Specifying Fire Resistive Coatings

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

2. Learning Objectives Comprehension 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 construction • Identify 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

3. Fire Resistive 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)

4. Fire Resistive Coatings • Intumescent Coatings: • Are categorized as SFRMs • Similar to conventional coatings • Have unique fire resistant properties

5. 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

6. 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

7. 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

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

13. 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

14. 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

15. 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

16. 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

17. Fire Resistance Classifications • ANSI/UL 263 Classified Coatings • Typical use for structural steel in commercial structures

18. 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

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

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

28. 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

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

30. 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.

31. 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

32. 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

33. Generic Coating Comparison

34. 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”

35. Testing for Coating Cure

36. 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) • Test sections recommended

40. 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

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

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

43. 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

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

45. Finish Coats • Acrylics • Advantages • Single component • Ease of application • Color & gloss retention • Flexibility • Low VOC content for waterbased

46. Finish Coats • Acrylics • Limitations • Limited alkali and solvent resistance • Moderate abrasion resistance • Application temperature >50ºF for waterbased

47. Finish Coats • Urethanes • Advantages • Color & gloss retention (aliphatic) • Adhesion • Acid, alkali resistant • Chemical resistant • Impact/abrasion resistant

48. Finish Coats • Urethanes • Limitations • Multi-component • Short recoat intervals • Limited pot life • Moisture sensitive during cure • Difficult to recoat

49. Fire Resistive Coating Inspection • 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)