Exhaust Fan Advice

[craigb]

I plan on redisigning my workshop soon and am looking for some advice on the advisability or otherwise of incorporating a wall exhaust fan in the design.

My workshop is under the house in a room that is built in the foundations of the house. Said foundations are of sandstone which is between 350 and 400mm thick. There is no window in the room so the only vetilation is a vent in the sandstone and keeping the door open :)

I thought that an option might be to get one of those exhaust fans that mount in a wall and are usually used in luandries and kitchens.

I have a bag type DC and thought that the fan could easily handle any fine airborne particles. It should be able to "turn over" the volume of air in the room several times in an hour.

Can anybody see a problem with this idea?


TIA
Craig

[seriph1]

its a good idea and I feel youre on the money, especially in the light of having a DC already..... perhaps you could get a fan that has a little more throughput though than the base domestic one - just in case.... also, something in my memory tells me two will work better than one, with one mounted at floor level

350 - 400mm sandstone walls!!!!!!!!!!!!!!!!!!!

lucky bugger

:D

[journeyman Mick]

Just something to watch here is possible fire hazard. I recently did some work on a house where the previous owner had a woodworking room under the house (timber pole home). There was a DC outside with PVC ducting into the room. Ventilation was not great so he had 3 ceiling type exhaust fans mounted in boxes against the ceiling (floor of next storey up) with PVC ducting leading outside through the gaps between the joists. The new owners wanted to snake proof the joist gaps so I removed the fans (they weren't needed anymore) in order to fit snake mesh. All the motors were coated with sawdust. Although the motors are not brush type (no sparking between brushes and commutator) it seems to me that just the heat generated in the motor (especially one where the airflow is partially blocked by all the sawdust) might be enough to cause a fire.

Mick

[himzol]

Have to agree with Mick on this one, recently had a situation in my bathroom where this exact thing happened. We had only been in the House a couple of month so still hadn't found all the "quircks" that the previous owner had put up with.

Dust build up on th an aged motor, and you can guess the rest.

Lucky for me I happened to be on the spot and was able to control the situation fairly quickly but if the fan was in a less visible spot I could have been looking at a real disaster.

If you install them get into a regime of cleaning them as often as possible.

Himzo.

[craigb]

Thanks for that.

Yes the fire possibility was the thing that was concerning me.

They are TEFC motors in the fans aren't they?

I guess if I can get into a routine of cleaning it out weekly it should be o.k.?

I wasn't planning to use any ducting, just straight through the wall. I'm going to batten over the sandstone on the inside and put Gyprock over that. Mainly so I get a smooth wall as the sandstone is irregularly cut which makes it v. diffucult to mount anything on it.

Mick,
Is it possible to extend the distance between the inlet and outlet on these fans, as they are made for double brick and the sandstone, battening and Gyprock will be thicker than double brick?

Cheers
Craig

[seriph1]

You may be right about TEFC. I seem to recall the last one I played with was but can't recall exactly - a call to Middy's or the makers would confirm ..... you could always get super-funky and have a fan passing air OVER an aperture through the wall so as to create a venturi effect - it would suck the material out and blow it sideways at the same time

:)

[journeyman Mick]

Craig,
never actually fitted any of these fans, only the ones that just go through a hole in the ceiling, however I'm assuming that if it breaks down into an inside & an outside piece then it should be possible to rig up something.

Mick