Has anyone had experience with and/or can find the difference between these two occupancy classifiations from the 2010 CBC ?


304.1 Business Group B occupancy includes, among others, the use of a building or structure, or a portion thereof, for office, professional or service-type transactions, including storage of records and accounts. Business occupancies shall include, but not be limited to, the following:

Laboratories: testing, research and [SFM] instruction

313.1 Laboratories Group L. [SFM] Group L occupancy includes the use of a building or structure, or a portion thereof, containing one or more laboratory suites as defined in Section 443.

LABORATORY SUITE. A laboratory suite is a space within a building or structure, which may include multiple laboratories, offices, storage, equipment rooms or similar support functions, where the aggregate quantities of hazardous materials stored and used do not exceed the quantities set forth in Table 443.7.3.1.


We have a forensic laboratory proposed in a portion of a Sherriff's Center in our jurisdication. The L occupancy is more restrictive, so we're leaning toward that. We don't have a list of what chemicals or other products that will be used yet.

Any help out there?

Original Post
Question, Isn’t a police lab more analytical than that of a research Lab at the Universities for which the L occupancy was modeled for & regulated by the State Fire Marshal’s Office?
Group B labs are typically community colleges and universities.

Group L labs are typically biotech businesses and chemical companies, sometimes materials research.

As I remember the code monographs circa 1990, there was quite some difficulty in those days with the higher educational occupancies and their typically very low quantities of hazardous materials and low use intensity compared to the commercial occupancies that were expanding at a very rapid rate.

A Sherrif's forensic lab would typically be an L occupancy group unless the lab was quite small or limited in test scope. Talk to the current lab director to get some better info and confer with the Fire Marshal for making sure all parties agree to the occupancy group and get a committment for the lab operations based on the lab state licensing (there is a group at the State level that certifies labs of all sorts in medical and forensics).
Sorry JIm,

Group L in California was specifically for universities. I was the Committee Chairman when Labs were discussed. I left the provisions to the many universities that were present.
Chuck Daleo

Add Reply

Link copied to your clipboard.