Key nonstructural changes to 2012 IBC
Learn about the significant nonstructural changes to the 2012 International Building Code that typically impact consulting and specifying engineers.
The new 2012 International Building Code (IBC) was published June 9, 2011, and is being adopted as the applicable building code by many states, counties, cities, and municipalities across the United States. As part of the triennial code development process, the 2012 IBC includes many new or revised code requirements not previously included in the 2009 IBC.
While it is important for the members of a design or building assessment team to understand the impact of building code changes on all the members of the team, this article focuses on the significant nonstructural changes to the 2012 IBC that typically impact consulting and specifying engineers, other than structural and material requirements. Separate articles would be necessary to discuss the changes to the structural/material requirements and changes that primarily impact the practice of architecture. For a more complete discussion of these changes in the 2012 edition of the IBC, one can refer to Significant Changes to the International Building Code, 2012 Edition, published by the International Code Council (ICC).
Fire service access elevators: Paragraph 403.6.1 has been revised to require a minimum of two fire service access elevators in buildings with an occupied floor level more than 120 ft above the lowest level of fire department vehicle access. The 2009 IBC required only one fire service access elevator. In addition, the paragraph now includes a requirement that each elevator have a capacity of at least 3,500 pounds. Under normal conditions, the revision results in at least two elevators being available for fire suppression personnel in such buildings. In addition, because an elevator may be out of service, the change results in a reasonable expectation that at least one fire service access elevator will be available at all times.
It should be noted that there have also been revisions to the detailed requirements for fire service access elevators and occupant evacuation elevators. For the most part, these revisions provide for the elevators to be able to continue to function and serve their intended purpose during an emergency (Sections 3007 and 3008, respectively). A complication unresolved in the 2012 IBC is related to the requirement for direct access between the fire service access elevators and the exit stair enclosure. This complication will likely be resolved in the 2015 IBC. Users of the code should consider reviewing the changes in the 2015 edition for potentially more reasonable design direction. Use of the 2015 language should be reviewed with the authorities having jurisdiction (AHJ).
Fire ratings of exterior walls: A new note “h” has been added to Table 602 to clarify that nonrated exterior walls are permitted when nonbearing exterior walls with unlimited openings are permitted by Table 705.8. This occurs when the building is protected with automatic sprinkler protection and the fire separation distance is at least 20 ft.
Using sprinklers to achieve a fire resistance rating: In the past there has been an ICC-ES Evaluation Report (ESR-2397) that describes a glass assembly protected with a specific automatic sprinkler as having a fire resistance rating of 2 hours. The 2012 IBC contains Section 703.4, which restricts the use of automatic sprinklers or any other fire suppression system when testing an assembly to achieve a fire resistance rating. When installing a sprinkler in the furnace, the tested assembly is not likely to be exposed to the standard temperature-time curve as required by the fire test because operation of the sprinkler will result in a cooling effect within the furnace. As such, the fire test would not be in strict compliance with the required fire test standard. That is not so say that an assembly that is protected with a specific sprinkler or specific sprinkler design may not be considered to be equivalent to a fire-rated building element or assembly, but rather that the sprinkler may not be part of the fire test used to qualify the building element or assembly. The IBC commentary on this code change clarifies that it is not the intent of the code to prohibit the use of such sprinklers. Rather, the change implies that the use of a window sprinkler system to provide such rating is to be considered under alternate materials and methods of construction. Therefore, such window sprinklers remain a viable candidate for the right applications.
Refuse and laundry chutes: Section 713.13 contains a provision to require the use of NFPA 82: Standard on Incinerators and Waste and Linen Handling Systems and Equipment, Chapter 5, for determining the requirements for refuse and laundry chutes in buildings of Group I-2. It should be noted that the 2015 IBC will require the use of NFPA 82 for refuse and laundry chutes in all occupancies (FS60-12).
Elevator lobbies: Elevators that only serve lower levels of a high-rise building (less than 75 ft above the lowest level of fire department access) need not have elevator lobbies since those elevator shafts should not experience the same pressure difference as the shafts serving the upper floors (Exception No. 4.3, Paragraph 713.14.1)
Floor penetrations: Historically the IBC has not required a T rating for through penetration firestop systems when the floor penetration was contained and located within the cavity of a wall. The 2012 IBC has extended this exemption for the T rating to include floor penetrations for floor drains, tub drains, and shower drains contained and located within a concealed space of a horizontal assembly (Exception No. 2, Paragraph 7188.8.131.52.2). As with a wall cavity, the provision assumes that a T rating is not required due to the reduced likelihood that combustibles will be exposed to any temperature increase of the penetrating item.
Duct penetrations of fire partitions: A new exception has been added to permit the omission of fire dampers where a ducted HVAC system penetrates a fire partition having a fire resistance rating of 1 hour or less and located in a building protected throughout with an automatic sprinkler system. The exception clarifies what is intended by a “ducted HVAC system,” and the provision is the same as what was previously permitted for duct penetrations of 1-hour fire barriers (Exception No. 4, Paragraph 717.5.4).