Garage extraction

[andeep]

I have bought an industrial 12" axial fan to wall mount in order to provide extraction in my garage. The garage is 52 cubic metres and the fan will move 0.55 cubic metres a second.

Just a few quick questions. Where would it be ideal to mount the fan? I'm thinking as far up the wall as a I can. Also will I need some form of intake? Should this be placed at the complete opposite end to the extraction fan?

The garage is rectangular, with the garage door on one end, and the other end is the door to the house. One of the long sides is attached to the house, the opposite long side is an external wall. So the only place I can really install the fan is the long side external wall, it can be at either end of the wall. So ideally where should I put the intake? I am thinking to open the garage door slightly and use this as an intake when I need extraction? If I do this, then I can put the fan on the long wall as closest to the opposite end of the garage of the garage door?

I do a lot of welding and grinding in the garage, will the occasional spraying.

 

[andeep]

Heres a picture to show the garage more clearly (top down view):

 

[brightspark]

put it in the middle high up as posible andf closable vents or a gap under the garage door .the fan will pull up the fumes from the floor as heat rises as well. if u just open the garage door nothing much will happen

 

[andeep]

Can't really put a gap under the garage door as it touches the floor when fully shut. Where should I put the intake vents? On the wall where the garage door is?

 

[brightspark]

Can't really put a gap under the garage door as it touches the floor when fully shut. Where should I put the intake vents? On the wall where the garage door is?

if its a 12 inch fan a couple of 6inch vents would be adequate low down one either side . u would get a good draw of them

 

[andeep]

Okay cheers. Will put 2 6" vents, one either side of the garage door.

Would it not be better to put the extractor fan on the long wall towards the left as opposed to the middle? That way it will surely clear the entire garage?

 

[steve.h]

have you looked at the big inline fans, like the ones the people who grow maughty plants use, a small 4 inch fan can pull 180 m3hr, very good little fans and dont need a big hole, you could have a 5 or 6 inch, have a two pipe splitter and draw from above and below or both above at either end of garage, simples.

 

[andeep]

I've already bought the axial wall mounted fan. Just need to find out what's the best placement for it

 

[chevy2]

I've got an approx 350?mm wall mounted industrial fan in my place,
24' x 18' workshop, it's mounted on the opposite end from the doors about a foot down from the ceiling,
Thought it would be better at pulling the welding fume if mounted high as the fumes rise,
Works real well, use it for both welding and grinding.

 

[andeep]

So it would make sense to have the intake vents at one end, and the extractor fan at the complete opposite end so the airflow and clear the entire garage?

Sorry if I'm being daft, just want to make sure before I cut a massive hole in the wall!

 

[chevy2]

So it would make sense to have the intake vents at one end, and the extractor fan at the complete opposite end so the airflow and clear the entire garage?

Sorry if I'm being daft, just want to make sure before I cut a massive hole in the wall!

makes sense to me,
you dont really want to be pulling out the clean air,

pulling out the crap then replacing it with clean has got to be better,

my fan is at the opposite end to the garage doors and when the fan is switched on it pulls the doors shut tighter proving it's pulling clean air from the doors area.

 

[andeep]

Sounds good, will install it in that configuration then.

Just noticed that you're in Chesunt, I'm just over in Cuffley

 

[chevy2]

Sounds good, will install it in that configuration then.

Just noticed that you're in Chesunt, I'm just over in Cuffley

Seeing as you're a neighbour and fellow welder please keep the noise down with that grinder... And point the extractor towards Potters bar, i'm creating enough crap down here already!

 

[kelsham]

Some years ago I worked on printing machines that used ammonia to develop Diazo coated paper.

Naturally fumes could be a problem on the developed paper. One customer complained bitterly about the smell.

The customer was an air conditioning and ducting company.
They spoke to me about it,and baffled me with CFM calculations. It was decided that they would fit axial fans to clear the fumes.

A few days later I was back, in spite of their best efforts nothing appeared to improve the situation. I took a smoke testing kit to the printroom and was amazed by the way the air flowed in the room.

I expected to see the air drawn from above the paper tray due to where the fans were placed.
In fact the fans drew the air along the walls they were mounted in. and left the air to eddy back towards the print machine,over the top and into the operators face.
We moved the machine and the fans in the room and eventually solved the problem.

The point being don't assume you know where the air flow will be.

Regards Kels.

 

[andeep]

Thanks, will keep that in mind Kels.

Chevy2, haha I will try my best!

Fan came today, lovely and big;



Do I need to install come kind of cover on the outside of the wall? Just thinking that water might come in? Don't want to restrict airflow too much with a restrictive cover.

 

[vwhotrod]

would a cooling fan from an old car rad not do the same job just need a belt and an old washing machine motor?

 

[Paul G]

I have a fan in the apex of the roof. The other end of the workshop I have an up & over door which I crack open a few mil.

I have a length of flexy ally duct fitted (I use the term loosely) to it and dangle this above the fume source,
the lathe when using oil, or a dirty welding job.

I think it's better to "suck it and chuck it" from source, than to breathe it in on its way to the fan.

The duct is sold as a tumble dryer outlet, 500mm long, but expands to 2m.

HTH
Paul G

p.s. No derogatory remarks about my pet spider please.

 

[gordon stephenson]

Will 2 X 6" inlets be enough?, I seem to remember from my college days if you are going with half the diameter of your fan then 4 inlet holes of 6" would be required to give a full flow?