Ionization system to reduce OA requirements

[Sifu]

Never encountered this before. I have a revised mechanical plan that shows a reduction in the min. outdoor airflow by 70% by using an ionization system. I figure this would be allowed by an analysis using the exception to 403.2. I have no idea what that analysis should look like, but figure it might be something more than a cloud on a ventilation schedule with the words "with ionization". Anybody ever encountered this? Any guidance on what the alternate method analysis should look like?

 

[Yankee Chronicler]

That exception is the one that could allow it. IMHO they key point is the first part of the exception:

Where the registered design professional
demonstrates that an engineered ventilation system
design will prevent the maximum concentration of
contaminants from exceeding that obtainable by the rate
of outdoor air ventilation determined in accordance with
Section 403.3

What documentation have they submitted to you to "demonstrate" that the engineered (ionization) system will properly prevent concentrations of contaminants? Is whatever documentation satisfactory to you in your capacity as the AHJ?

I agree that "demonstrates" will certainly require a lot more than a cloud and a note "with ionization."

 

[klarenbeek]

Its up to them to show you how it will be equivalent to introducing outdoor air, and I'm not sure how ionization will accomplish that. I've seen these put in homes, and they seem to really help with allergies and other issues like that, or in old bars where there used to be smoking they would have ionization smoke scrubbers. Not sure how this would account for occupant load though.
Where I usually see this exception used is in assembly occupancies with widely fluctuating loads, like churches or auditoriums. Carbon dioxide and temperature sensors modulate outside air dampers, bringing in more fresh air if CO2 levels go up due to increased occupant loads and modulating closed again when loads go down.

 

[Sifu]

The cloud and notation are it. Not even covered by the narrative.

I'll digress for a moment.

This is one of the frustrating parts of where applications and submittals are now. The original submittal provided a mechanical system that was approved. I spent quite a bit of time reconciling the system they submitted, checking each space, verifying total cfm, verifying OA settings, verifying each unit could provide the required ventilation. They had comments on architectural, a few scattered across the pluming and electrical. Mechanical was good. They addressed the comments and within a few days of the resubmittal started with the "what is the status of our resubmittal" questions. So far, the comments have been addressed. Then I get to go into all the changes they made that are unrelated to the comments. Hard to imagine they made these changes for any reason other than they just threw stuff on the pages to get to initial submittal then figured they could keep working while I reviewed it, and then submit what they actually planned on from the beginning.

So now, their emergency to get the plan issued gets bogged down while these changes get worked out. It will get placed on hold while they figure out how to demonstrate the OA reduction meets the intent of the provisions.

 

[Sifu]

Its up to them to show you how it will be equivalent to introducing outdoor air, and I'm not sure how ionization will accomplish that. I've seen these put in homes, and they seem to really help with allergies and other issues like that, or in old bars where there used to be smoking they would have ionization smoke scrubbers. Not sure how this would account for occupant load though.
Where I usually see this exception used is in assembly occupancies with widely fluctuating loads, like churches or auditoriums. Carbon dioxide and temperature sensors modulate outside air dampers, bringing in more fresh air if CO2 levels go up due to increased occupant loads and modulating closed again when loads go down.

Any information could find pertained to residential. This is odd, it is an administration building, B occupancy. Offices, with one large boardroom. Guaranteed to not allow smoking in the building. To me it is odd to do this since the equipment they have easily does the job. While I have never seen this, it just seems a little out of whack that a 70% reduction, across the board, from every unit is made.

 

[Sifu]

One of my previous comments was that the energy performance path report that they provided did not provide the reductions from the referenced design that the IECC required. Based on the revised energy report, it seems now that in order for them to reach the required reduction they have gone with the significant reduction in outside air that needs to be conditioned by treating the indoor air, and now they have achieved the 20% reduction.