Sensing a Silent Killer

Major revisions to NFPA 70 offer opportunities for security strategy changes

Carbon monoxide detection has been around for some time, but has not been mainstreamed—until now. When NFPA 720-2009, which is a complete rewrite of the CO detection standard, was published, it addressed the trend of CO detection with concise remedies to alleviate any uncertainties. The standard brought about the opportunity to help facilities hone in on new protection strategies. According to the National Fire Protection Association, CO detectors are only in about 15 percent of homes in the United States. By comparison, 96 percent of homes have smoke alarms. This new standard opens up the door to fill that gap.

Remember, CO is still a new thing—building professionals are often uncertain as to where and how CO detection should be installed. Building owners, their design teams and the responsible code-enforcement authorities all want direction for detector locations that will protect occupants from accumulations of CO gas—exactly what NFPA 720-2009 provides.

In fact, state and local governing entities have been amending their own adopted codes with more centralized and more stringent CO detection requirements. While many jurisdictions and cities, such as Chicago, have had additional CO detection requirements for longer than a decade, the trend is accelerating in such places as New York City and Florida. In addition, the recent changes to NFPA 720 validate the importance of CO detection and reinforce some of the building and life-safety codes that have prescribed CO detection requirements addressing these uncertainties.

Here is a basic review of NFPA 720 and the strategies to consider:

NFPA 720 opens the playing field. The new code standardizes CO detection for all buildings, not just residences. This includes schools, hotels, nursing homes and other commercial structures. This is the perfect opportunity to “cross sell” your security protection strategies. In addition, CO notification devices must meet certain audible and visible requirements. For example, public notification appliances for CO signaling cannot include the word “fire” or any fire symbol. And while notification appliances with multiple visible elements are permitted to have fire markings only on those visible elements used for fire signaling, the new standard provides ample opportunities for revisiting the security strategy within a facility.

CO signals must be different. The new code requires that the CO alarm signal is distinct from other signals when indicating sensor failure or end of life. Keep in mind that the CO alarm signal should take precedence over supervisory or trouble signals, and should be distinctly indicated as a CO alarm signal (visually and audibly) at the control panel and supervising station.

Additionally, the new code clarifies what supervisory stations should do when they receive a CO alarm signal. If the communications methodology is shared with any other usage, all fire alarm, CO alarm, supervisory and trouble signals will take priority, in that order of priority, over all other signals unless otherwise permitted by the AHJ.

CO meets smoke. According to the new standard, CO detectors will now be held to the same life-safety standard as smoke detectors. This means they will send trouble signals to the control panel and facilitate wiring supervision.

For example, the code now spells out where CO detectors should go. In commercial buildings, CO detectors need to be located on the ceiling in the same room as permanently installed fuelburning appliances and centrally located on every habitable level and in every HVAC zone of the building. In dwelling units, CO detectors must be installed outside each separate sleeping area and on every level of a dwelling unit, including basements.

Differences. One of the differences between fire alarm systems and CO detection systems is the secondary power supply requirements. NFPA 720- 2009 requires CO detection systems to have sufficient secondary power to operate the system under quiescent load for at least 24 hours. After that time, the system must operate all of the CO notification appliances for 12 hours if a supervising station does not monitor the system. If the CO detection system is monitored by a supervising station, the 12-hour requirement is reduced to 60 minutes. Functional tests won’t take effect until 2012, and sensitivity tests won’t take effect until 2015. This gives manufacturers enough time to implement safe testing protocols.

Good news. Some manufacturers already meet this testing requirement, providing a simple, inexpensive test that verifies the CO cell’s functionality when using canned CO. With a one-second spray, the user can ensure the sensing cell is functioning properly.

This article originally appeared in the November 2008 issue of Security Products.

About the Author

David George is the director of marketing at System Sensor.


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