Hello,
I understand the part of the credit involving CO2 sensors but do not understand the language involving the outdoor airflow measurement device:
"Complete Table IEQc1-2 for all mechanical ventilation systems where 20% or more of the design supply airflow serves nondensely-
occupied spaces."
In my design, all spaces are non-densely and I have multiple indoor units. I have one monstrous unit that provides direct OA to all of the indoor units. How would the phrase above be applied to my design?
Thanks,
Resmey
David Hubka
Director of OperationsTranswestern Sustainability Services
527 thumbs up
August 16, 2012 - 5:46 pm
All indoor units, served by the montrous unit, must be input into Table IEQc1-2. I assume the indoor units are fan coils or heat pumps; they are considered the system level and therefore each indoor unit must include a OA measurement device with an accuracy of +/- 15% of the design minimum outdoor air rate. Additionally an alarm must be triggered when conditions vary by 10%.
John Kitsalis
PrincipalNew England Engineering, Inc.
3 thumbs up
August 17, 2012 - 10:10 am
Thank you! That makes much more sense. Although, how does the 20% come into play? I am thinking that the OA provided to each individual indoor unit must be 20% or more of the supply of the "monstrous" unit.
Additional Info: (The "monstrous" unit is actually an ERV UNIT that provides 100% OA)
David Hubka
Director of OperationsTranswestern Sustainability Services
527 thumbs up
August 22, 2012 - 5:30 pm
If the project building contains an AHU in which at least 20% of it's design supply airflow is being provided to a non-densely occupied space; then an OA measurement device must be installed at the AHU. Your building does not include densely occupied spaces therefore every AHU must include an OA measurement device. If your project contained an AHU that exclusively served a densely occupied space; this AHU would not need to be included in table IEQc1-2 of the credit template.