Prior to 2005, NFPA 720, the carbon monoxide (CO) detection standard set by the National Fire Protection Association (NFPA), was little more than a recommendation. Then, in 2005, NFPA 720 was changed from a recommended practice to an installation standard that gave some teeth to the standard in reaction to greater public awareness of CO poisoning and local CO detection legislation.
The new edition, NFPA 720-2009, is due in October and will become the Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment. The standard has been completely rewritten to encompass more types of occupancies and more specifically define CO detection system usage.
There are eight main changes and additions to NFPA 720 that will affect you:
NFPA 720 NATIONALLY STANDARDIZES CO DETECTION FOR ALL BUILDINGS, NOT JUST RESIDENCES. THIS INCLUDES SCHOOLS, HOTELS, NURSING HOMES AND OTHER COMMERCIAL OCCUPANCIES.
The 2005 edition of NFPA 720 addressed only dwelling units. Since then, the number of states requiring the installation of CO detection in residential buildings, and in some cases commercial buildings, has more than doubled. Commercial occupancies where CO detection is required include hotels, rooming houses, dormitories, day care centers, schools, hospitals, assisted-living facilities and nursing homes.
In the absence of a national installation standard, each jurisdiction has been developing its own requirements. This has resulted in considerable confusion in the industry. Several key areas of concern and confusion are installation, testing and off-premise signal transmission to the supervising station. NFPA 720-2009 is a huge step forward in minimizing these concerns.
The new commercial installation requirements in NFPA 720-2009 contain extracts from NFPA 72, The National Fire Alarm Code, and can be found in chapters 1 through 8. Chapter 9 covers households.
CO ALARM SIGNALS NEED TO BE DISTINCT FROM OTHER SIGNALS AND INDICATE SENSOR FAILURE OR END OF LIFE.
In the 2005 edition of NFPA 720, CO detectors were required to be connected to a control panel via a supervisory circuit only. NFPA 720-2009 requires CO alarm signals to be distinct and “descriptively annunciated” from fire alarm, CO supervisory and CO trouble signals. Furthermore, the CO alarm signal should take precedence over supervisory or trouble signals. The actuation of a CO detector or system should be distinctly indicated as a CO alarm signal.
CO detector trouble signals must be indicated visually and audibly at the control panel and supervising station. Therefore, the CO detector must have an integral trouble relay that will send trouble conditions to the control panel, such as a sensor failure or sensor end-of-life signal.
CO DETECTORS ARE NOW HELD TO THE SAME LIFE SAFETY STANDARD AS SMOKE DETECTORS: THEY WILL SEND TROUBLE SIGNALS TO THE CONTROL PANEL AND FACILITATE WIRING SUPERVISION.
CO detector trouble signals are required to be indicated visually and audibly at the control panel and supervising station. Therefore, a conventional hard-wired CO detector must have an integral trouble relay that will send trouble condition to the control panel such as a sensor failure or end-of-life signal.
NFPA 720-2009 requires manufacturers of system-connected CO detectors to incorporate the same critical life safety supervision concepts as smoke detection devices to prevent undetected device failures. In addition to the trouble signals noted previously, CO detectors must facilitate wiring supervision.
The connection between the initiating device circuit conductors and the CO detector are required to be monitored for integrity.
22.214.171.124.4 Duplicate terminals, leads, or connectors that provide for the connection of installation wiring shall be provided on each initiating device for the express purpose of connecting into the carbon monoxide detection system to monitor the integrity of the signaling and power wiring (see figure).
These above requirements are of particular importance for installers when selecting a CO detector.
CO DETECTOR LOCATION IS MORE SPECIFIC THAN EVER.
Unlike smoke detectors, the 2005 edition of NFPA 720 had very limited requirements for the placement of CO detectors. The standard required CO detectors to be centrally located outside of each separate sleeping area in the immediate vicinity of the bedrooms and referred to the manufacturer’s published instructions. Instructions differed between manufacturers, however, and this confused installers and Authorities Having Jurisdiction (AHJ). Some manufacturers call for detectors to be installed on the ceiling, while others call for the units to be installed on the wall.
Based on research conducted by the Fire Protection Research Foundation, NFPA 720-2009 has specific requirements for the location of CO detectors in commercial buildings and dwelling units. In commercial buildings, CO detectors need to be located on the ceiling in the same room as permanently installed fuel-burning 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. Applicable laws, codes and standards may require additional locations.
NEW SECONDARY POWER SUPPLY REQUIREMENTS FOR CO DETECTION SYSTEMS DIFFER CONSIDERABLY FROM FIRE ALARM SYSTEMS.
NFPA 720-2009 requires CO detection systems to have sufficient secondary power to operate the system under quiescent load (system operating in a normal condition) 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 can be reduced to 60 minutes.
Although a five-minute requirement is mandated for fire alarm systems, a 12-hour alarm requirement for CO systems is necessary for non-monitored systems because occupants could be away from the unit for several hours. If the CO alarm signal stopped sounding before occupants returned, the occupants would be unaware that there were dangerous levels of CO gas present.
TESTING REQUIREMENTS HAVE BEEN INSERTED INTO THE NEW STANDARD, HOWEVER, FUNCTIONAL TESTS WON’T TAKE EFFECT UNTIL 2012, AND SENSITIVITY TESTS WON’T TAKE EFFECT UNTIL 2015.
One of the more significant requirements in NFPA 720-2009 pertains to the testing of CO detectors. Many AHJs, engineers and building owners have requested the ability to test a CO detector just as they are able to test a smoke detector with canned smoke. The NFPA technical committee agreed that testing should be required, but it wanted to give manufacturers enough time to implement safe testing protocols.
Thus, functional testing will only apply to system detectors installed after January 1, 2012. At that time, CO tests will need to be performed at initial acceptance and then annually by introduction of CO into the sensing chamber or element. An electronic check (magnets, analog values, etc.) is not sufficient to comply with this requirement.
Sensitivity testing will take effect January 1, 2015. In units other than one- and two-family dwellings, sensitivity of CO detectors and single- and multiple-station CO alarms will need to be checked within one year after installation and every alternate year thereafter unless otherwise permitted. After the second required calibration test, if sensitivity tests indicate that the device has remained within its listed and marked sensitivity range, the length of time between calibration tests can be extended to five years.
NFPA 720 CLARIFIES WHAT SUPERVISORY STATIONS SHOULD DO WHEN THEY RECEIVE A CO ALARM SIGNAL.
One area of considerable confusion in the industry has been what the supervising station should do when it receives a CO alarm signal from the protected premises. Off-premises signal transmission requirements for commercial buildings now set a priority of signals. A CO alarm signal must be distinctively indicated as a CO alarm signal and needs to be distinct from a fire alarm signal and take precedence over supervisory or trouble signals.
If the communications methodology is shared with any other usage, all fire alarm, CO alarm, supervisory, and trouble signals will take precedence, in that order of priority, over all other signals unless otherwise permitted by the AHJ. If the order of the signal priority cannot be assured, the maximum duration between the initiation of an alarm signal at the protected premises, transmission of the signal, and subsequent display and recording of the alarm signal at the supervising station should not exceed 90 seconds.
Upon receipt of a CO alarm signal, supervising station personnel will immediately retransmit indication of the signal to the communications center (where required by the emergency response agency) and contact responsible party(s) in accordance with the notification plan.
For households, off-premise transmissions should immediately retransmit indication of the CO alarm signal to the emergency response agency, where required, and contact responsible party(s). Once contacted, the occupants must be informed of actions to take, such as moving outdoors and taking head counts.
CO NOTIFICATION APPLIANCES MUST MEET CERTAIN AUDIBLE AND VISIBLE REQUIREMENTS.
In most cases, the integral sounder of a CO detector will be sufficient for notifying occupants of commercial and residential buildings. The audible CO alarm should be a temporal 4 signal consisting of a single tone pattern consisting of four cycles of 100 milliseconds +/- 10 percent “on” and 100 milliseconds +/- 10 percent “off,” followed by five seconds +/- 10 percent “off.” After the initial four minutes of alarm, the five-second “off” time can be changed to 60 seconds +/- 10 percent. The alarm signal should repeat until the alarm resets or is manually silenced and be synchronized within the notification zone.
The new standard does not require the installation of CO horns and strobes throughout a building. It allows occupant notification to be limited to the notification zone encompassing the area where the CO signal is originated if the CO alarm signal is transmitted to a constantly attended on-site location or off-premises location.
The new standard does spell out specific requirements for A/V devices if they are installed. Notification appliances used for CO signaling cannot have the FIRE, or any fire symbol in any form, on the appliance visible to the public. Notification appliances with multiple visible elements are permitted to have fire markings only on those visible elements used for fire signaling.