10 inch passive intake vent?

[cracker]

I just installed a 10 inch vent thru the roof . I used 5 ft of flext duct from the roof vent to the ceiling of my project room. I assume it's best to extend this intake vent down to the floor. Will a 10 inch duct handle a good amount of air flow? Where can I find some picts of vent setups for larger rooms? I'm working with a 10 by 10 foot room. I assume a small fan on this intake side will hinder a much larger fan on a separete output vent.

[pipeman]

10 inch duct is plenty mate, for any size room.

 

yes ideally to keep your fan stress to a minimum you should balance your intake and exhaust fans. often you make your intake fan smaller, so as to create negative air pressure inside the room so you don't get any smell leaks.

 

you also have to take into consideration if your extraction fan is pulling through a filter, because that will slow the airflow down and if you place a fan of equal capacity on the intake you will be blowing more air into the room than you are taking out which is not what you want.

 

just listen to the fan when you close the door. if it sounds like its really struggling you may need a bigger inlet fan.

[cracker]

Yes! negative pressure is my goal . I've visited a few places where just walking in the front door let Ya know what was going on. I want to keep the intake passive . I hope it is big anough that a strong exhaust fan will be sufficient. I don't expect to need a filter on the output side. This will keep it simple. I figure this is a learn as Ya go sort of thing ,but getting good advise on the basics is a real big help. I get a kick out of saying Thanks Mate!

[Frazz]

Good stuff cracker .....dont forget the intake should be insect-proof too

 

[pipeman]

cracker sound proofing fans is easy, especially for a growroom that big cause you got room to put em inside. Just wrap them in insulation as well as the duct for about 500mm each side. Rockwool is the best for sound insulation. Dont compress or compact the insulation if you can.

 

Something that sounds like a jet engine you will be hardly be able to hear after doing this. I'd also recommed covering the rockwool in plastic when you're finished. Its fibre shit and gets everywhere (Wear a dust mask when working with it)

 

[Luke Skywalker]

Good acoustic ducting as well as a fan baffle made from another short section of wider diameter acoustic duct does wonders for a fan's noise level. These use nylon fibre which won't kill you by inhaling it as it's not going to blow everywhere.

 

If you don't want to buy acoustic ducting you can get similar insulation to what's inside it called "Quiet Stuff" in various R ratings. R0.6 is what's typical for most acoustic duct, but if you can get a larger bat in the bag of Quiet Stuff (there's also another type made by the same company called "Green Stuff which isn't quite as good, but still excellent) and then wrap this around the fan and the ducting you'll get rid of an astounding amount of sound.

 

I wouldn't recommend using rockwool or fibreglass insulation anymore as there are far safer alternatives which do the job just as well, if not better.

 

A passive inlet should me a minimum of 2 times the size of your active outlet, and the larger you can make it the better. Provided you have a quality fan, particularly a centrifugal of reasonable size, you should get plenty of airflow.

 

You should definitely aim the duct down to the floor level.

 

Insect proofing is an excellent idea. Womens stocking is a great filter for these little buggers, although it's a good idea to give it a brush down or vacuum every month or so to keep it from clogging with too much dust. Some pests can still get through flywire unfortunately, although you would keep out some of the larger ones like aphis and perhaps sciarid flys.

 

Hope that helps.

 

p.s. can I ask why you don't expect to need a filter? A 3m x 3m room could produce a very large amount of weed, which would be very, very fragrant. Do you have any smell elimination/filtration happening or proposed?

[pipeman]

safer alternatives? luke rockwool isn't any more dangerous than perlite or clay balls, and same goes for fibreglass. But I wouldn't recommend fibreglass for sound insulation anyway its most effective as a thermal insulator.

[cracker]

Luke, I don't have the stones to maximize the room yet! I saw a room like that recently and the entire house reeked! So I do see your point. My only neighbor is a good 50 yards, away thats 50 meters . I intend to vent thru the roof. I really don't have any idea what the odor potential will be. I will be getting a very fragrant stock . I WILL take your advise and see what happens. I do have access to a used ozone machine as other indoor gardening equipment. The various water pumps I have on my aquariums make a lot of noise I'm used to it but I can here them at the other end of my house. Guests comment on how loud the hum is. Again I don't know how loud a big anough fan will be so that is another aspect I need to keep in mind. I also don't know exactly how I want to mount an exhaust fan. I'm interested in ideas on mounting a fan/fans in the room. I want to get 500 plus cfm this figure may be way low . I plan to start with what I can reasonably fit under a 1000watt mh on a 6 to 9 ft light mover I will take my time and great care in this endevour.

As for the hazzards of fiber glass insulation I'm still going crazy itching from working in the attic in shorts tee shirt and sandles Thanks ALL for sharing your knowledge with me.

[Luke Skywalker]

safer alternatives? luke rockwool isn't any more dangerous than perlite or clay balls, and same goes for fibreglass. But I wouldn't recommend fibreglass for sound insulation anyway its most effective as a thermal insulator.

 

So why wear a dust mask?

 

You should wear one when dealing with perlite and clay balls too, both of which give off dust which can lodge in your lungs. It is never a good idea to deal with substances which give off fine dust or fibres if you can at all avoid it, but with perlite and clay at the least you don't have to be exposed to any dust for any period of time if you moisten it in the bag and then pour it. With fibreglass or rockwool insulation, you haven't got that option.

 

Fibreglass is indeed a more effective thermal than acoustic insulator, but has been used quite well in acoustic ducting for many years. Only in the last few years have the nylon fibre types taken off, for reasons outlined above.

 

I do have access to a used ozone machine as other indoor gardening equipment.

 

Carbon filters are more effective and safer IMO. Even small gardens can produce very large amounts of smell. Anyone who even vaugely knows what that scent is, (and it's very distinctive) will have their curiosity aroused, possibly to your great detriment. Best to be safe rather than sorry. And the price of a decent carbon filter or other odour control is a very small one to pay for peace of mind, no?

 

Again I don't know how loud a big anough fan will be so that is another aspect I need to keep in mind.

 

Depending on how much lighting you have, even a small filter requires a fairly loud fan, (although manufacturers are getting quieter as the years go by). It never hurts to silence a fan. Except maybe a small temporary sting in the back pocket...

 

 

I'm interested in ideas on mounting a fan/fans in the room. I want to get 500 plus cfm this figure may be way low

 

Provided the room is entirely exhausted in under 5 minutes, (under 1 is better) then you're laughing.

 

Mounting a fan is usually fairly easy. Get some chain or thick gauge wire, then feed this through some vinyl tubing (the same as the watering tube). Two loops connected to a ceiling hook (with good anchorage mind) should hold either side of the fan by the flanges and give you a solid hold whilst reducing or eliminating vibration noise.

[pipeman]

So why wear a dust mask?

 

cause its a basic precaution you should take when working with anything that can produce dust but doesn't necessarily mean the stuff is dangerous (anything can be dangerous if you use it the wrong way). I mean if you did a study on what is more harmful to your health smoking bongs or working with rockwool I'm sure working with rockwool would be distant 2nd.

 

Fibreglass is indeed a more effective thermal than acoustic insulator, but has been used quite well in acoustic ducting for many years. Only in the last few years have the nylon fibre types taken off, for reasons outlined above.

 

not really. the reason the use of rockwool is limited is cause the stuff is so damned expensive. Nylon products are being used more because they are cheap, nothing to do with safety. Of course the manufacturing companies might spread some propaganda on safety, but this is just to try to increase sales. If rockwool was at all dangerous there would be strict WH&S guidelines covering its use, and there aren't.

 

but cost only really comes into it when you're on a big job and may be buying a truckload of the stuff. For the one off purchase to soundproof your fan the $ aren't a big issue.

 

you should realise you are talking ot someone who works in the construction industry.