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Thread: Ventilation specs for darkroom

  1. #11

    Re: Ventilation specs for darkroom

    Quote Originally Posted by Maris Rusis View Post
    First establish what fumes your chemistry will produce. If the fumes are irritating or toxic then you need a effective ventilation arrangement that pulls the fumes out of the darkroom before they get to your face. If you use smell-free chemistry then the only volatile is water vapour and you don't need a ventilation system at all. The commonest and nastiest fume producer in a black and white darkroom is acetic acid stop bath. There is no reason to use it. Change to odorless citric acid stop bath and the problem goes away at no cost.
    I believe everything you say but this is largely to put my wife at ease who worries. I've been processing for yeara without bother but as I get older she worries more

  2. #12

    Re: Ventilation specs for darkroom

    Quote Originally Posted by scheinfluger_77 View Post
    The question of air changes is a good one. IIRC some old darkroom books recommended 5-6 changes per hour. If that’s true you would not need a 240cfm fan for 252 cubic feet. I don’t remember where I’ve read that and I don’t really know what is appropriate, I’m really shooting in the dark on this.
    I will peruse my copies of the negative and see if he mentions ventilations

  3. #13

    Re: Ventilation specs for darkroom

    Quote Originally Posted by Tin Can View Post
    Your space is small which will vary widely in temp, odors and toxins

    Your indicated choice may work, but I doubt it equals a WhisperLine 240 CFM Remote Mount In-Line Ventilation Fan

    I have used the panasonic in 8000 cubic feet, which was too air tight and didn't move much air until I found a way to add makeup air. It was a one room studio, DR and living space.

    I am about to put the same one in a 1500 cubic feet bedroom now DR with filtered makeup air.

    You may as well try the $20 fan, I have looked at them in box stores.

    Install a flapper to keep birds and bugs out. This one Broan® 6" Aluminum Wall Cap Round Duct

    It survived inner city ghetto and nobody screwed with it,
    [/URL]
    Thank you. I dont live near a menards but that looks way easier to install than my first choice.

  4. #14
    Drew Wiley
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    Re: Ventilation specs for darkroom

    Every darkroom realistically needs adequate ventilation and fume extraction, no matter how innocuous you think your chemistry is. You might get away with being oblivious to the issue year after year, then suddenly get sensitized to something, or quickly develop respiratory problems devoid of any other explanation. It happens, more often than you might think. Even medical deductible expenses are going to cost you more than a good fan if that happens. You get what you pay for. $20 wouldn't even buy suitable ducting, not even a realistic intake vent. It all has to be light-tight or it's useless. Incidentally, I installed that Whisper 240 in-line fan for the darkroom remodel I'm working on right now. Pricey, but ideal. But my darkroom complex uses a huge external-mount Broan industrial squirrel cage - also quiet, but very powerful if there's an accidental spill of something nasty. Normally I use it at low power, and it's overkill for the average personal darkroom, but wonderful for my own needs.

  5. #15

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    Re: Ventilation specs for darkroom

    Quote Originally Posted by Drew Wiley View Post
    Positioning of your exhaust duct is important. You want air pulled away from you over the sink and through the wall behind the sink. Then you need a light proof air intake vent behind you of sufficient size.

  6. #16

    Re: Ventilation specs for darkroom

    Quote Originally Posted by Drew Wiley View Post
    Every darkroom realistically needs adequate ventilation and fume extraction, no matter how innocuous you think your chemistry is. You might get away with being oblivious to the issue year after year, then suddenly get sensitized to something, or quickly develop respiratory problems devoid of any other explanation. It happens, more often than you might think. Even medical deductible expenses are going to cost you more than a good fan if that happens. You get what you pay for. $20 wouldn't even buy suitable ducting, not even a realistic intake vent. It all has to be light-tight or it's useless. Incidentally, I installed that Whisper 240 in-line fan for the darkroom remodel I'm working on right now. Pricey, but ideal. But my darkroom complex uses a huge external-mount Broan industrial squirrel cage - also quiet, but very powerful if there's an accidental spill of something nasty. Normally I use it at low power, and it's overkill for the average personal darkroom, but wonderful for my own needs.
    Correct. But that's precisely what I am trying to find out - how much ventilation in terms of cfm are ideal for a 250 sq ft room?

  7. #17
    Tin Can's Avatar
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    Re: Ventilation specs for darkroom

    https://humanhealth.iaea.org/HHW/Med...ign_(IAEA).pdf

    Read that, consider your usage

    and it's Cubic feet not Square feet
    sin eater

  8. #18

    Re: Ventilation specs for darkroom

    Quote Originally Posted by Tin Can View Post
    https://humanhealth.iaea.org/HHW/Med...ign_(IAEA).pdf

    Read that, consider your usage

    and it's Cubic feet not Square feet
    Thanks sorry my math skills are deplorable

  9. #19

    Re: Ventilation specs for darkroom

    For anyone interested:

    (4) There should be at least 10 air changes per hour in the room to ensure removal of
    chemical fumes from the area. The supply should be located so that it does not “short
    circuit” and feed directly to the exhaust. A darkroom supply of 50% of the exhaust
    rate is ideal.

  10. #20
    Tin Can's Avatar
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    Re: Ventilation specs for darkroom

    Quote Originally Posted by RodinalDuchamp View Post
    Thanks sorry my math skills are deplorable
    your math 6X6X7=252 is perfect, your terms were off

    you have been very specific in yours posts

    carry on regardless
    sin eater

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