Division 7 Ebook Page 82 Enclosure Solutions FAQ

ENCLOSURE SOLUTIONS FAQs 3 9. What is NFPA 285? A: NFPA 285 is a fire test standard required by the International Building Code for many buildings of Types I, II, III or IV construction, the types that require non-combustible wall construction. It is designed to determine the extent to which an exterior wall may be ignited by a limited fire source (a fire plume exiting a window), and then propagate flame on its exterior surface and through its core away from the point of origin. Although NFPA 285, or a concept like it, has been in model building codes since the mid-1980's, it has gained prominence in recent years due to the common use of combustible air/water barriers and continuous foam plastic insulation in exterior walls that are otherwise required by code to be made of non-combustible components. NFPA 285 has been referenced by name in Chapter 26, Plastics, of the International Building Code since its first edition in 2000. 10. Are all walls required to comply with NFPA 285? A: For wall systems NFPA 285 is only applicable to Types I, II, III and IV construction. Those are the building construction types that are required to have noncombustible exterior walls. See Chapter 36 of the International Building Code for a complete listing of other sections that reference NFPA 285 compliance. 11. How is NFPA 285 conducted? A: NFPA 285 is conducted in a full scale, two-story, three sided test rig. The fourth side is enclosed with a full scale wall assembly built exactly as it would be in the field. The test wall has a window opening. During the test, in the lower story, an interior test fire designed to replicate flashover conditions inside the test room creates a fire plume that exits the window head exposing the wall, inside and out, to flame and increasing temperature for 30 minutes. Pass/fail criteria is based on the extent of flame propagation on the face and inside the core of the wall measured primarily by thermocouples placed throughout the full scale wall assembly. Smoke leakage and flame penetration from the first floor room of fire origin into the second story of the test structure is also observed and can trigger a failure. 12. Can gypsum sheathing/air/weather barrier be eliminated and FOAMULAR extruded Polystyrene continuous insulation be installed directly to steel stud framing with joints taped for air/weather resistance behind masonry veneer? A: Yes. If gypsum sheathing is not otherwise required, FOAMULAR XPS may be attached directly to the steel stud framing with joints taped using Owens Corning JointSealR Joint Sealing Tape. The assembly has passed NFPA 285 (fire propagation, ASTM E2357 (air leakage and ASTM E331 (water leakage) testing. 13. What are the continuous insulation (CI) requirements for my steel stud or CMU project? A: Continuous insulation is often necessary to meet any one of several compliance paths available in energy codes. Because there are alternative paths to compliance, continuous insulation is not "required". Instead energy codes "prescribe" or "recommend" CI R-value amounts that are often based on "optimum insulation levels". Most energy codes have a "prescriptive path" to compliance. In that case, if the prescribed details, including CI are followed, the final design is "deemed to comply". Regardless of the compliance path utilized continuous insulation is a major contributor to compliance, energy efficiency and sustainability. To determine the amount of continuous insulation that is "prescribed" for a particular project always consult local energy codes, and, see the family of Enclosure Solutions Wall Systems guides to prescribed CI R-values.

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