Measuring device for system running at constant speed and rate?

This is a great question that really speaks to the intent of this credit. I'm at a presentation right now with John Straube, P.E., and I put this question to him at the lunch break. He told me that you need the monitoring because without it, the engineer actually cannot know a) what rate the fan is actually operating at, and b) how much air it is actually delivering, when accounting for friction and other operational peculiarities. It is such a common issue that a system is "supposed" to be delivering a certain quantity of air and just isn't. This credit is a good check. A thermistor is a good way to implement it.

Look at LEED Interpretation #2099 which addresses using CTs (circuit transducers providing fan status) for constant volume and 100% OA systems as an alternative to the airflow station to comply with this credit. If you have a constant volume system AND a 100% Direct OA system, you don't need the air station if you have fan status. However, it must be BOTH 100% OA and Constant Volume. This CIR is from LEED NC V2.2, but may be applied to BD+C V3.0 projects. See the applicability tab for this Interpretation in the database.