NFPA 72 and 720 code changes

Hereā€™s what fire protection engineers need to know about the NFPA 72 and 720 code requirements for sleeping rooms
By Ted Milburn, Eaton February 12, 2015

Figure 1: The Wheelock Exceder LED low frequency sounder line was designed to meet both NFPA low-frequency code requirements for sleeping areas in one device. Courtesy: EatonLearning objectives

  • Understand the need for compliance with NFPA 72 and 720 for commercial buildings with sleeping areas.
  • Recognize the value in alarms and fire alarm systems that can effectively wake sleeping occupants during an emergency.
  • Learn about current alarm solutions that provide the required distinct alarm tones for both fire and CO detection. 

When it comes to buildings where people sleep, the rules have changed. Effective January 2014, NFPA 72: National Fire Alarm and Signaling Code mandates that audible alarms in sleeping rooms must produce a low-frequency (520 Hz) alarm tone to alert occupants of a fire in the building. As of Jan. 1, 2015, the updated NFPA 720: Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment requires that a separate and distinct low-frequency tone is mandated to indicate the possible presence of CO. This year’s CO requirement represents the latest iteration of evolving fire codes, which are critical for building owners and facility managers, a mandate aimed at saving lives.

The latest code can trace its roots to a 2006 NFPA study. At that time, the NFPA petitioned three research projects supported by the Fire Protection Research Foundation. The results of the research showed that a low-frequency (520 Hz) square signal was more effective than a high-pitched (3150 Hz) alarm signal when trying to effectively wake sleeping individuals during a building emergency. In fact, the low-frequency 520 Hz woke 92% of the participants in the study who had hearing difficulties such as hearing loss or alcohol impairment.

As a result of this study, the NFPA instituted new requirements in NFPA 720, all aimed at improving effectiveness and reliability when it comes to the initial sound of an alarm and when individuals can hear it, react to it, and get to safety.

The 2010 edition of NFPA 72 required sleeping rooms to be fitted with Code 3 temporal pattern (T3) low-frequency alarms to indicate the presence of a potential fire in building. Shortly after, in 2011, the NFPA 720 code expanded to mandate CO detection with a low-frequency (T4) alarm in areas with sleeping occupants. The updated NFPA 72 and 720 apply to sleeping areas in buildings such as hotels, motels, college dorm rooms, assisted living facilities, and living rooms in apartments and condominiums.

A 2010 study by the U.S. Fire Administration determined that 50% of deaths as a result of residential fires occur between 10 p.m. and 6 a.m. This emphasizes the importance of maximizing those crucial seconds between the initial sounding of an alarm and waking individuals so that they can react appropriately when there is a building emergency. With the new NFPA 72 and 720 codes in place, now is the time for building owners and managers to conduct audits of their alarm systems and ensure these systems are both compliant and primed to get people to safety.

Fire protection engineers can assist with this by ensuring multi-family dwellings have the appropriate detection systems specified at the onset of each project.


Ted Milburn is vice president of marketing for Eaton’s life safety and mass notification solutions. He is a mass notification industry expert with 35 years of experience in the life safety market as technology leader, educator, and executive. 

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