Question about Ventillation near a Gas Water Heater

Discussion in 'Darkroom Equipment' started by brent8927, Feb 16, 2008.

  1. brent8927

    brent8927 Member

    Messages:
    310
    Joined:
    Feb 27, 2005
    Location:
    Milwaukee, WI
    Shooter:
    Medium Format
    I'm building a darkroom in my storage unit, which is about 12x10 ft, with a gas water heater in one corner. Is it an issue to have a fan (and probably an air purifier as well) about 6 ft. away from the heater? For the record, I have been using an electric drill in the unit and nothing has exploded yet.

    My guess is this should be fine, considering that ventillation fans are placed just above gas stoves all the time, where you strongly smell gas when you turn your burners on. But I want to make sure to be safe. Also, I don't smell gas in my storage unit, so presumably any leaks would be very minor.

    Thanks for any suggestions.

    -Brent
     
  2. Monophoto

    Monophoto Member

    Messages:
    1,691
    Joined:
    Aug 27, 2004
    Location:
    Saratoga Spr
    Shooter:
    Multi Format
    There is indeed a problem if there is a risk that a ventillation fan could ignite gas leaking from a nearby water heater.

    But the problem is that the water heater is leaking and needs to be serviced, not with the fan.
     
  3. Bob-D659

    Bob-D659 Member

    Messages:
    1,300
    Joined:
    Feb 10, 2008
    Location:
    Winnipeg, Ca
    Shooter:
    Multi Format
    A bigger problem is your fan pulling the exhaust from the heater into the room instead of it going up the chimney. Make sure you have a fresh air inlet, or lots of air leaks in the structure.
     
  4. Craig

    Craig Subscriber

    Messages:
    786
    Joined:
    Apr 8, 2004
    Location:
    Calgary
    Shooter:
    Multi Format
    I had that problem with an exhaust fan in my woodshop, it was pulling the air down the chimny and out the window where I had the fan. I didn't notice until the furnace kicked in (which uses the same chimney as the water heater) and I could smell the exhaust.

    I then opened a window at the opposite side fo the room to allow a draw and that allowed the fumes to go up the chimney. It takes very little draw to start pulling air down the chimney, rather than allowing the fumes to rise, espcially if just the pilot is lit, and not the main burner.
     
  5. brent8927

    brent8927 Member

    Messages:
    310
    Joined:
    Feb 27, 2005
    Location:
    Milwaukee, WI
    Shooter:
    Medium Format
    I'm not sure what you mean by chimney, since when I hear chimney I tend to think of what the smoke from your fireplace goes up. There is a large wide non-circular pipe, which I assume is the chimney.

    There are certainly lots of air leaks in the structure--below the door, and there are two vents for ventillation, one of which would be the outlet for the fan.

    I wonder if it would be best to reverse the direction of the fan, and bring fresh air into the unit. Then I wouldn't need to worry about any fumes being pulled into the fan (and the dust problem would be simplified...)

    I forgot to mention that when I used the drill (which generates much more power than a fan) I was within a matter of inches from the heater.
     
  6. JBrunner

    JBrunner Moderator Staff Member Moderator

    Messages:
    7,077
    Joined:
    Dec 14, 2005
    Location:
    Basin and Range Province
    Shooter:
    8x10 Format
    If your heater is functioning correctly, there is no risk. You should have it checked and serviced once a year, in any case. Natural gas needs to achieve a precise ratio with air to be combustible. If there is a problem you will smell the gas before that ratio is reached, that's why they make it stink. Natural gas is oderless before they add the rotton egg smell. Natural gas is also lighter than air, and rises. If it is propane, IDK. I do know that propane is heavier than air, and can "puddle".

    The back draft problem already mentioned is the real danger here, because you risk CO, which is a silent and deadly killer. Using the fan to vent air into the space may be a more sound set up.

    The "chimney" is the pipe the combusted gasses leave the heater and exit to the outdoors by, not to be confused with the pipes that carry the heated air.
     
    Last edited by a moderator: Feb 17, 2008
  7. Larry.Manuel

    Larry.Manuel Member

    Messages:
    291
    Joined:
    Jan 23, 2005
    Location:
    Kuiper Belt
    Shooter:
    Medium Format
    Consider a natural gas detector and carbon monoxide detector.

    Both are readily available and can give you great peace of mind. That seems like a pretty small volume to be sharing with a fuel-burning appliance. If anything did go wrong, it would go wrong - as far as gas concentrations building up - quickly. Good luck.
     
  8. JBrunner

    JBrunner Moderator Staff Member Moderator

    Messages:
    7,077
    Joined:
    Dec 14, 2005
    Location:
    Basin and Range Province
    Shooter:
    8x10 Format
    Sound advice.
     
  9. Drew B.

    Drew B. Subscriber

    Messages:
    2,017
    Joined:
    Feb 25, 2005
    Location:
    The Cape
    Shooter:
    Multi Format
    call the local fire prevention officer and/or the tank manufacturer for specs. The pipe above is the stack that goes into a chimney. Is it a pilotless unit? If you had to ask this question on a photo website...you need to ask a local fire official for a ruling on the state code.
     
  10. jnanian

    jnanian Advertiser Advertiser

    Messages:
    20,251
    Joined:
    Jun 21, 2003
    Location:
    local
    Shooter:
    Multi Format
    new waterheaters will shut off if it senses flamable materials.
    you might consider getting one ... but be advised if you do, the new heaters requier a lot more
    "air" to work correctly so if your room is enclosed, there might be a problem.

    drew's advice is spot on ...