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Local Law 191 New York City- NYC DOB

NYC Local Law No. 191 amended the New York City Building code to require CO detectors to now be installed in existing commercial buildings that have fire alarms retroactively that contain Occupancy Group A-1, A-2, A-3, Group M (Mercantile) and B (Business) buildings. The local law was released in 2018 and was finally signed by the commissioner into law on November 9, 2019.

This law, much like the law that required CO detectors in places of Assembly relies heavily on the criteria to describe the details of the requirements, and appears to read much like that previously released Local Law 10 of 2014 for CO detectors within Assembly spaces although it has the new section “e” for Mercantile and Business Buildings.

The law basically states that by January 1, 2021 that existing Group M and B buildings equipped with a fire alarm system, have fossil fuel sources, indoor parking or a loading dock need to have CO detectors installed. Therefore, building managers and owners must ensure that CO detection system plans and specifications are designed and installed according to the NYC Building code and the work must be filed with the FDNY prior to the January. 1, 2021 deadline. 

Please note the following requirements: Local Law 10 did not have an effective date for compliance for places of Assembly, which Local Law 191 now adds. • Mercantile and Business buildings that meet the above “triggers” (fire alarm system with fossil fuel source or indoor parking, or loading dock) need CO detectors in the following locations: 

1. In any room containing CO producing equipment (except kitchens).

2. In any corridor where CO producing equipment is located, plus one story above and one story below. 

3. In any corridor on floors where enclosed parking or a loading dock is located, plus one story above and one below.


4. In any parking attendance office or booth located within an enclosed garage or loading dock.

And Finally:

  • Detection zones are a maximum of 10,000 square feet with each detector centrally located 

  • The CO detector that is located at the fossil fuel source must shut the source down upon alarm detection 

  • CO detectors are required to have a sounder base which emits a Temporal 4 sound (4 pulse tone) when it detects the appropriate level of CO

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