Office of the State Fire MarshalPhoto of building exterior.

I-3 Occupancy Group

Interpretive Manual

February 2022





The CAL FIRE - Office of the State Fire Marshal (OSFM) convened representatives from various disciplines related to in-custody, correctional, justice, and the rehabilitation industry. The OSFM I-3 Occupancy Group Interpretive Manual Committee created this document to clarify the intent of the California Building Code, and specifically how these code sections would be enforced by the OSFM and other Authorities Having Jurisdiction (AHJ).

Prior to the 2007 edition California Building Code (CBC), the model code for the CBC was the Uniform Building Code (UBC). Subsequent to the 2007 CBC, California has used the International Building Code (IBC) as model code. The California Building Standards Commission (CBSC) has amended code language for regulations that are specific to California for fire and life safety. When the transition from UBC to IBC as model code occurred, some of the California requirements were lost in translation and at times interpreted differently causing confusion and disharmony in the design enforcement community.

Starting in 2001, several OSFM I-3 Committee Task Groups were assembled to analyze and propose code language to clarify the intent of the CBC. The products of these efforts were approved by the CBSC and have since been added to the subsequent CBC editions, with additional changes anticipated to occur in future code cycles.

While authors of the IBC and the additional California amendments have endeavored to write these code requirements in such a way to be easily understood, architectural design is a complicated and creative process and detention environments demand complex solutions which often challenge designers, owners, and code officials. This committee recognizes that the first priority is to ensure that these facilities are safe relative to fire and life safety. We also understand the mission of detention and correctional facilities and account for the other dangers that detainees, custody officers, and other service provider occupants face on a daily basis; dangers that often require open floorplans with adequate transparency to overcome threats to occupants at the hands of other occupants or sometimes themselves.

This committee also considered historical data to understand the intent of the amendments and has provided commentary, diagrams, and flow charts to educate and unify application of the regulations. This committee has endeavored to account for: operational requirements, security, constructability, and access compliance. Working within these parameters, the goal is always to maintain a safe environment, uncompromised by any safety dangers.

Interior photo of prison.

Design Elements Table of Content

1. Smoke Control Requirements CBC Section 408.9

  1. Background
  2. Adopted Code
  3. Commentary
  4. Flow Chart for Smoke Control
  5. Diagrams

2. Corridor Requirements/Intervening Space Exceptions CBC Sections 1016 and 1020

  1. Background
  2. Adopted Code CBC 1016
  3. Commentary for CBC 1016
  4. Adopted Code CBC 1020
  5. Commentary for 1020
  6. Diagrams

3. Exercise Area Exiting Requirements CBC Section 1028

  1. Background
  2. Adopted Code
  3. Commentary
  4. Flow Chart for Number of Exits Required in Exercise Areas
  5. Diagrams