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Speaking Sprinkler

Wednesday, April 03, 2019

The 2019 edition of NFPA 13 “Standard for the Installation of Sprinkler Systems” was recently revised. Each new edition is intended to create a document that is easier to use than the previous. Inherently, this document can often be interpreted in many differing opinions and create unintentional complexity to what would appear to be simple, clear intent. Chapter 3, in its entirety, is dedicated to the definitions as it relates to sprinkler fire protection and is often very helpful when defining specific terms.

However, with so many stakeholders involved in the process of designing, approving and installing sprinkler fire protection systems, you may not be surprised the most simple definition can at times find multiple definitions. Let’s take a look at the definition of “bathrooms”. Here’s a portion of an article from a recent issue of a NFSA TechNotes newsletter.


1“If someone was walking through your house, there would be no doubt which room is the bathroom. It's the one with a toilet and sink for a half-bathroom, or a toilet, sink, and shower/bathtub for a full-bathroom. NFPA 13-2019 defines a bathroom below:

3.3.16* Bathroom. Within a dwelling unit, any room or compartment dedicated to personal hygiene containing a toilet, sink, or bathing capability such as a shower or tub.

While most of us think of bathrooms having the two or three items discussed above, NFPA 13 clarifies that a bathroom, within a dwelling unit, must contain only one of these items or another fixture with "bathing capability." This is a key designation, especially when laying out sprinkler systems for hotels, motels and other residential structures. NFPA 13 permits the omission of sprinklers from bathrooms that do not exceed 55 ft2 per section 9.2.4.1:

9.2.4.1 Bathrooms.

9.2.4.1.1* Unless sprinklers are required by 9.2.4.1.2 or 9.2.4.1.3 sprinklers shall not be required in bathrooms that are located within dwelling units, that do not exceed 55 ft2 (5.1 m2) in area, and that have walls and ceilings of noncombustible or limited-combustible materials with 15-minute thermal barrier rating, including the walls and ceilings behind any shower enclosure or tub.
9.2.4.1.2 Sprinklers shall be required in bathrooms of limited care facilities and nursing homes, as defined in NFPA 101.
9.2.4.1.3 Sprinklers shall be required in bathrooms opening directly onto public corridors or exitways.

Often times in hotels and contemporary homes, the bathroom will be split up into separate spaces for the sink, toilet, and shower. If all three of these spaces individually meet the definition of a bathroom per section 3.3.16, then sprinkler protection could be omitted from all of them...if they are a room or compartment:

3.3.38 Compartment. A space completely enclosed by walls and a ceiling. Each wall in the compartment is permitted to have openings to an adjoining space if the openings have a minimum lintel depth of 8 in. (200 mm) from the ceiling and the total width of the openings in each wall does not exceed 8 ft. (2.4 m). A single opening of 36 in. (900 mm) or less in width without a lintel is permitted where there are no other openings to adjoining spaces.

Make sure your general contractor is installing a layer of gypsum board behind the shower enclosure or tub and the minimum lintel depth and maximum openings are met, otherwise you may be stuck installing sprinklers in the room as it no longer meets the requirement to have 15-minute thermal barrier and that room with a toilet and a shower is no longer a bathroom per NFPA 13. Note that NFPA 13 does not define the term “room” so the “ordinarily accepted meanings” contained within Merriam-Webster’s Collegiate Dictionary, 11th Edition shall be used. The tolerance of “ordinarily accepted meanings” would be up to the AHJ’s discretion.”


There are several examples of sprinkler fire protection terminology and definitions with multiple interpretations. Contributing to the challenge can be definitions based on regional adoptions of industry terminology, along with the possibility of varying interpretations among several parties including manufacturers, engineers, contractors, jurisdictional authorities, and owners.

The reality is all stakeholders share in the responsibility of a mutual and clear understanding of the definitions inside the NFPA Standard. Although, there may be differing opinions, there should only be one final interpretation and everyone needs to be on the same level of understand to produce an effectively designed and installed sprinkler fire protection system.

It is essential that an effective collaboration and mutually understanding of the building use, occupancy, commodities, storage, fire hazards, etc. are all clearly defined and consistent with the definitions of the NFPA. Written communication of the intent is always encouraged. This will ensure the design, installation, and sprinkler systems are installed consistent with NFPA requirements for property and life safety protection.

1NFSA TechNotes Issue #415

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