Importance of Monitoring Carbon Monoxide in Building Interiors

Ankit Javeri
Author : Ankit Javeri
6 Minutes Read
  • Home
  • Blog
  • Importance of Monitoring Carbon Monoxide in Building Interiors

    We tend to associate harmful substances with foul odors and visible fumes, but this is not the case when dealing with carbon monoxide (CO). The gas cannot be detected by human senses, since it has no color, odor or taste. However, it is extremely dangerous and can cause death within seconds if the concentration is high enough. CO should not be confused with carbon dioxide (CO2), which is a normal product of human metabolism, requiring a much higher concentration than CO to become dangerous.

    In indoor spaces, the main source of carbon monoxide is incomplete combustion. It can be produced from fuels such as gasoline, propane, heating oil, natural gas, coal and even wood. In other words, any appliance or building system based on combustion comes with the risk of CO emissions. This includes ovens, ranges, fireplaces and even cars in enclosed garages.

    Make sure your building is safe from carbon monoxide.

    Contact Us

    General Requirements for Carbon Monoxide Detectors in NYC

    All CO detectors and alarms must be Listed according to UL standards 2034 and 2075. Battery backup is mandatory in case of power interruption, and the units can be of a combination type CO and smoke detectors.

    When CO is present, shutting down the source is the top priority. If anyone starts experiencing even the slightest symptoms of CO poisoning, the dwelling should be left empty and with the windows open, and the NY Fire Department should be called immediately.

    Before CO reaches a lethal concentration, it causes symptoms such as headache, nausea and dizziness. If many persons in a building start experiencing these symptoms at once, there is a high likelihood of high CO levels. According to Underwriters Laboratories (UL), 60% of Americans cannot identify the warning signs of CO leakage.

    Where Does the NYC Building Code Require CO Detection?

    UL Listed carbon monoxide detectors are mandatory in the occupancy groups listed below. Note that specific requirements vary for each case.






    Always required.

    I-1, I-2, I-4


    Always in I-2 and I-4. As indicated in section 908 for I-1.

    A-1, A-2, A-3


    If equipped with fire alarm system, as indicated in section 908.



    If equipped with fire alarm system, as indicated in section 908.

    R-1, R-2, R-3


    As indicated in section 908.

    Groups E, I-2 and I-4

    CO detectors in these occupancies must have built-in sounder bases, and must be able to communicate with a centralized supervising system. An audible and visible alarm is required for locations under constant occupancy, and the sensors themselves must installed in the following areas:

    1. Rooms with equipment that produces CO, except for labs and kitchens.
    2. Corridors on floors with equipment that produces CO, enclosed spaces or loading areas. Also, corridors on floors immediately above or below.

    Groups A-1, A-2, A-3 and B

    CO detectors with built-in sounder bases are required in buildings containing these occupancies, if equipped with a fire alarm. In the case of Group B, the requirement only applies for assembly places as described in Section BC303, Exception 1. The communication and audiovisual signaling requirements are the same as in Groups E, I-2 and I-4, and the required locations are as follows:

    1. Rooms with equipment that produces CO, except for labs and kitchens.
    2. Occupiable rooms meeting the following conditions: area of at least 75 sq. ft, not provided with mechanical ventilation, and located on the same floor as CO emitting equipment or the immediate floor above or below.
    3. Corridors on floors with enclosed parking areas or loading docks, along with corridors in the floor immediately above or below.
    4. Offices in enclosed garages or loading dock, including parking attendant booths.

    Groups R-1, R-2, R-3 and I-1

    These occupancies require CO detectors and audible notification systems in every dwelling unit meeting certain conditions. They must send a signal to a permanently attended location, where fire alarms can be activated manually. The CO detectors can have a stand-alone design and can be powered locally.

    The requirement is for all dwelling units meeting any of the following conditions:

    1. Located in the same floor as equipment that produces CO, or enclosed parking areas.
    2. Located in floors directly above CO-emitting equipment or enclosed parking areas.
    3. Located in a building with a centralized furnace, boiler or water heating system that produces CO. Also applies for dwelling units in adjacent buildings, if they share the same centralized system.

    With regards to the specific locations of these sensors, the code indicates the following areas:

    1. Outside any room used for sleeping, within a maximum range of 15 ft. from the door.
    2. Inside any room used for sleeping.
    3. All floors in a dwelling, including penthouses and those below grade. Crawlspaces and attics not suitable for habitation are excluded.

    Concluding Remarks

    Carbon monoxide is a serious issue. There are many building systems that waste energy or cause discomfort when poorly designed, but inadequate CO detection can lead to loss of human life - there is zero room for error.

    Note that the presence of CO indoors represents an abnormal operating condition: properly-vented combustion appliances remove this substance continuously, keeping it away from occupied spaces. Nevertheless, the risk of CO leakage still exists even with adequate ventilation, which means detection systems play a critical role.

    Contact Us

    Tags : new york NYC building code Carbon Monoxide

    Leave Comment

    Please avoid adding links in comments. Any comment with external website links will not be published.

    Join 15,000+ Fellow Architects and Contractors

    Get expert engineering tips straight to your inbox. Subscribe to the NY Engineers Blog below.

    Looking for more information?
    Contact Us