I've just built a darkroom, approx 16 x 8 which also houses my office. There are 3 opening windows plus the door (which can all be blacked out) which give me plenty of fresh air. I'm thinking of some form of air purifier to filter out any odours and chemical fumes when using the darkroom, (Ive seen this model but its hideously expensive,,,,Filtaire Air Filter Unit Model 300) or would this be unnecessary given the level of ventilation already there?:)
I think a sensible purpose for an air purifier is to reduce dust. Sounds like you have enough air to breathe.
Thanks Bill, Forgot to mention the dust aspect, that would certainly be useful. It feels almost mansion-like in my darkroom now (my previous was 5 ft x 5 ft), a lot more space to clean now though!!
If you're saying you are willing to open up the blacked out windows (i.e., they're not sealed), that seems like the best quickest and cheapest solution to airing out, if as already pointed out you are not especially concerned with dust (loading film holders) or outside airborne contaminants. While I don't work with a lot of different chemicals in my space, I do open up the door occasionally after a printing session if I want to decrease the relative humidity and dry out the space quickly (or when cleaning).
I don't have a darkroom but, if I understand well, your one has three openings while not in operation, but has no ventilation while in operation, i.e. while in its dark state? If that is the case, I would consider some form of ventilation for the dark state, which is when you are there breathing all the fumes.
As far as I understand, the air flow should pass above your trays and take the fumes away. You should not breathe just above the trays. Chemicals are not good for the photographer's health, even when he has not headache or any particular symptoms.
Open windows are going to give you a horrible dust problem that you'll probably never conquer.
My d/r uses a regular bathroom exhaust fan with a long black hose to the outside vent, curled around so it keeps out extraneous light.
The air intake is through a filtering system built into the wall, with the air intake outside the d/r near the ceiling and the d/r vent near the floor. The wall interior is painted flat black.
Nothing beats air exchange for ventilation. Ionizing air purifiers use ozone to reduce odors and does nothing for air exchange. It might reduce odors, but I don't think it does anything to purify air other than reduce particulates. This is just my opinion of course. I have a bathroom fan and a light proof vent in my darkroom and it works well. The better solution is to have a hood type of ventilator close to the source of fumes.
16x8 is pretty big. If it is a permanent darkroom and you intend being in it for more than a couple of hours without a break then consider ventilation but if you have even a short break for 15 mins then opening the door and or windows will quickly refresh the air.
Give it a try without ventilation and see how you get on.
Normal processing involves exposure to dev, stop and fix. Nothing really noxious there.
I used a Doran Darkroom Light Tight Fan For Rooms ($130 Adorama), that I configured to be my exhaust fan. I was able to pull out the basement window and use a sheet of plywood that I got at a garage sale for $1, it has a neat Native American motif on it that I had always wanted to hang, found a great spot for it. Then used HVAC ducting ($50) to create the below. Don't mind the pink walls, the house came that way and have yet to paint....
I don't intentionally have any ventilation, but each time I print I guess the vacuum frame sucks out a good bit of the fume-laden air and vents it into the loft.