International Fire Code 2021 vs 2024

Synthesis of Key Changes — Chapters 5, 9, and Appendix B

Purpose of this Synthesis

This document provides a section-by-section comparison of the 2021 and 2024 editions of the International Fire Code (IFC), focused on Chapter 5 (Fire Service Features), Chapter 9 (Fire Protection and Life Safety Systems), and Appendix B (Fire-Flow Requirements for Buildings). The 2024 update is a substantial revision: while the framework of each chapter is preserved, the new edition introduces a major terminology shift in emergency responder communications, an extensive new lithium-ion and lithium metal battery framework throughout sprinkler and detection requirements, a restructured carbon monoxide detection program, and tightened signage, supervision, and acceptance-test requirements.

The synthesis below summarizes the most impactful changes a designer, installer, plan reviewer, or AHJ should be aware of when transitioning from the 2021 edition to the 2024 edition. It is organized thematically rather than section-by-section so that the practical implications of the update can be quickly understood. Detailed clause-level changes follow this synthesis in the body of the document.

Why this update matters for state code adoptions. The IFC is the model code from which most state fire codes are derived. The California Fire Code 2025 is based upon the 2024 edition of the IFC, and many other state-adopted fire codes are likewise based upon this model code. Understanding the 2021-to-2024 IFC delta is therefore foundational for understanding the corresponding state-code revisions: most of the technical changes described here will appear in California and similar state code editions, although individual jurisdictions may amend, defer, or supplement specific provisions. Designers and AHJs working in jurisdictions that adopt either the IFC directly or a state code derived from it should treat this synthesis as a roadmap to changes they will encounter in their day-to-day practice.

High-Level Themes of the 2024 Revision

Five overarching themes characterize the 2024 update. Most clause-level edits trace back to one of them.

1. From “radio coverage” to “communications enhancement.” Section 510 has been comprehensively rewritten and renamed from “Emergency Responder Communication Coverage” to “Emergency Responder Communications Enhancement Systems,” introducing the acronym ERCES. The shift is more than terminology: the design framework moves from prescriptive minimum signal thresholds (the 2021 edition’s hard –95 dBm requirement) to a technology-neutral performance framework based on Delivered Audio Quality (DAQ ≥ 3.0), Bit Error Rate (BER), or Signal-to-Interference-plus-Noise Ratio (SINR), accommodating narrowband analog, digital, and wideband LTE signals. Inbound/outbound terminology becomes downlink/uplink. Frequency license holders are given formal standing in design, approval, and installation. The referenced standard is updated from NFPA 1221 to the dedicated NFPA 1225.
2. A comprehensive lithium-ion and lithium metal battery framework. The 2024 edition introduces lithium battery requirements throughout Chapter 9 in a coordinated way. New Section 903.2.2.2 requires sprinkler protection in any Group B fire area used for the research, development, or testing of lithium-ion or lithium metal batteries. New triggers in 903.2.4 (Group F-1 manufacturing of batteries or of vehicles, ESS, or equipment containing them), 903.2.7.3 (Group M storage), 903.2.9 and 903.2.9.1 (Group S-1 fire areas exceeding 500 ft² used for storing lithium-powered vehicles, including in repair garages) extend the requirement across multiple occupancy types. New Section 903.3.1.1.3 requires that sprinkler designs for areas containing lithium-ion or lithium metal batteries be based on a series of fire tests conducted or witnessed by an approved testing laboratory. A new lithium battery storage entry is added to the Section 903.2.11.6 table. The energy storage system reference (Section 1207) is also tied into the telecommunications-building exception in 903.2.
3. A restructured Section 915 carbon monoxide detection program. Section 915 has been substantially rewritten. The trigger framework in 915.1.1 collapses from six scenario-specific subsections to four plain-language items (CO source, CO-producing forced-air furnace, attached private garages, and — new in 2024 — buildings where a CO-producing vehicle is used within the building). The location framework in 915.2 retains the three traditional locations (dwelling units, sleeping units, Group E classrooms) and adds three new ones (forced-air furnace served spaces, private garage adjacencies, and all other occupancies). New Section 915.3 establishes a clean hierarchy: where a fire alarm system is required, CO detection must connect to it per NFPA 72; where one is not required, four alternative arrangements are permitted. The reference standard is updated from NFPA 720 (now withdrawn) to NFPA 72 throughout, and a new interconnection requirement (915.4.4) and occupant notification requirement (915.5.4) are added.
4. Tightened sprinkler supervision, alarm, and signage requirements. Section 903.4 has been restructured into a clean hierarchy of supervision (903.4.1), monitoring (903.4.2), and alarms (903.4.3). The exterior alarm device must now be both audible and visual (the 2021 edition required only audible). Where a waterflow switch is electrically supervised, the waterflow alarm devices must be powered by a fire alarm control unit or, where provided, the fire alarm system. The high-rise floor control valve requirement migrates from Section 903.4.3 to Section 903.3.9. Section 912.5 (FDC signage) expands from a single requirement into four prescriptive subsections covering lettering, multiple buildings, multiple or combined systems, and pressure indication.
5. NFPA 13R height expansion for Group R-2. Section 903.3.1.2 introduces a meaningful expansion of where NFPA 13R may be used. For occupancies other than Group R-2, the existing 30 ft (above the lowest level of fire department vehicle access) limit is preserved. For Group R-2 occupancies, however, the trigger becomes a roof assembly less than 45 ft above that same datum, with a specific geometric measurement method (to the eave of the highest pitched roof, the intersection of the highest roof to the exterior wall, or the top of the highest parapet, whichever yields the greatest distance). This change has significant implications for mid-rise residential design and may affect when NFPA 13 versus NFPA 13R applies on a given project.

Most Impactful Changes by Practitioner Role

For Designers

Lithium-ion and lithium metal battery sprinkler triggers (multiple sections in 903.2). Designers should screen every project against the new battery-specific triggers: Group B research/development/testing areas (903.2.2.2), Group F-1 battery manufacturing or manufacturing of vehicles/ESS/equipment containing them (903.2.4 items 4 and 5), Group M storage rooms (903.2.7.3), and Group S-1 storage of lithium-powered vehicles where the fire area exceeds 500 ft² (903.2.9 and 903.2.9.1). Where any such area requires sprinkler protection, the design must be based on fire-test data per the new 903.3.1.1.3.

NFPA 13R height limit expanded for Group R-2 (903.3.1.2). Group R-2 buildings may now use NFPA 13R where the roof assembly is less than 45 ft above the lowest fire department vehicle access level, measured to the eave, roof-to-wall intersection, or top of the highest parapet (whichever yields the greatest distance). Other occupancies remain limited to the previous 30 ft floor-of-highest-story rule.

ERCES design framework is now performance-based (510.4.1 and 510.4.2). Replace the 2021 –95 dBm absolute threshold with the 2024 framework based on DAQ ≥ 3.0, BER, or SINR — selectable based on whether the signal is narrowband analog, digital, or wideband LTE. Inbound/outbound becomes downlink/uplink. Coordination with the frequency license holder(s) is now required at design, permit, installation, and acceptance.

Sprinkler riser strategy in tall buildings (914.3.1.1). A clean two-tier rule replaces the 2021 single-rule structure: in buildings 420 ft or less, a single standpipe or sprinkler express riser per vertical water supply zone is sufficient; in buildings over 420 ft, at least two such risers per zone are required, with sprinklers on alternating floors and adjacent floors not supplied from the same riser.

Standpipes are no longer required in Group R-2 townhouses (905.3 Exception 1). A new exception complements the existing Group R-3 exception. Designers should confirm whether their state code adoption preserves this exception.

Class I standpipe hose-connection scope expanded to exterior exit stairways (905.4 Item 1). Hose connections are now required in every required interior exit stairway or exterior exit stairway for each story above and below grade plane.

Smoke control: smokeproof enclosure definition tightened (909.20). The “ventilated vestibule” option is removed from the smokeproof-enclosure definition, leaving only the open exterior balcony as the qualifying element. The mechanical ventilation alternative at 909.20.4 is also removed entirely. Designers relying on ventilated vestibules under the 2021 edition should plan to redesign these features under the 2024 edition.

Audible signal frequency requirement expanded to Group I-1 (907.5.2.1.3). The 520-Hz low-frequency signal requirement now applies to Group R-1, R-2, and I-1 sleeping rooms. Group I-1 facilities (assisted living and similar) should be screened for compliance.

Mass notification risk analysis required for large Group E projects (917.2). Prior to construction of a new building containing a Group E occupancy that requires a fire alarm system and has an occupant load of 500 or more, a mass notification risk analysis per NFPA 72 must be conducted; where the analysis identifies a need, an approved mass notification system must be provided.

Hybrid fire-extinguishing systems formally recognized (904.12). New Section 904.12 requires hybrid fire-extinguishing systems to be designed, installed, maintained, and periodically inspected and tested in accordance with NFPA 770, with records to be maintained.

For Installers and Contractors

FDC signage now has four explicit subsections (912.5). Lettering, multiple-building, combined-system, and pressure-indication requirements are now spelled out in 912.5.1–912.5.4. The required text options are expanded to explicitly include “STANDPIPE AND AUTOSPKR” and “AUTOSPKR AND STANDPIPE” as named alternatives. For manual standpipe systems, the sign must indicate that the system is manual and whether it is wet or dry. Pressure indication is required unless the required pressure is 150 psi or less.

Exterior alarm devices must now be audible and visual (903.4.3). A waterflow alarm device on the exterior of the building must now be audible and visually indicating, where in 2021 only audibility was required. Where a waterflow switch is electrically supervised per 903.4.1, the waterflow alarm devices must be powered by a fire alarm control unit or, where provided, the fire alarm system.

Backflow preventer test valves on limited-area sprinkler systems (903.4.1). Test valves must be locked in the open position; in occupancies required to have a fire alarm system, they must be electrically supervised by a tamper switch installed per NFPA 72 and separately annunciated.

Smoke alarm replacement criteria expanded (907.10.1). Replacement is now required when any one of the following applies: failure of an operability test; 10 years from the date of manufacture (or earlier per manufacturer’s instructions); end-of-life signal sounded; or date of manufacture cannot be determined. Replacement smoke alarms are not required to include the 520-Hz signal unless the units being replaced included it.

Fire damper testing referenced to NFPA 80 and 105 (909.18.3). Damper function testing in installed condition must now be performed in accordance with NFPA 80 and NFPA 105. The Section 901.6.1 inspection, testing, and maintenance table also adds NFPA 80 (fire dampers) and NFPA 105 (smoke dampers) entries that did not exist in 2021.

Type 4 cabinet language simplified (510.4.2.4 Item 1). “NEMA 4-type waterproof cabinet” becomes “NEMA Type 4 cabinet.”

Signal booster requirements expanded (510.4.2.4 Item 5). Built-in oscillation detection and control circuitry must reduce gain and maintain operation. When oscillation is detected, a supervisory signal must be transmitted; in the event of uncorrectable oscillation, the system is permitted to shut down.

For Plan Reviewers and AHJs

New ERCES operational permit (510.3.2). The 2024 edition splits the single 2021 permit into a construction permit (510.3.1, now referencing 105.6.5) and a new operational permit (510.3.2) that may be required at the discretion of the fire code official for the operation of an in-building ERCES.

ERCES acceptance test flexibility (510.5.4). The 2024 edition adds “or by a method approved by the fire code official” after the standard test procedure, giving jurisdictions explicit flexibility to accept alternative testing approaches.

New Section 510.4.2.9 — Noise interference. Where a signal booster is used, signal booster type(s) and the uplink signal and noise levels must be coordinated with and approved by all frequency license holders that may be adversely impacted by transmitted noise.

Single supervisory input now permitted for ERCES (510.4.2.5.1). Where approved, a single supervisory input to the fire alarm system to monitor all ERCES supervisory signals is permitted.

Group A-5 outdoor bleacher exceptions for manual fire alarm boxes (907.2.1 Exceptions 2 and 3). Two new exceptions exempt manual fire alarm boxes and the associated occupant notification or EVACS system for Group A-5 outdoor bleacher-type seating with occupant loads in specified ranges, subject to public-address-with-standby-power, enclosed-space-area, separation, and means-of-egress conditions.

Special amusement areas: detection now in Section 914.7 (907.2.12). The 2021 special-amusement detection content in 907.2.12.1–.3 has been moved into Section 914.7. Two new parent-level exceptions are added: open-air amusement areas without walls or roof, and puzzle rooms with unlocked, readily identifiable, always-available means of egress.

Stages: standpipe requirement removed; sprinkler exception added (905.3.4 removed; 914.6). The 2021 dedicated stage standpipe requirement (905.3.4 with hose-and-cabinet provisions in 905.3.4.1) is removed entirely from the 2024 edition. Section 914.6.2 (stage standpipe) is also removed; only 914.6.1 (automatic sprinkler system) is retained, and a new fourth exception permits sprinklers to be omitted under catwalks and galleries where permitted under Section 903.3.1.1.

Group A-1/A-2 hose connection locations simplified (905.5.1). The 2021 requirement for hose connections on each side of any stage, on each side of the rear of the auditorium, on each side of the balcony, and on each tier of dressing rooms is reduced in 2024 to: each side of the rear of the auditorium and each side of the balcony only.

Carbon monoxide reference standard now NFPA 72 (915.6). NFPA 720 has been withdrawn and is replaced by NFPA 72 throughout Section 915. Reviewers should not accept submittals citing NFPA 720 under the 2024 edition.

Carbon monoxide detection scope expanded to vehicles used inside buildings (915.1.1 Item 4). A new trigger applies to buildings that have a CO-producing vehicle used within the building (e.g., warehouses with internal-combustion forklifts). This is a meaningful scope expansion compared to 2021.

CO occupant notification (915.5.4) and duct-detector clarification (915.5.5). Activation of a CO detector must annunciate at the control unit and initiate audible and visible alarm notification throughout the building (with a defined exception for zone-limited notification). CO detectors placed in environmental air ducts or plenums cannot be used as a substitute for the required protection in Section 915.

Appendix B — Fire-Flow Requirements

Section B104 consolidated. The 2021 edition’s separate B104.1 (general) and B104.3 (Type IA and IB construction) are consolidated into a single B104.1 in 2024. The Type IA/IB rule and the open parking garage rule are now presented as Exceptions 1 and 2 within B104.1, rather than as a standalone subsection.

Referenced standards rolled forward (Section B106). IBC, IRC, and IWUIC are all updated from their 2021 to their 2024 editions.

Notable New Sections in 2024

Section 510.3.2 — ERCES operational permit. New permit category at the discretion of the fire code official for the operation of an in-building ERCES.

Section 510.4.2.5.1 — Single supervisory input. Permits a single supervisory input to the fire alarm system to monitor all ERCES supervisory signals where approved.

Section 510.4.2.9 — Noise interference. New requirement for coordination with frequency license holders to manage uplink noise effects.

Section 510.5.2.1 — Active RF-emitting devices. New requirements for FCC certification, simultaneous compatibility, and written authorization from frequency license holders prior to initial activation.

Section 903.2.2.2 — Group B lithium battery research and development. Sprinkler protection required throughout fire areas used for the research, development, or testing of lithium-ion or lithium metal batteries.

Section 903.3.1.1.3 — Lithium-ion or lithium metal battery sprinkler design. Design must be based on a series of fire tests conducted or witnessed and reported by an approved testing laboratory addressing the range of variables associated with the intended hazard arrangement.

Section 904.12 — Hybrid fire-extinguishing systems. Recognized as a system type subject to NFPA 770 design, installation, maintenance, inspection, and testing.

Section 914.7 Exceptions — Open-air and puzzle-room special amusement areas. Two new exceptions to the special amusement area requirements at the parent level.

Section 915.2.4, 915.2.5, 915.2.6 — New CO detection location categories. Forced-air-furnace served spaces, private garage adjacencies, and “all other occupancies” with CO sources are now explicit location categories.

Section 915.3.2, 915.3.3, 915.3.4 — New CO system selection hierarchy. Buildings required to have a fire alarm system must connect CO detection to it; buildings without a fire alarm system have four enumerated alternatives.

Section 917.2 — Group E mass notification risk analysis. New requirement for a risk analysis prior to construction of new Group E buildings with fire alarm systems and occupant loads of 500 or more.

Terminology and Editorial Changes Worth Noting

“Radio coverage” → “communications enhancement coverage” throughout Chapter 5 (and Section 510 retitled).

“Two-way emergency responder communication coverage system” → “emergency responder communications enhancement system” (ERCES) throughout Section 510.

“Inbound” / “outbound” → “downlink” / “uplink” in signal-strength provisions (510.4.1 and 510.4.2).

NFPA 1221 → NFPA 1225 in ERCES system design and installation references (510.4.2 and 510.5).

NFPA 720 → NFPA 72 throughout Section 915 (CO detection).

“Readily accessible” → “ready access” in Sections 504.1 and 509.2.

“Landscaped roofs” → “vegetative roof, includes a landscaped roof area” in Section 504.3, with a similar pairing in Section 905.3.7 (now titled “Vegetative roofs and landscaped roofs”).

“Group H-5 Sprinkler Design Criteria” → “Group H-5 Automatic Sprinkler System Design Criteria” (903.2.5.2 table).

“Testing and maintenance” → “Inspection, testing and maintenance” (Section 903.5 title).

“Fire Protection System Maintenance Standards” → “Fire Protection System Inspection, Testing and Maintenance Standards” (Table 901.6.1).

“Special amusement buildings” → “Special amusement areas” (907.2.12 / 914.7 title).

“Sprinkler risers” → “standpipe or sprinkler express risers” in tall-building provisions (914.3.1.1.3).

“Fully sprinklered buildings” → “buildings equipped throughout with automatic sprinkler systems” (909.6.1).

“Patrons” → “occupants” in special amusement area alarm activation (914.7.2.2).

“Fuel-burning appliance” → “CO-source” / “CO-producing” throughout Section 915.

How to Read the Detailed Comparison That Follows

The remainder of this document is organized in IFC section order across Chapter 5, Chapter 9, and Appendix B. For each section that changed between the 2021 and 2024 editions, the entry shows the relevant 2021 text, the 2024 text, and where applicable a brief discussion of the practical change. New sections are flagged “(New in 2024)”; deleted clauses are noted as removed; and clauses that were renumbered or restructured are tagged with their 2021 origin where helpful.

Designers should pay particular attention to Section 510 (ERCES design framework), Section 903 (lithium battery sprinkler triggers and the expanded NFPA 13R height for Group R-2), Section 909 (smoke control and smokeproof enclosure changes), and Section 914 (riser strategy in tall buildings, and special amusement areas). Installers and contractors should focus on Section 912 (FDC signage), Section 903.4 (supervision, monitoring, and alarms), and Section 907 (smoke alarm replacement criteria). Plan reviewers and AHJs will want to review Section 915 in its entirety, the new permit and acceptance-test flexibility in Section 510, and the new Group A-5 outdoor bleacher exceptions in Section 907.

Practitioners working in California should additionally note that the California Fire Code 2025 (the 2022 California edition) is based upon the 2024 (and 2021) editions of the IFC; many other state-adopted fire codes are likewise based upon this model code. Most of the changes described in this synthesis will appear in the corresponding state code editions, but individual jurisdictions may amend specific provisions. The state-code adopting amendments should always be consulted alongside the model code language.

This synthesis is intended to orient the reader; it is not a substitute for reading the underlying clause text or the official 2024 International Fire Code. Where a clause-level decision turns on subtle wording, the detailed comparison in the sections that follow should be consulted, and the official code should be the controlling reference.

Chapter 5 Comparison

Chapter Introduction

The user note was updated to replace “radio coverage” with “communications enhancement coverage,” reflecting the broader terminology shift that runs throughout the entire chapter.

Section 504 — Access to Building Openings and Roofs

Two minor wording changes here:

504.1 Required Access

504.1 Required Access: “maintained readily accessible for emergency access” was changed to “maintained with ready access for emergency access.”

• 2021: “Exterior doors and openings required by this code or the International Building Code shall be maintained readily accessible for emergency access by the fire department. An approved access walkway leading from fire apparatus access roads to exterior openings shall be provided where required by the fire code official.”
• 2024: “Exterior doors and openings required by this code or the International Building Code shall be maintained with ready access for emergency access by the fire department. An approved access walkway leading from fire apparatus access roads to exterior openings shall be provided where required by the fire code official.”

504.3 Stairway Access to Roof

504.3 Stairway Access to Roof: The stairway-to-roof requirement was updated to replace “landscaped roofs” with “vegetative roof, includes a landscaped roof area.”

• 2021: “New buildings four or more stories above grade plane, except those with a roof slope greater than 4 units vertical in 12 units horizontal (33.3-percent slope), shall be provided with a stairway to the roof. Stairway access to the roof shall be in accordance with Section 1011.12. Such stairway shall be marked at street and floor levels with a sign indicating that the stairway continues to the roof. Where the roof is a vegetative roof, includes a landscaped roof area, or is used or for other purposes, stairways shall be provided as required for such occupancy classification.”
• 2024: “New buildings four or more stories above grade plane, except those with a roof slope greater than 4 units vertical in 12 units horizontal (33.3-percent slope), shall be provided with a stairway to the roof. Stairway access to the roof shall be in accordance with Section 1011.12. Such stairway shall be marked at street and floor levels with a sign indicating that the stairway continues to the roof. Where the roof is a vegetative roof, includes a landscaped roof area, or is used or for other purposes, stairways shall be provided as required for such occupancy classification.”

Section 508 — Fire Command Center

508.1.6 Required Features: Item 18 (elevator emergency/standby power selector switches) previously only applied “where emergency or standby power is provided.” The 2024 edition removes that conditional phrase and instead requires compliance “in accordance with ASME A17.1/CSA B44,” tying the requirement to a specific standard rather than leaving it conditional.

• 2021: “Elevator emergency or standby power selector switch(es), where emergency or standby power is provided.”
• 2024: “Elevator emergency or standby power selector switch(es) in accordance with ASME A17.1/CSA B44.”

Section 509 — Fire Protection and Utility Equipment Identification and Access

509.2 Equipment Access

509.2 Equipment Access: One minor wording change: Section 509.2 changed “readily accessible” to “ready access,” consistent with the same change made in 504.1.

• 2021: “Approved access shall be provided and maintained for all fire protection system equipment to permit immediate safe operation and maintenance of such equipment. Storage, trash and other materials or objects shall not be placed or kept in such a manner that would prevent such equipment from being readily accessible.”
• 2024: “Approved access shall be provided and maintained for all fire protection system equipment to permit immediate safe operation and maintenance of such equipment. Storage, trash and other materials or objects shall not be placed or kept in such a manner that would prevent such equipment from ready access.”

Section 510 — Emergency Responder Communications Enhancement Systems

The section was renamed from “Emergency Responder Communication Coverage” to “Emergency Responder Communications Enhancement Systems.” Throughout the entire section, all references to “two-way emergency responder communication coverage system” were replaced with “emergency responder communications enhancement system,” introducing the acronym ERCES. This reflects a shift in how the system is conceptualized, from passive coverage to active enhancement.

Section 510.1 — Emergency responder communications enhancement systems in new buildings.

The 2024 version adds that the type of ERCES shall be determined by the fire code official and the frequency license holder(s); the latter being a new party given formal standing in the process.

The term “radio” was replaced in multiple places with “communications”. A fourth exception was also added: “One-story buildings not exceeding 12,000 square feet (1115 m2) with no below-ground area(s).” The 2021 version had only three exceptions.

Section 510.3 — Permits

The 2021 edition had a single permit section covering only the construction permit. The 2024 edition restructures this into two subsections:

• 510.3.1 Permit Required: retains the existing construction permit requirement (now referencing Section 105.6.5 instead of 105.6.4).
• 510.3.2 Operational Permit (New in 2024): “Where required by the fire code official, an operational permit shall be issued for the operation of an in-building emergency responder communications enhancement system.”

Section 510.4.1.1 and 510.4.1.2 — Signal strength requirements

The inbound/outbound signal terminology was updated to downlink/uplink. More substantively, the 2021 edition specified a hard minimum inbound signal threshold of -95 dBm. The 2024 edition removes this absolute value entirely, replacing it with a technology-neutral framework that accepts narrowband analog, digital, or wideband LTE signals, and allows compliance via DAQ ≥ 3.0, bit error rate (BER), or SINR.

• 510.4.1 Minimum signal strength into the building (2024): “The minimum downlink signal strength shall be sufficient to provide usable voice communications throughout the coverage area as specified by the fire code official. The downlink signal level shall be sufficient to provide not less than a Delivered Audio Quality (DAQ) of 3.0 throughout the coverage area using either narrowband analog, digital or wideband LTE signals or an equivalent bit error rate (BER), or signal-to-interference-plus-noise ratio (SINR) applicable to the technology for either analog or digital signals.”
• 510.4.2 Minimum signal strength out of the building (2024): “The minimum uplink signal strength shall be sufficient to provide usable voice communications throughout the coverage area as specified by the fire code official. The uplink signal level shall be sufficient to provide not less than a delivered audio quality (DAQ) of 3.0 using either narrowband analog, digital or wideband LTE digital signals or an equivalent bit error rate (BER), or an equivalent SINR applicable to the technology for either analog or digital signals.”

Section 510.4.2 — System design standard

Both subsections 510.4.2 and 510.5 now reference NFPA 1225 instead of NFPA 1221. NFPA 1225 is a newer dedicated standard specifically for Emergency Responder Communications Enhancement Systems.

• Section 510.4.2.4 — Signal booster requirements (items updated)
  • Item 1 simplified “NEMA 4-type waterproof cabinet” to “NEMA Type 4 cabinet.”
  • Item 5 was significantly expanded. The 2021 version simply required built-in oscillation detection and control circuitry. The 2024 version adds “…and control circuitry to reduce gain and maintain operation. When a signal booster detects oscillation, a supervisory signal shall be transmitted. In the event of uncorrectable oscillation, the system shall be permitted to shut down.”
  • Item 6 now requires coordination and approval from both the fire code official and the frequency license holder(s): “The installation of amplification systems or systems that operate on or provide the means to cause interference on any in-building emergency responder communications enhancement network shall be coordinated and approved by the fire code official and the frequency license holder(s).”
• Section 510.4.2.5 — System monitoring
  • Item 3 changed from “Malfunction of the donor antenna(s)” to “Signal source malfunction,” broadening the trigger beyond just the donor antenna to any signal source.
  • Item 5 reworded the low-battery threshold from “Low-battery capacity at 70-percent reduction of operating capacity” to “Low-battery capacity at 70 percent of the 12-hour operating capacity has been depleted.”
  • 510.4.2.5.1 Single supervisory input (New in 2024): “Where approved, a single supervisory input to the fire alarm system to monitor all system supervisory signals shall be permitted.”
• Sections 510.4.2.8 — Near-far effect (Completely rewritten)
  • Section 510.4.2.8 was completely rewritten. The 2021 version was titled “Radio communication antenna density” and addressed the near-far effect by requiring sufficient antenna density. The 2024 version retitles it “Near-far effect” and takes a different approach: “Where a signal booster is required by the RF system designer, the dynamic range of the in-building emergency responder communications enhancement system shall be designed to minimize the effects of strong signal automatic gain control on weak signal uplink performance.”
• 510.4.2.9 — Noise interference (New in 2024)
  • Section 510.4.2.9 is entirely new, addressing noise interference. It says: “Where a signal booster is used, signal booster type(s) and the uplink signal and noise levels shall be coordinated with and approved by all frequency license holder(s) that may be adversely impacted by any transmitted noise resulting from the in-building emergency responder communications enhancement system. Systems shall be in compliance with all frequency licensing authority requirements.”

Section 510.5.2 — Approval prior to installation

Now requires prior coordination and approval from both the fire code official and the frequency license holder, whereas the 2021 version only required the fire code official.

• 510.5.2.1 — Active RF-emitting devices (New in 2024)
  • “Active RF-emitting devices shall meet the following requirements in addition to any other requirements determined by the fire code official or the frequency license holder(s):
    1. Active RF-emitting devices that have a transmitted power output sufficient to require certification of the frequency licensing authority shall have the certification of the radio frequency licensing authority prior to installation.
    2. All active RF-emitting devices shall be simultaneously compatible for their intended use, as required by the frequency licensing authority, the frequency license holder(s) and the fire code official, at the time of installation.
    3. Written authorization shall be obtained from the frequency license holder(s) prior to the initial activation of any RF-emitting devices required to be certified by the frequency licensing authority.”

Section 510.5.4 — Acceptance test procedure

The 2024 edition adds the phrase “or by a method approved by the fire code official” after the standard test procedure, giving jurisdictions flexibility to accept alternative testing approaches.

ICC Chapter 9 (Sections 901–903) — 2021 vs 2024 Comparison

Section 901 — General

901.5 — Administration of installation acceptance testing (Section title change)

The section title was updated from “Installation acceptance testing” to “Administration of installation acceptance testing.”

TABLE 901.6.1 — FIRE PROTECTION SYSTEM INSPECTION, TESTING AND MAINTENANCE STANDARDS

The table title changed from “Fire Protection System Maintenance Standards” to “Fire Protection System Inspection, Testing and Maintenance Standards,” reflecting the full scope of the activity. Two new entries were added to the table that were absent in 2021:

• Fire dampers — NFPA 80
• Smoke dampers — NFPA 105

901.6.3 — Records

The 2021 version simply said records “shall be maintained.” The 2024 version adds “in accordance with Section 110.3,” tying the records requirement to a specific administrative section of the code rather than leaving it as a standalone obligation.

Section 903 — Automatic Sprinkler Systems

903.2 — Where required

• Exception: The telecommunications building exception was updated. The 2024 version adds a carve-out for batteries “not required to have an automatic sprinkler system by Section 1207 for energy storage systems,” meaning that battery rooms governed by the energy storage system provisions of Section 1207 are not automatically swept into this telecommunications exemption.

903.2.2 — Group B (New in 2024)

• In 2021, ambulatory care facilities appeared as a standalone section numbered 903.2.2 with no parent group designation. In 2024, the section is restructured under “Group B” as the parent, with ambulatory care moving to 903.2.2.1. A new subsection 903.2.2.2 is added requiring automatic sprinkler systems throughout any fire area in a Group B occupancy used for the research, development, or testing of lithium-ion or lithium metal batteries. This is entirely new — there was no equivalent in 2021.
  • 2021: Section titled Ambulatory Care Facilities.
  • 2024: Section retitled Group B, with two subsections:
    • 903.2.2.1 Ambulatory care facilities
    • 903.2.2.2 Laboratories involving research and development or testing (New in 2024): “An automatic sprinkler system shall be installed throughout the fire areas utilized for the research and development or testing of lithium-ion or lithium metal batteries.”

903.2.4 — Group F-1 (lithium battery manufacturing)

Two new triggering conditions were added to the Group F-1 sprinkler requirements:

• Item 4: “A Group F-1 occupancy used to manufacture lithium-ion or lithium metal batteries.”
• Item 5: “A Group F-1 occupancy used to manufacture vehicles, energy storage systems, or equipment containing lithium-ion or lithium metal batteries where the batteries are installed as part of the manufacturing process.”

903.2.5.2 — Group H-5 table title

• The table title was updated from “Group H-5 Sprinkler Design Criteria” to “Group H-5 Automatic Sprinkler System Design Criteria,” and the section text correspondingly changed “sprinkler system” to “automatic sprinkler system.”

903.2.7 Group M

• 903.2.7.3 — Lithium-ion or lithium metal battery storage
  • “An automatic sprinkler system shall be provided in a room or space within a Group M occupancy where required for the storage of lithium-ion or lithium metal batteries by Section 320 or Chapter 32.”

903.2.8 — Group R-4, Condition 2 removed as a standalone subsection

• In 2021, this section had four subsections: 903.2.8.1 (Group R-3), 903.2.8.2 (Group R-4, Condition 1), 903.2.8.3 (Group R-4, Condition 2), and 903.2.8.4 (Care facilities). In 2024, the Group R-4, Condition 2 subsection disappears as a standalone entry, and Care facilities moves up to 903.2.8.3. The NFPA 13R criteria for Group R-4, Condition 2 are effectively addressed through the revised 903.3.1.2 conditions (see below).

903.2.9 — Group S-1 (lithium-powered vehicle storage)

• Item 5 (New in 2024): “A Group S-1 fire area used for the storage of lithium-ion or lithium metal powered vehicles where the fire area exceeds 500 square feet.”

903.2.9.1 — Repair garages (lithium-powered vehicle storage)

• Item 5 (New in 2024): “A Group S-1 fire area used for the storage of lithium-ion or lithium metal powered vehicles where the fire area exceeds 500 square feet.”

903.2.11.6 — Table of additional required fire protection systems

• A new first entry was added to the table:
  • Section 320.2 — Lithium-ion and lithium metal battery storage
• Several other entries were renumbered or slightly retitled to reflect updates elsewhere in the code. The energy storage table references were also reordered.

903.3.1.1.1 — Exempt locations

• 2021 version had six exempt location items. The 2024 version has five. The first two items in 2021 were:
  • Item 1: A room where the application of water, or flame and water, constitutes a serious life or fire hazard.
  • Item 2: A room or space where sprinklers are considered undesirable because of the nature of the contents, where approved by the fire code official.
• Consolidated in 2024: “A room or space where sprinklers constitute a serious life or fire hazard because of the nature of the contents, where approved by the fire code official.”

903.3.1.1.3 — Lithium-Ion or lithium metal batteries. (New in 2024)

• “Where automatic sprinkler systems are required by this code for areas containing lithium-ion or lithium metal batteries, the design of the system shall be based on a series of fire tests. Such tests shall be conducted or witnessed and reported by an approved testing laboratory involving test scenarios that address the range of variables associated with the intended arrangement of the hazards to be protected.”

903.3.1.2 — NFPA 13R: Expanded height condition for Group R-2

• 2021: “The floor level of the highest story is 30 feet (9144 mm) or less above the lowest level of fire department vehicle access.”
• 2024:
  • “For other than Group R-2 occupancies, the floor level of the highest story is 30 feet (9144 mm) or less above the lowest level of fire department vehicle access.”
  • “For Group R-2 occupancies, the roof assembly is less than 45 feet (13 716 mm) above the lowest level of fire department vehicle access. The height of the roof assembly shall be determined by measuring the distance from the lowest required fire vehicle access road surface adjacent to the building to the eave of the highest pitched roof, the intersection of the highest roof to the exterior wall, or the top of the highest parapet, whichever yields the greatest distance.”

903.3.9 — High-rise building floor control valves. (relocated from 903.4.3)

• “Approved supervised indicating control valves shall be provided at the point of connection to the riser on each floor in high-rise buildings.”

903.4 — Supervision and alarms (major restructuring)

2021’s structure was:

• 903.4 (the main body) — Electronic supervision requirements with exceptions
• 903.4.1 — Monitoring (transmission to supervising station)
• 903.4.2 — Alarms (exterior audible device)
• 903.4.3 — Floor control valves for high-rise buildings

2024’s (Reorganized) structure became:

• 903.4 (the main body) — Introductory statement only, pointing to 903.4.1 through 903.4.3
• 903.4.1 — Electronic supervision (content moved from old 903.4 body, retitled)
• 903.4.2 — Monitoring (same content as old 903.4.1)
• 903.4.3 — Alarms (expanded from old 903.4.2, see below)
• Floor control valves moved entirely to new 903.3.9

903.4.1 in 2024 integrates the backflow prevention exception (2) more cleanly, now instead of being in 903.4.1 Monitoring exception, it is included directly: “Limited area sprinkler systems in accordance with Section 903.3.8, provided that backflow prevention device test valves located in limited area sprinkler system supply piping shall be locked in the open position unless supplying an occupancy required to be equipped with a fire alarm system, in which case the backflow preventer valves shall be electrically supervised by a tamper switch installed in accordance with NFPA 72 and separately annunciated.”

903.4.3 — Alarms

• The 2024 alarm requirements go further than 2021 in two respects. First, the exterior alarm device must now be both audible and visual, the 2021 version required only an audible device. Second, a new requirement was added: where a waterflow switch is required by Section 903.4.1 to be electrically supervised, the waterflow alarm devices must be powered by a fire alarm control unit or, where provided, a fire alarm system. The 2021 version had no such power source requirement. A new exception was also added exempting one- and two-family dwellings from the 903.4.3 requirements.

903.5 — Section title

The section title changed from “Testing and maintenance” to “Inspection, testing and maintenance,” adding inspection to the list.

Section 904 — Alternative Automatic Fire-Extinguishing Systems

904.12 — Hybrid fire-extinguishing systems (New in 2024)

• “Hybrid fire-extinguishing systems shall be designed, installed, maintained, periodically inspected and tested in accordance with NFPA 770. Records of inspection and testing shall be maintained.”

904.14.1 — Manual system operation

• Item 2 (New in 2024): “Where locating the manual actuation device between 10 feet (3048 mm) and 20 feet (6096 mm) from the cooking area is not feasible, the fire code official is permitted to accept a location at or near a means of egress from the cooking area, where the manual actuation device is unobstructed and in view from the means of egress.”

Section 905 — Standpipe Systems

905.3 — Required installations

• Exception 1 (New in 2024): Standpipe systems are not required in Group R-2 townhouses.
• Exception 2: Standpipe systems are not required in Group R-3 occupancies (carried over from 2021).

905.3.4 (2021) — Stages (Removed)

• The 2021 edition had a dedicated subsection 905.3.4 requiring Class III wet standpipe systems with 1½-inch and 2½-inch hose connections on each side of stages greater than 1,000 square feet, including a subsection 905.3.4.1 covering hose and cabinet requirements. Both of these subsections are entirely absent from the 2024 edition.

905.3.7 (2024) — Vegetative roofs and landscaped roofs.

• The former landscaped roofs section (905.3.8 in 2021) was renamed from “Landscaped roofs” to “Vegetative roofs and landscaped roofs” and updated accordingly, now requiring standpipe extension to the roof level for buildings with either vegetative roofs or landscaped roofs.

905.4 — Location of Class I standpipe hose connections

• Item 1 (expanded). The 2021 version required hose connections in every required interior exit stairway for each story above and below grade plane. The 2024 version extends this to “every required interior exit stairway or exterior exit stairway.”
• The exceptions to items 2 and 3 were also updated to reference “interior exit stairway or exterior exit stairway” hose connections rather than only interior ones.

905.5.1 — Groups A-1 and A-2 hose connection locations

• The 2021 version required hose connections on each side of any stage, on each side of the rear of the auditorium, on each side of the balcony, and on each tier of dressing rooms.
• The 2024 version significantly simplifies this to: on each side of the rear of the auditorium and on each side of the balcony only.

Section 906 — Portable Fire Extinguishers

Section 907 — Fire Alarm and Detection Systems

907.2.1 — Group A

• The 2021 version had a single exception allowing elimination of manual fire alarm boxes in fully sprinklered buildings with waterflow-activated notification. The 2024 version retains that exception and adds two entirely new ones, both addressing outdoor bleacher-type seating in Group A-5 occupancies:
  • Exception 2: “Manual fire alarm boxes and the associated occupant notification system or emergency voice/alarm communication system are not required for Group A-5 outdoor bleacher-type seating having an occupant load of greater than or equal to 300 and less than 15,000 occupants, provided that all of the following are met:”
    • 2.1: A public address system with standby power is provided.
    • 2.2: “Enclosed spaces attached to or within 5 feet (1524 mm) of the outdoor bleacher type seating compose, in the aggregate, a maximum of 10 percent of the overall area of the outdoor bleacher-type seating or 1,000 square feet (92.9 m2), whichever is less.”
    • 2.3: “Enclosed accessory spaces under or attached to the outdoor bleacher-type seating shall be separated from the bleacher-type seating in accordance with Section 1030.1.1.1.”
    • 2.4: “All means of egress from the bleacher-type seating are open to the outside.”
  • Exception 3: “Manual fire alarm boxes and the associated occupant notification system or emergency voice/alarm communication system are not required for temporary Group A-5 outdoor bleacher-type seating, provided that all of the following are met:”
    • 3.1: “There are no enclosed spaces under or attached to the outdoor bleacher-type seating.”
    • 3.2: “The bleacher-type seating is erected for a period of less than 180 days.”
    • 3.3: “Evacuation of the bleacher-type seating is included in an approved fire safety plan.”

907.2.2.2 — Laboratories involving research and development or testing. (New in 2024)

• “A fire alarm system activated by an air-sampling-type smoke detection system or a radiant-energy-sensing detection system shall be installed throughout the entire fire area utilized for the research and development or testing of lithium-ion or lithium metal batteries.”

907.2.4 Group F

907.2.4.1 — Manufacturing involving lithium-ion or lithium metal batteries

• “A fire alarm system activated by an air-sampling-type smoke detection system or a radiant-energy-sensing detection system shall be installed throughout the entire fire area where lithium-ion or lithium metal batteries are manufactured; and where the manufacturer of vehicles, energy storage systems or equipment containing lithium-ion or lithium metal batteries where the batteries are installed as part of the manufacturing process.”

907.2.7 — Group M (restructured with lithium battery addition)

• The 2021 version had a single 907.2.7 section covering occupant load thresholds, with a subsection 907.2.7.1 for occupant notification timing. The 2024 version restructures this by creating a parent “907.2.7 Group M” that states “Fire alarm systems shall be required in Group M occupancies in accordance with Sections 907.2.7.1 and 907.2.7.2.” then places the occupant load trigger content in 907.2.7.1 and the occupant notification content in 907.2.7.1.1.
• 907.2.7.2 Storage of lithium-ion or lithium metal batteries (New in 2024)
  • “A fire alarm system activated by an air-sampling-type smoke detection system or a radiant-energy-sensing detection system shall be installed in a room or space within a Group M occupancy where required for the storage of lithium-ion or lithium metal batteries in accordance with Section 320.

907.2.10 — Group S (restructured with lithium battery addition)

• The same restructuring pattern applied here. The 2021 version had a single 907.2.10 covering public- and self-storage occupancies. The 2024 version creates a parent 907.2.10 pointing to two subsections: 907.2.10.1 (the original public- and self-storage content, unchanged) and new 907.2.10.2, requiring the specialized detection system in fire areas where lithium-ion or lithium metal battery storage is required by Section 320.

907.2.11 — Single- and multiple-station smoke alarms

• The introductory sentence was updated to add “and the manufacturer’s instructions” to the installation compliance requirements, alongside NFPA 72 and the listed sections.

907.2.11.3 — Installation near cooking appliances.

• The 2021 version had three separate items covering different detector types at different distances: ionization alarms at 20 feet (or 10 feet with a silencing switch) and photoelectric alarms at 6 feet. The 2024 version replaces all three items with a single blanket rule: “Smoke alarms shall be installed not less than 10 feet (3048 mm) horizontally from a permanently installed cooking appliance.” There is a single exception that allows 6 feet where necessary to comply with 907.2.11.1 or 907.2.11.2: “Smoke alarms shall be permitted to be installed not less than 6 feet (1829 mm) horizontally from a permanently installed cooking appliance where necessary to comply with Section 907.2.11.1 or 907.2.11.2.”

907.2.12 — Special amusement areas

• 2021: contained detailed special amusement requirements in 907.2.12.1 through 907.2.12.3, including system response and EVACS language.
  • Title “Special amusement buildings”
  • “An automatic smoke detection system shall be provided in special amusement buildings in accordance with Sections 907.2.12.1 through 907.2.12.3.”
• 2024:
  • Title “Special amusement areas”
  • “Fire detection and alarm systems shall be provided in special amusement areas in accordance with Section 914.7.”

907.5.2.1.3 — Audible signal frequency expanded to Group I-1

• The section title and scope were expanded from covering only “Group R-1 and R-2 sleeping rooms” to covering “Group R-1, R-2 and I-1 sleeping rooms.” Correspondingly, 907.5.2.1.3.1 fire alarm system audible signal and 907.5.2.1.3.2 smoke alarm signal in sleeping rooms were both updated to include Group I-1 throughout their text. The 520-Hz low-frequency signal requirement now explicitly applies to Group I-1 sleeping rooms.

907.10 — Smoke alarm maintenance (expanded and restructured)

The 2021 version had a single sentence stating smoke alarms shall be tested and maintained per manufacturer’s instructions, and replaced when they fail operability tests or exceed 10 years from manufacture. The 2024 version restructures this into a parent section “Smoke alarms shall be tested and maintained in accordance with the manufacturer’s instructions and this code.” and a new subsection:

• 907.10.1 Smoke alarm replacement
  • Smoke alarms shall be replaced when any of the following apply:
    1. The smoke alarm fails to respond to operability tests.
    2. The smoke alarm exceeds 10 years from the date of manufacture marked on the unit, unless an earlier replacement is specified in the manufacturer’s instructions.
    3. The smoke alarm end-of-life signal is sounded.
    4. The smoke alarm date of manufacture cannot be determined.
  • Where the replacement of smoke alarms is required by this section, smoke alarms shall not be required to include the 520-Hz signal unless the smoke alarms to be replaced include that signal.

Section 909 — Smoke Control Systems

909.6 — Pressurization method

909.6.1 — Minimum pressure difference

• The 2021 version stated the minimum pressure difference applies “in fully sprinklered buildings.” The 2024 version restates this as “in buildings equipped throughout with automatic sprinkler systems.” The second sentence was correspondingly updated from “buildings permitted to be other than fully sprinklered” to “buildings permitted to be not equipped throughout with automatic sprinkler systems.”

909.18.3 — Dampers

• 2021: “Dampers shall be tested for function in their installed condition.”
• 2024: “Dampers shall be tested for function in their installed condition in accordance with NFPA 80 and NFPA 105.”

909.20 — Smokeproof enclosures

• “The 2021 version defined a smokeproof enclosure as an interior exit stairway or ramp combined with “an open exterior balcony or ventilated vestibule.” The 2024 version drops “or ventilated vestibule” from this definition, leaving only the open exterior balcony as the qualifying element.”

909.20.1 — Access

• The minimum vestibule dimension was refined. The 2021 version required the vestibule dimension to be “not less than the required width of the corridor leading to the vestibule.” The 2024 version changes this to “not less than the required clear width of the corridor,” adding the word “clear.” The length measurement was also clarified by adding “in the direction of egress travel into the stairway, measured in a straight line between the centerline of the doorways into the vestibule and stairway,” which provides a specific geometric method for measuring the 72-inch minimum.

909.20.4 — Mechanical ventilation alternative (Removed)

• The 2021 version had a mechanical ventilation alternative at 909.20.4 (with four subsections covering vestibule doors, vestibule ventilation, smoke trap, and stairway/ramp shaft air movement), followed by the stairway pressurization alternative at 909.20.5.

909.21 — Elevator hoistway pressurization alternative

• The introductory paragraph of 909.21 was expanded in 2024: “Where elevator hoistway pressurization is provided in lieu of required enclosed elevator lobbies, the pressurization system shall comply with Sections 909.21.1 through 909.21.11. The design shall consider the interaction effects of the operation of multiple smoke control systems for all design scenarios in accordance with Section 909.4.7. All components or systems associated with the means of mitigating adverse interaction shall comply with the applicable subsections of Section 909.”

909.21.6 — Activation of pressurization system

• 2021 required the elevator pressurization system to activate upon activation of either the building fire alarm system or the elevator lobby smoke detectors, and stated that where both are present, each must be independently capable of activation.
• 2024 simplifies this to activation only upon activation of the elevator lobby smoke detectors: “The elevator pressurization system shall be activated upon activation of the elevator lobby smoke detectors.”

Section 911 — Explosion Control

Table 911.1 — Explosion control requirements (three additions)

• Footnote h (New in 2024): “Not required for Category 1B Flammable Gases having a burning velocity not exceeding 3.9 inches per second.”
• Footnote i (New in 2024): “Does not apply to consumer fireworks, 1.4G.”

Section 912 — Fire Department Connections

912.5 — Signs section significantly expanded

• 2021 had a single 912.5 section requiring a metal sign with raised letters at least 1 inch high on all fire department connections, with prescribed text reading “AUTOMATIC SPRINKLERS” or “STANDPIPES” or “TEST CONNECTION” or a combination thereof, and a requirement for a sign where the FDC does not serve the entire building.
• 2024 replaces this single section with a parent 912.5 where the listed options are expanded to include “STANDPIPE AND AUTOSPKR” and “AUTOSPKR AND STANDPIPE” as explicitly named alternatives, formalizing what was previously covered by the general “combination thereof” language. Four new subsections are added, each addressing a specific signage scenario:
  • 912.5.1 Lettering: “Each fire department connection (FDC) shall be designated by a sign with letters not less than 1 inch (25.4 mm) in height. For manual standpipe systems, the sign shall also indicate that the system is manual and that it is either wet or dry.”
  • 912.5.2 Serving multiple buildings: “Where a fire department connection (FDC) services multiple buildings, structures or locations, a sign shall be provided indicating the building, structures or locations served. Where the FDC does not serve the entire building, a sign shall be provided indicating the portions of the building served.”
  • 912.5.3 Multiple or combined systems: “Where combination or multiple system types are supplied by the fire department connection, the sign or combination of signs shall indicate both designated services.”
  • 912.5.4 Indication of pressure: “The sign also shall indicate the pressure required at the outlets to deliver the standpipe system demand.”
    • Exception: “Where the pressure required is 150 pounds per square inch (1034 kPa) or less.”

Section 914 — Fire Protection Based on Special Detailed Requirements

914.3.1.1 — Sprinkler risers restructured by building height

• 2021 had a single subsection (914.3.1.1 Number of sprinkler risers and system design) requiring that buildings more than 420 feet in height be supplied by not fewer than two risers, with each riser supplying sprinklers on alternate floors.
• 2024 restructures this into a parent 914.3.1.1 Number of sprinkler risers and system design that states the number of risers and design shall comply with 914.3.1.1.1 or 914.3.1.1.2 based on building height, then creates two subsections:
  • 914.3.1.1.1 Buildings 420 feet or less in height (New in 2024): “In buildings 420 feet (128 m) or less in height, sprinkler systems shall be supplied by a single standpipe or sprinkler express riser within each vertical water supply zone.”
  • 914.3.1.1.2 Buildings over 420 feet in height (New in 2024) carries over the dual-riser requirement from 2021 and updates the terminology: “In buildings more than 420 feet (128 m) in height, not fewer than two standpipes or sprinkler express risers shall supply automatic sprinkler systems within each vertical water supply zone. Each standpipe or sprinkler express riser shall supply automatic sprinkler systems on alternating floors within the vertical water supply zone such that two adjacent floors are not supplied from the same riser.”
  • 914.3.1.1.3 Riser location renumbers from the old 914.3.1.1.1 and updates the term from “sprinkler risers” to “standpipe or sprinkler express risers,” consistent with the terminology change above.

914.6 — Stages

• 2021 had two subsections for stages: 914.6.1 Automatic sprinkler system and 914.6.2 Standpipe system.
• 2024 retains only 914.6.1Automatic sprinkler system and removes 914.6.2 entirely.
  • Additionally, a new fourth exception was added to 914.6.1 Automatic sprinkler systems in stages: “sprinklers are not required under catwalks and galleries where they are permitted to be omitted in accordance with Section 903.3.1.1.”

914.7 — Special amusement areas

• 2021 had no general exceptions to Section 914.7.
• 2024 adds two exceptions at the parent level before the subsections:
  • Exception 1: “Special amusement areas that are without walls or a roof and constructed to prevent the accumulation of smoke are not required to comply with this section.”
  • Exception 2: “Puzzle rooms provided with a means of egress that is unlocked, readily identifiable and always available are not required to comply with this section.”
• 914.7.2.1 Alarm presignal (2021 Origin 907.2.12.1). The language is largely the same but now also allows activation by “any other single automatic fire detection device” rather than being limited to detectors and sprinklers.
• 914.7.2.2 Alarm activation (2021 Origin 907.2.12.2), updated to add “two or more other approved fire detection devices” and “a manual control located at the constantly attended station required by Section 914.7.2.1” as additional activation triggers beyond the 2021 list. Item 3 changes “activate an approved directional exit marking that will become apparent in an emergency” to simply “activate approved directional exit markings,” and item 4 changes “patrons” to “occupants.”
• 914.7.2.3 Emergency voice/alarm communications system (2021 Origin 907.2.12.3): “An emergency voice/alarm communications system complying with Section 907.5.2.2 shall be installed in and audible throughout special amusement areas. The emergency voice/alarm communications system is allowed to also serve as a public address system.”

Section 915 — Carbon Monoxide (CO) Detection

915.1 — General

• Exception (New in 2024): “Carbon monoxide detection is not required in Group S, Group F and Group U occupancies that are not normally occupied.”

915.1.1 — Where required

• 2021 listed six specific scenarios (fuel-burning appliances, forced-air furnaces, appliances outside units, private garages, and exempt garages) in separate subsections 915.1.1 through 915.1.6.
• 2024 consolidates all triggers into a single 915.1.1 with four plain-language items:
  • Item 1: “In buildings that contain a CO source.”
  • Item 2: “In buildings that contain or are supplied by a CO-producing forced-air furnace.”
  • Item 3: “In buildings with attached private garages.”
  • Item 4 (New in 2024): “In buildings that have a CO-producing vehicle that is used within the building.”
• The 2024 version eliminates the separate subsections 915.1.2 through 915.1.6 entirely, replacing the detailed scenario-by-scenario structure with these four broad triggers.

915.2 — Locations

• 2021 had three location subsections (dwelling units, sleeping units, Group E classrooms).
• 2024 version retains those three with slight modifications; The term fuel-burning appliance is replaced by “CO-source” and “CO-producing”. It also added three new subsections:
  • 915.2.3 Group E 2021 required “carbon monoxide detectors,” while the 2024 version specifies “a carbon monoxide system that uses carbon monoxide detectors,” which is a subtle but meaningful distinction.
  • 915.2.4 CO-producing forced-air furnace (New in 2024): “Carbon monoxide detection complying with Item 2 of Section 915.1.1 shall be installed in all enclosed rooms and spaces served by a fuel-burning, forced-air furnace.”
    • Exception 1: “Where a carbon monoxide detector is provided in the first room or space served by each main duct leaving the furnace, and the carbon monoxide alarm signals are automatically transmitted to an approved location.”
    • Exception 2: “Dwelling units that comply with Section 915.2.1.”
  • 915.2.5 Private garages (New in 2024): “Carbon monoxide detection complying with Item 3 of Section 915.1.1 shall be installed within enclosed occupiable rooms or spaces that are contiguous to the attached private garage.”
    • Exception 1: “In buildings without communicating openings between the private garage and the building.”
    • Exception 2: “In rooms or spaces located more than one story above or below a private garage.”
    • Exception 3: “Where the private garage connects to the building through an open-ended corridor.”
    • Exception 4: “An open parking garage complying with Section 406.5 of the International Building Code or an enclosed parking garage complying with Section 406.6 of the International Building Code shall not be considered a private garage.”
    • Exception 5: “Dwelling units that comply with Section 915.2.1.”
  • 915.2.6 All other occupancies (New in 2024): “For locations other than those specified in Sections 915.2.1 through 915.2.5, carbon monoxide detectors shall be installed on the ceiling of enclosed rooms or spaces containing CO-producing devices or served by a CO source forced-air furnace.”
    • Exception: “Where environmental conditions prohibit the installation of carbon monoxide detector in an enclosed room or space, carbon monoxide detectors shall be installed in an approved enclosed location contiguous with the room or space that contains a CO source.”

915.3 — Carbon monoxide detection (new subsections)

The 2021 version simply stated that CO detection shall be provided by alarms (915.4) or detection systems (915.5). The 2024 version retains this but adds four new subsections:

• 915.3.1 Alarm limitations (2021 Origin 915.4.3): “Carbon monoxide alarms shall only be installed in dwelling units and in sleeping units. They shall not be installed in locations where the code requires carbon monoxide detectors to be used.”
• 915.3.2 Fire alarm system required (New in 2024): “New buildings that are required by Section 907.2 to have a fire alarm system and by Section 915.2 to have carbon monoxide detectors shall be connected to the fire alarm system in accordance with NFPA 72.”
• 915.3.3 Fire alarm systems not required (New in 2024): “In new buildings that are not required by Section 907.2 to have a fire alarm system, carbon monoxide detection shall be provided by one of the following:
  1. Carbon monoxide detectors connected to an approved carbon monoxide detection system in accordance with NFPA 72.
  2. Carbon monoxide detectors connected to an approved combination system in accordance with NFPA 72.
  3. Carbon monoxide detectors connected to an approved fire alarm system in accordance with NFPA 72.
  4. Where approved by the fire code official, carbon monoxide alarms maintained in accordance with the manufacturer’s instructions.”
• 915.3.4 Installation (New in 2024): “Carbon monoxide detection shall be installed in accordance with NFPA 72 and the manufacturer’s instructions.”

915.4 — Carbon monoxide alarms (restructured)

• 2021 had four subsections: power source, listings, locations (the alarm-only restriction), and combination alarms.
• 2024 drops the locations subsection (moved to 915.3.1), retains power source, listings, and combination alarms, and adds a new 915.4.4:
  • 915.4.4 Interconnection (New in 2024): “Where more than one carbon monoxide alarm is required to be installed, carbon monoxide alarms shall be interconnected in such a manner that the actuation of one alarm will activate all of the alarms. Physical interconnection of carbon monoxide alarms shall not be required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.”

915.5 — Carbon monoxide detection systems

• 2021 version had three subsections (general, locations, combination detectors).
• 2024 version retains those and adds two new ones:
  • 915.5.1 removes the NFPA 720 compliance reference. The 2021 version required CO detection systems to comply with NFPA 720; the 2024 version references only UL 2075 listing for detectors. The system-level NFPA 72 reference is now addressed upstream in 915.3.2 and 915.3.3.
  • 915.5.4 Occupant notification (New in 2024): “Activation of a carbon monoxide detector shall annunciate at the control unit and shall initiate audible and visible alarm notification throughout the building.”
    • Exception: “Occupant notification is permitted to be limited to the area where the carbon monoxide alarm signal originated and other signaling zones in accordance with the fire safety plan, provided that the alarm signal from an activated carbon monoxide detector is automatically transmitted to an approved on-site location or off-premises location.”
  • 915.5.5 Duct detection (New in 2024): “Carbon monoxide detectors placed in environmental air ducts or plenums shall not be used as a substitute for the required protection in Section 915.”

915.6 — Maintenance

• The reference standard changed from NFPA 720 (2021) to NFPA 72 (2024).

Section 917 — Mass Notification Systems

917.2 — Group E occupancies (New in 2024): “Prior to construction of a new building containing a Group E occupancy requiring a fire alarm system and having an occupant load of 500 or more, a mass notification risk analysis shall be conducted in accordance with NFPA 72. Where the risk analysis determines a need for mass notification, an approved mass notification system shall be provided in accordance with the findings of the risk analysis.”

Appendix B — Fire-Flow Requirements for Buildings: 2021 vs 2024 Comparison

General / User Note

The 2024 version adds a code development reminder note stating that code change proposals to this appendix will be considered by the IFC Code Development Committee during the 2024 (Group A) Code Development Cycle. This is an editorial addition with no regulatory effect.

Section B104 — Fire-Flow Calculation Area

• 2021 had two subsections:
  • B104.1 General covering the basic floor area rule
  • B104.3 Type IA and IB construction as a separate subsection with an exception for open parking garages.
• 2024 consolidates everything into a single B104.1, eliminating the separate B104.3. The Type IA and IB rule and the parking garage exception are now presented as two numbered exceptions within B104.1 itself rather than in a standalone subsection. B104.2 (Area separation) is retained unchanged.
  • 2024 B104.1 General reads as follows: “The fire-flow calculation area shall be the total floor area of all floor levels within the exterior walls, and under the horizontal projections of the roof of a building, except as modified in Section B104.3.”
    • Exception 1: “The fire-flow calculation area of buildings constructed of Types IA and IB construction shall be the area of the three largest successive floors.”
    • Exception 2: “The fire-flow calculation area for open parking garages of Types IA and IB construction shall be determined by the area of the largest floor.”

Section B106 — Referenced Standards

All four referenced standards were updated to their current editions:

• IBC updated from IBC-21 to IBC-24.
• IRC updated from IRC-21 to IRC-24.
• IWUIC updated from IWUIC-21 to IWUIC-24.
• NFPA 1142 updated from the 2017 edition to the 2022 edition, and its title changed from “Standard on Water Supplies for Suburban and Rural Fire Fighting” to “Standard on Water Supplies for Suburban and Rural Firefighting”.