Division 7 Ebook Page 589 CMU Perimeter Fire Containment Joint ASTM E2307 Tech Bulletin

Technical Bulletin CMU-04 ENCLOSURE SOLUTIONS CMU Wall Systems, Fire Resistant Joints Containing Fire Spread Through Joints Fire resistant joint systems and perimeter fire containment joints are designed to prevent fire and hot gases from entering the room/stories above the room where a fire originates. Story to story spread occurs through voids or joints that exist in or between fire resistance rated walls, and floor or floor/ceiling assemblies, and roof or roof/ceiling assemblies. An unprotected void at the floor/wall intersection potentially creates a pathway for fire and/or smoke to spread from floor to floor in a building. Although such joints are often small, 2"-3" wide, consider that for a building with a floor plate size of 200' 200' (800 lineal feet), an unprotected joint 3" wide creates 200 square feet of open area along the perimeter that will allow smoke and hot gases to flow freely from floor to floor. Fire can also pass through voids or combustible materials in the exterior wall itself. Given that the condition exists at each floor, the potential for fire and smoke spread is significant. Owens Corning Enclosure Solutions for CMU wall systems provides details and fire safing products if needed to design and construct fire resistant joints as required in Section 715 of the International Building Code. International Building Code (IBC) The 2015 IBC, Section 715.1 requires approved perimeter fire resistant joint systems where a gap exists in or between fire resistance rated walls, and floor or floor/ceiling assemblies, and roof or roof/ceiling assemblies. Although local codes may vary, generally fire resistance rated floor/ceiling assemblies are required in construction types I-A, I-B, II-A, III-A, and V-A. Fire resistant joint systems may be inherent to common CMU construction techniques, see Figure 1, or, if voids are created, joint systems that are tested in accordance with ASTM E 1966 or UL 2079 may be required (See Figures 2 and 3). Fire resistant joint systems must be tested, or determined via an engineering judgment, to provide an "F-rating" for a time period not less than the required fire resistance rating of the wall, floor or roof assemblies between which the joint is installed. Often the manner in which CMU wall systems intersect with floor systems creates an inherently fire resistant perimeter containment condition. See Figure 1. However, when there are openings or pathways created in the construction as shown in Figures 2 and 3 Owens Corning Enclosure Solutions Thermafiber Fire Safing products can be used to serve any typical building situation with an F-rating of two hours, equal to type I-A construction, the highest floor/ceiling assembly fire resistance rating specified in Table 601 of the IBC. Even when the floor/ceiling assembly is not required to be fire resistance rated, Section 715.4.1 still requires that the joint be sealed with an approved material or system such as Owens Corning Thermafiber Safing and FireSpan Insulations to retard the interior spread of fire and hot gases between stories. ANSI/UL 2079 & ASTM E 1966 The ANSI/UL 2079 and ASTM E 1966 test methods evaluate the ability of a fire resistive joint system to undergo movement without reducing the fire rating of the adjacent fire separating elements, and the duration for which test specimens will contain a fire and retain their integrity. Among the characteristics evaluated is the durability of the joint system through movement cycles, the ability of the joint system to prohibit the passage of flames and hot gases, transmission of heat through the joint system. The test methods also include optional air leakage tests to determine the rate of air leakage through joint systems resulting from a specified air pressure difference applied across the surface of the joint systems. Fire Resistant Joint Design Section 715.1 of the 2015 IBC requires "approved" fire resistant joint systems. Although exterior wall system designs vary significantly, the Owens Corning Enclosure Solutions for CMU is often inherently a fire resistant joint system due to the typical construction details as shown in Figure 1 that contains no voids or openings. If openings exist in the construction they can be closed by using Owens Corning Thermafiber Safing products. Where gaps exist between the exterior wall and the floor slab, and if a fire resistant joint is required, Owens Corning Thermafiber can be used in a number of Underwriters Laboratories tested and listed fire resistant joint systems such as Figure 2 (CW-D-2005), Figure 3 (CW-D-2006) and Figure 4 (FW-D-1016). Unprotected Perimeter Joint Perimeter Fire Containment System

Previous Page
Next Page