Path 2 Flushout

Amy, I'm not sure what the benefit is for extending the readings as you suggested. If the RH rose above that level, you're not meeting the credit reuqirements, unfortunately. To the letter of the LEED language, you're not complying for the flush-out occurring during that time. I would either extend the flush out, or if it's too late to fix the situation, note the issue in your narrative and hope that GBCI doesn't get too fixated on it.

Tristan does LEED allow for the flush out to be extended to offset periods of time that RH or temperature could not maintained?

Yes, that's the solution—if you're not meeting the specs for part of the flushout, just extend it.

Okay, so someone emailed me and said that GBCI had not accepted this approach on a project. But it was secondhand info and they did not have details. Has anyone else had trouble with this?I can see an issue if RH gets really off the charts and is not handled properly, but I would be surprised if there is an issue, otherwise.

In March 2016 we had GBCI deny IEQc3.2 for to this same issue on a LEED-S project and were not given the option of providing additional documentation to address the comment. We heard from a contact at GBCI that this review was done by a consultant, not by GBCI in house (not that it should matter but interesting nonetheless).
This approach has been approved by GBCI several times in the past so the outright denial was a surprise to us.
Here is the reviewer's comment:
"The LEED Form states that an Indoor Air Quality (IAQ) Management Plan was developed and implemented and that the project complies with Option 1, Path 2: Early occupancy flush-out. However, the documentation does not demonstrate compliance. This credit requires the rate of outside air should
not cause the interior temperature to drop below 60 degrees and relative humidity should not exceed 60%. The documentation indicates that these parameters were exceeded on several occasions."
Any recommendations on how we should proceed?

Renee - By the literal interpretation of the Credit with no considerations for common sense, previous scientific studies, or real world applications it appears you are out of luck. The issue is the flushout Credit and procedure itself. I would ask for the scientific peer reviewed studies that show flushout has any significant value regarding improving indoor air quality. I am sure the sound of crickets will be deafening. The professional indoor air quality professional and industrial hygiene community has known for decades that flush-out is pretty much useless for improving indoor air quality, especially long term. Reference a study in Washington state cited as: James Burt , Nancy A. Nelson & Nancy A. Nelson (1996) Effects of Ventilation Flushout on Indoor Air Quality in a Newly Constructed Office Building, Applied Occupational and Environmental Hygiene, 11:6, 546-552, DOI:10.1080/1047322X.1996.10389372. This document concludes "flushout procedure offers only minimal potential as a means to reduce airborne contaminants, particularly VOCs, that off-gas from construction materials and furnishings". This study was done at the time the State of Washington was requiring its new buildings to be flushed out before occupancy. I believe that the flush out Credit in the first and subsequent LEED systems was, in part, based on this requirement from Washington state. I also believe, not positive, that the State of Washington removed this requirement after getting data such as that presented in the article showing the flushout had little value. My point would that if flushout is practically worthless as is, then why does the temperature and humidity it is conducted under even matter.

To update my previous comments on this topic, I have heard directly from GBCI that they are interpreting the temp/humidity requirement quite strictly. If you go outside of those bounds it's "game over" for the credit, on the logic stated in the LEED reference guide: "Not all outside air is equal. Depending upon geography and season, it can be very cold or damp. Because of this, prudent limits have been set to ensure no harm comes to the building and potentially to the occupants..."Another reason to consider air testing as the better path for this credit, particularly in a region and season where air quality requirements might not be met.

So, does this mean that if there are 2 minutes out of a 72-day flushout where the recorded temperature is 59.4F (eg. if contractor uses a 61F setpoint and the HVAC doesn't respond quick enough), the credit will be denied?

How does the reviewer verify that 60/60 was met to this level of scrutiny?

If the data logger has missing data, is the credit denied?

What is the harm of sub-60F temperatures "to the building and potentially to the occupants" if RH is maintained below 60%?

Lyle, all good questions. In my contact with GBCI they indicated they are looking at this ths pretty strictly, so I would assume the worst.I hope the EQ TAG will look at this more closely. If in the meantime you need specific project guidance I would contact GBCI or submit an CIR. And let us know what you learn.

@Lyle's comments - see my post above on how the GBCI will backcheck the narrative and log of your flush out. I was specifically requested for hourly log information; however, I'm guessing there are other reasonable durations. Now; all that said....if you are running equipment with OA and it is showing 100% RH outside by weather archives - we can infer that GBCI will request to confirm that your indoor reading on RH/temp were maintained. Further, I would expect there are some basic charts on "reasonable agreement" windows for OA percentages vs. outdoor RH values that would trigger comments - meaning "I question your log since you are showing 75% OA was set for the system and it was 100% RH on the weather archive". I did ask though if there was a minimum time for a Path 2 flush out could be maintained - answer was no. So...after achieving your 3500 CF/SF....It would be logical that you could present an approach to compliance (with a RH/temp log of ongoing data) despite it taking an extended length of time to achieve the balance of the full 14k requirement. Of course, 60/60 conditions must be met for the duration of a Path 2 as well.

Agree with Tristan on this credit...it is time for the EQ TAG to take a good look at purpose and endstate of this process.