#101Wednesdays: Building separation walls in the Life Safety Code

Blog Post created by gharrington Employee on Oct 18, 2017

I’ve had a couple questions come across my desk asking what the Life Safety Code would require for wall construction to subdivide a building into separate smaller “buildings.” This subdivision is for the purposes of avoiding a requirement for automatic sprinkler protection by reducing the height or area of the smaller buildings to below the prescribed threshold values at which sprinkler protection is required. 

The short answer is that the Life Safety Code contains no such provision. It is not a building code, therefore it does not contain requirements for barriers to create “separate buildings.” If the code requires automatic sprinkler protection throughout the building, it is then up to the authority having jurisdiction to determine what constitutes the boundaries of the building, usually with the help of the applicable building code.  Having said that, there are some provisions in the code that flirt with the concept of building separation walls, so the questions I received were not without merit. 

One of those provisions deals with separating portions of buildings with different types of construction for the purpose of classifying the construction type: Where the building or facility includes additions or connected structures of different construction types, the rating and classification of the structure shall be based on one of the following: 

(1) Separate buildings, if a two-hour or greater vertically aligned fire barrier wall in accordance with NFPA 221 exists between the portions of the building

(2) Separate buildings, if provided with previously approved separations

(3) Least fire-resistive construction type of the connected portions, if separation as specified in or is not provided   

For example, if I have an existing building of Type II(222) construction (noncombustible, two-hour rated structure), and I add on to it using Type II(000) construction (noncombustible, nonrated structure), the building’s overall construction classification will be downgraded to Type II(000). This is the least fire resistive type present, unless the addition is separated from the existing building by a two-hour or greater vertically aligned fire barrier wall in accordance with NFPA 221, Standard for High Challenge Fire Walls, Fire Walls, and Fire Barrier Walls, in which case the existing building continues to be classified as Type II(222) and the addition is classified as Type II(000). From the Life Safety Code’s perspective, however, it is still one building, and if the building requires automatic sprinkler protection throughout, then both the existing building and the addition must be protected. The provision of relates only to separating different types of construction for the purpose of construction classification. 

Another question I received asked whether an existing building with two, side-by-side dwelling units could add a new third dwelling unit separated by a two-hour fire barrier and classify the addition as a new one-family dwelling (sprinklered) and the existing portion as an existing two-family dwelling (nonsprinklered). Or would the entire building be classified as an apartment building (three or more dwelling units) and require sprinklers throughout? The Life Safety Code says if there are three or more dwelling units, it’s an apartment building, and Chapter 43, Building Rehabilitation, says automatic sprinklers would be required throughout the building. However, NFPA’s building code, NFPA 5000, Building Construction and Safety Code, says you can separate townhouses with not more than two dwelling units from each other by two-hour fire barriers and classify them as a series of attached, one- and two-family dwellings (see Section 22.5 of NFPA 5000 for details). The International Building Code, which is widely used here in the U.S., might have similar criteria. 

Another (paraphrased) question asked whether a new school could be subdivided into fire compartments formed by two-hour fire barriers, each not more than 12,000 square feet in area, to avoid requiring automatic sprinklers under the 2015 edition of NFPA 101. (Note that the 2018 edition was revised to require sprinklers in all new educational occupancies other than those not more than 1,000 square feet in area or consisting of a single classroom. See 14.3.5.) The answer to this one was “maybe,” because Annex A contained the following provision:

A. It is the intent to permit use of the criteria of to create separate buildings for purposes of limiting educational occupancy building area to not more than 12,000 square feet (1120 square meters). 

So this suggestion left it up to the AHJ to determine if subdivision by two-hour barriers was permitted in lieu of sprinklers. I’ll be honest, I wasn’t a fan of this language. Either permit something via code language or don’t. It doesn’t help anyone to have wishy-washy “suggestions” in Annex A and then force me to tell people “it’s up to the AHJ.” Frankly, I’m glad this provision in Annex A is gone (thank you, Technical Committee on Educational and Day Care Occupancies). It’s not uncommon to hear me say in technical committee meetings, “I’m going to have to answer questions on this…” The code isn’t perfect, but we try really hard to make it as perfect as we can. You can help; participate in the process by submitting public input for revisions. The 2021 edition revision cycle is right around the corner. Your opportunity to make your voice heard is now!


Got an idea for a topic for a future #101Wednesdays? Post it in the comments below – I’d love to hear your suggestions! Did you know NFPA 101 is available to review online for free? Head over to and click on “FREE ACCESS.” Follow me on Twitter: @NFPAGregH