n/a

Hello Stella, CO2 sensors in the return air duct does not meet the requirements of the LEED credit NOR does it meet the requirements of ASHRAE 62.1. To meet the LEED credit, the CO2 sensors must be within the densely-occupied zones and within the breathing zone (3-6ft above the floor). The CO2 setpoint for each zone should be calculated individually based on the occupancy density and the expected occupant activity level (i.e., metabolic rate). Refer to Appendix C in the Standard for more on how to do this. Lastly, airflow measuring devices are required for any system for where 20% or more of the design supply airflow serves nondensely occupied spaces. So it depends on how you are providing the outdoor air to the zones served by the FCUs and AHUs. If you are using a central system to deliver the outdoor air to each FCU (i.e., not relying on the FCU fan to draw the outdoor air into the space) then a single airflow measuring device on the central system should be sufficient. Otherwise, you'll need a separate airflow measuring device on each FCU. Note, even with CO2 sensors in some zones served by the AHU, the AHU may need to have airflow measuring device as well. Hope this helps. -John