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  1. #1
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    Commercial fresh air minimum question

    Okay I haven't jumped into the info of fresh air through ashrae or the epa just yet but I wanted to hear your thoughts on this example. So obviously many businesses are closed as of now because of the virus and I noticed that the property management company for a business park I work at has shut off all the mechanical equipment most likely to pat themselves on the back for saving energy. I am unable to find my Indoor Air Quality solutions book but I just wanted to get your thoughts since staff from security and janitorial still have to walk through these 110k sq ft buildings. I am wondering if the odds of getting sick of anything other than the virus are greater due to no air flow?

  2. #2
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    Dec 2006
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    Depends on what is off gassing inside the building. If it’s a new building then you may still have adhesives and paints and glues curing. Chemicals in carpets, drywall, etc..., cleaning products, CO2 build up...

    Some buildings monitor for that stuff and operate their OA requirements based on the sensor input.

    Other buildings go with the ASHRE minimum fresh air numbers for the occupancy and type of building it is.

    I didn’t not have a great answer for you but if there are people in the building then it is still occupied and should be treated as such. I would instead suggest they should adjust the amount of OA to suit the new occupancy levels. Janitors are people who have rights to a safe work place and deserve to work in a conditioned place just like the rest of us...

    ...

    ...

    ... As I think about this more I recall the number of times I’ve worked in a freezer and on a sweltering hot roof top. The difference here is that I signed up to work in those temperature and they did not.


    Sent from my iPhone using Tapatalk
    Quickly, I must hurry, for there go my people and I am their leader!

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  4. #3
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    That's a good question ( what is considered occupied and what isn't ) worth looking up in the International Mechanical Code.

  5. #4
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    We would use 10% of total capacity as Occupied / Unoccupied

    If the base personnel Security, janitorial, electricians, engineering is below that # does it really matter? Look at it this way 110K Sq Ft with a hand full of personnel there probably plenty of air leaks, fans that are operating should be at there 10% minimum anyway.

  6. #5
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    Quote Originally Posted by VTP99 View Post
    That's a good question ( what is considered occupied and what isn't ) worth looking up in the International Mechanical Code.
    Your right, I should be more careful about how in express that. I was not stating a known fact, that was a personal opinion, I haven’t confirmed that and it would need to be checked for accuracy before they approach the customer with that information.


    Sent from my iPhone using Tapatalk
    Quickly, I must hurry, for there go my people and I am their leader!

  7. #6
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    This is only a guess and a remembrance by memory, buy I thought the fresh air requirement used to be 15% and it was change up to 20% by code?
    Then the amount of people exhaling a given amount of CO2 entered into the figuring, I think.

  8. #7
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    in that situation, I would be more worried about problems like high humidity causing mold or mildew.

  9. #8
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    Quote Originally Posted by 71CHOPS View Post
    in that situation, I would be more worried about problems like high humidity causing mold or mildew.
    20% is a lot when you're trying to cool a place,as now desired sometimes 70, when it's 100 out with 58% humidity.

  10. #9
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    Quote Originally Posted by theoldscroll View Post
    20% is a lot when you're trying to cool a place,as now desired sometimes 70, when it's 100 out with 58% humidity.
    That totally depends on the Design!

  11. #10
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    Quote Originally Posted by theoldscroll View Post
    20% is a lot when you're trying to cool a place,as now desired sometimes 70, when it's 100 out with 58% humidity.
    I agree that 20% sounds like a lot, but what is the ASHRAE,ACCA printed requirement?

  12. #11
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  13. #12
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    Mar 2015
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    www.Contracting Business. June 1,2006 an article by Rob 'Doc' Falke, titled "How Much Fresh Air Is Enough?" In his given condition and formula the #'s say 20%

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  15. #13
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    DCV plus enough damper position for minimum occupancy cfm.

    This is not official

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