Latest NFPA 72 Changes Meld CO Standards

Latest CO detector requirement changes address monitoring stations, battery operation and more.

This is the third and final installment of my articles highlighting proposed changes to the 2019 edition of NFPA 72, “The National Fire Alarm and Signaling Code.”

This month let’s take a look at Chapters 26 and 29. Chapter 26, “Supervising Station Systems,” addressed a number of issues.

As NFPA 720, which covers the standard for CO alarms and systems, is being melded into NFPA 72, the handling of CO signals will now be found within Chapter 26.

New text was added for Carbon Monoxide Alarm Signal Disposition:

  • CO signals shall take precedence over supervisory and trouble signals
  • Signals received shall be distinctively indicated as a carbon monoxide signal
  • Servicing of a CO system that cannot be reset shall occur within four hours

These requirements will be found with-in the general alarm signal processing section and are not specific to central station service, proprietary supervising station or remote supervising station alarms.

Also from NFPA 720 are requirements regarding how a CO alarm signal shall be handled once received. Supervising station personnel shall:

  • Where required by the emergency response agency, immediately retransmit the signal to the communication center
  • Contact the responsible party(s) in accordance with the notification plan

Chapter 26 now includes language that will allow for the handling of a trouble signal to be delayed for up to 15 minutes. If during this time period a restoral should be received, no further action would be required.

This was added primarily to address a momentary trouble that would likely be generated by a communication failure.

Changes Affect Secondary Power; ‘Immediately’ Placement

The text was changed in several areas within the chapter to add “managed facilities-based voice network” following “public-switched telephone network.” The purpose was to clarify that there is an intended equivalency between the two.

Of some controversy, a new exception was included addressing the requirements for secondary power on shared equipment at a protected premises for the transmission of signals to a super-vising station.

This would be for routers and other such equipment that may be part of an IP system. Secondary power would not be required for this equipment if this path is the secondary means of signal transmission and where the primary path meets all of the secondary power requirements of the standard.

Also generating some debate is moving the standard definition for “immediately” from the Annex to the main body of the standard. Until the 2019 edition, the word was defined within the Annex, which was not in the enforceable part of NFPA 72.

Accompanying the definition now in the main body is the inclusion of the verbiage “without unreasonable delay.” This phrase, however, is not defined, and could be left for interpretation of what’s unreasonable.

CO Detector Battery Operation Put to Test

The final chapter to cover is 29, “Single- and Multiple-Station Alarms and Household Fire Alarm Systems.” Within this chapter, the requirements found in NFPA 720 for CO detection within residential occupancies were brought over.

This includes that there shall be a CO detector within 21 feet of any door to a sleeping area and in every room that has a fuel burning appliance. Of some concern is the secondary power requirement for a system that may have CO detection.

The following was added: “At the battery voltage at which a trouble is signal is obtained, the unit is capable of producing a fire alarm signal for at least 4 minutes, or a carbon monoxide alarm signal for at least 12 continuous hours, followed by not less than seven days of trouble signal operation.”

The reason is if the system should activate while the resident of the dwelling unit is not present, they would be alerted to the fact that there may be CO present upon their return, up to 12 hours after the event. This will need to be calculated as part of the standby battery requirements for a system that may be installed within a dwelling.

Effort to Combat Nuisance Alarms Suffers Setback

For several cycles of NFPA 72, there has been work toward the reduction of unwanted alarms. These efforts are ongoing. There has been work within the industry on the development of smoke alarms and detectors that would be resistant to common nuisance sources.

Within the 2016 edition of the standard, such detectors and alarms would be required no later than January 1, 2019. However, the manufacturers of these products have been stating that UL has yet to develop the testing standard and testing room for these units.

As such, the date is being changed again to January 1, 2021. The general consensus is even this date will not be obtainable. The industry needs to take a hard look at this.

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About the Author


Shane Clary, Ph.D., is Security Sales & Integration’s “Fire Side Chat” columnist. He has more than 37 years of security and fire alarm industry experience. He serves on a number of NFPA technical committees, and is vice president of Codes and Standards Compliance for Pancheco, Calif.-based Bay Alarm Co.

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