# Ventilation 101



## meds4me (Jul 2, 2009)

I'll throw this out there....as if i didnt have enough shizzle to do. BUT, the issue of venting is all over the place here. As an ex- tin bender (hvac guy) anyone that needs some #'s crunched for calculating air flow for indoor use. Feel free to drop me a PM and a drawing of the set-up and i'll get you dialed in.  

I have 16 yrs as an hvac guy and have vented more rooms than i care to admit to..that means make-up air to exhaust neeeds. yes, I could post basic req's for venting and will do so in the near future as a permanet sticky. For now post it up or Pm me .... Peace 


Oh, heres a pic of my glass ventilation made of stainless bench and hood !


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## meds4me (Jul 2, 2009)

As a side note thats a Herbert Arnold 50mm torch with custom graphite marvers and molds from me....The torch throws a 6' x 3' flame at its hottest and widest points !! *FIRE FIRE*


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## meds4me (Jul 10, 2009)

Typically, you will want to exchange the air in your grow room every five minutes. To figure this out use the formula Length x Width x Height = Cubic Ft, then Divide by 5 to get your recommended CFM (Cubic Feet per Minute)
(Example 8ft x 12ft x 8ft = 768 divided by 5 = 153.6 so you would need at least a 153 cfm fan/filter combo to exhaust your room


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## phatpharmer (Jul 10, 2009)

I like my space to be vented 3 times a minute, IMO 1 every 5 minutes is way to long! Thanks for the info on how to calculate the air exchange that will come in handy!

                                                   Phatpharmer


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## meds4me (Jul 10, 2009)

youre welcome..i do what i can !


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## FruityBud (Jul 10, 2009)

So 4ft x 4ft x 6ft = 96 divided by 5 = 19.2?

That seems a bit small to me, i was told before to get a 425.

What do you guys think?


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## pcduck (Jul 10, 2009)

FruityBud said:
			
		

> What do you guys think?




I prefer to exchange the air in my room 3-4 times per minute


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## NorCalHal (Jul 11, 2009)

I guess a question I have allways had is how do you calculate the ducting runs into the CFM? As far as bends and length.


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## meds4me (Jul 11, 2009)

NorCalHal said:
			
		

> I guess a question I have allways had is how do you calculate the ducting runs into the CFM? As far as bends and length.


 


All duct work thats manufactured today has to meet federal construction standards. Smacna Sheetmetal manufactures assoc. has standards that  dictate  flow per 100 ft. Same as all fittings ( in a side note as old as 100 yrs ago the calculations were already "Good". Even since the computer age the orig calc were spot on).

I've started this thread to show it isnt rocket science but pretty simple. Volume - restriction = output.


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## meds4me (Jul 11, 2009)

You can also look at my : DIY; Ductulator posts as i use the common 4" and 6" ducting as examples. The #'s there are true  manufactures numbers. The bends , offsets, terminations ( flapper styles are the worst btw).All can be forund online, i'm just trying to throw in my field exp. of 16 plus yrs workin them tin snips.


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## meds4me (Jul 11, 2009)

You can also look at my : DIY; Ductulator posts as i use the common 4" and 6" ducting as examples. The #'s there are true  manufactures numbers. The bends , offsets, terminations ( flapper styles are the worst btw).All can be forund online, i'm just trying to throw in my field exp. of 16 plus yrs workin them tin snips.   
Thats why I state things on the safe side 'cause i dont have xray vision from here....I dont know what youre electrical system is based on ( Aluminium wire was used alot back in the 60-70's. But it "swells and Cools" with the circuit, whereas , Copper stays relatively the same thus no loose connections causing fires, etc.


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## meds4me (Jul 11, 2009)

Thats the thing about being a tin bender. We have to know all the basic's of electrical,framing, plumbing, venting, refrigeration. All work within a single system , to work on it , to repair or install the new "Version" .........5 trades for a single paycheck, it sucked. But i' loved the work....what can i say i'm a sucker for work....now im retired !


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## stillsmokin43 (Jul 18, 2009)

hey guys and gals looking for some input  i have a decent size growroom i have always just used about half of it for all phases . what i want to do is put in this old army locker its 3 feet by 18 inches about seven feet tall. and try to grow moms to clone in it so i can just keep my flowering cycle going . gonna use a 250 watt metal halide for this. all that to say this its gotta be light tight cause its in there with my budding girls , looking at squirrel cage fans and such online to exhaust but not sure how to mount them without light leaks someone please tell me their way to do this


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## stillsmokin43 (Aug 29, 2009)

thanks everyone for all the feedback i figured it out as usual


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## jb1984 (Sep 12, 2009)

im build a grow box using my computer. what kind of fans is the best for ventilation?


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## MindzEye (Sep 12, 2009)

Hey meds4me, Im in HVAC also... Im a journeyman in a large union... I work in central plants.. My specialty is Centrifugal and absorbtion chillers as well as cooling towers... Dont know much about duct work though, thats the tin knockers job LOL... Good to see somone else in the trade around here...


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## meds4me (Sep 14, 2009)

Hey :Mindzeye good to hear there's a bit of us in here ~ yep us ol tin benders are known for coming up with the answers~


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## mikeybtoken (Sep 17, 2009)

I should have known that I would find more construction workers around here. I'm Ex/injured 20yr GC/Carpenter/Residential Builder
I have a two part question about my 747cfm 8" vortex fan, first I will be trying to use it to cool three 8" XXXL Sun Mag lights. Any ideas of where the most effecient place to put it will be?
Second, any ideas of how to make it any quieter, the thing sound like a darn jet motor. I'm thinking about building some sort of box around the darn it to see if that will help, any thoughts? 
Thanks In Advance!


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## mikeybtoken (Sep 18, 2009)

Right now I have my vortex fan in the middle of of two 1000w lights(pushing air threw one and pulling air threw the other, I plan on adding the third here soon. I was thinking that I should either put the fan at the end of the third light to push air threw all of them to my vent, or I can just leave it where it is and see what happens.  
I will likely put the third light up today just to see if it will cool it by pulling air threw it? Hell I don't even know if it will effeciently cool all three lights?
This is my first attemp at any of this so I may just have to get really stoned and move it around?


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## anaujiram_Es (Sep 21, 2009)

hey whats goin on dude. if you have the option id say run a duct to a window or atleast a cooler part in the room ( just expect the room to warm and your overall temp to go up a lil) but if you have a window you can just duct the exhaust right out woo.

whats the cfm on the fan?

just my two cents hope it gets you on the right track


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