An Introduction to the 2006 International Building Code
by Thomas D. Culp, Ph.D.
Earlier this year, the latest version of the International Building Code (IBC) was published. The 2006 IBC weighs in with 35 chapters, 11 appendices and 679 pages, so understanding and complying with the code can be a daunting task. Although it is impossible to cover all aspects of the code in a short article, I will attempt to give a basic introduction to who makes the code, what it covers and the latest changes that will affect glazing contractors.
What is the ICC?
The IBC is one of several codes developed by the International Code Council (ICC), a nonprofit organization whose members include building code officials, design professionals, consultants, industry representatives and others. The ICC develops and updates national model codes through a public proposal and review process. Although many think of the government when talking about codes, it is important to note that ICC is a private organization, not a part of the federal government. Therefore, these model codes have absolutely no power until they are adopted for use. It is also common for state or local governments to make modifications that suit their specific needs. As a result, the use of different versions of building codes varies significantly across the country. If you take away only one message from this article, let it be this: don’t rely on whatever national code is on your bookshelf; always check the specific code requirements where the project is located.
In general, the IBC applies to all building types except detached residential dwellings no more than three stories high, which are covered by the International Residential Code (IRC). The IBC covers all aspects of building design, including occupancy and construction types, maximum heights and areas, fire-resistance and protection, egress, accessibility, wall and roof construction, structural design and material specifications. By reference to other I-codes, it also includes requirements for electrical, plumbing and mechanical systems, as well as energy efficiency.
The areas that most directly affect glazing are fire-resistance (Chapter 7), structural design (Chapters 16 and 17) and glass material specifications (Chapter 24).
Chapter 7 sets requirements for materials and assemblies used for fire-resistance. This includes when openings must be protected by the use of fire-rated glazing, area limitations, fire resistance ratings for different applications and test standards for fire-rated glazing in doors or walls. One new change in the 2006 IBC is that all fire-rated glazing must be labeled with a new identification mark, which indicates the approved application and fire rating. The identification indicates whether the glazing was tested for use in openings (O), fire doors (D) or wall assemblies (W), whether or not it meets the hose-stream requirements (H or NH), whether or not it meets the temperature rise requirements for doors (T or NT) and the fire rating in minutes. “OH-45” or “D-H-T-60” are examples.
Chapter 16 governs the structural design of buildings, including design load requirements for fenestration. The most important factor for fenestration is windload, although provisions for snowloads and dead loads are also included for sloped glazing.
Windload design pressures are calculated in accordance with the updated standard ASCE 7-05. The procedure is the same as in previous versions, based on basic wind speeds for the building location, building use/importance factors, exposure category and information about the specific building design and height. However, some technical changes in ASCE 7-05 result in a 3 to 11 percent increase in design pressure compared to previous versions. This increase may be large enough to affect compliance for some products close to the design limit. One additional word of caution: be sure to check the local code or project specifications, which may utilize a higher basic wind speed than that found in the ASCE 7-05 maps.
Chapter 16 also includes requirements for impact-resistant glazing in hurricane-prone areas. The IBC specifies applications in which either impact-resistant glazing or protective covers are required, as well as the appropriate test standards (ASTM E 1886-04, and either the large or small missile test of ASTM E 1996-04). In previous versions of the IBC, impact-resistant glazing was not required if the building was designed to survive with openings if all the glazing failed. Even if the building does not collapse, this approach did not adequately address the safety concerns of flying debris and water damage when the glazing fails. Therefore, this allowance was removed from the 2006 IBC, requiring impact-resistant glazing or protective coverings in almost all applications in the wind-borne debris region. One exception is glazing 60 feet above grade and 30 feet above any aggregate surface roofs within 1500 feet. However, again, local code requirements can vary significantly such as the different requirements in Miami-Dade, Florida, Texas, etc.
Once the overall structural requirements for fenestration are determined by Chapter 16, specific structural tests are prescribed in Chapters 17. Windows, sliding doors and skylights must be tested in accordance with the updated AAMA/WDMA/CSA 101/I.S.2/ A440-05 standard, which includes tests for air leakage, water penetration resistance, structural load at 150 percent design pressure, durability, etc. This new version of the standard includes added requirements for doors. However, side-hinged doors still have the option to be tested in accordance with either 101/I.S.2/A440-05 or ASTM E 330 at 1.5 times the design pressure. Curtainwall, storefront and other products not within the scope of 101/I.S.2/A440-05 can only be tested in accordance with ASTM E 330. As a result of the state-to-state variations in building code adoption, window manufacturers will have to label their products to at least two of the three versions of the AAMA standard in use: 1997, 2002 or 2005.
Glass Material Specifications
Finally, Chapter 24 includes other considerations specific for glass and glazing materials, such as edge deflection, glass strength, skylights and safety glazing requirements. The edge deflection limits have not changed: the frame must be designed such that under the design load, the glass edge will not deflect more than 1/175 of the edge length or 3/4 inch, whichever is less. This basically requires metal or highly reinforced framing in most applications. However, products labeled to 101/I.S.2/A440-05 with performance class R, LC or C are exempt. Glass strength must be determined in accordance with ASTM E 1300-04e1, which determines what glass thickness and type is required to meet the design load from Chapter 16 with breakage less than 8 out of 1000. This is a new version of the ASTM standard with many new charts for laminated glazing and different types of side support, but the basic procedure is the same. However, the IBC does make adjustments for wired, patterned and sandblasted glass not included in ASTM E 1300, due to the inherently lower strength of these materials.
Chapter 24 also specifies what types of glazing materials are allowed in skylights and sloped glazing, and when protective screens are required underneath. It also defines where safety glazing is required, and which human impact test standard must be used. One significant change in the 2006 IBC relates to wired glass. Previously, wired glass only had to meet the ANSI Z97.1 standard when used as safety glazing in fire-rated applications (e.g. fire doors). Now, it must meet the same CPSC 16 CFR Part 1201 standard as other safety glazing. Practically, this means wired glass must be used with an applied film or in a laminate or an alternate product must be used. Finally, Chapter 24 includes requirements for glazing in special applications such as handrails, athletic facilities and elevator enclosures (new).
Although building codes are tedious and often confusing, they can have a major impact on your business. The 2006 IBC governs several important areas that affect glazing, and as it starts to be adopted by states and counties, you cannot afford to ignore recent changes. There are far too many details to include here, so make sure to use the resources available to you such as ICC, GANA and
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