Division 7 Ebook Page 85 Enclosure Solutions FAQ

ENCLOSURE SOLUTIONS FAQs 6 Perimeter Fire Containment Joints in Glass Curtain Wall Systems 21. What is a perimeter fire containment joint system? A: Perimeter fire containment joints are required by Section 715.4 of the International Building Code (IBC) where fire resistance rated floor or floor/ceiling assemblies are required. Voids created at the intersection of the exterior curtan wall assemblies and such floor assemblies must be sealed with an approved joint closure system to prevent the interior spread of fire from a floor below to a floor above via voids at the perimeter intersection. The code requires an approved fire resistant joint system to be tested, or approved via engineering analysis, in accordance with ASTM E2307, to provide an "F Rating" for a time period not less than the fire resistance rating of the floor assembly. See Section 715.4 of the IBC for other important exceptions and details. 22. What thickness of mineral wool do I need to get an hourly rating? A: Thermafiber Insulation does not have an hourly fire rating because it is not a stand-alone product. Thermafiber materials are dependent upon mechanical fasteners and other construction components that withstand the rigors of fire exposure and stay in place for the time period of the rated "assembly". If these components fail, then the Thermafiber insulation will fall out of place, jeopardizing the fire performance of the assembly. For hourly fire ratings on specific assemblies, go to Underwriters Laboratories Online Fire Resistance Directory at http://www.ul.com/ or Intertek's (Omega Point Laboratories Inc.) directory at http://www.intertek-etlsemko. com/. 23. Can I install Safing Insulation only within the safe-off void between the intersection of the exterior non rated curtain wall and the rated floor slab and still meet the requirements of the code? A: The model building code, International Building Code 2012 and 2015, Section 715.4- "Exterior curtain wall/floor intersection" both require the interior joint between the face of a fire-resistance-rated floor assembly and a non-rated exterior curtain wall assembly to be sealed with an approved "system" to prevent the interior spread of fire. Such systems shall be securely installed and tested in accordance with ASTM E2307 to provide an F rating for a time period not less than the fire- resistance rating of the floor assembly. All "approved" tested and listed perimeter fire containment systems require the curtain wall spandrel to be protected with mineral wool insulation (per the system design criteria) so that the spandrel stays in place during the fire. If the spandrel fails, then the exterior wall will fall away allowing the Safing Insulation installed within the interior joint to also fall away. Once the insulation is gone, fire will quickly propagate to the floor above. 24. If my building is equipped throughout with automatic sprinklers, do I still have to provide fire containment protection at the perimeter of the building? A: There is often confusion between the requirements of section 715.4 and section 705.8.5. Section 705.8.5 is the vertical separation of openings and this has to do with the 3' tall fire-resistant rated spandrel requirement. 705.8.5 basically tells you that you have to have a minimum 3' fire-resistant rated spandrel between openings but allows for exceptions. Those exceptions are: 1. If your building is 3 stories or less in height, 2. If your building is equipped throughout with automatic sprinklers, and 3. If it is an open parking garage. So if you meet one of these exceptions, then you aren't required to have a 3' tall fire resistance rated spandrel. However there is no place in the codes that allows for any exceptions to section 715.4 "Exterior curtain wall/floor intersection". Therefore, it must be followed. In fact, section 715.5 "spandrel walls" was added to the codes to clarify the confusion. This states that height and fire- resistance requirements for curtain wall spandrels shall comply with Section 705.8.5. Where Section 705.8.5 does not require a fire- resistance-rated spandrel wall, the requirements of Section 715.4 shall still apply to the intersection between the spandrel wall and the floor.

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