Our building is nearly 100% naturally ventilated. Every office space has more than enough window area to be compliant. However, there are several stretches of corridor that are not within 25ft of an opening even though the opening at the end of the hall represents over 4% of the total hall area. Does the whole corridor really have to be within 25ft of an opening? We also have a constant volume HVAC system with 4 AHU's. We did our outside air test and have those numbers available. However, there are no hvac vents in the hallway, only returns. I do not know how to calculate the Vdzd for the Hallway alone. The HVAC runs for about 2 months a year because of our mild climate in Southern California. Any ideas how to achieve compliance? We already had our preliminary review and this is the last issue standing in the way of our Silver project. Any help would be much appreciated.
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Ryan Gardner
LEED EBOM CoordinatorRincon Consultants
September 11, 2013 - 6:42 pm
Another option that I was considering is using the Option B method and reporting the hallways as not meeting ASHRAE standards and as there is 0 occupancy for those areas 0 cfm would need to be provided. Does that sound reasonable?
Julia Weatherby
PresidentWeatherby Design & Co. Engineers
94 thumbs up
October 15, 2013 - 2:34 pm
Hi, Ryan-
I don't know if you've submitted already, but I will reply here since I just noticed your post. Whatever, you choose to do, you could explain in the Special Circumstances and/or Alternate Compliance Path sections of the credit form. If you choose a reasonable approach and back it up with numbers and calculations, my experience is that it will most often be accepted.
If it came down to it, as a last resort, you could probably operate your HVAC systems in air circulation mode only, whenever the building is occupied. This would pull outdoor air from the offices into the corridors through the returns. But it would be a shame to have to spend energy running the HVAC fans year round when you only need them for 2 months of the year.
If a corridor is a "dedicated emergency exit" corridor, then it does not need to be included in the IEQp1 calculations, per the EQ space matrix available on USGBC.org. I imagine the corridors in question are general circulation corridors though, so that would be of no help.
I'm not sure whether the 10 cfm per person method (with zero people in the corridor) would fly or not, because the 10 cfm/person seems to be part of the mechanical ventilation path. If you are not operating your air systems at all during some occupied periods, then I think you need to say your space is naturally ventilated, not mechanically ventilated. BUT, aha! EUREKA, I do see a sentence in the refernce guide that might be of help to you:
Under Naturally Ventilated Spaces, in the EBOM reference guide (April 2010), the last paragraph says, "Alternatively, projects may show compliance with this prerequisite by documenting that the naturally ventilated spaces meet the requirements of IEQ Credit 1.3: Best Management Practices - Increased Ventilation."
Looking at IEQc1.3, perhaps Option 2 under naturally ventilated spaces would be useful to you, as only 90% of occupied spaces have to meet the criteria. I've never done the calculations required, but this may be worth pursuing in your case.
Good luck!
-Julia
Andrew Tse
LEED Project EngineerLilker EMO Energy Solutions
2 thumbs up
April 10, 2014 - 3:49 pm
Could the 10% floor space exemption be applied to corridors and other spaces? Page xxiii of the RefGuide says it is applicable to all but IEQp2, ETS control, followed by an "if" statement. I think this could qualify via the project team "does not have control over the required element". Would that be allowed for a similar situation but in a mechanically-ventilated building in which some corridors aren't conditioned?
And has Ryan or anyone used the 0 cfm/person argument to effectively except the space via calculation claiming no occupants?
Thanks in advance!