California Code, Education Code - EDC § 32081

(a) By July 1, 2015, the State Fire Marshal shall propose for adoption by the California Building Standards Commission, for the commission's next triennial code adoption cycle, appropriate standards for the installation of carbon monoxide devices in school buildings.  The proposed building standards shall require carbon monoxide devices to be installed in public and private school buildings that meet all of the following criteria:

(b) A private or public school that uses a school building for educational purposes for kindergarten or any of grades 1 to 12, inclusive, that was built before the adoption of the 2016 California Building Standards Code (Title 24 of the California Code of Regulations), and has a fossil fuel burning furnace located inside the school building is encouraged to have a carbon monoxide device installed in the building.