Notable Changes to the 2025 Edition of NFPA 13

The 2025 edition of NFPA 13 “Standard for the Installation of Sprinkler Systems” has several changes from the 2022 edition. The following is a brief overview of some of these changes, along with important comments discussed at the annual Society of Fire Protection Engineering (SFPE) conference in Louisville, KY, in October.

Each year Sprinkler Age Magazine in their November/December issue provides a table listing each state and which edition of NFPA 13 they have adopted. Imagine writing a plan review letter and wondering which version of NFPA 13 applies? Take a look at the confusion below:

• 1 state has adopted the 2022 edition
• 3 states have adopted the 2019 version
• 11 states have adopted the 2016 version
• 15 states have adopted the 2013 version
• 9 states have adopted the 2010 version
• 3 states have adopted the 2007 version
• 4 states use versions prior to 2007
• 1 state still uses the 1999 edition
• 2 states do not indicate what edition they have adopted
• We prefer what Illinois requires, which is the edition that is current at the time of installation shall be used.

To avoid this confusion Chapter 1 now states, “Where a newer edition of NFPA 13 is published, that standard should be permitted to be used in its entirety.”

Clarifying Rules for Sloped Ceilings and Storage Sprinklers

There were significant changes for storage sprinklers and sloped ceilings. In the past, NFPA 13 simply required that for sloped ceilings using the density/area method of calculation, the area should be increased by 30%. Sloped ceilings will now be allowed for storage occupancies as detailed in Section 20.9.

Below are three options for protecting storage occupancies where the ceiling slope exceeds 2 in 12:

1. Install a flat or lesser slope false ceiling
2. Install in-rack automatic sprinklers (IRAS)
3. Install sprinklers per Chapters 20 – 26

Below are three options for protecting storage occupancies where the ceiling slope exceeds 4 in 12:

1. Install CMDA design in every channel
2. For unobstructed ceilings increase the design area by 50%
3. There are four options in Section 20.9 for sprinklers installed with purlins

ESFR Sprinkler Design

ESFR sprinklers for a 12 head design are designed based on the most remote four sprinklers on three branch lines. With obstructed construction, Section 20.9 states the design should be increased 50% to 18 heads where five sprinklers on the most demanding three branch lines and three sprinklers on the next most demanding branch line should be used.

For sloped ceilings there was confusion in the past on whether the sprinkler deflector should be installed parallel to the roof slope or floor. For storage occupancies Section 9.5.4.3 states the deflector must be aligned parallel to the floor. For non-storage occupancies the deflector can either be parallel to the floor or roof slope.

New Requirements for High-Ceiling Occupancies

There are new requirements for non-storage occupancies with high ceilings. A high ceiling is considered 30 ft. or higher.

Sprinkler Types for Ceiling Heights over 30 ft (19.2.3.2.5): The 2025 edition of NFPA 13 will restrict sprinkler types for ceilings over 30 ft as follows:

• OH-1 and higher – sidewall sprinklers not permitted
• OH-2 and higher – minimum K-factor 11.2 sprinklers required
• OH-2 and higher – no extended coverage sprinkler with a K-factor of 22.4 or less
• OH-2 with ceiling height over 40 ft – no standard response sprinklers

Sprinkler Density/Areas for Ceiling Heights over 30 ft (19.2.3.5.2)

Occupancy Hazard	Ceiling Height, H (ft)	Sprinkler Orientation	Sprinkler Coverage	K-factor	Minimum Density	Increase of Design Area
OH-1	H > 30	Upright or Pendent	Standard or Extended	≥ 5.6	Per Table 19.2.3.1.1	30%
OH-2	30 < H ≤ 40	Upright or Pendent	Standard or Extended	≥ 11.2	0.37	None
OH-2	H > 40	Upright or Pendent	Standard	≥ 11.2	0.45	30%
OH-2	H > 40	Upright or Pendent	Extended	25.2	0.45	None
EH-1 & EH-2	H > 30	Upright or Pendent	Standard	≥ 11.2	0.45	None
EH-1 & EH-2	H > 30	Upright or Pendent	Extended	≥22.4	0.45	None

Sprinklers under obstructions (ex. duct > 4 ft.)

These are now called supplemental sprinklers. Below are three new definitions:

• Supplemental Sprinkler (3.3.221.3.6): Section 3.3.221.3.6 now defines a supplemental sprinkler as “A sprinkler that is installed below an obstruction.”
• Non-Flat Obstruction (3.3.142): Section 3.3.142 now defines a non-flat obstruction as “An obstruction where the underside of the obstruction is not in the same plane and not capable of collecting heat.”
• Non-Solid Obstruction (3.3.143): Section 3.3.143 now defines a non-solid obstruction as “An obstruction that consists of openings that constitute at least 30 percent of the footprint of the obstruction.”

New Requirements for Supplemental Sprinklers (9.5.5.3.3)

• Must be quick response or have a fast response element.
• Permitted to have different K-factor, orientation, and coverage than the ceiling sprinklers under certain conditions.
• Required to have water shield (or otherwise shielded) where installed:
  • Under non-flat obstructions
  • Under non-solid obstructions
  • Beyond outer edge of obstruction
  • Under open grating

Other important notes from the recent SFPE conference

If NFPA 13 allows you to use an equivalent standard (ex. FM), you must use that standard in its entirety and not just cherry pick the one section of interest.

Although not part of the NFPA 13 changes, it was stressed at the SFPE conference that the Owner’s Information Certificate needs to be provided as part of a completed submission for every plan review.  The Owner’s Information Certificate was first added to NFPA 13 in 2002 and is often not used/submitted. A sample can be found in the Annex A in NFPA 13.

A water supply safety factor, such as 10 psi or 10%, is not required in NFPA 13 as a prescriptive requirement, but should be applied as a judgement review by the designer/reviewing engineer.

Risk Logic Can Analyze Your Sprinkler Systems

Please contact Risk Logic for us to conduct an engineering analysis of your automatic sprinkler systems to determine their compliance with the current edition of NFPA 13.

Special thanks to John Denhardt from the American Fire Sprinkler Association who presented at the SFPE Annual Conference as well as the National Fire Sprinkler Association Tech Notes dated 7/23/24.