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Stepping Outside the Lines but Staying Within the Framework

The Delicate Dance of Code Innovations (Part 1)

Alan Vincent

In my March 2018 column, “The Push and Pull of Building Performance,” I explored the role of energy codes in energy-efficient design. This is the first of a three-part series looking at creative ways to design within the established bounds of code frameworks while deviating from traditional means of compliance to improve project outcomes. This month we will look at two examples of cost-conscious approaches taken by Code Unlimited to address fire protection of steel buildings that also reduced powered mechanical system and fireproofing chemical requirements.

The first project is an existing 150,000-square-foot steel-framed warehouse that needed a 30,000-square-foot addition to meet the owner’s expanding need for transient storage of lumber and finished wood products. The architect was guiding the addition through plan review when the county plans examiner raised two questions that nearly stopped the project in its tracks. The increase in the building size triggered requirements to bring the existing building up to code, including two regulations related to high-piled storage of combustible materials:

  • The county interpreted Oregon Fire Code section §3206.3 requirements to mean that one-hour-rated fire barriers are required, separating individual storage piles. This would divide the open warehouse into multiple compartments with one-hour rated walls between them, impeding the function of the space.
  • The county also stated that per §910.2.1, the building must have roof-mounted heat and smoke vents throughout, a significant cost and schedule impact.

At this point, Code Unlimited stepped in to find a solution. When they looked at the fire separation issue, they realized that the county had made a calculation error. The county was looking at the interior volume of the building, rather than the volume of the storage as the code intended. The code language is not clearly written, and the county stuck to their interpretation.

The fire protection engineer contacted the International Code Council technical staff and obtained a written clarification about the intent of the code language and how it should be applied. The project team shared this with the building and fire reviewers, explaining the code language and the fire science behind the regulations, and the county accepted the proposed design without fire compartments.

The heat and smoke-vent requirement was more difficult since the code language was very clear. The existing warehouse had heat and smoke vents on the roof, but not nearly as many as required per the current Oregon Fire Code, and meeting this requirement would add approximately $1 million to the project cost. Code Unlimited developed a plan based on the requirements from the next edition of the code, which had not yet been adopted by Oregon. This edition had revised calculations to account for the ability of the sprinklers to control the heat and smoke in a fire. The fire protection engineer validated the new calculations based on fire tests of heat and smoke vent performance in buildings with automatic sprinkler systems and demonstrated to the county that a quarter as many vents would meet the requirements of the new code. The county accepted this forward-looking interpretation, which saved the owner approximately $750,000 and extended the useful life of this building.

The second project was a million-square-foot office and laboratory building for a technology company. The proposed building had steel framing supporting composite deck and the architect wanted the crisp look of exposed steel framing, also a more cost-effective approach.

However, building area requirements included fireproofed structure. To meet the owner’s programmatic requirements, the proposed building had an 18-foot floor-to-floor height and the structural design was substantially stronger than normal to address programmatic design criteria for vibration sensitive equipment. The owner was also concerned about the impact on equipment of dust from spray-applied fireproofing, and intumescent fireproofing was very cost prohibitive.

After analyzing the design, Code Unlimited determined that the building design met the special requirements that apply to high-rise buildings even though the building was just shy of the high-rise threshold. This allowed the building to get a reduction in the required fire proofing requirements of one-hour type IIA construction instead of those of two-hour rated type IB construction. The robust structural frame and the high floor-to-floor height allowed the project to follow a performance approach to meet fire resistive design requirements.

The first step was to conduct a building fire risk analysis as outlined in the Society of Fire Protection Engineers Handbook to model fire development and its effect on the building structure, based on a worst-case fuel package (the anticipated concentration of flammable furniture and finishes in the building). Code Unlimited used computational fluid dynamics software developed by the National Institute of Standards and Technology, to calculate the heat that would be generated by the fire and the resulting surface temperature of the steel structural members. With the results from the modeled fire design scenario, a thermal structural analysis was conducted per “Performance-Based Design Procedures for Fire Effects on Structures” outlined in Appendix E of the 2016 ASCE-7 standard. The analysis found that the unprotected structure could withstand exposure to fire for an hour without suffering a reduction in structural strength. This negated the need for expensive fireproofing and finish materials that would adversely impact the project budget.

These examples illustrate the importance of understanding the basis of the code and being ready to challenge conventional interpretations and prescriptive approaches.


Alan Scott, FAIA, LEED Fellow, LEED AP BD+C, O+M, WELL AP, CEM, is an architect with over 30 years of experience in sustainable building design. He is a senior associate with WSP in Portland, Ore. Vincent Collins, FPE, PE, is a fire protection engineer and mechanical engineer with more than 30 years of experience. He is a principal with Code Unlimited in Denver. To learn more, visit www.wsp.com/en-US/services/built-ecology and follow Scott on Twitter @alanscott_faia.