The IBC’s modification to exit access travel distance
Understanding the International Building Code’s increase for Group F-1 and S-1 occupancy.
The 2015 International Building Code includes a key modification, increasing the length of exit access travel distance from 250 ft to 400 ft (if it meets specific criteria) for buildings containing Group F-1 and/or S-1 occupancy.
This change is significant to the design industry, building owners and occupants of large distribution and manufacturing facilities. Understanding the code's implications for your existing and future facilities will ensure you're properly prepared.
A brief timeline of exit access travel distance
- 1994: In the 1994 Uniform Building Code, the exit access travel distance in a building protected with a fire sprinkler system was typically 200 ft. The exit access travel distance could be increased to 400 ft when facilities storing or manufacturing noncombustible products were provided with smoke/heat vents in addition to the fire sprinkler system.
- 1997: In the 1997 Uniform Building Code, this section was revised to allow this increase to apply to all warehouses and factories if they were protected with a fire sprinkler system and smoke/heat vents. This exit access travel distance increase resulted in larger buildings with open, undivided areas. A typical warehouse ranged from 600 to 700 ft wide. As buildings continued to grow, 600 ft became the narrow dimension for a warehouse, with many buildings exceeding 1000 ft in length.
- 2009/2012: The 2009/2012 editions of the International Building Code were revised to eliminate the 400 ft exit travel distance for large Group S-1 warehouses and large Group F-1 manufacturing facilities equipped with smoke and heat vents. This change was made because thermally activated vents were judged not to warrant such an increase.
The effects of eliminating the 400 ft exit travel distance
Due to the 400 ft loss, designers had to modify new warehouse and manufacturing facilities' proportions or incur the cost of providing additional exits. And while it was clear to many in the industry that the original rationale for 400 ft was faulty, eliminating the requirement in its entirety was not an option.
The industry focused on ways to increase the travel distance for large buildings containing Group F-1 and/or S-1 occupancy.
Task group 400
An industry group in California came together as "Task Group 400" and conducted a fire modeling study, which demonstrated that the vast volume of large buildings could be used to contain smoke.
The group's report was reviewed by the California State Fire Marshal's Office and presented to the California Building Standard Commission, requesting a reinstatement of the 400 ft travel distance without any special protection, provided all of the following are met:
1. The portion of the building classified as Group F-1 or S-1 is limited to one story in height.
2. The minimum height from the finished floor to the bottom of the ceiling or roof slab or deck is 24 ft.
3. The building is equipped throughout with an automatic fire sprinkler system in accordance with section 903.3.1.1.
California's code change was later adopted into the 2015 edition of the International Building Code - the model code for most states.It should be noted that, although code no longer requires smoke and heat vents for this travel distance increase, vents or mechanical smoke removal system, are still required by Section 910.3 and 910.4 for Group S-1 and F-1 buildings of more than 50,000 sq ft. There are exceptions, however, for frozen food warehouses and areas with specific types of sprinkler systems.
Sonja Antunovic-Curcic has over 15 years of experience in architectural design. She has a strong technical background and ability to effectively transform challenges into opportunities. Her experience involves design of new buildings, expansions or alterations to existing buildings. This article originally appeared on Stellar Food for Thoughts. Stellar is a CFE Media content partner. Edited by Joy Chang, digital project manager, CFE Media, firstname.lastname@example.org