Fire-Resistance-Rated Brick Veneer Exterior WallsBy Rick Thornberry, P.E., President, The Code Consortium, Inc.
At ground level, the structural brick seen here contained the fire within the building. Brick fire walls are effective nearly 100 percent of the time.
These new exterior wall designs with brick veneers will provide architects/engineers/ building designers with user friendly prescriptive designs for those applications where a brick veneer is desired but the exterior wall is required to have a one-hour or two-hour fire-resistance rating by the IBC. 2009 IBC Section 720, Prescriptive Fire-Resistance references Table 720.1(2) and states that the materials of construction listed in that table shall be assumed to have the fire-resistance ratings prescribed therein. So a design professional need only consult the table to get the information necessary to design such a one-hour or two-hour fire-resistance-rated brick veneer exterior wall using steel or wood studs without having to consult a directory or listing provided by an independent third-party testing laboratory.
These new item entries in Table 720.1(2) are the result of the approval of Code Change Proposal FS151-06/07, which was submitted by the author on behalf of the Western States Clay Products Association (WSCPA). The WSCPA retained the author to develop and submit the Code Change Proposal during the first 18-month cycle (2006/07) for the development of the 2009 IBC. It did this to incorporate the brick veneer exterior wall designs into the code and preserve those designs previously contained in the International Conference of Building Officials (ICBO) Evaluation Service Report ER-5058 titled, “Brick Veneer Fire Endurance Ratings of Wall Assemblies” issued to the WSCPA. ICBO is one of the legacy organizations of the International Code Council (ICC).
In the early 1990s, the WSCPA retained Walter Dickey, Consulting Engineer, Los Angeles, to conduct a series of reduced-scale and large-scale ASTM E119 fire endurance tests of brick veneer walls at Warnock Hersey in Pittsburg, Calif. The testing was conducted in 1993 to develop data that resulted in the approval and publication of the ICBO Evaluation Service Report ER-5058 containing generic fire-resistance-rated wall designs for one-hour and two-hour ratings for both adhered and anchored brick veneers, as well as for hollow brick walls. The first publication of ER-5058 occurred in 1993 (See Figure 1 – Fire Ratings of Brick Veneer Walls taken from the last edition of that report which ICBO reissued on Sept. 1, 2002).
Click here to see Figure 1 – Fire Ratings of Brick Veneer Walls - taken from the last edition of that report which ICBO reissued on Sept. 1, 2002.
With the merging of the ICBO Uniform Building Code (UBC) into the IBC and the impending adoption of the IBC by the State of California, the WSCPA decided to preserve the fire-resistance ratings for the one-hour and two-hour fire-resistance-rated brick veneer walls documented in ER-5058 by including them in Table 720.1(2) of the IBC. The WSCPA retained the author to develop the appropriate code change submittal with supporting documentation and submit it to the ICC in March 2006 for the 2006/07 code development cycle. The ICBO Evaluation Service Report ER-5058, as well as the 1997 UBC and the 2006 IBC, were thoroughly reviewed to assure that a technically correct translation of ER-5058 was made for inclusion in Table 720.1(2) with the appropriate referenced standards and specific design criteria.
This Code Change Proposal was designated as FS151-06/07. The IBC Fire Safety Committee approved it as modified at the ICC Code Development Committee Hearings held in September 2006 in Lake Buena Vista, Fla. The Committee made modifications to the original Code Change Proposal to clarify the minimum air space width and the minimum thickness for the brick units required for the anchored masonry veneer in Items 15-2.3 and 15-2.4. It also provided a specific reference to ASTM C216 for the brick units. Subsequent to the publication of the Committee recommendations resulting from the public hearings in Florida, the City of Seattle, Wash., submitted a Public Comment to Code Change Proposal FS151-06/07 to request approval as further modified by adding Footnote (d) to each item. Footnote (d) to Table 720.1(2) states: “Shall be used for nonbearing purposes only.”
This oversight occurred when the Committee approved the Code Change as modified, since the ICBO Evaluation Service Report ER-5058 clearly stated that the wall assemblies were nonbearing. At the ICC Final Action Hearings held in May 2007 in Rochester, N.Y., the author, representing the WSCPA, spoke in support of the Public Comment, and ICC Class A voting members in attendance approved it. As a result, the ICC published Code Change Proposal FS151-06/07 in the 2007 Supplement to the International Codes and that is now a part of the 2009 IBC (see Figure 2, which reproduces page 136 of the 2009 IBC containing Items 15-2.1 through 15-2.4, along with the complete list of Footnotes to Table 720.1(2) found on page 137).
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