Choosing a filter for flow hood.

Discussion in 'MUSHROOM CULTIVATION' started by Vibration, Sep 14, 2012.

  1. Vibration

    Vibration Active Member

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    I've mainly heard about HEPA filters linked to mycology..

    Now I'm planning to make a flow hood of my own and I'm trying to choose myself a filter.

    So I found one local store selling those.

    The highest class of HEPA filter available is EU17 with an efficiency of 99,99999997%.

    But as I understand ULPA filters are even more efficient. True?

    What should I do?
     
  2. mycborg

    mycborg Well-Known Member Supporter

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    This is not the place you'r looking for
    17 is a bit high, H14 is good shit and you can get away with H13.
    I picked H14

    And yes ulpa is serious shitt, don't know what it takes to deliver a steady laminar flow..
     
  3. Vibration

    Vibration Active Member

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    You mean it's hard to blow air through ULPA? :D
     
  4. Vibration

    Vibration Active Member

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    Well, I want to be 100% sure to get myself a good ENOUGH filter. I don't want to have contamination problems when operating with my new hood.

    I have no experiences with flow hoods what so ever. That far I've been only using my SAB which have given me pretty high success rates.

    I hope the flow hood will not bring my success rates down :D
     
  5. mycborg

    mycborg Well-Known Member Supporter

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    Well H14 filters out practically all particles in the air. When it comes to ulpa they are ridiculous efficient in filter the air.
    I'm not shure but the win in filtration must give you more resistant. I haven't research it cous I settled with H14, it's what most people settle with if I got it right.
    Here's some good reading on the hepa standard,
    http://en.wikipedia.org/wiki/HEPA

    My filter is still in production, I can't stand the wait...
     
  6. rogue

    rogue ♥ Hooked on Mycelium ♥ Moderator Mushroom Doctor Supporter

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  7. Mephistophelian

    Mephistophelian Six Legged Pilot Mushroom Doctor

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    Fwiw Vibe, I ran with the standard HEPA 99.97% (or is it 99.997) whichever it is, I've never had an issue and the majority of people that I've met with hoods only have 99.97's in their hoods. Good price, good quality, never had any worries. ULP is extreme...
     
  8. joyless

    joyless Member

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    i have 99.95 which seems to be h13. no complaints whatsoever, if it ever breaks i would buy it again
     
  9. beratung

    beratung Gnome

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    :popcorn1:

    I'll be starting on my own soon, looking forward to any advice that comes up.
     
  10. the_chosen_one

    the_chosen_one there are no answers.. only choices Moderator Mushroom Doctor

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    indeed. keep in mind that the filter will also gain in efficiency with use. just how fast depends on a lot of factors, but it's an inevitable fact.. 100% efficiency is no air flow at all ;)
     
  11. Larynx

    Larynx Well-Known Member Mushroom Doctor

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    Not necessarily, if my understanding is correct.

    That would mean that my 500cfm blower, blowing through a 99.97% filter would only be putting out .15cfm. I dont have a way to test the air flow from a hood right now, but I know other ones I've used felt like more air was coming out than that. It's less than 1cfm outa a surface that big, I don;t think you would feel anything.

    I think the efficiency percentage is the percentage of particles (from dust to virus) that gets filtered out of the air. So it's 99.97% of the particles are filtered out, and not 99.97% of the air so to speak.

    I could be mistaken.
     
    Last edited: Sep 15, 2012
  12. Jeff

    Jeff Well-Known Member Moderator Mushroom Doctor Supporter

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    One thing that you forgot to factor in Larynx is that rating is for particle size also. 99.9997 down to 3 microns. I would have to agree with TCO. A 100% hepa would equal no air flow.
     
  13. Larynx

    Larynx Well-Known Member Mushroom Doctor

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    Ahh Gotcha. Thanks Jeff
     
  14. Vibration

    Vibration Active Member

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    Well, 99,97% it is going to be then. I thank you for sharing this knowledge with me.

    Rogue, thanks for the link. There seems to be many questions answered for me, but at first it looked pretty complicated.

    I guess I will just need to take step by step.

    First step is going to be the FILTER :)

    Although in EvilMushrooms666 tek he mentions 99,99% filter: "I searched for HEPA's and found a lot of good companies in the states
    offering exactly what I needed. A 24"X24"X6" HEPA %99.99 @.03 micron
    filter.
    "
     
    Last edited: Sep 15, 2012
  15. saltshaker

    saltshaker Member

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    My most challenging point while I too have been looking for flowhood pieces is the blower. Damn they vary a lot. Both in price and style.

    What size is the Trichoderma spore?
     
    Last edited: Sep 15, 2012
  16. the_chosen_one

    the_chosen_one there are no answers.. only choices Moderator Mushroom Doctor

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    yeah, it's an inside the industry joke actually. air can go clear down to a molecular level in size, but so can some contaminants. none of those contaminants are anything to worry about in our hobby though. the way hepa's measure efficiency always has kind of bothered me. the MERV rating system is much easier to understand..
    http://en.wikipedia.org/wiki/Minimum_efficiency_reporting_value
    the company i work for makes and sells MERV 13 filters. i was actually involved in the development years ago. with some shopping you may be able to find MERV 17-20 on the internet. the last time i looked they were close to hepas in price, but it's been several years and the air quality industry has boomed since then. perhaps prices have come down.
     
  17. Jeff

    Jeff Well-Known Member Moderator Mushroom Doctor Supporter

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    Yeah it is not likely that you will ever hit zero flow but it does match the true definition.
     
  18. the_chosen_one

    the_chosen_one there are no answers.. only choices Moderator Mushroom Doctor

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    unlike the lower resitance merv ratings that are simply rated using CFM calculations, the thing that makes merv 15 and above different is that water column (W.C.) pressure is what drives air through the filter. one could throw 3 tons of air (1200 cfm) at a hepa all day and get no flow at all until a W.C. pressure is established. this means the hepa filter must be used in some sort of plenum where air is trapped and the filter would be the weakest point. i believe most hepas operate at 1" W.C.

    i've been meaning to put together a thread using a MERV 13 filter and a UV light as a flow hood for several years now lol... jeeze :facepalm:
    one can purchase both of these, run a much lower CFM blower (maybe even some bath fans) and build a plenum for less than the cost of just the HEPA filter alone.
     
  19. mycborg

    mycborg Well-Known Member Supporter

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    interesting TCO!
    I would definitely read that MERV13 + UV thread. Start writing :)
     
  20. CAPN_TURTLE

    CAPN_TURTLE MYCO-BUG

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    What did you end up getting and how did it work out? I see you said you were going with a 99.97 then say you found a 99.99 at the bottom. I'm still trying to figure out a filter myself and would love to see what you ordered.