Committee says Bellevue IEBC 'work area' question needs project details before an opinion

The Building, Fire, Residential and WUI Code Committee reviewed an opinion request from the City of Bellevue about how the International Existing Building Code (IEBC) defines "work area" when a horizontal fire-resistance-rated assembly is replaced during a change of occupancy.

Dustin Curb, SBCC managing director, summarized a three-part question from Darren McGillivray (Bellevue) about whether the area below a replaced horizontal assembly must be included in the work-area calculation, whether modifying components of the assembly brings the lower space into the work area, and how changes could trigger separation or sprinkler requirements. "My perspective is that the area below that horizontal assembly is not part of the work area," Curb said, calling the assembly an incidental work area in many cases, but he asked for committee feedback.

Committee members agreed the first question (whether the lower space is 'reconfigured' and thus part of the work area) could often be answered in the negative in general terms, but they said the second question—whether replacement triggers greater separation or sprinkler requirements—depends on project specifics. Micah and Angela Haupt noted that a nonconforming occupancy (an A2 used without a recorded change of occupancy) complicates the analysis and may require the local jurisdiction to address safety and conformity. Dustin described the specific project facts from Bellevue: a 4,900-square-foot basement with mixed A2 and B occupancies, removal of original lath-and-plaster/tin ceiling that approximated a 1-hour separation, and uncertainty whether counting the lower space would push the work-area percentage above the 50% threshold that could trigger sprinklers under IEBC/IBC.

Members concluded staff should follow up with Darren to request plan sets or additional details; the committee deferred issuing a generalized opinion and left resolution of the project-specific questions to the local jurisdiction or to a later Council discussion if Bellevue provides more information.

Dustin will contact the City of Bellevue to request clarifying documentation and return the item to the committee or present it to the full Council if necessary.