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joshxjosh
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Registered: 12/08/15
Posts: 38
Last seen: 2 months, 6 days
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HEPA filter selection
#23442507 - 07/14/16 11:25 PM (7 years, 6 months ago) |
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I'm having a hard time choosing a HEPA filter, maybe im not educated enough yet but all of the filters im finding are rated for 2000 cfm like http://www.ebay.com/itm/Koch-Biomax-HEPA-Filter-24-x-24-x-12-99-97-High-Capacity-/162113396462?hash=item25beb61eee:g:JY0AAOSwx-9Wt66g and http://www.ebay.com/itm/162113396510?item=162113396510&rmvSB=true
Would these filters work with a lower CFM fan? According to fungifun only about a 500cfm fan should be necessary to run this size right? any input is appreciated
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Re: HEPA filter selection [Re: joshxjosh]
#23442604 - 07/15/16 12:28 AM (7 years, 6 months ago) |
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Quote:
joshxjosh said: I'm having a hard time choosing a HEPA filter, maybe im not educated enough yet but all of the filters im finding are rated for 2000 cfm like http://www.ebay.com/itm/Koch-Biomax-HEPA-Filter-24-x-24-x-12-99-97-High-Capacity-/162113396462?hash=item25beb61eee:g:JY0AAOSwx-9Wt66g and http://www.ebay.com/itm/162113396510?item=162113396510&rmvSB=true
Would these filters work with a lower CFM fan? According to fungifun only about a 500cfm fan should be necessary to run this size right? any input is appreciated
That flanders filter will need a little stronger fan, this one will work https://www.zoro.com/dayton-blower-549-cfm-115v-205a-1640-rpm-1tdt2/i/G1061216/?gclid=CPDzyrvr9M0CFYRrfgodiesMwg&gclsrc=aw.ds
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joshxjosh
Stranger


Registered: 12/08/15
Posts: 38
Last seen: 2 months, 6 days
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Quote:
Marty Mycfly said:
Quote:
joshxjosh said: I'm having a hard time choosing a HEPA filter, maybe im not educated enough yet but all of the filters im finding are rated for 2000 cfm like http://www.ebay.com/itm/Koch-Biomax-HEPA-Filter-24-x-24-x-12-99-97-High-Capacity-/162113396462?hash=item25beb61eee:g:JY0AAOSwx-9Wt66g and http://www.ebay.com/itm/162113396510?item=162113396510&rmvSB=true
Would these filters work with a lower CFM fan? According to fungifun only about a 500cfm fan should be necessary to run this size right? any input is appreciated
That flanders filter will need a little stronger fan, this one will work https://www.zoro.com/dayton-blower-549-cfm-115v-205a-1640-rpm-1tdt2/i/G1061216/?gclid=CPDzyrvr9M0CFYRrfgodiesMwg&gclsrc=aw.ds
Thanks for the reply. A ~550cfm blower would be sufficient to give me a laminar flow?
Edited by joshxjosh (07/15/16 12:38 AM)
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Re: HEPA filter selection [Re: joshxjosh]
#23442662 - 07/15/16 12:59 AM (7 years, 6 months ago) |
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Yes it's perfect for that size of filter, A lot of people that run a 24x24x12 filter use that exact same fan, I do as well. Most of the specs out there on filters and fans are for filters half that depth, hence why a stronger fan is needed for a 12" thick filter.
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joshxjosh
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Registered: 12/08/15
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Last seen: 2 months, 6 days
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Quote:
Marty Mycfly said: Yes it's perfect for that size of filter, A lot of people that run a 24x24x12 filter use that exact same fan, I do as well. Most of the specs out there on filters and fans are for filters half that depth, hence why a stronger fan is needed for a 12" thick filter.
Quote:
Marty Mycfly said: Yes it's perfect for that size of filter, A lot of people that run a 24x24x12 filter use that exact same fan, I do as well. Most of the specs out there on filters and fans are for filters half that depth, hence why a stronger fan is needed for a 12" thick filter.
So the fact that the filter is rated at 1" @ 2000cfm means nothing to us, correct?
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Re: HEPA filter selection [Re: joshxjosh]
#23442736 - 07/15/16 01:45 AM (7 years, 6 months ago) |
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It's fine, a 12" deep filter isn't ideal anyways, but they work fine, it's far less complicated than we make it out to be. I have a filter the same size and rating with the same fan I showed you, it rocks.
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Supalemonhaze
Spore syringe hater.



Registered: 10/02/15
Posts: 6,725
Loc: 12" down Europe's butthole
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Quote:
Marty Mycfly said: Yes it's perfect for that size of filter, A lot of people that run a 24x24x12 filter use that exact same fan, I do as well. Most of the specs out there on filters and fans are for filters half that depth, hence why a stronger fan is needed for a 12" thick filter.
Wrong. A 12" filter has less resistance so it actually needs a less powerful blower.
Also, 12" filters are not really what you want for hoods. They work just fine but are bulky as shit and the plenum needs to be as thick as the filter. The hood can easily be 2ft+ deep, incredibly bulky and heavy as fuck. I would try and find a 4-6" one instead. 6" filters are specifically made for laminar flow, 12" ones are made for cleaning entire rooms.
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Quote:
Supalemonhaze said:
Quote:
Marty Mycfly said: Yes it's perfect for that size of filter, A lot of people that run a 24x24x12 filter use that exact same fan, I do as well. Most of the specs out there on filters and fans are for filters half that depth, hence why a stronger fan is needed for a 12" thick filter.
Wrong. A 12" filter has less resistance so it actually needs a less powerful blower.
Also, 12" filters are not really what you want for hoods. They work just fine but are bulky as shit and the plenum needs to be as thick as the filter. The hood can easily be 2ft+ deep, incredibly bulky and heavy as fuck. I would try and find a 4-6" one instead. 6" filters are specifically made for laminar flow, 12" ones are made for cleaning entire rooms.
Exactly, a 12" filter is not ideal for laminar flow, the fan I showed him is what everybody uses though for that size filter anyways. https://www.shroomery.org/forums/showflat.php/Number/19357797#19357797
this is where I first saw a 12" filter get built, he ended up using a smaller fan at first and eneded up needing the dayton 1tdt2. He explains it in there a little more why.
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Supalemonhaze
Spore syringe hater.



Registered: 10/02/15
Posts: 6,725
Loc: 12" down Europe's butthole
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That blower he mentioned is smaller than the one I have on my 4" hepa. 12" filters are made to clean entire rooms and in order to do that, manufacturers build them with less resistance so more air can be filtered faster. If you compare the rated CFM of a 12" to a 6", this will be obvious.
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Quote:
Supalemonhaze said: That blower he mentioned is smaller than the one I have on my 4" hepa. 12" filters are made to clean entire rooms and in order to do that, manufacturers build them with less resistance so more air can be filtered faster. If you compare the rated CFM of a 12" to a 6", this will be obvious.
What are the full dimensions of your filter?
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Supalemonhaze
Spore syringe hater.



Registered: 10/02/15
Posts: 6,725
Loc: 12" down Europe's butthole
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20x22"
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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What blower are you using? It could be specs of the blower is different, is it a dayton? That one is a Dayton 1TDT2.
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Either way, he should find a filter with a smaller depth, I was just telling him what people are using for that particular size.
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Supalemonhaze
Spore syringe hater.



Registered: 10/02/15
Posts: 6,725
Loc: 12" down Europe's butthole
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My blower is ~600cfm at free air, don't have exact specs, I've built this last year. It's not the "blower's different specs", it's that a 4-6" filter has more resistance than a 12" filter.
Quote:
RogerRabbit said: You won't get laminar flow with that filter. 12" filters are for clean rooms, not flow hoods. In a clean room, you want lots of flow with little resistance. For laminar flow, you want lots of resistance so you can achieve a small rate of laminar flow. You want the +/- 6" filters for a flow hood. RR
Quote:
RogerRabbit said:
Based on the specs above, I'd go with the 6" deep filter because it has higher resistance. The resistance is what helps achieve laminar flow by creating pressure on the back side of the filter. If every inch of the back side is under pressure, the air flows smoothly out the front side.
I'd go with the 6" filter and a blower rated at 450 cfm @ 1" W.G. RR
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Agreed on a smaller filter is true laminar flow, RR says right there he suggests a 450cfm fan, what size of filter was he referring too? 12x24?
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Supalemonhaze
Spore syringe hater.



Registered: 10/02/15
Posts: 6,725
Loc: 12" down Europe's butthole
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Bigger filters still get laminar flow pretty easy. RR was just saying that to avoid going into the unknown at the time. There was a guy a few months back post a few guidelines on laminar flow hoods and he said there is no static pressure requirement for laminar flow. I'm inclined to believe him because I've helped a member with a 12" flow hood build and he only has about 0.3" s.p w.g with the prefilter included.
Keep in mind that RR is reccommending that blower at a s.p of 1.0" w.g. The guy in the other thread has 550cfm at a s.p of 0.0" w.g (free air). The blower RR was recommending was still more powerful than the one you linked.
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mushpunx
Fungus Punk


Registered: 04/20/14
Posts: 13,394
Last seen: 11 days, 22 hours
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I agree that you should probably look around for a 6" deep filter. It just makes life easier when building a hood. Unfortunately most of the filters sold on eBay are 12" deep.
Thats why I just bit the bullet and bought my filter off Fungi Perfecti- its a fair price considering you know the filter will be shipped safely (they are super delicate). I bought my blower off Ebay though.
From what I understand though- if you do use a 12" deep filter you will want *at least* a 12" deep plenum behind it.
As far as blowers go.... you NEED to read the specs. They all have a graph showing what CFM they blow at various SP.
Blowers are listed by what they push @ free air (no SP). For a 24 x 24 " filter you need a blower that pushes 400CFM @ an SP of 1 - 1.2 (.2 for the pre filter)... so you would ask the seller for the blower specs before you buy it, then look at the chart to see what it pushes at 1.2sp.
You might have 2 different blowers that are listed as 900CFM (free air), but one might push X @ 1 sp while the other pushes Y @ 1 sp
Thats why you gotta check the specs. Pick your filter size first, then start shopping for a blower
--------------------
 Amateur Mycologists United AMU Q&A
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Supalemonhaze
Spore syringe hater.



Registered: 10/02/15
Posts: 6,725
Loc: 12" down Europe's butthole
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Re: HEPA filter selection [Re: mushpunx]
#23444428 - 07/15/16 04:13 PM (7 years, 6 months ago) |
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Quote:
mushpunx said:
Thats why I just bit the bullet and bought my filter off Fungi Perfecti- its a fair price

Pretty sure FP and fair price don't go together. I mean damn, some shit is double the price you would get them on ebay. I find it comical that FP and fair price have the same initials haha.
You're right though, buying from a mycology store will bring peace of mind, although, I would only ever buy from FP as a last resort. And I really do mean, last.
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mushpunx
Fungus Punk


Registered: 04/20/14
Posts: 13,394
Last seen: 11 days, 22 hours
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My filter was around 150-160 at the time I bought it, its about 170 now
It came sealed up new at the time with flat boards on both sides and banded with plastic shipping bands
I don't think that's all that unreasonable is it?
My Dayton blower I got new in box off Ebay for 80$ and free shipping
--------------------
 Amateur Mycologists United AMU Q&A
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Marty Mycfly
Time Traveler


Registered: 12/16/13
Posts: 976
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Re: HEPA filter selection [Re: mushpunx]
#23445007 - 07/15/16 07:16 PM (7 years, 6 months ago) |
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I was going to buy one from them a while ago, so I called up to order it over phone and decided not to because the shipping was outrageous, I dont remember what it was but it was enough to say fuck that!
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