UM System AHJ Code Determination
Code Determination Number: 16R
Date: October 4, 2024, revised December 5, 2025
Code Edition: 2024 IBC, 2024 IEBC, 2012 NFPA 101
Subject: Determining occupant loads for Class Lab spaces and Research Laboratories.
Questions (from various UM Staff and Design Consultants):
The code is not specific regarding the square footage assumptions for occupants in Research Laboratories and Class Lab rooms. How many square feet per occupant should be assumed for these rooms?
Can I use a net calculation for these rooms (re. not include fixed casework, equipment, or fixed working surfaces in the overall calculation)?
Answer (from UM AHJ):
- Research Laboratories: The occupant load of a space is dependent on the function of the space per IBC Table 1004.5, not the occupancy classification per IBC Chapter 3. Although Chapter 3 identifies laboratories as a Business occupancy, the function of a research laboratory most closely aligns, in Table 1004.5, with Shops and other Vocational Room Areas (50 net square feet).
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Class Laboratories: It is understood that the Educational setting occupant loads for Classrooms (20 net square feet), and Shop or Vocational areas (50 net square feet) do not accurately describe the space necessary for each occupant in higher ed Class Labs. Class lab areas tend to be more collaborative in nature, and do not align with the typical space criteria required for classrooms, shops, or labs.
- UM AHJ has determined that designers shall use a 50 square feet per person multiplier for Research Laboratories and a 30 square feet per person multiplier in Class Labs.
- Net space calculations are allowed. The net space calculations for Class Lab spaces shall be shown on the code sheet of the construction drawings for record purposes and future reference.
- Provisions for the number of Class Lab exits doors, egress door widths, door swing, fire alarm horn/strobe requirements, etc., shall be included in the overall space design based on the resulting Class Lab occupancy load calculations.
- Where the resulting Class Lab room occupancy load is 50 or more, Occupancy Load signage shall be posted in the room, as required by code.
Published: December 16, 2025
Reviewed 2025-12-16