Reference
What changed between editions
Changes to the damper requirements in IBC Section 717 and related sections between the 2018, 2021 and 2024 editions. The damper tool applies the rules of the edition you select.
| Edition | Section | Topic | What changed |
|---|---|---|---|
| 2021 | 717.5.2 Exc. 3 | Fire barriers rated 1 hour or less | The exception now requires a fully ducted HVAC system and allows nonmetal flexible air connectors only at the air handler in the mechanical room and from an overhead metal duct to a ceiling diffuser in the same room. |
| 2021 | 717.5.3 Exc. 1.1 | Exhaust subducts in shafts | To skip the fire damper, the steel subduct must be at least 0.0187 inch thick and the shaft needs an exhaust fan at the top powered continuously per IBC 909.11. The 2018 text only required continuous upward airflow to the outside. |
| 2021 | 717.5.3.1 | Continuous upward airflow | New section: fire and smoke dampers may not be installed in shafts that must keep a continuous upward airflow if closing the damper would stop it. |
| 2021 | 717.2.3 | Static dampers | Fire dampers and ceiling radiation dampers listed for static systems may be installed only in HVAC systems that shut down automatically in a fire. The 2018 edition stated the dynamic requirement in 717.3.1. |
| 2021 | 717.6.2.1.1, 717.6.2.1.2 | Ceiling radiation dampers | New rules for dynamic and static ceiling radiation dampers, including smoke detector and occupant sensor control options for static dampers. |
| 2021 | 717.4.1, 717.4.2 | Damper access | Section 717.4 was split into access and identification. New: dampers with fusible links or internal operators need an access door at least 12 inches square or a removable duct section. The 2018 text only required approved access large enough for inspection and maintenance. |
| 2021 | 717.4.1.2 | Restricted access | New: where access is restricted, single- or multi-blade dampers with remote inspection per NFPA 80 or NFPA 105 are required. |
| 2021 | 713.12.1 | Rooftop penthouses | New: no fire/smoke damper is required where a shaft rises through the roof into a rooftop mechanical penthouse and the ductwork connects directly to the HVAC equipment. |
| 2021 | 1024.6 | Exit passageways | Ductwork for independent ventilation, not only pressurization, may now penetrate an exit passageway. |
| 2024 | 717.6.1 | Floors in Group I-2 and I-3 | The "occupancies other than Groups I-2 and I-3" limit moved from the main rule to the exception. Hospitals and detention buildings may now use a fire damper at the floor line for a duct connecting two stories, but not the three-floor exception. |
| 2024 | 717.2.4, 717.2.4.1 | Controls in ducts | New: mechanical, electrical and plumbing controls may not be installed in air ducts (with an exception for wiring tied to the air distribution system) or through dampers unless the manufacturer and listing allow it. |
| 2024 | 717.5.6, 705.11 | Exterior walls | The reference for exterior wall openings moved from Section 705.10 to 705.11. The damper requirement itself did not change. |
Changes are listed in the edition where they first appear. Editorial changes that do not affect where dampers are required are not listed.