. When vaporretarders are used.. gallons ofcold adhesive is applied below thevapor retarder to adhere it to themetal deck. and. 7 gal.

9 It applied ontop of the vapor retarded to adherethe roof insulation. For poured-in-place and other non-nailable sur-faces. the deck is normally primedusing 1 gal/square of an asphaltprimer. then the insulation is em-bedded in a minimum mopping of of steep asphalt. Wherejoints exist. precaution must be takento prevent asphalt drippage. Fornailable surfaces. a mopping surfacemust be provided that is adequate toobtain proper adherence of theinsulation. Possible mopping sur-faces might be a base sheet. or a glassfiber felt. or red resin and No. 15felt. These added mopping surfacesare nailed to the deck. and then theroof insulation is adhered to them byusing a solid mopping of hot steelasphalt applied 30 vapor retarders arerequired over the decks. thosecommonly used are acceptable;however. caution must be exercisedto be certain that the insurance andcode requirements are being a c~Uulating ag~nt.

10 Thismixture is placed in a mold andsubj~ct~d to a t~mp~ratur~ of ap-proximat~ly 950 F in a fumac~. Atthis t~mperatur~. th~ glass turns to aliquid. th~ c~llulating ag~ntd~composes. and the mass ~xpandsto fiU th~ mold. This r~sults inmillions of closed c~lIs. containing anin~rt gas. connected to ~ach oth~r toform an insulating mat~rial that isimp~rm~abl~. strong. non-com-bustibl~. and has a constant in-sulating ~ '" Note: Carl Dim is currentlyBusiness Manager, ArchitecturalProducts Division, for P,.ttsburghCorning Corporation. He has beenassociated with Pittsburgh Comingsince 1970, haling previously workedfor Corning Works in a numberof engineering and '".t:.CELLULAR GLASS AS AROOF INSULATORThe function of the insulation in aroof system is to resist the passage ofheat and. to do so, it should alsoresist the passage of water in liquidand vapor form. The insulation mustprovide a strong and stable base forthe membrane and it must becompatible with.