Are fire sprinklers required? It’s complicated

Are fire sprinklers required? It’s complicated

1 year, 3 months ago

Note: This is Part 1 of a series:

By Ellen McCulley
Licensed Architect, Nelson Design, Inc.

Does my building need a sprinkler system? It’s a common question that arises amongst our clients, but one I can’t provide an answer to until I have more information. (If you are my design client I can often utilize alternate strategies to avoid having to install a sprinkler system while still meeting code requirements). Therefore, I will be addressing this topic in the next few issues of this newsletter to help you gain a better understanding of the multiple factors that must be examined in order to conclude whether or not a sprinkler system is required. I will begin the series by discussing when sprinkler systems are required in new construction, whether it be a freestanding building or an addition onto an existing building.

Question 1: What is the occupancy of your building?

Typically, our industrial clients are either a group F-1 or F-2 occupancy for the production areas of their facility and a group S-1 or S-2 for the storage areas. F-1 and S-1 classifications are designated to those facilities that are producing and/or storing goods that are moderate hazards and are more combustible than the low-hazard groups F-2 and S-2. Groups F-2 and S-2 are for non-combustible materials that pose a low fire risk.

If the quantity of hazardous materials exceeds the threshold outlined in the code, then the building would be classified as a High-hazard Group H occupancy. Automatic sprinkler systems are required in buildings with a Group H occupancy classification.

Any office areas would be classified as a Group B occupancy.

Question 2: What is the construction type of your building?

Our clients often use metal building construction, which would be classified as a Type IIB. If any structural elements such as walls, floors, roof or columns are light wood-framed, then the building is typically classified as a Type VB. The building code allows for a larger unsprinklered building with a non-combustible construction classification, Type I and Type II, rather than with a combustible construction classification, Type VB. Side note: if you had a metal building and then added in a wood-framed mezzanine or wood-framed interior wall to your building you have just changed your construction classification from IIB to VB and might be out of code compliance.

Question 3: What are the number of stories and area of your building?

Chapter 5 of the International Building Code (IBC) contains two charts that designate the maximum building area and maximum number of stories. The building elements that are taken into account when determining this amount are occupancy, construction type, and whether or not the building contains an automatic sprinkler system. The code also allows for an area increase based on the amount of frontage space surrounding the building perimeter.

Below is an excerpt from Table 506.2 in the 2015 IBC. (Please check with your local Authority Having Jurisdiction to identify the building codes that apply to your facility). As you can see, the allowed area varies greatly based on the factors I’m discussing in this article.

Occupancy ClassificationFire ProtectionConstruction TypeConstruction Type
Type IIB Type VB
F-1 Not Sprinklered 15,500 SF8,500 SF
Sprinklered, One Story 62,000 SF34,000 SF
Sprinklered, Multistory 46,500 SF 25,500 SF
F-2 Not Sprinklered 23,000 SF13,000 SF
Sprinklered, One Story 92,000 SF52,000 SF
Sprinklered, Multistory 69,000 SF39,000 SF
S-1 Not Sprinklered 17,500 SF9,000 SF
Sprinklered, One Story 70,000 SF36,000 SF
Sprinklered, Multistory 52,500 SF 27,000 SF
S-2 Not Sprinklered 26,000 SF13,500 SF
Sprinklered, One Story 104,000 SF54,000 SF
Sprinklered, Multistory 78,000 SF40,500 SF
Type IIB Type VB
15,500 SF8,500 SF

For our clients that need large facilities and/or expect future growth, we often recommend that they utilize the unlimited area building provision of the code. This allows for buildings up to two stories that are sprinklered throughout and are a group F or S occupancy to have an unlimited area if they are surrounded by public ways or yard not less than sixty feet wide. For Group F-2 and S-2 occupancies, the code allows non-sprinklered, one-story buildings surrounded by sixty-foot wide public ways or yards to have an unlimited area.

Question 4: What does Chapter 9 say?

Chapter 9 of the IBC delineates specific requirements for fire protection systems based on occupancy and use. I will start there next time.

About the Author

Ellen McCulley graduated magna cum laude with a Bachelor of Architecture degree from Iowa State University, where she received the Pella Architectural Award from the Department of Architecture in the College of Design. She is a registered architect in Iowa, Illinois, Nebraska and Missouri, and joined Nelson Design, Inc., a wholly owned subsidiary of Carl A. Nelson & Company, in 2012.

How to obtain code review for your project or facility

Carl A. Nelson & Company is available to help clients address code-related issues in their facilities. Call (319) 754-8415 and ask for Ellen McCulley. Review past installments of Decoding the Code at