Fire Resistant Coatings Presented by: Jayson L. Helsel, P.E. KTA-Tator, Inc.

Learning Objectives Comprehension of the Fire Resistant Webinar will enable the participant to: Describe how intumescent coatings protect underlying steel from heat exposure Identify the US authority that evaluates and approves intumescent coatings List two fire rating classification tests that are used to qualify intumescent coatings for use in building construction Identify two primary resin types that are used to formulate intumescent coatings

Learning Objectives (cont.) List characteristics of the resin systems used to formulate intumescent coatings Explain how steel size and structure design affect specified thickness and number of coats Describe the methods used to improve the appearance of the texture of intumescent coatings Describe a method to measure the hardness of the applied coating to assess cure Identify the generic types of primer and finish coats commonly used in conjunction with intumescent coatings

Fire Resistant Coatings Sprayed Fire Resistive Materials (SFRM) are broad group of materials including: Cementitious and gypsum based materials Intumescent coatings (Note: There is a separate category for “Fire Retardent” coatings, which are not reviewed here)

Fire Resistant Coatings Intumescent Coatings: Are categorized as SFRMs Similar to conventional coatings Have unique fire resistant properties

Intumescent Coatings How they function: Intumescent coatings char and swell when exposed to fire/heat The charred layer acts to insulate the steel from fire

Intumescent Coatings Performance ratings Coatings rated by how long steel is protected at specified thickness Ratings from 1 to 3 hours (at 30 minute intervals Specific to shape/size of steel, e.g. W10 x 49 column

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

Fire Resistance Classifications Certifications are “design” specific by coating manufacturer Numbering system defines an alphanumeric design number

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

Fire Resistance Classifications Columns Minimum column size and configuration specified in X and Y series designs Same hourly rating applies when section with equal or greater W/D ratio is substituted for same configuration

Fire Resistance Classifications Beams and Columns Required coating thickness increases as weight of steel decreases Lighter steel heats up more rapidly and requires more protection

Fire Resistance Classifications Intumescent (and Mastic) Coatings Coating thickness specification in a design is minimum average thickness measured in accordance with Technical Manual 12-B Average thickness should not exceed maximum thickness published (if listed) in individual designs or by No individual measurement <80% of specified design thickness

Fire Resistance Classifications Technical Manual 12-B Published 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 Resistance Classifications Technical Manual 12-B Scope General Information Substrate Conditions Site Conditions Inspection Procedures Method of Tests Conditions of Finished Application Patching

Fire Resistance Classifications ANSI/UL 263 Used for resistance to cellulosic fire (e.g. combustion of wood or building materials) Slower rise in temperature 1000 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 Classifications ANSI/UL 263 Classified Coatings Typical use for structural steel in commercial structures

Fire Resistance Classifications ANSI/UL 1709 Used for resistance to a hydrocarbon fire Rapid rise in temperature 2000 F at 5 minutes Interior and exterior exposures Environmental tests include, accelerated aging, high humidity, salt spray, thermal cycling for exterior exposure

Fire Resistance Classifications ANSI/UL 1709 Classified Coatings Typical use for steel structures at petrochemcial facilities, e.g. Chemical plant Refineries Offshore oil platforms

Other Approvals Intumescent coatings may also need approval by city building codes Coating manufacturers should provide approvals as applicable

Generic Coating Types Intumescent coatings are generally the following generic resin types: Acrylic/vinyl Epoxy Intumescents are also generally categorized as “thin-film” or “thick-film” coatings

Generic Coating Types Acrylic/vinyl Thin-film coating Solvent or water-based Single component Typically rated under UL 263

Generic Coating Types Acrylic/vinyl Applied in several coats Time-frame for a complete application may span several days Additional time may be needed before application of any required exterior finish coat.

Generic Coating Types Epoxy Thick-film coating Applied by plural component spray equipment in one or two coats Rapid cure Typically rated under UL 1709

Generic Coating Types Epoxy May 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 Type Required Thickness (mils) Number of Coats Recoat Time (between coats) @50ºF Time to Finish Coat @50ºF Solvent-based acrylic 130 5 24 hours 25 days Solvent-based vinyl 375 4 4 hours 20+ days Water-based acrylic 180 6 8 hours 10+ days Epoxy 1 n/a Epoxy w/mesh 340 1-2 48 hours

Testing for Coating Cure Intumescents may require testing for proper cure Typical test is Durometer Hardness (Shore D) Resistance of coating film to indentation by Durometer instrument ASTM D2240, “Standard Test Method for Rubber Property-Durometer Hardness”

Testing for Coating Cure

Coating Appearance Intumescents generally have a rough or orange peel appearance Methods to improve include: Back rolling following spray application Sanding (not recommended) Finish coat application (may be required)

Coating Systems Intumescent design approvals typically include a primer and/or finish coat When included in design primer/finish must be applied to meet fire rating Primer/finish must be endorsed by intumescent coating manufacturer Preference always for same manufacturer

Use of Primers Intumescent coating manufacturer may have approved list of primers Types include alkyd, acrylic, epoxy and zinc-rich Application thickness important

Primers Function of primer Provides adhesion to substrate Provides suitable surface for intumescent Provides additional barrier protection Can also provide inhibitive or sacrificial protection 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.

Use of Finish Coat May be required in design approval for exterior exposure Intumescent coating manufacturer must endorse finish material Types include 100% acrylic and aliphatic urethane coatings May affect/improve appearance

Finish Coats Function of topcoat Color and gloss Abrasion resistance Chemical resistance Washability Resistance to the environment 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.

Finish Coats Acrylics Advantages Single component Ease of application Color & gloss retention Flexibility Low VOC content for waterbased Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19 Notes 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.

Finish Coats Acrylics Limitations Limited alkali and solvent resistance Moderate abrasion resistance Application temperature >50ºF for waterbased Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19 Notes 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.

Finish Coats Urethanes Advantages Color & gloss retention (aliphatic) Adhesion Acid, alkali resistant Chemical resistant Impact/abrasion resistant Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19 Notes 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.

Finish Coats Urethanes Limitations Multi-component Short recoat intervals Limited pot life Moisture sensitive during cure Difficult to recoat Add after alkyds, delete all Calcium Suflonate Alkyd slides on Pg 2-18 & 2-19 Notes 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.

Summary of Key Points When specifying intumescents consider: Required UL approval City building code approval Include required primer and finish coats Applicator certification if needed (e.g. plural component materials) Include test sections to evaluate appearance

Fire Resistive Coatings Questions?