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HomeMy WebLinkAboutMiscellaneous Structural Calculations 1982-5-19 '0'" ~..:i:l . ::~: r:---, \':';'..J" c. . ChaP. Sec. Chap. ,43, 503(d) 53, 25 State of Oregon Code Interpretation POKE HOLES Requested by: Structural Codes Advisory Board and State Fire Marshal Room 401 Labor & Industries Building Salem OR 97310 / Issue or Request: At the request of the Structural Codes Advisory Board and the State Fire Marshal, the staff has prepared the following information on "poke holes". Code Section: 43 on Fire Standards 1979 edition. Fire and Draft and Section 2517(f) Chapter Stops. Background Data: By letter of November 30, 1981, ICBO has reviewed the use of glass fibers as fire ,and draft stop material based on their past code interpre- tations and minutes of the Fire and Life Safety Code subcommittee. ICBO finds that glass fiber materials, such as insulation batts, comply with the intent of Code Section 2517(f) for fire and draft stopping materials. Rulings: (1) Two-hour walls and ceilings. Metal boxes no greater than 16 square inches in area may be used within two-hour rated wall or ceiling assemblies when protected with at least two inches of fiber glass, foam, rock- wool, or other approved noncombustible insulating materials (without combustible wrapping) tightly packed around the box on the unfinished side of the wall or ceiling. Exception: Nonmetallic boxes may be used in walls when protected as prescribed herein when located not more than one foot from the finish floor line in any story. (2) One-hour walls and ceilings. (a) Metal boxes no greater than 16 square inches in area may be used within anyone-hour rated walls or ceiling assembly. (b) Nonmetallic boxes may be used in walls and ceilings when protected with at least two inches of fiber glass, foam, rockwoo1, or other approved noncom- bustible insulating materials (without combustible wrapping) when tightly packed around the box on the unfinished side of the wall or ceiling. (3) Other Openings. Similar service openings larger than 16 square inches in area when installed in rated fire walls or ceilings must be protected by materials equal to the wall or ceiling being penetrated or be approved to be installed in the rated wall or ceiling assembly. (4) Vents and Ducts. Code section 4303 requires all duct openings in rated floor ceiling or roof ceiling assemblies to be protected by fire dampers. Kitchen vents that are not classified as grease ducts need be treated only as air ducts. In most cases, fire dampers placed at the entrance of the duct will provide adequate protection. Revised 6/82 PI-2004 . . (5) Nonmetallic Pipes, Ducts or Vents. When nonmetallic pipes, ducts, or vents penetrate one or both surfaces of a rated wall or ceiling assembly such pipes, ducts or vents shall be encased in a rigid ferrous metal tube extending from the surface(s) at least 18 inches. The encasing tube shall be draft stopped by packing with noncombustible insulating material. Exception: (a) Penetration of one square inch or smaller using nonmetallic materials need not be encased. (b) Penetrations exceeding 16 square inches in area and accommodating non- metallic materials must be protected by fire dampers. c". ,:~.f"- / (6) Penetrations to be Tightly Fitted. All penetrations in fire-rated , assemblies must be tightly fitted into an opening or filled around the protru- sion with approved noncombustible insulating materials to make it tight fitting. If a building is designed for future electrical or mechanical outlets, those holes may be constructed and "plugged" with suitable fire-protective materials for future "use. (7) Code Interpretation on Two-hour Walls: In two-hour walls with wood studs, can the wall be pierced by electrical boxes and conduit? Can this same wall have nonmetallic plumbing pipes in the wall? Answer: No. (See PI-4094) Code Sections: The following code sections pertain to poke holes: (a) Section 503(d)(4) states, in part, that ,"fire dampers are not required in (:. ducts piercing the separation wall between a dwelling (R-3) and a garage (M) provided the duct is 26 gauge galvanized steel". (b) Section 1706. For openings extending vertically through floors, see'sec- tion 1706 "Shaft Enclosures". (c) Chapter 43. Chapter 43 of the For other requirements for fire protection of openings, see Structural Code. '(d), Section 25l7(f) for requirements on fire and draft stops. Board Postion: 'The Structural Codes Advisory Board and the State Fire Marshal . support -the ruling as set forth in this report. Approved by the Board May 19. 1982 References: Sec. 503(d) ,Chapters 17, 43, and 53 Building Standards Jan/Feb 77 Building Standards Mar/Apr 77 ICBO Letter to Thomas Campbell, dated 11/30/81 Fed. Spec HH-I-52lF, dated 7/24/72 ANSI/ASTM Std. C168-67 on Thermal Insulating Material Formerly PPPI 2004 Revised 6/82 PI-2004 l)