In 1998, the Journal of the American Medical Association issued a report revealing that 2,100 deaths occurred annually due to unintentional carbon monoxide poisoning. This article was among the leading reasons why the International Code Council introduced Section 915 for Carbon Monoxide Detection to the 2015 International Building Code (IBC) and Fire Code (IFC). This section laid out the requirements for carbon monoxide detection in K-12 schools, certain care facilities, and residential buildings. It is important for building owners to be educated on the risk of carbon monoxide gas, the associated health hazards, and options for carbon monoxide detection. Carbon monoxide detection is imperative in a building’s emergency preparedness plans.

What Is It?

Carbon monoxide (CO) gas is a colorless and odorless gas that is a by-product of incomplete or partial combustion. In the public eye, carbon monoxide gas is probably associated more with residential structure fires. In a structure fire, as combustibles ignite, the fire consumes the oxygen in the room and continues to grow. As the oxygen supply becomes depleted and the fire growth begins to slow, portions of the fuel begin to undergo incomplete combustion. It is at this point where carbon monoxide levels begin to rise.

In buildings under normal occupation, the presence of carbon monoxide is usually contributed to faulty gas-fired equipment, such as boilers, water-heaters, or gas-fired HVAC air handling equipment. 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, carbon monoxide gas is not created. However, as the equipment ages, it can develop small cracks, leaks, or general inefficiencies due to normal wear-and-tear. These faults can very quickly lead to incomplete combustion of the gas resulting in production of carbon monoxide.

The 2015 edition (or newer) of the International Building Code and Fire Code requires carbon monoxide detection in K-12 occupancies and other occupancies such as daycares where small children and young adults are the main occupants. Looking at the mechanism of action in carbon monoxide poisoning and characteristics of symptoms, it becomes clear as to why these occupancies are listed as needing carbon monoxide detection. When carbon monoxide gas is inhaled, it interacts with the body through the blood stream, specifically by interacting with the hemoglobin present in blood. Hemoglobin in the bloodstream is responsible for collecting and distributing oxygen throughout the body and the body’s organs. Carbon monoxide molecules attach to the hemoglobin and prevent the hemoglobin from attaching to and carrying oxygen.

As carbon monoxide levels rise in a person’s blood, their oxygen levels decrease, resulting in symptoms of asphyxiation such as headache, dizziness, nausea, confusion, lethargy, and others. According to Ada Health, adult men and women have hemoglobin levels of about 11.5-18 g/dl (grams per deciliter). Children aged one to six have levels of 9.5-14 g/dl. This lower hemoglobin level, paired with higher respiration rates in children, allows carbon monoxide to circulate faster and reduce oxygen levels more quickly. This places children at a higher risk than adults for developing illnesses caused by low levels of carbon monoxide 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 these carbon monoxide related illnesses or deaths.

What Should Be Done?

As mentioned, the current editions of the International Building and Fire Code requires carbon monoxide detection for K-12 schools. This requirement is only applicable to new K-12 buildings. None of the widely adopted codes (IFC, IBC, or NFPA 101: Life Safety Code) retroactively requires carbon monoxide detection for existing schools. Only certain scenarios where additions to existing schools or renovations of existing schools occurs would carbon monoxide detection requirements be applicable. Understanding that carbon monoxide leaks are commonly caused by malfunctioning or faulty gas-fired equipment, existing schools with aging systems are more susceptible to carbon monoxide leaks and carbon monoxide gas exposure. While it is important to incorporate carbon monoxide detection in new K-12 buildings with gas-fired equipment, older, existing schools should be made a priority when it comes to retrofitting buildings with carbon monoxide detection.

When it comes to how and where in a building to provide carbon monoxide detectors or alarms, the building and fire codes point us to the National Fire Protection Association (NFPA) standard: NFPA 720 – Standard for the Installation of Carbon Monoxide(CO) Detection and Warning Equipment. 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 – National Fire Alarm and Signaling Code. Carbon monoxide 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 carbon monoxide detection systems or carbon monoxide alarms.

Our Approach

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 include in our designs or recommend the following be applied to fire alarm system design in new and existing K-12 schools:

• Provide CO detection in classrooms where gas-fired equipment is present.
• 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.
• 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 carbon monoxide exposure and poisoning.

Providing carbon monoxide detectors is merely the first step of the system design. We also apply codes and standards, paired with an intimate understanding of K-12 emergency preparedness plans, to provide compliant and cost-effective notification of carbon monoxide gas detection. Most fire alarm system manufacturers use a carbon monoxide detector or combination carbon monoxide/smoke detector paired with an installation base that has an associated address or location identifier. This identifier appears on the fire alarm system display when activated. Instead of providing the standard base, we specify the use of an addressable sounder base with all carbon monoxide detectors. This addressable sounder base provides a distinct evacuation tone (separate from the fire alarm system notification appliances) when carbon monoxide gas is detected. This local alarm notifies the occupants in the immediate vicinity of the carbon monoxide gas and initiates a prompt evacuation of the area.

In addition to providing the local alarm, the carbon monoxide 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. 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.

Another aspect of the automatic carbon monoxide detection and notification system are the auxiliary functions performed when carbon monoxide gas is detected. As mentioned, the gas can be introduced into a building from boiler systems, gas-fired water heaters, HVAC equipment, or direct gas connections in lab spaces. Detectors are provided based on the location of equipment and auxiliary functions are performed accordingly. For example, when a detector located in a classroom that is served by a gas-fired roof-top unit is activated, a relay from the fire alarm system can be provided to shut down the unit. This shut down limits the area impacted by the carbon monoxide leak. Similarly, when a detector in the same room as a boiler is activated, boiler shutdown sequences can be initiated. 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 carbon monoxide detection.

With the detection, notification, and auxiliary functions addressed, the next step becomes incorporating these features into a new or existing fire alarm system. New fire alarm systems can easily be specified to accomplish all the above features. The challenge of fire alarm system design and the incorporation of carbon monoxide detection in existing K-12 schools is the age, condition, or capabilities of the existing fire alarm system. Through a detailed review of existing fire alarm systems, coordination with building and fire officials, and adjustments to fire alarm or electrical system configuration, one of several options can be deployed to achieve the desired protection.

If you have any questions about carbon monoxide detection in new or existing K-12 schools, or would like to have your existing systems reviewed to understand the potential hazards or work needed to add carbon monoxide detection to your facility, please contact us.