darkroom ventilation advice needed

[aleksmiesak]

Hi there!

I'm almost done with building my darkroom and was doing some research on fans. My space is about 7ft wide and 30ft long. I plan on replacing one of the windows (there is a total of 4 that will be covered) with plywood with a fan installed in that. Could someone recommend a ventilation system I should be looking at? I have looked on B&H and Freestyle websites and they both have pretty much the same kits and very few review. Anything I should stay away from?

In advance huge thanks for any help!

Cheers!
Aleks

 

[zsas]

<$200 for the whole caboodle if I can remember:

(there was a url link here which no longer exists)

(there was a url link here which no longer exists)


I had to mess with the Doran fan to get it to vent out. I suppose a different maker's fan could be used, like a bathroom exhaust fan, I just happened to have been given the Doran and make it work as the above show....

 

[tkamiya]

My recommendation will be a Panasonic fan. If you google Panasonic Bathroom Fan, you'll see a bunch. While they are more expensive, they are very quiet. All you hear is a rushing of air, not the motor going BWAAAAAAAAAAAAANNNNNNNN!!!!!!!!!!!!!!

 

[aleksmiesak]

I should probably mention that my ceilings are about 12 ft tall and I really don't want to deal with suspending anything that way. The window is pretty much my only option and I'm hoping that will be sufficient without the need of a hood over the sink. I'm hoping that louvers installed in my door at the other end of the room (about 20ft away) will help with generating sufficient enough air flow through the room.

 

[Jim Jones]

When you force air out of a darkroom, air must also enter it. Consider forcing filtered air into the darkroom to control dust. Perhaps there will be enough leaks for the outflow. If not, an exhaust port with a light trap can be installed in one of the windows, preferably far from the fan for cross ventilation. Having the fan exhaust air from around the developing trays would be healthier, but a dust free darkroom saves a lot of spotting. Anyone who can build a darkroom can improvise an efficient ventilation system cheaper and perhaps better than buying one.

 

[jeffreyg]

Aleks,

You should figure out the cubic feet of the room. Although you didn't mention the height of the ceiling I will assume it is about 8ft. so about 1600cubic feet. Pro-lab made a fan that will handle a 20x20ft room and exhausts 600CFM there are others that are about half the price that are designed for smaller rooms that exhaust 400+CFM but may be less effective in a larger room. They are light tight and as mentioned you need a light tight intake and the fan exhaust the chemicals not pull them towards you. The one that exhausts 600CFM would give you a change of air about every three minutes. So if going with some other type of fan you could use these specs as a guide.

 

[SkipA]

jeffreyg, he said 12 foot ceiling in a subsequent post, so 7 x 30 x 12 feet = 2520 cubic feet. I don't think any of the Panasonic bathroom fans will be effective for a room that size. I would probably consult an HVAC person in my area, but probably something like this Doran Pro-lab SL/PS Darkroom Exhaust Fan would do the trick for a room that size. It's not that much more expensive than a Panasonic 150 CFM fan.

 

[Henry Alive]

I would like to recommend you the system that I have. Look here: (there was a url link here which no longer exists)
I hope it helps!
Henry.

 

[Ken Nadvornick]

Lots of really good setups from everyone. I'll go ahead and add my somewhat unique approach using matched twin high-capacity industrial fan units, described in (there was a url link here which no longer exists) from 3/31/2010.

It's worth noting that I live in the Puget Sound (Seattle, Washington) area where the summers and winters are relatively mild. This means I almost always have a pleasantly cool pool of air available right outside for my direct ventilation needs, even in January. Don't know how well it would work if the temps were like Phoenix, Arizona.

Like you, I also boarded up an existing window, then mounted my fans inside a completely enclosed external box outside the house. This keeps down the noise considerably. For those occasional very cold winter days (it was -2F/-19C one night a few years back) I also installed a light bulb socket inside the exterior fan enclosure, with a wall switch inside the darkroom next to the speed control. I can use this to keep the fans warm and running smoothly when it's so cold outside that I only need to run them at very low RPMs.

Ken

 

[Fujicaman]

Years ago, Petersen's Photographic had a series of books. Several of them had plans for things you could make. One of them had plans for a vent hood to go over your darkroom sink. If you're interested,PM me and I'll copy the plans and mail them to you