Does my building need a sprinkler system? Part 2

2 years, 2 months ago

Note: This is Part 2 of a series:

By Ellen McCulley
Licensed Architect, Nelson Design, Inc.

In my last column I started a series discussing the factors that determine whether or not a building is required by code to have an automatic sprinkler system. I addressed the building occupancy, construction type, and the number of stories and area of the building. Chapter 9 of the International Building Code (IBC) and International Fire Code (IFC) established the basic requirements regarding automatic sprinkler systems in the code. Requirements are organized based on building occupancy.

The requirements in chapter 9 are often based on the total fire area. A fire area is the aggregate floor area that is enclosed and bounded by fire walls, fire barriers, exterior walls, or horizontal assemblies. Fire barriers can be strategically located in a building to reduce the size of the fire area and thus avoid a sprinkler system in some situations.

Group A

Meeting/training rooms (Group A-3 occupancy) with a cumulative occupant load over 300 and break rooms (Group A-2 occupancy) with an occupant load of 100 or more would likely be the only conditions where the presence of a Group A occupancy in an industrial facility would require a sprinkler system. Break rooms over 1,500 square feet would exceed 100 occupants and thus necessitate a sprinkler system. In Group A occupancies with the aforementioned occupant loads, the sprinkler system is required throughout the fire area containing the Group A occupancy, and throughout all stories from the Group A occupancy to the level of exit discharge. Therefore, if the Owner desires to avoid an automatic sprinkler system, it is best to limit the size of these rooms or create fire areas.

Group B

Group B occupancies would be assigned to the office portion of an industrial facility. A Group B occupancy does not automatically trigger the need for a sprinkler system. Other code sections may trigger the need for a sprinkler system.

Groups F-1 and S-1

Both factory and storage occupancies are divided into two categories. F-1 and S-1 are the moderate hazard categories and F-2 and S-2 are the low hazard categories. Groups F-1 and S-1 have the same requirements in the IBC and IFC. In our experience, the most likely trigger for a sprinkler system in new facilities would be exceeding the cumulative 24,000 square feet for all fire areas, since fire barriers can be strategically placed to avoid exceeding 12,000 square feet per fire area.

Groups F-2 and S-2

Groups F-2 and S-2 occupancy do not automatically trigger a sprinkler system. Other code sections may trigger the need for a sprinkler system.

Group H

Automatic sprinkler systems are required in Group H occupancies.

Summary of Occupancy-Related Automatic Sprinkler Thresholds
Occupancy	Threshold
A-2	• Fire area > 5,000 SF
	• Fire area has an occupant load ≥ 300
	• Fire area is located on floor other than level of exit discharge
A-3	• Fire area > 12,000 SF
	• Fire area has an occupant load ≥ 100
	• Fire area is located on floor other than level of exit discharge
B	• No occupancy threshold for sprinkler system. Sprinkler system may be required by other sections
F-1 and S-1	• Fire area > 12,000 SF
	• Fire area is located more than 3 stories above grade plane
	• Combined area of all fire areas, including mezzanines is > 24,000 SF
F-2 and S-2	• No occupancy threshold for sprinkler system. Sprinkler system may be required by other sections.
H	• Sprinkler required

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