Listed below is my list of questions:
A) We have several FRESH air handling units and REGULAR air handling units on the roof of our building. Fresh Air handling units provide 100% Fresh Air that is not circulated. Regular air handling units on the other hand provide air that is circulated, 13 percent of which is fresh air. LEED states that we need to supply an air volume of 14000 CFM per square foot, but it doesn’t specify whether or not the air needs to be fresh. My question is as follows: The total air flow for one of the air handling units is 10000 CFM, 1300 CFM of which is fresh air. For the purposes of calculations, I would assume that I would have to take 1300 into account and not 10000. Could someone please confirm? It would be (14000 x square footage of my area) / 1300.
Air handling units Specs
(Total Air Flow: 10000CFM)
(Total Fresh Air: 1400 CFM)
B) We have HVAC systems that operate independently; we will flush out portions of the building as they are completed. My question is: how do we completely 100% isolate an area?
C) LEED states that we need to maintain an internal temperature of 60 F? Is this the minimum or the maximum? What is the acceptable range?
D) The size of our building is roughly 400 000 Square foot (Basement plus three floors). LEED states that we need to maintain a temp of 60F and a relative humidity of 60 percent. How many data loggers or sample points do we need per square foot to confirm temp and humidity level? What do you think is the acceptable range? Should the data loggers be connected to the BMS? Should they be dependent or independent? Are there any other options besides a data logger?
E) What should I be looking for when the flush out starts? How do I effectively monitor this? What should I be doing on a weekly basis? And what happens when the temp and relative humidity are not in line with leed standards? Do I perform a re-flush out? What are the known problems or concerns during a flush out?
F) When the flush out is complete, Is there a report that I need to provide to LEED online? All the form says is to upload the IAQ management plan and to describe the flush out procedure. Is there anything else? How do I verify that an air volume of 14000 CFM per square foot has been supplied?
G) Option 2, path 1 states “Once the space is occupied, it must be ventilated at a minimum rate of 0.3CFM per square foot of outside air” I’m assuming that I can still leave the air handling unit running @100 percent (operating 24/7) once people move in. Could someone confirm plz.
James Wilson
Sustainable Design ResearchBKSK Architects
9 thumbs up
January 8, 2017 - 5:57 pm
Ethen,
A) The air supplied during the flush-out should be 100% filtered outdoor air. I recommend enlisting the project's mechanical engineer to assist with and confirm these calculations.
B) You should reference SMACNA guidelines to be sure that you use appropriate measures for isolating areas that are being flushed from non-flushing areas. Provide GBCI with documentation that shows that these measures were implemented during each flush-out.
C) 60° F is the minimum internal temperature that should be maintained during each flush-out.
D) 60° F is the minimum internal temperature and 60% is the maximum relative humidity. To my knowledge, LEED does not specify how the temperature and humidity are to be monitored. The project team should use whatever monitoring method they deem appropriate to ensure that these levels are maintained throughout the flush-out.
E) The Resources section contains links to a number of guides and publications with useful information pertaining to IAQ procedures and practices.
If the minimum temperature and maximum relative humidity levels are not maintained throughout each flush-out period, GBCI will deny credit compliance. GBCI does not offer a path for making up for this issue.
F) For this credit you only need to provide GBCI with the IAQ Management Plan and a narrative description of each flush-out conducted. This narrative should include all relevant details: calculations, the performed flush-out dates, schedule, humidity levels, temperatures and total air volumes.
G) As long as occupied space is ventilated at a minimum rate of 0.3CFM per square foot of outside air, it does not matter what level the AHU is operating at.
Lyle Axelarris
Building Enclosure ConsultantBPL Enclosure
64 thumbs up
January 9, 2017 - 3:48 pm
I agree with everything you said, James. I have seen discussion below about how to handle hours where the 60/60 rule is not met, and you see you state here that GBCI denies credit compliance if this happens. I only wonder how GBCI ever has the opportunity to deny compliance for temp/RH irregularities. You do not have to submit your data trends, so how do they ever know that 60/60 wasn't met?
I am very hard on contractors to provide me with uninterrupted data logs proving 60/60 compliance, but I never been asked to give that data to GBCI. Am I missing something?
James Wilson
Sustainable Design ResearchBKSK Architects
9 thumbs up
January 10, 2017 - 4:04 pm
Lyle,
You are correct, you do not have to submit your data trends to GBCI. It is expected that the project team will monitor temperature and relative humidity throughout each flush-out period and include confirmation in the narrative description that the 60/60 rule was met. My understanding is that there have been cases in which the project team has submitted a narrative description reporting that at some point during the flush-out period the 60/60 rule was broken and that GBCI, instead of offering possible options for making up for this issue, have denied the credit definitively.