Cal. PUC § 1625

(a) To ensure proper ventilation is maintained throughout the school year, all classrooms shall be equipped with a carbon dioxide monitor that meets all of the following requirements:

(1) The monitor is hard-wired or plugged-in and mounted to the wall between three and six feet above the floor and at least five feet away from the door and operable windows.

(2) The monitor displays the carbon dioxide readings to the teacher through a display on the device or other means such as a web-based application or cellular phone application.

(3) The monitor provides a notification through a visual indicator on the monitor, such as an indicator light, or other alert system, such as an electronic mail, text, or cellular telephone application, when the carbon dioxide levels in the classroom have exceeded 1,100 ppm.

(4) The monitor maintains a record of previous data that includes at least the maximum carbon dioxide concentration measured.

(5) The monitor has a range of 400 ppm to 2000 ppm or greater.

(6) The monitor is certified by the manufacturer to be accurate within 75 ppm at 1,000 ppm carbon dioxide concentration and is certified by the manufacturer to require calibration no more frequently than once every five years.

(b) If a classroom carbon dioxide concentration exceeds 1,100 ppm more than once a week as observed by the teacher or the facilities staff, the classroom ventilation rates shall be adjusted by qualified personnel to ensure peak carbon dioxide concentrations in the classroom remain below the maximum allowable carbon dioxide ppm setpoint. Verification of the installation of carbon dioxide monitors in all classrooms shall be included in the assessment report required pursuant to Section 1626.

(c) The requirements of paragraphs (1) to (6), inclusive, of subdivision (a) may be amended by the Energy Commission as necessary to reflect available technology and to achieve the intent of this section.