Author(s): Kristin Bigda. Published on May 3, 2021.

In Compliance | NFPA 101

Protecting against the 'silent killer': Carbon monoxide requirements in the Life Safety Code


In February, Texas was hit with a winter storm that brought bitter cold to a region unaccustomed to arctic conditions. With many homes uninsulated and not built to withstand the extreme cold, and with millions of people without power due to electrical grid failures, Texans were forced to find alternative ways to heat their homes and survive the extreme weather.

Some of those methods had consequences. According to media reports, fire departments in Harris County, which is the state’s most populous county and includes the city of Houston, responded to 475 carbon monoxide-related calls and emergencies during the week of the storm. At least 57 people statewide died during the event, with many of the lives lost attributed to carbon monoxide (CO) poisoning caused by the operation of fuel-burning equipment, such as generators and grills, inside homes and running vehicles inside garages. CO is often referred to as the “silent killer” because it is colorless and odorless, and without detection and alarm equipment it is nearly impossible to notice.

Requirements mandating CO detection first entered NFPA 101®, Life Safety Code®, in 2012 and called for CO detection equipment in new residential occupancies (one- and two-family dwellings, lodging or rooming houses, hotels, dormitories, and apartments), and in day care homes characterized by the presence of occupants who are sleeping and the presence of an attached garage or fuel-burning appliances. New and existing health care occupancies containing fuel-burning fireplaces also added a mandate for CO detection and warning equipment. The 2015 edition of the Life Safety Code mandated that CO detection equipment be provided for new educational occupancies in rooms with permanently installed fuel-burning appliances, in areas adjacent to attached garages, and in occupiable spaces served by supply air from a fuel-burning HVAC system. In 2018, similar requirements were added for new assembly occupancies. CO detection was also mandated that year for residential board and care occupancies; it was required in new, smaller facilities with attached, communicating garages, or where the facility contains fuel-burning appliances/fireplaces, and it was also required in new, larger facilities with attached, communicating garages, or where the individual sleeping rooms or suites contain fuel-burning appliances/fireplaces.

The 2021 edition of the Life Safety Code includes an important addition to that evolution—for the first time since CO provisions entered the code, those requirements have been extended to existing occupancies. Today, existing hotels and dormitories require CO detection equipment in guest rooms/suites with communicating attached garages and in guest rooms/suites containing a permanently installed fuel-burning appliance/fireplace.

The requirements for CO detection and warning equipment are not based on safety from fire; rather, they are intended to mitigate the risk posed to building occupants by exposure to CO gas. Where combustion gases from equipment—such as generators or vehicles, in the Texas example—are not properly vented, or in areas where CO gas can infiltrate, such as spaces attached to garages, occupants run the risk of CO poisoning. This is not the only example of the code expanding its reach to provide protection requirements beyond that of safety from fire. To address this hazard, NFPA 101 added a goal in 2018 that its requirements would provide reasonable life safety during emergency events involving hazardous materials regulated by a number of NFPA standards. In 2021 that list of regulations added NFPA 72®, National Fire Alarm and Signaling Code®, to recognize carbon monoxide detection as a hazardous material emergency mitigation strategy employed by the code.

For those occupancies that mandate it, NFPA 101 provides requirements for CO detection and warning equipment via a reference to NFPA 72, where requirements were consolidated into the 2019 edition. Previously, these requirements could be found in NFPA 720, Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment. Once it is determined when an occupancy requires the presence of CO detection and warning equipment, further details are provided within the occupancy chapter for where the equipment is to be installed. For the purpose of applying the requirements for CO detection, where NFPA 72 (or NFPA 720 in earlier editions) is applied via the adoption of NFPA 101 and where the occupancy chapter requirements in NFPA 101 differ from the requirements in NFPA 72 (or NFPA 720), the requirements of NFPA 101 should apply. Where both NFPA 101 and NFPA 72 (or NFPA 720) are separately adopted and enforced, the more stringent requirements should be followed to meet the requirements of both documents.

The current requirements for CO detector installation are summarized in a new report, “Carbon Monoxide Detection and Alarm Requirements: Literature Review,” published by the Fire Protection Research Foundation ( Requirements for a variety of occupancies are reviewed based on codes, standards, and state regulations.

Protecting people from carbon monoxide cannot be achieved by assuming that those who face these dangers are aware of the provisions in NFPA 101, or that this silent killer is only a hazard during cold weather. The dangers of CO poisoning are ever-present, especially during extreme weather events where people find themselves without power and other resources. Reducing the risk of CO exposure requires not only the application of current codes and standards, but also educating the public on safe practices such as the proper storage, use, and operation of fuel-burning equipment such as generators, and the CO hazards associated with the use of vehicles. Additionally, many local jurisdictions mandate the installation of CO detection beyond that required by NFPA 101. All applicable local requirements must be followed to ensure complete and adequate protection for new and existing conditions.

For more information, including resources on carbon monoxide safety, visit

KRISTIN BIGDA is technical lead for Engineering Technical Services at NFPA. NFPA members and AHJs can use the Technical Questions tab to post queries on NFPA 101 at Top photograph: Getty Images