CO2 sensors in non-densely occupied spaces

CO2 monitors cannot replace outdoor air monitors. CO2 sensors do not provide the same benefit in non-densely occupied spaces as they do in densely occupied spaces. CO2 sensors measure only CO2 generated by human occupants and they are typically not a good way to indicate indoor air quality in non-densely occupied spaces.

I have the same problem: the project is a Comercial Interiors on three floors of a non-LEED building. The project is reusing the central HVAC form the building which comply with more than a 30% rate of Outdoor Air. The air flow is constant. The HVAC expert installed CO2 sensors all over the place with the folowing rationale: CO2 sensor would indicate the air quality while the flow sensors would measure the air flow, but they do not assure the air quality of that flow. This apparently will jeopardize this credit, however other technicians agree with the criteria. Really, there are no "special circumstances" in this case? Thank you

It sounds like you have both outdoor airflow measurement devices and CO2 sensors. Is that correct? If so, CO2 sensors are redundant from a LEED perspective if they are also installed in the non densely occupied spaces. Though your project will meet the LEED criteria if both are installed.

Allison, thanks for your answer, but no, unfortunately I have only a lot of CO2 sensors. The HVAC engineer discarded the option of flow meters because of the constant flow from the AHUs and the 30%+ calculated rate of outdoor air. he says that the flow meter is unnecesary because the flow is assured at a constant rate, and the flowmeter will not ensure the "quality" of this flow.

CO2 sensors cannot replace outdoor air flow monitors in non-densely occupied spaces. And per the July 2010 LEED addenda, it appears that both CO2 sensors and outdoor air flow monitors are required in densely occupied spaces. I can understand your rationale, and we have had an ongoing conversation in our office about this issue, but I think that the value of the outdoor air flow monitors is to confirm that the system is operating as designed and to problem solve later on if any maintenance issues arise.