Codes and Standards

What’s new in NFPA 72?

The 2019 update of NFPA 72 provides fire protection engineers, along with other engineering professionals, improved mass notification and emergency communication guidelines.
By Matthew Zega, PE, RTM Engineering Consultants, Chicago March 21, 2019
Figure 2: NFPA 72-2019, Chapter 18, is dedicated to notification appliances, such as this horn strobe device. Courtesy: RTM Engineering Consultants

Learning objectives

  • Learn which codes and publications are referenced throughout the 2019 edition of NFPA 72: National Fire Alarm and Signaling Code.
  • Obtain an overview of the main additions and modifications made to NFPA 72-2019.

Like most of the NFPA codes, NFPA 72: National Fire Alarm and Signaling Code is updated every 3 years. While this article does not address every single nuance of the code, it will serve as an overview of some of the main modifications made, chapter by chapter.

Chapter 1

The first chapter of NFPA 72 talks about the purpose, administration, and application of the fire alarm code and signaling code. The primary new addition to this section is a clarification in the use of carbon monoxide (CO) detectors.

As such, the code goes on to state in section 1.1.3 that the purpose of CO detection is for life safety and not for property protection. It is also important to note that as a result of adding CO requirements to NFPA 72, NFPA 720 was withdrawn by NFPA.

Chapter 2

Chapter 2 of NFPA 72 lists other codes and publications that are referenced within the current edition. A number of new codes that are now referenced include ASME A17.1: Safety Code for Elevators and EscalatorsIEEE 450: Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for Stationary Applications and IEEE 1106: Recommended Practice for Installation, Maintenance, Testing, and Replacement of Vented Nickel-Cadmium Batteries for Stationary Applications that outline battery applications; Telecommunications Industry Association publications that detail fiber-optic systems; and a long list of UL standards.

While ASME A17.1 and the UL standards should be fairly well-known to fire alarm designers, IEEE documents cover the application of different battery technologies, bringing a greater awareness of such technology to this code than before.

Chapter 3

Chapter 3 contains definitions that apply to terms used within this codebook. The following definitions were added to the most recent edition: CO alarm, battery (plus nine subdefinitions), building system information unit, CO detection system (plus two subdefinitions), cell (plus six subdefinitions), design professional, electromechanical releasing device, emergency response agency (ERA), energy-storage systems (ESS) (plus four subdefinitions), fire alarm control panel (FACP), high-volume low-speed fan, immediately, and wireless mesh network (WMN).

The main takeaway from these new definitions is that there is heavy emphasis placed on battery systems, CO systems, and energy-storage systems along with emerging technology, such as WMNs. There also is emphasis placed on the design professional as the individual who is registered or licensed to practice their respective profession as defined by governing regulation.

Figure 1: NFPA 72-2019, Chapter 17, is dedicated to initiating devices like this manual pull station. Courtesy: RTM Engineering Consultants

Chapter 7

Chapter 7 contains documentation criteria and requirements, with a few additions to the 2019 edition. One of the most substantial modifications includes the area specifically addressing design professionals. Sections 7.3.3.2 through 7.3.3.4 summarize the new additions to this section of the code:

  • Design professionals shall be qualified to prepare documentation.
  • Documents shall incorporate performance criteria.
  • Design documents shall clearly communicate the intended performance and functionality.

NFPA is making it very clear through these new sections that plans prepared in accordance with this code need to be accurate and compliant.

Chapter 10

Chapter 10, covering fundamentals of fire alarm and signaling, includes information that is new to NFPA 72 and is inclusive of CO detection systems. Much of this information has been transferred from NFPA 720, which is being retired and will not be published in 2019. Most notably, two new sections fall under secondary power supply.

There have been sections added such as:

“ … where CO detection is not monitored by a supervising station, the secondary power supply shall have sufficient capacity to operate the CO detection system under quiescent load for a minimum of 24 hours, and at the end of that period, shall be capable of operating the CO detection system and all CO notification appliances for 12 hours.”

To further clarify, a quiescent load is in an operating system that is not operating in alarm condition, thus driving no load. Section 10.6.7.2.4 goes on to say:

“ … where CO detection is monitored by a supervising station, the secondary power supply shall have sufficient capacity to operate the CO detection system under quiescent load for a minimum of 24 hours, and at the end of that period shall be capable of operating the CO detection system and all notification appliances for 5 minutes.”

There also are two main additions to the battery and charger section of Chapter 10. These two sections require a separate storage battery and separate automatic charger for starting the engine-driven generator, and they shall not be used for any other purpose. That battery shall be sized in accordance with NFPA 110: Standard for Emergency and Standby Power Systems.

One final addition to Chapter 10 includes the ability to silence a CO notification appliance that is built with integral sounder if the alarm or supervisory status continues to be displayed at the control unit. All CO alarms shall comply with Chapter 18 of the code.

Figure 2: NFPA 72-2019, Chapter 18, is dedicated to notification appliances, such as this horn strobe device. Courtesy: RTM Engineering Consultants

Chapter 12

Chapter 12, outlining circuits and pathways, contains a new section to the ground connections excerpt. An earlier section of the code, 12.2.4.1, requires fire alarm systems to test free of grounds. The purpose is to eliminate the failure of the system due to an additional ground connection on the same system.

The code goes on to relax this sentiment when parts of circuits or equipment are intentionally and permanently grounded to provide ground-fault detection, noise suppression, emergency ground signals, and circuit-protection grounding.

Chapter 14

Chapter 14, covering inspection, testing, and maintenance, includes changes related to CO detectors as well as changes to the battery requirements in both visual inspection and testing; Tables 14.3.1 and 14.4.3.2 have been modified significantly to remove old battery technology and address new battery technology.

For testing methods, as stated in 14.4.3.5, all CO system detectors installed after Jan. 1, 2012, tests shall be performed on initial acceptance and annually via the introduction of CO into the sensing chamber or element. For single and multiple station alarms, a couple of new sections have been added to NFPA 72. According to 14.4.6.3, the occupant of the dwelling unit shall be deemed qualified to perform inspection, testing, and maintenance on single and multiple station alarms protecting that dwelling unit when provided with information from the manufacturer. Also, per 14.4.5.6, CO alarms shall be replaced when either the end of life is actuated or the manufacturer’s replacement date is reached.

Figure 3: Smoke detectors have been impacted by code changes in the 2019 edition of NFPA 72: National Fire Alarm and Signaling Code. Courtesy: RTM Engineering Consultants

Chapter 17

Chapter 17 discusses initiating devices and has quite a bit of new material in comparison to the chapters discussed thus far. Mechanical protection now has sections requiring devices to be protected when subject to physical damage in addition to mandating guards/covers be listed and calling out that such protection shall not adversely affect the operation of the device. The ambient ceiling-temperature rating of heat detectors shall be selected in accordance with provided tables and the temperature rating of the detector shall be at least 20°F above the maximum expected temperature at the ceiling.

A note about smoke detectors: When installed in ducts with high air velocities, they shall be rated for such conditions. For peaked construction, detectors shall be spaced within 36 in. of the peak. Similarly, for shed construction, detectors shall be spaced and located within 36 in. of the high side of the ceiling, measured horizontally.

Quite a few paragraphs have been added to the air-sampling-type smoke detector section. In the absence of performance-based criteria, each sampling port shall be treated as a spot-type smoke detector for the purpose of location and spacing. This is an important new requirement that recognizes that air-sampling system characteristics impact the sensitivity of the detector and sets a minimum prescriptive requirement for sampling port locations in the absence of an assessment of the system. Air-sampling smoke detectors also shall produce trouble signals when airflow is outside of the specified range.

New sections go on to add information about pipe networks, in that they shall be designed on the basis of, and shall be supported by, computer-based fluid dynamics design calculations to ensure required performance. The sampling pipe network design calculations shall include pressure, volumetric flow, and alarm sensitivity at each sampling port. Sampling system piping shall be conspicuously identified as a smoke detector sampling tube. For the installation and spacing, the sampled air shall be exhausted to a lessor or equal pressure zone.

In the same smoke-sensing fire detector section under HVAC, detector spacing and locations shall be selected on the basis of anticipated airflow patterns and fire type. An important note about smoke detection for air duct systems is that, where the detection of smoke in the supply air system is required by NFPA, a detector listed for the air velocity present shall be installed in the supply air duct downstream of both the fan and the filters.

Chapter 17 also has content added about CO detectors due to the retirement of the NFPA 720 code.

In both Table 14.3.1 (visual inspection) and Table 14.3.2 (testing), there are significant changes. The tables have been updated to eliminate older battery technology while making requirements more clear for new battery technologies.

Figure 4: A fire alarm annunciator panel provides a remote status of the building’s overall fire alarm system. Courtesy: RTM Engineering Consultants

Chapter 18

A number of new code excerpts outlined in Chapter 18, for notification appliances, cover both audible and visual devices. For audible characteristics, as outlined in 18.4.1.4, sound from temporary sources lasting less than 60 seconds shall not be required to be included when measuring the maximum ambient sound level. Included in 18.4.1.5.3, where audible occupant notification is required for all or part of an area, the coverage shall only be required in occupiable areas.

As expected, CO devices have also been addressed in this chapter of the code. Where CO detectors or alarms are required by the code, section 18.4.3.1 requires a distinctive signal pattern that is different from a fire-evacuation signal. Where an audible signal is required, 18.4.3.2 states the CO signal shall be a four-pulse temporal pattern. The signal shall be synchronized within a notification zone of a protected premise as outlined in 18.4.3.3.

A few additional code exceptions contained in Chapter 18 also bring new clarification to the code. As for exit marking, section 18.4.8.3 states that the exit marking audible notification appliance signal shall penetrate both the ambient noise and the fire alarm signal.

As it relates to pulse characteristics, section 18.5.3.3 notes that light-pulse durations greater than 20 milliseconds, but not greater than 100 milliseconds, shall be permitted where the alerting capability of the visual-notification appliance is demonstrated to be equal to or greater than visual-notification appliances with a 20-millisecond pulse duration. It is also noted in section 18.5.3.8 that visual-notification appliances used for CO signaling shall be as required by the emergency plan and the authority having jurisdiction (AHJ) for the area of the building and shall not exceed 1,000-candela effective intensity.

In terms of appliance location, 18.5.5.3 details where ceiling heights do not permit wall mounting at a minimum of 80 in., the room size covered by a visual-notification appliance of a given value shall be reduced by twice the difference between the minimum mounting height of 80 in. and the actual lower mounting height. Finally, relating to spacing, 18.5.5.5.8 states if the ceiling-mounted visual notification appliance is not located at the center of the room, the effective intensity shall be determined by doubling the distance from the appliance to the farthest wall to obtain the maximum room size.

Figure 5: Initiating devices, such as this wall-mounted horn strobe, were impacted by recent changes to the 2019 edition of NFPA 72: National Fire Alarm and Signaling Code. Courtesy: RTM Engineering Consultants

Chapter 21

Chapter 21 includes a moderate amount of changes, although many are considered more of a reconfiguration rather than new content. One addition to the code requires fire alarm-initiating devices to be installed inside an elevator hoistway. As stated in 21.3.7, initiating devices shall be required to be accessible for service, testing, and maintenance from outside of the elevator hoistway. While much of the overall occupant-evacuation elevators (OEE) section was modified, some of the main changes occur in 21.6.2.3, occupant evacuation operation (OEO) initiation section.

An active, automatic fire alarm-initiating device that does not initiate the elevator’s Phase 1 emergency recall operation shall cause the fire alarm system to provide a signal to the elevator system, indicating the floor of an active alarm. The space to be evacuated shall be a contiguous block of floors designated as the elevator evacuation zone, consisting of at least the floor with an active alarm, two floors above the floor with the active alarm, and two floors below the floor with the active alarm.

When the floor designated as the elevator discharge level falls within the elevator evacuation zone, it is not to be evacuated by the elevator; the fire alarm system shall initiate a voice message to instruct the occupants on the level to exit the building. If an activation of an automatic fire alarm-initiating device that does not initiate elevator recall occurs on an additional floor—including the elevator discharge level at any time while OEO is in effect—the elevator evacuation zone shall be expanded to include all floors with an active alarm, all floors between the highest and lowest floor with an active alarm, plus two floors above the highest floor with an active alarm and two floors below the lowest floor with an active alarm.

If the first active alarm is on the elevator discharge level, automatic initiation of OEO shall not be permitted for all elevators having the same elevator discharge level. When the first active alarm is on an elevator discharge level, the fire alarm system shall not send a signal to the elevator system for that alarm or any other active alarm that does not initiate elevator recall for that group of elevators. When OEO has been suspended, the in-building fire emergency voice-alarm communications system shall transmit messages coordinated with the elevator system’s variable message signs. Likewise, when OEO has been partially terminated, the in-building fire emergency voice-alarm communications system shall transmit messages coordinated with the elevator system’s variable message signs.

Another important point to highlight within this chapter is the requirement of 21.8 high-volume low-speed fans to be interlocked to shut down upon actuation of a sprinkler waterflow switch, which indicates waterflow in the area served by the fans.

Chapter 23

In Chapter 23, detailing protected premises’ alarm and signaling systems, the requirements shall not preclude the use of separate fire, CO, or other life safety systems provided the systems do not generate simultaneous, conflicting notification to the building occupants or conflicting actuation of safety functions.

Chapter 24

Chapter 24, on emergency communication systems, goes into more detail than previous editions on the area of refuge. It is noted in this section that when a remote communications station is activated by a building occupant, section 24.10.2.1 requires that two-way live-voice communication shall be required to operate between the remote communications station and a constantly attended location.

Section 24.10.2.3 mandates that the constantly attended location shall reside either within the building or at an offsite monitoring location, and it shall be approved by the AHJ. Section 24.10.6 states that in the event of an offsite connection, a signal shall be transmitted to the offsite monitoring location, identifying the specific building prior to initiating the live-voice two-way communication. Meanwhile, 24.10.9 requires remote communications stations shall provide for hands-free, two-way communication, provide an audible and visual signal to indicate communication has occurred, and indicate to the receiver the location sending the signal.

Chapter 26

Among the procedural and operational changes to Chapter 26 on supervising station alarm systems, one of the main highlights is to wireless mesh networks. Section 26.6.5.2.8 details that WMN using listed components do, in fact, satisfy the requirements set forth by the digital alarm communicator receiver section.

Chapter 27

Chapter 27 outlines public emergency alarm reporting systems, including changes from public reporting systems, rectifiers, and monitoring for integrity. Section 27.1.1 states public emergency alarm reporting systems shall consist of alarm boxes and alarm processing equipment that communicate on a wired or wireless network, one-way or two-way.

These reporting systems shall include communication infrastructure that is publicly owned, operated, and controlled. In systems requiring rectifiers, 27.5.2.6.3 requires one spare rectifier shall be provided for every 10 operating rectifiers on a system, and all systems shall have at least one spare. In monitoring for integrity, per 27.5.5.3.1, all wireless box systems shall provide constant monitoring of each radio frequency in use; both an audible and a visual indication of any sustained signal in excess of a 15-second duration shall be provided for each receiving system at the communications center.

It is quite obvious that the NFPA committee has done a great deal of work in updating this code to contain the most relevant and accurate information for engineering professionals. While not all-encompassing, this article summarizes some of the major code changes.

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Matthew Zega, PE, RTM Engineering Consultants, Chicago
Author Bio: Matthew Zega is an associate at RTM Engineering Consultants. He has more than 13 years of diversified experience in the design and management of electrical and fire alarm systems.