The 2025 edition of NFPA 13D: Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes introduces a noticeable shift in editorial style and structure. While the technical intent of the standard remains consistent, the new edition places a stronger emphasis on concise, directive language and removes many of the explanatory discussions that were present in 2022.
This document outlines those differences section by section, highlighting both technical updates and editorial reductions, to provide a clear picture of how NFPA 13D has evolved from 2022 to 2025.
Chapter 1 – Administration
1.1 SCOPE
2025 adds one new applicability statement:
A one- or two-family dwelling used as a rental property can still appropriately be protected with an NFPA 13D system.
This clarification removes ambiguity around whether rental dwellings fall outside the intended scope of NFPA 13D, helping designers and AHJs apply the standard consistently.
1.4 Equivalency
2025 introduces a new A.1.4 statement clarifying:
Newer editions of NFPA 13D may be used in their entirety even if not yet adopted by a jurisdiction.
This addition reinforces the permissibility of designing to a newer edition when allowed by the AHJ, reducing uncertainty during plan review.
Minor Wording Change in 1.4 — “Shall” instead of “is intended to”.
| 2022 Edition | 2025 Edition |
|---|---|
| “Nothing in this standard is intended to prevent…” | “Nothing in this standard shall prevent…” |
The replacement of advisory phrasing with directive language strengthens enforceability and reduces interpretive ambiguity.
1.5 Units
2025 significantly expands Table 1.5.3 to include a broad set of SI conversion factors.
It is purely a data expansion for convenience and now includes:
- Length
- Area
- Volume
- Fluid capacity
- Flow (L/min)
- Pressure
- Discharge density
- K-factor
- Weight
- Density
- Temperature
- Velocity
- Force (Newton)
- Stress
- Sheet-steel gauge
Chapter 2 – Referenced Publications
2.1 New Technology
Numerous Reference Updates (Edition Changes)
The 2025 edition updates nearly all referenced NFPA, ASME, ASTM, and AWS documents to more recent editions. Examples of major updates:
- NFPA 13 → updated from 2022 to 2025
- NFPA 70 → 2020 → 2023
- NFPA 72 → 2022 → 2025
- NFPA 220 → 2021 → 2024
- NFPA 750 → 2019 → 2023
Additional notes:
- Nearly all ASME fittings standards were updated 3–5 years forward.
- Most ASTM steel pipe, copper tube, and CPVC fitting standards were updated by 1–4 years.
New Referenced Standards Added in 2025
Added in 2025:
- ASTM SI 10 – Metric practice standard
- NFPA 24 (2025) – Private fire service mains
- NFPA 13 (2025) – Added as extract reference in §2.4
Chapter 3 – Definitions
3.1 General
No technical definition changes. Chapter 3 in 2025 is reorganized for clarity and stripped of explanatory handbook material, but the rules governing definitions remain identical to the 2022 edition.
3.3 General Definitions
3.3.1 – Bathroom
Bathroom definition was updated to focus on “lavatory dedicated to personal hygiene, or a water closet, or bathing capability.”
| 2022 Edition | 2025 Edition |
|---|---|
| “room/compartment with lavatory (sink), toilet, or bathing capability” | “room/compartment dedicated to personal hygiene, containing a toilet, sink, or bathing capability.” |
3.3.2 – NEW in 2025: Ceiling Pocket
Added in 2025. Not present in 2022.
Definition (2025)
Architectural feature where a portion of ceiling is at a higher elevation, bounded by the surrounding lower ceiling.
Annex Clarifications
- Ceiling pocket rules do not apply to beam channels.
- Pockets can be “protected” or “unprotected.”
- If the upper surface is within vertical distance limits from the sprinkler, it’s treated as a protected pocket.
3.3.11 — Shadow Area
Similar definition but removes “dry” and expands obstruction examples (“other obstruction”).
| 2022 Edition | 2025 Edition |
|---|---|
| “The dry floor area within the protection area of a sprinkler created by the portion of sprinkler discharge that is blocked by a wall or partition.” | “The floor area within the protection area of a sprinkler created by the portion of sprinkler discharge that is blocked by a wall, partition, or other obstruction. [13, 2025]” |
3.3.13 Sprinkler Systems — General
Minor wording updates in some definitions 3.3.13.2 (Dry Pipe Sprinkler System) and 3.3.13.8 (Sprinkler System).
3.3.13.2 Expands allowable pressurized gas types
| 2022 Edition | 2025 Edition |
|---|---|
| “air or nitrogen” | “air, nitrogen, or other approved gas” |
3.3.13.2 3.3.13.8 Minor re-ordering for clarity
2025 rewrites sentence structure, also adds “waterflow alarm (where required).”
| 2022 Edition | 2025 Edition |
|---|---|
| “A system that consists of an integrated network of piping designed in accordance with fire protection engineering standards that includes a water supply source, a water control valve, and a drain. The portion of the sprinkler system above ground is a network of specifically sized or hydraulically designed piping installed in a building, structure, or area, generally overhead, and to which sprinklers are attached in a systematic pattern. The system is commonly activated by heat from a fire and discharges water over the fire area.” | “A system that is commonly activated by heat from a fire and discharges water over the fire area, that consists of an integrated network of piping designed in accordance with fire protection engineering standards, and that includes a supply source, a water control valve, a waterflow alarm (where required), and a drain. The portion of the sprinkler system above ground is a network of specifically sized or hydraulically designed piping installed in a building, structure, or area, generally overhead, and to which sprinklers are attached in a systematic pattern.” |
3.3.15 Valve
3.3.15.2 Control Valve is one of the few meaningful changes. It has a broader scope as it is NOT limited only to “indicating” valves and it is NOT limited only to sprinkler systems (now all water-based fire protection)
| 2022 Edition | 2025 Edition |
|---|---|
| “An indicating valve employed to control (shut) a supply of water to a sprinkler system.” | “A valve capable of stopping the flow of water to water-based fire protection systems and devices.” |
Chapter 6 – Water Supply
6.5 Common Supply Pipes
2025 edition includes a new, concise A.6.5.2 which clarifies that the required 5 gpm domestic allowance for common supply pipes is per connection.
Chapter 7 – Installation
The single technical enhancement is the new allowance in 7.2.2.1, formally permitting drain piping to terminate directly at the drain valve with an optional temporary hose—reflecting common field practice rather than introducing a new mandate.
7.2 Drains and Test Connections
Update appears in 2025 with the addition of 7.2.2.1 and A.7.2.2.1, which clarifies that the drain piping is permitted to terminate right at the drain valve itself, optionally using a temporary hose for discharge.
7.5 Sprinklers
7.5.3 – Sprinklers permitted into unheated, non-living spaces
2022 Edition: Allowed “listed residential or quick-response standard spray dry pendent or dry sidewall sprinklers” to be extended into unheated areas (phrase-based).
2025 Edition: Rewritten as an explicit enumerated list of permitted types:
- Residential dry pendent
- Residential dry sidewall
- Quick-response standard spray dry pendent
- Quick-response standard spray dry sidewall
7.5.6 – Temperature Ratings
Table 7.5.6.3 minor change:
| 2022 Edition | 2025 Edition |
|---|---|
| Includes “Light fixture” rows with watt ranges (0–250 W, 250–499 W) and required clearances. | The light-fixture row is changed to read “Light fixture except LED” and retains the same distance values for the watt ranges. |
Chapter 8 – Sprinkler Position and Location
8.1.1 Sloped Ceilings – General
Enhanced Content removed. Added 8.1.1.4. Residential Sidewall Sprinklers Under Sloped Ceilings:
2022 Definition:
- NO equivalent section. The standard had no dedicated rule for how sidewall sprinklers must be installed under sloped ceilings.
2025 Definition:
- New section establishing two acceptable installation methods when slope exceeds 2 in 12:
- At high point, discharging down the slope (Fig. 8.1.1.4(a))
- On slopes ≤ 8 in 12 with deflector parallel to slope, discharging across the slope (Fig. 8.1.1.4(b))
The 2025 edition fills a long-standing gap in NFPA 13D by finally outlining how sidewall sprinklers must be oriented under sloping ceilings.
8.2.5 Obstructions to residential sprinklers (general / annex material)
- Annex/intro material: Largely the same explanatory material about intent and test series — very similar wording, but:
- 2022 annex references laboratory test standard UL 1626 (and mentions UL-style test protocol).
- 2025 annex replaces that reference with CAN/ULC 199.
- Version 2025 is more specific regarding cabinets. Instead of using the general term of cabinets it now specifies rules for “Wall Cabinets”.
- 2022: 8.2.5.5 Soffits and Cabinets.
- 2025: 2.5.5 Soffits and Wall Cabinets.
8.3.3 Closets, Linen Closets, Pantries
2022 Edition: Sprinklers shall not be required in clothes closets, linen closets, and pantries that meet all of the following conditions:
- Area ≤ 24 ft²
- Walls/ceiling are surfaced with noncombustible or limited-combustible materials.
2025 Edition: Sprinklers shall not be required in clothes closets, linen closets, or pantries with or without doors that meet all of the following conditions:
- Area ≤ 24 ft² (same)
- Noncombustible or limited-combustible surfaces (same)
- NEW REQUIREMENT:
- “The closets without doors meet the definition of a compartment (3.3.3).”
8.3.5 Fuel Fired Equipment
2025 Added:
- 8.3.5.1.2
- 2022: Where fuel-fired equipment is located beneath an occupied area of the dwelling unit, at least one quick-response intermediate temperature sprinkler shall be installed above the equipment.
- 2025: Where fuel-fired equipment is located within or beneath an occupied area of the dwelling unit, at least one quick-response or residential intermediate temperature sprinkler shall be installed above the equipment.
- 8.3.5.1.3 – Where the installation of a sprinkler is required by 8.3.5.1.2, the sprinkler shall be positioned so that the footprint of the fuel-fired equipment is within the calculated coverage area of the sprinkler.
- 8.3.5.1.4 – Where fuel-fired equipment is installed within a concealed space and a portion of the fuel-fired equipment is exposed to the dwelling unit, sprinkler protection shall not be required within the concealed space.
- 8.3.5.1.5 – Where a chimney or flue from fuel-fired equipment passes through a concealed space, sprinkler protection shall not be required in the concealed space.
Chapter 9 – Protection from Freezing
9.2 Antifreeze Systems
Figure 9.2.3.2.1 has been updated.
| 2022 Edition | 2025 Edition |
|---|---|
 |  |
Chapter 10 – Discharge and Hydraulic Calculations
10.2 Pipe Sizing
The 2025 edition provides two new calculation sheets.
General Pipe Sizing Method:
General Pipe Sizing Method Calculation Sheet – Elevated Tank, Booster Pump, Pump Tank Supply:
10.4.9 Alternative Method to Hydraulic Calculations (Prescriptive Method)
The 2025 edition provides text that is now clearer and concise by removing the enhanced content. A “Prescriptive Pipe Sizing Method Worksheet” was added.
