UL Smoke Alarm Standards Required by 2025 NFPA Fire Alarm and Signaling Code: What it Means for Your Home's Safety

Beginning January 1, 2025, home chefs and bakers will be one step closer to freedom from false, nuisance alarms that go off while food is cooking.

This is because recent updates to the latest edition of the National Fire Alarm and Signaling Code, NFPA 72, 2025, will go into effect, requiring smoke alarms and detectors in residential and commercial buildings (in jurisdictions that have adopted the code) to comply with the eighth edition of UL 217, Smoke Alarms, or the seventh edition of UL 268, Smoke Detectors for Fire Alarm Signaling Systems, if they are within certain distances from cooking appliances. 

What are the new requirements for protection from nuisance alarms in the National Fire Alarm and Signaling Code?

The code states that smoke alarms and smoke detectors shall not be installed between 10-20 ft along a horizontal flow path from a stationary or fixed cooking appliance, unless the devices are listed for resistance to nuisance alarms in accordance with UL 217 or UL 268.

Additionally, it states that smoke alarms and smoke detectors shall not be installed within a 10 ft radius from a stationary or fixed cooking appliance, unless the distance would prohibit the placement of a smoke alarm or smoke detector. In this case, smoke alarms or smoke detectors shall be permitted within a 6-10 ft radius from the appliance if listed for resistance to nuisance alarms in accordance with UL 217 or UL 268.

How do UL 217 and UL 268 limit nuisance alarms from smoke detectors?

In order to conform to UL 217 and UL 268, smoke alarms and smoke detectors must pass a cooking nuisance smoke test. During the test, smoke alarms are mounted 10 feet away from an electric range, which is turned to full power with frozen hamburger patties cooking inside on a broiler tray underneath electric broiler coils. In order to pass the test, the alarms must not go off while the patties are cooking prior to the smoke reaching a certain obscuration level and/or measuring ionization chamber value.

Why is it important to limit nuisance alarms from smoke detectors?

Nuisance alarms are more than just annoying — they’re also dangerous, as they are often the reason why people disable the power sources from their smoke detectors. According to a 2024 NFPA research report, smoke alarms were present in three-quarters of reported home fires from 2018 to 2022, but in 16% of cases, they failed to operate. In these cases, 35% of non-functioning alarms had missing or disconnected batteries, and 6% had a hardwired power failure, shutoff, or disconnect.

Smoke alarms provide the earliest warning of a home fire, and with only three minutes or less to escape (according to research findings by the Fire Safety Research Institute), every second matters. Quite simply, if a smoke alarm or detector has been disabled due to a nuisance alarm, it cannot alert residents in the first moments of a fire — when escape is critical.

Is the National Fire Alarm and Signaling Code mandatory?

The National Fire Alarm and Signaling Code, NFPA 72, 2025, provides safety provisions to help jurisdictions meet fire detection, signaling, and emergency communications demands. The code is not mandatory unless adopted and enforced by local, state, provincial, or national governments.

As of this writing, jurisdictions that have adopted the previous edition, NFPA 72, 2022, include California, Los Angeles County, Los Angeles City, San Diego, San Francisco, and Ohio. Twenty-seven states have adopted the preceding edition, NFPA 72, 2019.