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Specifying Fire Resistive Coatings

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Specifying Fire Resistive Coatings. Presented by: Jayson L. Helsel, P.E. KTA-Tator, Inc. Learning Objectives. Comprehension of the webinar will enable the participant to: Describe how intumescent coatings protect underlying steel from heat exposure - PowerPoint PPT Presentation

Text of Specifying Fire Resistive Coatings

  • Specifying Fire Resistive CoatingsPresented by:Jayson L. Helsel, P.E.KTA-Tator, Inc.*

  • Learning ObjectivesComprehension of the webinar will enable the participant to:

    Describe how intumescent coatings protect underlying steel from heat exposure List two fire rating classification tests that are used to qualify intumescent coatings for use in building constructionIdentify two primary resin types that are used to formulate intumescent coatings Explain how steel size and structure design affect specified thickness and number of coats

  • Fire Resistive CoatingsSprayed Fire Resistive Materials (SFRM) are broad group of materials including:Cementitious and gypsum based materialsIntumescent coatings

    (Note: There is a separate category for Fire Retardent coatings, which are not reviewed here)

  • Fire Resistive CoatingsIntumescent Coatings:Are categorized as SFRMsSimilar to conventional coatings Have unique fire resistant properties

  • Intumescent CoatingsHow they function: Intumescent coatings char and swell when exposed to fire/heatThe charred layer acts to insulate the steel from fire

  • Intumescent CoatingsPerformance ratingsCoatings rated by how long steel is protected at specified thicknessRatings from 1 to 3 hours (at 30 minute intervalsSpecific to shape/size of steel, e.g. W10 x 49 column

  • Fire Resistance ClassificationsUnderwriters Laboratories (UL) is recognized authority that evaluates and approves intumescent coatings for a certain classification and fire ratingCertifications can be verified online at www.ul.com

  • Fire Resistance ClassificationsCertifications are design specific by coating manufacturerNumbering system defines an alphanumeric design number

  • Fire Resistance ClassificationsBeamsW, M or S shaped steel sections (AISC)Minimum beam size for fire resistance is expressed as W/D ratioW = weight of beam per lineal footD = perimeter of protection materialBeams of same configuration with greater W/D ratio may be used in design

  • Fire Resistance ClassificationsColumnsMinimum column size and configuration specified in X and Y series designsSame hourly rating applies when section with equal or greater W/D ratio is substituted for same configuration

  • Fire Resistance ClassificationsBeams and ColumnsRequired coating thickness increases as weight of steel decreasesLighter steel heats up more rapidly and requires more protection

  • Fire Resistance ClassificationsANSI/UL 263Used for resistance to cellulosic fire (e.g. combustion of wood or building materials)Slower rise in temperature1000 F at 5 min.; 1550 F at 30 min.; 1700 F at 60 min.; 1925 F at 180 min.; 2000 F at 240 min.Interior and exterior exposures

  • Fire Resistance ClassificationsANSI/UL 263 Classified CoatingsTypical use for structural steel in commercial structures

  • Fire Resistance ClassificationsANSI/UL 1709Used for resistance to a hydrocarbon fireRapid rise in temperature2000 F at 5 minutes Interior and exterior exposuresEnvironmental tests include, accelerated aging, high humidity, salt spray, thermal cycling for exterior exposure

  • Fire Resistance ClassificationsANSI/UL 1709 Classified CoatingsTypical use for steel structures at petrochemical facilities, e.g.Chemical plantRefineriesOffshore oil platforms

  • Other ApprovalsIntumescent coatings may also need approval by city building codesCoating manufacturers should provide approvals as applicable

  • Generic Coating TypesIntumescent coatings are generally the following generic resin types:Acrylic/vinylEpoxyIntumescents are also generally categorized as thin-film or thick-film coatings

  • Generic Coating TypesAcrylic/vinylThin-film coatingSolvent or water-basedSingle component Typically rated under UL 263

  • Generic Coating TypesAcrylic/vinylApplied in several coatsTime-frame for a complete application may span several daysAdditional time may be needed before application of any required exterior finish coat.

  • Generic Coating TypesEpoxyThick-film coatingApplied by plural component spray equipment in one or two coatsRapid cureTypically rated under UL 1709

  • Generic Coating TypesEpoxyMay require mesh reinforcement (e.g. metal, fiberglass, carbon)Typically requires the use of applicators licensed or approved by the coating manufacturer

  • Generic Coating Comparison*

    Coating TypeRequired Thickness (mils)Number of CoatsRecoat Time (between coats) @50FTime to Finish Coat @50FSolvent based acrylic130524 hours25 daysSolvent based vinyl37544 hours20+ daysWater based acrylic18068 hours10+ daysEpoxy1801n/a24 hoursEpoxy w/mesh3401-2n/a48 hours

  • Testing for Coating CureIntumescents may require testing for proper cureTypical test is Durometer Hardness (Shore D)Resistance of coating film to indentation by Durometer instrumentASTM D2240, Standard Test Method for Rubber Property-Durometer Hardness

  • Testing for Coating Cure

  • Coating AppearanceIntumescents generally have a rough or orange peel appearanceMethods to improve include:Back rolling following spray applicationSanding (not recommended)Finish coat application (may be required)Test sections recommended

  • Coating SystemsIntumescent design approvals typically include a primer and/or finish coatWhen included in design primer/finish must be applied to meet fire ratingPrimer/finish must be endorsed by intumescent coating manufacturerPreference always for same manufacturer

  • Use of PrimersIntumescent coating manufacturer may have approved list of primersTypes include alkyd, acrylic, epoxy and zinc-richApplication thickness important

  • PrimersFunction of primerProvides adhesion to substrate Provides suitable surface for intumescentProvides additional barrier protectionCan also provide inhibitive or sacrificial protection

  • Use of Finish CoatMay be required in design approval for exterior exposureIntumescent coating manufacturer must endorse finish materialTypes include 100% acrylic and aliphatic urethane coatingsMay affect/improve appearance

  • Finish CoatsFunction of topcoatColor and glossAbrasion resistanceChemical resistanceWashabilityResistance to the environment

  • Finish CoatsAcrylicsAdvantagesSingle componentEase of applicationColor & gloss retentionFlexibilityLow VOC content for waterbased

  • Finish CoatsAcrylicsLimitationsLimited alkali and solvent resistanceModerate abrasion resistanceApplication temperature >50F for waterbased

  • Finish CoatsUrethanesAdvantagesColor & gloss retention (aliphatic)AdhesionAcid, alkali resistantChemical resistantImpact/abrasion resistant

  • Finish CoatsUrethanesLimitationsMulti-componentShort recoat intervalsLimited pot lifeMoisture sensitive during cureDifficult to recoat

  • Fire Resistive Coating InspectionTechnical Manual 12-BPublished by Association of the Wall and Ceiling Industries (AWCI International)Individual measurement = average of 3 gauge readings (similar to SSPC-PA 2)Testing frequency one bay per floor or one test per 10,000 square feet (further defines required shapes)

  • Fire Resistive Coating InspectionTechnical Manual 12-BScopeGeneral InformationSubstrate ConditionsSite ConditionsInspection ProceduresMethod of TestsConditions of Finished ApplicationPatching

  • Fire Resistive Coating InspectionIntumescent (and Mastic) CoatingsCoating thickness specification in a design is minimum average thickness measured in accordance with Technical Manual 12-BAverage thickness should not exceed maximum thickness published (if listed) in individual designs No individual measurement
  • Summary of Key PointsWhen specifying intumescents consider:Required UL approvalCity building code approvalInclude required primer and finish coatsApplicator certification if needed (e.g. plural component materials)Include test sections to evaluate appearance

  • Specifying Fire Resistive CoatingsQuestions?

    *The primer is the first coating layer of the system. It provides adhesion of the coating system to the underlying substrate and must provide a suitable surface for the next coat. Depending on its formulation, the primer may provide barrier, inhibitive or sacrifical protection, often a combination of these. The primer most often is the coat employing sacrificial protection, as with zinc primers.*The function of the top coat is for both aesthetics and corrosion protection. The top coat provides the final color and gloss, abrasion and chemical resistance, washability, and resistance to the environment.*Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19Notes for slide:Silicone alkyds combine the excellent adhesion and easy handling properties of the alkyds with the exterior durability of the silicone resin. The coating cures by air drying and oxidation which may be slow.

    Typical coating application is for hulls and superstructures on ships. The significantly improved weathering properties as compared to alkyds include gloss and color retention and resistance to chalking.*Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19Notes for slide:Silicone alkyds combine the excellent adhesion and easy handling properties of the alkyds with the exterior durability of the silicone resin. The coating cures by air drying and oxidation which may be slow.

    Typical coating application is for hulls and superstructures on ships. The significantly improved weathering properties as compared to alkyds include gloss and color retention and resistance to chalking.*Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19Notes for slide:Silicone alkyds combine the excellent adhesion and easy handling properties of the alkyds with the exterior durability of the silicone resin. The coating cures by air drying and oxidation which may be slow.

    Typical coating application is for hulls and superstructures on ships. The significantly improved weathering properties as compared to alkyds include gloss and color retention and resistance to chalking.*Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19Notes for slide:Silicone alkyds combine the excellent adhesion and easy handling properties of the alkyds with the exterior durability of the silicone resin. The coating cures by air drying and oxidation which may be slow.

    Typical coating application is for hulls and superstructures on ships. The significantly improved weathering properties as compared to alkyds include gloss and color retention and resistance to chalking.