Carbon Monoxide Gas Detection

CARBON MONOXIDE GAS DETECTION TECHNICAL BULLETIN

INTERNATIONAL BUILDING AND FIRE CODE CHAPTER 9, SECTION 915 CARBON MONOXIDE DETECTION The 2015 edition (or newer) of the International Building Code (IBC) and International Fire Code (IFC) requires carbon monoxide (CO) detection in K-12 occupancies and other occupancies such as daycares where small children and young adults are the main occupants. Children have lower levels of hemoglobin and higher respiration rates than adults. This allows carbon monoxide to circulate faster and reduce oxygen levels more quickly, placing them at a higher risk than adults for developing illnesses caused by low levels of CO poisoning. With children spending eight or more hours a day in K-12 buildings served by gas-fired equipment, a sufficient detection system is needed to prevent CO-related illness or deaths.

The presence of CO gas in buildings is usually contributed to faulty gas-fired equipment, such as boilers, waterheaters, or gas-fired HVAC air handling equipment.

Something as simple as a blocked fresh air intake is all it takes to disrupt the equipment’s combustion process leading to the production of CO gas. When it comes to this equipment, the combustion that occurs uses a precise mixture of air and fuel, which results in efficient and complete combustion. Under normal operation, CO gas is not created. However, as the equipment ages, it can develop small cracks, leaks, or develop general inefficiencies due to normal wear-and-tear.

These faults can very quickly lead to incomplete combustion of the gas resulting in production of CO gas. This makes existing schools with aging gas-fired equipment more susceptible to CO gas leaks.

When it comes to how and where in a building to provide CO detectors or alarms, the building and fire codes point us to NFPA 720. The National Fire Protection Association website indicates that NFPA 720 has been excluded from the most recent code cycle updates.

Instead, NFPA 720 has been merged with NFPA 72. CO detection design requirements were first included in NFPA 72 in the 2019 edition, making the 2019 and 2022 editions of NFPA 72 the most current guide for CO detection systems or CO alarms.

At Henderson Engineers, we design systems for K-12 buildings that allow students and staff to reach their full potential.

This includes providing an environment safe from fire, smoke, or hazardous gasses such as carbon monoxide. Applying the principles of NFPA 72 paired with a comprehensive review of gas-fired equipment and the potential hazards, we provide fire alarm system design that addresses CO gas detection through occupant notification in the event of CO gas detection and the initiation of auxiliary functions to prevent further spread of the CO gas. The following is a summary of recommendations regarding CO gas detection: CAR BO N M ON OX IDE D ET EC T I O N

O CCU PANT NOTIFICATIO N O F CA R BO N MO NOX IDE G AS

AUX ILLARY FU NCTIONS UP ON CO G AS DETE CTIO N

Provide CO detection in classrooms where gas-fired equipment is present.

Most of the major fire alarm system manufacturers provide a CO detector or combination CO/smoke detector paired with a sounder base. This sounder base provides a distinct evacuation tone (separate from the fire alarm system notification appliances) when CO gas is detected.

This local alarm notifies the occupants in the immediate vicinity of the CO gas and initiates a prompt evacuation of the area.

HVAC air handling system shutdown initiated via fire alarm relay.

Provide CO detection in classrooms served by gas-fired, forced-air furnaces or other gas-fired air handling equipment.

Provide CO detection in classrooms with communicating spaces between the classroom(s) and the room containing the gas-fired equipment.

Provide CO detection in science, chemistry, or similar labs that are provided with gas connections for Bunsen burners or similar flame sources.

Provide CO detection in kitchens with gas-fired cooking appliances.

While CO detection may not necessarily be required in a room containing gas-fired equipment (through code exceptions), we recommend providing detection on a case-by-case basis.

Considerations should be given to how often the room is occupied, how long the room is occupied, by whom the room is occupied, and the size of the gas load present. Although boiler rooms will likely never be occupied by children, the large gas load paired with extended time spent in these rooms by maintenance and facility managers increase the risk of CO exposure and poisoning.

In addition to providing the local alarm, the CO gas detection signal will activate an alarm at the main fire alarm control panel and any remote annunciator panels present on the system. In new schools, our designs include the provision of a fire alarm annunciator panel in a location that is constantly attended by school staff, alerting them of the CO gas detection.

Boiler system shutdown initiated via fire alarm relay.

Closure of electric solenoid valves serving kitchen cooking equipment.

Closure of electric solenoid valves serving science classrooms with Bunsen burners.

When gas-fired equipment does not have the ability to be shut down by the fire alarm system, an electric solenoid valve can be provided on the gas supply line to the unit, which can then be closed upon associated CO detection.

With the combination of local alarms evacuating the immediate vicinity, and the notification of school staff outside of the detection area, the school’s emergency preparedness plan is initiated directly and indirectly.

If you have any questions about CO detection in new or existing K-12 schools, or merely wish for a review of your existing systems to understand the potential hazards or work needed to add CO detection to your facility, please contact us.

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