We are currently confusion regarding a review we received. Our building is a multizone building that is supplied with 100% outdoor air. From the review team it is required to perform critical zone calculations even though spaces are supplied with 100% outdoor air. From my understanding critical zone calculations are required for recirculation systems to determine the Primary Outdoor air Fraction (Zp) and System Ventilation Efficiency (Ev).
How can i determine the critical zone for systems with 100% outdoor air supply? Shall I use instead the occupant density and zone distribution configuration (Ez) as the critical figures?
Thanks
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Samantha Harrell
LEED Project Reviewer certificate holder115 thumbs up
March 26, 2012 - 8:30 am
You are correct, the critical zone is not an applicable calculation factor when the system supplies 100% outdoor air. A quick way to test this is to download the latest IEQp1 Sample Form (v04, active version) from LOv3 and indicate that the project is 100% outdoor air. The form will only allow inputs for applicable calculation factors.
Sofia Otterheim
November 26, 2012 - 11:31 am
We saw this discussion regarding IEQp1 you had in March 2012.
In our project, our building is also supplied with 100% outdoor air. Is it correct that we can not use calculations with critical zones according to 62MZ? Instead, we must use the VRP Compliance Calculator?
If we shall use the VRP Compliance Calculator, must all occupiable areas be included for these calculations (and not only the critical zones). Is this correct?
Thank you in advance.
Christopher Schaffner
CEO & FounderThe Green Engineer
LEEDuser Expert
963 thumbs up
November 26, 2012 - 12:01 pm
Yes, as stated, the concept of "critical zones" does not apply to a 100% OA system. Provide the calculation for all the spaces.