The following column, “Are Sprinklers Required?” appeared in Plumbing Engineer magazine in July 2009. It was the first of 120 FPE Corner columns that I contributed to the magazine. For this first column, it was my intention to establish by example the primary purposes of the FPE Corner. Specifically, to try to provide useful and practical information to the plumbing engineer involved in the design and engineering of fire protection systems, as well as to provide the readers a sense of how a fire protection engineer approaches engineering challenges. Though the codes and standards cited in the column are dated, the general concepts are still applicable. I thoroughly enjoyed my time with the FPE Corner, and I am very grateful to those who took the time to read the columns. I also appreciate all the help and support from the magazine’s editorial staff during that time. Congratulations, Plumbing Engineer, on your 50th anniversary!

Current codes call for the installation of fire sprinklers in many instances in new construction, but there are still many cases where sprinklers are not required. How does one determine if sprinklers are required? At the start of a design of a building, the plumbing engineer often receives a call from the architect asking this very question.

Since the plumbing engineer is responsible for the design of the fire sprinkler system, the architect may presume that he or she should be able to easily answer this question. This is not always the case, as the decision to provide sprinklers for a building can be based on factors that are beyond the control of the plumbing engineer. 

Let us assume that the jurisdiction is using 2006 edition of the International Building Code (IBC) and 2006 International Fire Code (IFC). This article will attempt to outline many (but not all) areas in the codes where sprinklers are required or where sprinklers are used to take advantage of the many “trade-offs” giving architects and builders flexibility and possibly cost savings in the design and construction of a building. Armed with this information, the plumbing engineer can be ready to assist the architect in answering this question. 

The plumbing engineer should be familiar with IBC Chapter 9 dealing with fire protection systems. In this chapter, Section 903.2 identifies several instances where a sprinkler must be provided. The sprinkler requirements in this section are based on occupancy. In the case of High-Hazard (Group H), Institutional (Group I) and Residential (Group R) occupancies, sprinklers are required across the board. 

Now regarding R occupancies, keep in mind that in many jurisdictions, one- and two-family dwellings do not fall under the building code, but rather are covered by a separate residential or housing code. The plumbing engineer will need to check there to determine if sprinklers are required. For other occupancies, Section 903.2 requires sprinklers when the building exceeds a certain floor area or when some special condition exists. For example, a retail store (Group M occupancy) with a fire area over 12,000 square feet will require sprinklers.

For the most part, these requirements apply to the entire building, but there are instances where only a portion of the building requires sprinklers, as is the case for stories or basements without openings (IBC Section 903.2.10.1).

IBC Table 903.2.13 also identifies other areas of the IBC and, in one case, the International Fire Code, where sprinklers will be required.

IBC Chapter 9 does not provide all the answers to the question of whether or not sprinklers are needed in a building. A requirement for sprinklers can result from the type of construction selected for a given occupancy. IBC Section 506.3 allows an increase in the basic allowable floor area of 200% for multistory buildings and 300% for single-story buildings for most situations. An architect, therefore, can opt for sprinklers to get a larger building without an upgrade in the type of construction. 

Note that the increases cannot be taken for buildings containing a Group H-1 occupancy, or floors containing a Group H-2 or H-3 occupancy, or if the fire resistive substitution allowed by IBC Table 601 note e is used.

The fire resistive substitution allows the sprinklers to be “substituted” for the one hour fire-resistance ratings required for Type IIA, Type IIIA or Type VA buildings. Note that it cannot substitute for exterior wall fire resistance. Also, the fire resistance substitution cannot be used if sprinklers are required by other provisions of the IBC and as noted above if sprinklers are used to obtain an area increase or, as noted below, if sprinklers are used to obtain an increase in building height.

The architect can also use sprinklers to add one story in height to the building and increase the maximum allowed height by 20 feet using the requirements in IBC Section 504.2. This provision can be taken advantage in addition to the area increases, but cannot be used for hospitals with unprotected or combustible construction, H-1, H-2 or H-3 occupancies, or if the fire resistive substitution is used.

Sprinklers in combination with large, open yard spaces around the building can also play a role in allowing certain occupancies in unprotected (i.e., no fire resistance requirements) noncombustible or combustible construction to be of unlimited areas under the provisions of IBC Section 507. 

The use of sprinklers can also help with requirements for the fire protection rating of openings in exterior walls. IBC Table 704.8 limits the amount of openings in exterior walls based on whether the opening is unprotected or protected and the fire separation distance. In this case, the term “protected” means the opening is provided with an opening protective assembly, i.e., a fire door/window or fire-rated glazing. 

For a one-hour exterior wall, a 3/4-hour fire protection rating is required and for a two-hour wall, a fire protection rating of 1 1/2 hours is required. With the exception of Group H-1, H-2 and H-3 occupancies, IBC Section 704.8.1 considers unprotected openings in fully sprinklered buildings to be “protected,” saving the owner the cost of fire-rated openings.

IBC Chapter 4 also contains sprinkler requirements for covered-mall buildings, high-rise buildings, buildings with atriums, underground buildings, stages, special amusement buildings and aircraft hangers.

Chapter 8 Table shows a reduction in interior finish requirements when the building is sprinklered. Typically, a reduction of one class level is allowed. Section 803.6.1 requires sprinklers to be provided if textile wall coverings are used for interior finish. Section 804.4.1 permits a reduction in requirements for interior floor finish also.

IBC Chapter 10 on means of egress provides several areas where sprinklers can be used to reduce requirements, including: 

• For other than hospitals (I-2) occupancies, egress capacities are increased;

• For other than H-1, H-2, H-3, H-4 and H-5 occupancies, travel distances within the exit access to an exit are increased (IBC Table 1016.1);

• For select occupancies, corridor fire-resistance rating is reduced or eliminated (IBC Table 1017.1);

• Dead ends for B and F occupancies are increased from 20 feet to 50 feet (IBC Section 1017.3, Exception 2);

• Common path of travel in Group B, F and S occupancies may be increased to 100 feet (IBC 1014.3, exception 1);

• Remoteness of exits. The separation of exits is reduced from 1/2 the diagonal to 1/3 the diagonal (IBC 1015.2.1, exception 2);

• With the exception of R-3 occupancies, emergency escape and rescue openings are not required for Group I and R occupancies (IBC Section 1026.1, exception 1).

Now, if the International Fire Code (IFC) also applies in the jurisdiction, there are several situations where this code may establish a requirement for sprinklers.

In IFC Section 503.1.1, which pertains to fire apparatus access to buildings, the fire chief is allowed to grant an exception to the 150-foot requirement if sprinklers are provided.

In IFC Section 508.5.1, Exception 1 allows the distance requirement for a fire hydrant on a fire apparatus access road to increase from 400 feet to 600 feet if sprinklers are provided.

If the fire flow requirements of IFC Appendix B apply to your jurisdiction, IBC Section B105.1 allows an exception to reduce the fire floor requirement for one- and two-family dwellings by 50% if the building is fully sprinklered. Section B105.2 allows a reduction of up to 75%, but not less than a minimum fire flow of 1,500 gpm, in the case of buildings other than one- and two- family dwellings.

IFC Table 903.2.13 contains a very long list of areas where fire sprinklers are required, of which many people are not aware.

In the case of high-piled combustible storage, IFC Table 2306.2 provides information as to when sprinkler protection is required.

This article identifies many of the sprinkler-related code provisions based on the IBC and IFC model codes. As is always the case, the engineer must check for variations in the codes adopted in the jurisdiction to ensure that a given item is still applicable. 

By becoming familiar with the provisions of the IBC and IFC which pertain to sprinklers, not only those in IBC Chapter 9, the plumbing engineer helps the architect answer the question, “Are sprinklers required?

Editor’s note: This republished column is slightly edited for style and punctuation.