Terrorism-Resistant Buildings That May Impact Fire Protection Engineering

Issue 27: Issues Identified Within ICC'S Ad Hoc Committee on Terrorism-Resistant Buildings That May Impact Fire Protection Engineering

By John R. Battles, P.E.

The International Code Council (ICC) Board of Directors authorized the creation of the Ad Hoc Committee on Terrorism-Resistant Buildings in mid-2004. The Ad Hoc Committee process has been used frequently by the ICC to enable the devotion of sufficient time and resources to a particular topic or subject area. A call for committee members was posted in July, 2004, and the Ad Hoc Committee convened for the first time in February of 2005 by conference call.

About six months into the Committee's efforts, the NIST World Trade Center (WTC) Study1 was released to the public (in September, 2005).

The Committee reviewed the report and developed a list of action items within the purview of the model codes based upon the recommendations contained within the report. The items addressed include the following issues: progressive collapse (NIST Recommendation #1), building burnout (NIST Recommendation #4 & #8), spray-on fire resistant materials (NIST Recommendation #6), redundancy of active fire protection systems (NIST Recommendation #12), stairway width (NIST Recommendation #17 & #18), stairway remoteness (NIST Recommendation #17 & #18), stairway shaft robustness (NIST Recommendation #17 & #18), and command and control systems (NIST Recommendation #24).

 

A total of fourteen code changes were submitted during the 2006/2007 code cycle. Ten unsuccessful code change proposals were amended in accordance with public comments and re-submitted for the 2007/2008 code cycle.

The following are the changes implemented by the Ad Hoc Committee on Terrorism-Resistant Buildings consistent with the NIST WTC Recommendations impacting fire protection engineering that will appear in the 2009 International Building Code:

  • Increases the reliability of automatic sprinkler systems in buildings more than 420 feet (128 meters) in height.
    Each sprinkler zone must be supplied by a minimum of two risers. Each riser must be placed in remotely located stairs and supply sprinklers on alternate floors.
  • Increases the cohesive/adhesive bond strength of cured, sprayed fire-resistive materials (SFRM) for high rise buildings.
    The minimum bond strength for all buildings regardless of the height of buildings was 150 pounds per square foot (psf) (7200 Pa). The bond strength has increased by nearly 3 times to 430 psf (21,000 Pa) where the height of buildings is more than 75 feet (23 meters) and up to 420 feet (128 meters). The bond strength has increased by nearly 7 times to 1,000 psf (48,000 Pa) where the building height is more than 420 feet (128 meters).

  • Adds application requirements for sprayed fire-resistive materials (SFRM).
    The application must be in accordance with the manufacturer's installation instructions including, but not limited to, substrate temperature and surface conditions, and SFRM handling, storage, mixing, conveyance, method of application, curing and ventilation. The substrate to receive SFRM is required to be clean and free of any condition that prevents adhesion. For SFRM that is to be applied over primers, paints, or encapsulants other than those specified in the listing, the material must be field tested in accordance with ASTM E736.2 The finished condition of the installed SFRM, upon complete drying or curing, shall not exhibit cracks, voids, spalls, delamination or any exposure of the substrate.
  • Enhances special inspection requirements for sprayed fire-resistive materials.
    Special field inspection of SFRM is required to be performed after the rough installation of electrical, mechanical and plumbing systems. Physical and visual tests must be performed regarding the condition of substrates, thickness of application, density, bond strength – adhesion/cohesion, condition of finished application, and field bond tests needed to qualify application over certain primers, paints, and encapsulants.

John Battles, P.E., is with the International Code Council

  1. Final Report of the National Construction Safety Team on the Collapses of the World Trade Center Towers. NIST NCSTAR 1. National Institute of Standards and Technology, 2005.
  2. ASTM E736 "Standard Test Method for Cohesion/Adhesion of Sprayed Fire-Resistive Materials Applied to Structural Members." ASTM International, West Conshohocken, PA, 2006.
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