Occupancy Classification is used in the state building code and categorizes structures based on their primary usage, such as a home’s main purpose is Residential (R) or a hospital’s main purpose is Healthcare (I-2). Other examples of Occupancy Classification are Assembly (A), Business (B), and Factory (F). 

Knowing a project’s Occupancy Classification is a vital step toward determining if an architect or professional engineer is required. If you know a structure’s classification, use the chart in E&A Regulation Act to determine if a project is exempt or not, based on square footage.

If a structure contains more than one Occupancy Classification, use the most restrictive occupancy for determining if a licensee must be involved.

On a single-family through four-family dwelling, this includes all enclosed, potentially-habitable space on any level, up to a maximum of three levels.

A structure with two or more occupancy classifications is governed by the exemption limits for the most restrictive occupancy.

For example, a project consists of Storage and Business occupancies. Storage classification has a minimum of 5,000 square feet and Business classification has a minimum of 3,000 square feet. As the Business classification is the most restrictive, the entire project would be considered a Business classification for purposes of the E&A Regulation Act. A building with a Business Occupational Classification of 3,000 square feet or more would require the involvement of licensees.