7/25/2011. THERMAL BARRlERS AND IGNITION BARRIERS. What is a Thermal Barrier? Thermal Barrier Code

Transcription

1 FUNDAMENTALS OF SPF FOR THE INDEPENDENT BE INSPECTOR CHAPTER 4 THERMAL BARRlERS AND IGNITION BARRIERS What is a Thermal Barrier? A material applied over polyurethane spray foam designed to slow the temperature rise during a fire situation. Minimum requirement to separate the spray foam from the interior (living areas) of a building Thermal Barrier Code Definition Thermal barriers limit the temperature rise of the underlying polyurethane foam not to exceed more than 121 O C. (250 O F) after 15 minutes of exposure. 1

2 Where a Thermal Barrier Should Be Applied? Habitable side of structure. Between the interior of the structure and the polyurethane foam. All interior SPF must have a 15-minute thermal barrier. Why do Codes Require Thermal Barriers? Spray Polyurethane Foam Combustible organic material Flame Spread Ratings - ASTM E-84 Numerical indices (and) ratings do not reflect actual fire hazards Ignition sources i.e.: Welding torches, Red hot metals may ignite SPF Thermal Barriers con t Flashover Confined spaces can accumulate combustible gases Reduce Risks Proper thermal barriers delay the possibility of the auto ignition temperature being reached. Contractor always responsible to ensure the builder/owner is aware of the Thermal Barrier requirement 2

3 Selection of Thermal Barriers Building code requirements 15 minute thermal barrier Adhesion (when appropriate) to the sprayed polyurethane foam Environment in which it is to be used Aesthetic qualities Ease of maintenance Cellulose Thermal Barriers Composition Dry wood pulp based fiber latex adhesive and fire retardants. Code Approval Current code certification listing report number and date. Spray Applied Cementitious Materials Composition Portland cement fiber fillers and dry adhesives and water. Wet slurry sprayed to ½ - ¾ thickness or to applicable building codes. 3

4 Gypsum Wallboard Gypsum 1/2 minimum Versatility Large % of Projects Ignition Barriers Definition An ignition suppressor used in attics and crawl spaces. The ICC-ES Acceptance Criteria 377 for Spray Polyurethane Foams provides accepted test procedures for approval of alternative ignition barrier systems consisting of a coating over SPF or SPF alone There may be different tests used for attic area and crawl space areas, depending on the test procedure utilized. Ignition Barriers Code permits an ignition barrier cover the spray foam in attics and crawlspaces when: Attic or crawlspace access is required The attic or crawlspace access is only for purposes of repair or maintenance of utilities 4

5 Ignition Barriers, Used in Attics and Crawl Spaces Prescriptive Ignition Barriers 1-1/2 Mineral fiber 1/4 Wood structural panels (paneling or sheathing) 3/8 particleboard ¼ hardboard (0.375 inch)(3/8 ) gypsum board (wallboard); Corrosion resistant steel have a base metal thickness of inch; Alternative Ignition Barrier Assemblies (via assembly fire testing) Other approved material installed in such a manner that the foam plastic insulation is not exposed. [2003 IBC, Section ] The ignition barrier is not required where the foam is tested in accordance with section R IRC or IBC. Tested Coatings Only coatings that have been tested and approved with specific SPF systems (an assembly) may be used in place of prescribed ignition barriers. Fire test procedures for alternative ignition barrier assemblies are defined in Acceptance Criteria A code approved thermal barrier provides for the SPF. a. increases R-value b. a barrier against radiant heat loss c. minimum fire protection in unoccupied spaces d. minimum fire protection in living areas e. a barrier to prevent the loss of heat by convection 5

6 2. A code approved thermal barrier must provide minutes or more protection to SPF during a full scale fire test a. 15 b. 25 c Building codes require a thermal barrier for interiors to a. reduce outgassing of spray foam b. reduce the risk of flash fire c. extend the life of the polyurethane foam d. stop thermal losses e. a and d 4. Where is a 15 minute thermal barrier required? a. on the outside of masonry cavity walls b. between the drywall and framing in heating climates c. between shared wall multifamily housing d. on all doors and windows e. habitable side of the structure 6

7 5. A good example of an approved thermal barrier would be: a. vapor barrier paint b. 6 mil plastic film c sheet metal d. minimum ½ gypsum board 6. A cellulose thermal barrier is composed of: a. cellular plastic foam b. dry wood pulp based fiber and latex adhesive c. Portland cement slurry d. cellulose fibers embedded in a polyurethane coating 7. A cementitious thermal barrier is composed of: a. cellulose embedded in a polyurethane coating b. drywall joint compound c. dry wood pulp based fiber and latex adhesive d. Portland cement slurry e. d and b f. b and c 7

8 8. The use of a coating as an ignition barrier on foam requires full scale fire testing of the specific coating and foam. True False 9. A good example of an approved ignition barrier would be: a. 1-1/2 mineral wool b. reflective insulation film c. bubble-wrap insulation d. Aluminum foil e. 6 mil poly sheeting f. all of the above 10.Ignition barriers are permitted over SPF and other foam plastics when the foam is installed in: a. All crawlspaces. b. All attics. c. Attics without any access. d. A and B. e. Attics and crawlspaces where access is only for maintenance of utilities. 7/22/11 8