How much negative pressure?

[HIGHGROOVE]

hey community just trying to figure out how much negative pressure is neededto keep smell from leaking out? right now in my xxl hut i have enough neg presure to hold a regular piece of paper to the vent and it sucks right against the tent...if i put two pieces of paper staple them and try it falls down....how much do i need?

 

[DrunkenMessiah]

All you need is slightly more than the pressure of whatever volume you are exhausting into. You can completely eliminate smell leaks with virtually no flow at all, your needed pressure from your fan will not be determined by smell control, that isn't the toughest job it has. Enough pressure to control the smell may not be enough pressure to keep your cab temps down to an acceptable level. If you have enough air flow to keep the sucker cool, you have enough to keep the smell from leaking. Good luck, and happy gardening!

-DM

 

[HIGHGROOVE]

ya i have a 8 inch canfan max...sucking thru a can 100 and pushing thru two 600s...im suprised i can get neg pressure by sucking thru the can 100 i thought id have to put it outside the tent and push thru it

 

[FreezerBoy]

Any amount of negative pressure will keep smells in check assuming the filter is strong enough for the fan. Negative is low pressure; Positive is high pressure. Air and objects move from high to low. It's why airplanes fly. With negative pressure, all air in the vicinity wants into the cab. The only way out is the filter.

You can't pump out more than you bring in. You CAN bring in more than you pump out! That's positive pressure and it generates from intake fans. Now all air want's out of the cab anyway it can EXCEPT the filter because the filter provides resistance. The best way to avoid advertising your grow with positive pressure generation is to avoid positive pressure generators, aka intake fans.

While you can use a fan to push air, they work far better when they pull. Because negative pressure comes from increased airflow, it's best to place the fan at the exhaust end of the line.

 

[greenisgold]

You want just enough negative pressure so when you open the door it has slight resistance. The problem, like stated before, is the filter. It's very easy to suck the air out if your fan is sucking air without a filter on it, it's another story with one on. Try and get the biggest damn filter you can fit.