CO2 sensors must be tested and calibrated at least once every five years, or per the manufacturer’s recommendation, whichever timeframe is shorter. The sensors must have an accuracy of no less than 75 parts per million (ppm) or 5% of the reading, whichever is greater.
Install at least one CO2 sensor within each densely occupied space. CO2 sensors must be located within the breathing zone, which is 3–6 feet above the floor.
Determine whether you need to follow Case 2 in addition to Case 1. Case 2 applies to buildings with densely occupied spaces—defined as spaces designed for 25 or more people per 1,000 ft2 (40 ft2 or less per person). However, if these spaces add up to less than 5% of your total occupied square footage, you’re exempt from the Case 2 requirements. Rooms smaller than 150 ft2 are also exempt and should not be included in your calculations.
Measurement devices must be monitored by a control system, such as a BAS, that will record the outdoor airflow data at intervals of 15 minutes or less and generate trending graphs or tables so that building managers can analyze airflow levels over time.
Install permanent outdoor airflow measurement devices that provide continuous monitoring and generate an alarm if the minimum outdoor airflow rate falls more than 15% below the minimum rate specified in the building operating plan. You should have already figured out this minimum airflow rate for your building to meet the requirements of IEQp1: Minimum Indoor Air Quality Performance.
This credit has three compliance paths: Cases 1, 2, and 3. Unlike many other LEED credits where you choose one to follow, you may need to follow two or three of these, depending on your building:
Case 1 is for predominantly mechanically ventilated buildings.
Case 2 applies to buildings with densely occupied spaces such as cafeterias or meeting rooms.
