Summary of Differences in NFPA 13, 13R, & 13D

This week's resource was a fun one to put together.

Frequent Questions about NFPA 13 vs. 13R
I've been asked a handful of times in early project planning phases on whether NFPA 13R would be allowed in lieu of NFPA 13 for a project. In short, the two standards have very different objectives and as a result require very different means.

While those who ask are generally looking for ways to save on construction for the project, the differences are important and worth discussing early in a project.

Designed for Different Purposes
It's important to note that NFPA 13R systems are designed primarily with the intent for life safety (extending the amount of time occupants have to escape a burning building). It's stated purpose is to additional "prevent flashover in the room of fire origin, where sprinklered" (NFPA 13R 2019 1.2.2).

Unlike NFPA 13, NFPA 13R works to make the installation of the sprinkler system more affordable and accessible for residential occupancies by targeting the areas of highest fire risk to life safety with sprinkler systems. Swapping NFPA 13 and NFPA 13R is not simply a one-for-one exchange, as their goals are overall quite different.

​Summary of Differences
Here's the summary of differences I use between NFPA 13, 13R, and 13D as a downloadable PDF (at the bottom of this page). References to the building code are to the International Building Code, as it's typically the most prevalent used in the US.

As always, there's far more detail to many of these requirements than can be summarized in two pages - so be sure to use the supplied section references to gather more information on specifics for your project.

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CODE PLANNING

-	NFPA 13	NFPA 13R	NFPA 13D
Objective	Life Safety + Property Protection [NPFA 13 2002-2019 1.2.1]	Life Safety Only [NFPA 13R 2002-2019 1.2]	Life Safety Only [NFPA 13D 2002-2019 1.2.1]
Considered "Fully-Sprinklered" ?	Yes [IBC ref. section 903.1.1 as fully-sprinklered]	No [IBC references 'buildings equipped with a sprinkler system per 903.3.1.1, which is an NFPA 13 system]	No
Building Height Increases Permitted	Yes [IBC Table 504]	Only for R-Occupancy [IBC Table 504]	No​
Permitted in One & Two-Family, or Group R-3 & R-4 Condition 1 and Townhouse R-Occupancies?	Yes [IBC 903.1.1]	Yes [IBC 903.1.2]	​Yes [IBC 903.3.1.3]
Permitted in R-Occupancies up to 4 stories?	​Yes [IBC 903.1.1]	Yes [IBC 903.1.2]	​No
Permitted in Mixed Use / Non-Residential Occupancies?	Yes [IBC Table 508.4, 508.3.1]	No [IBC 903.1.2]	​No

​OMITTED AREAS

-	NFPA 13	NFPA 13R	NFPA 13D
Omit in Attics	If non-comb., small, or filled with non-comb. insulation [NFPA 13 2002 8.14.1.2, 2007-2016 8.15.1.2]​	Yes [NFPA 13R 2002 6.8.5, 2007 6.9.6, 2010-19 6.6.6]​	Yes [NFPA 13D 2007-10 8.6.5, 2019 8.3.5]​
Bathrooms in Units less than 55 sqft w/ 15-min. Non-Combustible Lining	Yes  [NFPA 13 2002 8.14.8.1, 2007-16 8.15.8.1.1]	Yes [NFPA 13R 2002 6.8.2, 2007 6.9.2, 2010-19 6.6.2]	Yes [NFPA 13D 2007-10 8.6.2, 2013-19 8.3.2]
Closets in Hotel or Motel w/ Non-Combustible Surface less than 24 sqft, or Hospital Less than 6 sqft?1	Yes [NFPA 13 2002 8.14.8.2, 2007-16 8.15.8.2]	Yes [NFPA 13R 2002 6.8.3, 2007 6.9.3, 2010-19 6.6.3]	N/A
Closets w/ Non-Combustible Surface less than 24 sqft?1	No, Required	Yes [NFPA 13R 2002 6.8.3, 2007 6.9.3, 2010-19 6.6.3]	Yes [NFPA 13D 2007-10 8.6.3, 2013-19 8.3.3]
Closets on Exterior Balconies or Breezeways & Exterior Access?1	No, Required	Yes [NFPA 13R 2002 6.8.6, 2007 6.9.7, 2010-19 6.6.7]	Yes [NFPA 13D 2013-19 8.3.8]
Concealed Spaces	Yes if non-comb., filled with non-comb. insulation1 [NFPA 13 2002 8.14.1.2, 2007-2016 8.15.1.2]	Yes [NFPA 13R 2002 6.8.5, 2007 6.9.6, 2010-19 6.6.6]	​Yes [NFPA 13D 2007-10 8.6.5, 2013-19 8.3.5]
Concealed Spaces with only Ventilation Equipment?	No, Required	Yes [NFPA 13R 2002 6.8.5, 2007 6.9.6, 2010-19 6.6.6]	Yes [NFPA 13D 2007-10 8.6.5, 2013-19 8.3.5]
Elevator Machine Rooms?	​No, Required	Yes [NFPA 13R 2002 6.8.5, 2007 6.9.6, 2010-19 6.6.6]	Yes [NFPA 13D 2007-10 8.6.5, 2013-19 8.3.5]
Garages, Carports, Attached Porches?	​No, Required	Yes [NFPA 13R 2002 6.8.5, 2007 6.9.6, 2010-19 6.6.6]	Yes [NFPA 13D 2007-10 8.6.3, 2013-19 8.3.4]
Penthouse Equipment Rooms?	​No, Required	Yes [NFPA 13R 2002 6.8.5, 2007 6.9.6, 2010-19 6.6.6]	Yes [NFPA 13D 2007-10 8.6.5, 2013-19 8.3.5]

HYDRAULIC CALCULATIONS

-	NFPA 13	NFPA 13R	NFPA 13D
Max Number of Adjacent Calculated Residential Sprinklers	Four 1 [NFPA 13 2002 11.2.3.5.1, 2007-16 11.3.1.1]	Four 1 [NFPA 13R 2007 6.7.1.2, 2007 6.8.1.2, 2010-19 7.1.1.3]	Two 1 [NFPA 13D 2002-10 8.1.2, 2013-19 10.2]
Hose Allowance Required?	Yes [NFPA 13 2002 11.2.3.5.5, 2007 11.3.1.5, 2010-16 11.3.1.6]	No [NFPA 13R 2007 A.6.8.2, 2010-19 A.7.2]	No
Minimum Residential Density	New: 0.10 gpm/sqft Existing: Listing of Sprinkler [NFPA 13 2002 11.2.3.5.2, 2007 11.3.1.2, 2010-16 11.3.1.3]	0.05 gpm/sqft or listing of sprinkler [NFPA 13 2002 6.7.1.1.2.2, 2007 6.8.1.1.1.2, 2010-19 7.1.1]	0.05 gpm/sqft or listing of sprinkler [NFPA 13D 2002-10 8.1.1, 2013-19 10.1.1]
Calculation Method	NFPA 13 Hydraulic Calculations	NFPA 13 Hydraulic Calculations	NFPA 13D Worksheet Calculations

DOWNLOAD NFPA 13 vs 13R vs 13D SUMMARY

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