Avoiding carbon monoxide

geauxpez · Apr 23, 2007

My wife has given me the thumbs up to convert our laundry room over to darkroom duty as long as we can still reasonably access the washer and dryer. This small room is not heated or cooled which is not a huge problem (I live in Gorgia, USA). The largest issue is the gas hot water heater in the room. There is an opening in the lower part of one wall to the outside for ventilation which brings things up to code, BUT my concern is that if I run a ventilation fan to push air out (and draw air in through the wall opening), could it also pull carbon monoxide that is supposed to go up the exhaust chimney on the gas heater into the room?

Loose Gravel · Apr 23, 2007

Is there a way to separate yourself from the water heater? Consider your own input and output air supply. All this depends on how leaky the room is to outside air and how good your draft is. I don't image it would be a problem, but it is good to be cautious. Buy a CO sensor at the hardware store.

Roger Hicks · Apr 23, 2007

geauxpez said:
My wife has given me the thumbs up to convert our laundry room over to darkroom duty as long as we can still reasonably access the washer and dryer. This small room is not heated or cooled which is not a huge problem (I live in Gorgia, USA). The largest issue is the gas hot water heater in the room. There is an opening in the lower part of one wall to the outside for ventilation which brings things up to code, BUT my concern is that if I run a ventilation fan to push air out (and draw air in through the wall opening), could it also pull carbon monoxide that is supposed to go up the exhaust chimney on the gas heater into the room?

Why not operate the fan as positive pressure?

I did this in a darkroom with a gas fire (see 'Our Darkrooms' in the Photo School at www.rogerandfrances.com) and always had clean sweet air.

Cheers,

R.

Denis P. · Apr 23, 2007

The advice about CO sensor is very good.

Be careful about gas water heaters which are located in rooms/spaces which have exhaust fans wich pull the air OUT... If the fan is too strong (and/or the air inlet is not big enough), the fan will start extracting ("pulling") air from the gas heater chimney!

A neighbour almost died in her bathroom about a month ago, due to the same problem - gas heater is in the bathroom, and the bathroom has automatic fan, which turns on as soon as the light is switched on. The air inlets on the bathroom door were not big enough, and the fan started sucking air from the chimney! She fainted, and luckily a family member found her within minutes.... Still, she was in hospital for almost a week.

So, be very careul, and make sure there's another air inlet, bigger than the gas heater chimney....

donbga · Apr 23, 2007

geauxpez said:
My wife has given me the thumbs up to convert our laundry room over to darkroom duty as long as we can still reasonably access the washer and dryer. This small room is not heated or cooled which is not a huge problem (I live in Gorgia, USA). The largest issue is the gas hot water heater in the room. There is an opening in the lower part of one wall to the outside for ventilation which brings things up to code, BUT my concern is that if I run a ventilation fan to push air out (and draw air in through the wall opening), could it also pull carbon monoxide that is supposed to go up the exhaust chimney on the gas heater into the room?

I had a gas hot water heater in my darkroom for many years (no washer and dryer though.)

As long as your heater is working properly you will have no problems since I assume your heater is vented and has a proper exhaust flue.

Your biggest problem will be dust created by the clothes dryer.

Don Bryant

geauxpez · Apr 23, 2007

There is already an exhaust fan in place....not sure if it could be reversed. The air inlet in there currently SHOULD be big enough to take care of the fan. I will get a CO sensor to be on the safe side.

I didn't think about the dust issue. MAAAAANNN... Well, I didn't intend to leave my enlarger in there anyway. I was going to roll it in & out on a cart to minimize the exposure of my lenses and such to temperature fluctuations. Trying to avoid fungi.

Thanks for the advice guys. If...WHEN I get this thing going in coming weeks, I'll post an update.

Adam

geauxpez · Apr 23, 2007

Just realized that I misspelled GEORGIA in my initial post. That's what happens when I try to sneak a little personal time at the office.

bdial · Apr 23, 2007

You might be able to add a powered vent to the water heater just to make sure. It's mounted on the heater's flue and comes on whenever the burner is operating. When you get to replacement time, you can investigate sealed units that use no room air at all.

resummerfield · Apr 23, 2007

Roger Hicks said:
Why not operate the fan as positive pressure?

I did this in a darkroom with a gas fire (see 'Our Darkrooms' in the Photo School at www.rogerandfrances.com) and always had clean sweet air.

Cheers,

R.

Roger is exactly right here. A fan that exhausts, creating a negative pressure in the room, has a potential to create a back-draft situation with a combustion appliance. Plus, a positive pressure fan with a filter will minimize dust problems.

Photo Engineer · Apr 23, 2007

Carmen Monoxide?

Is it the sports figure or Bob Trow? http://en.wikipedia.org/wiki/Bob_Trow

Oh, CARBON. Sorry.

PE

Curt · Apr 23, 2007

There should be a Co2 detector in there now and in all of the living rooms in a house with gas. I worked in an ER at a medical center with a hyperbaric chamber and I can tell you that diving accidents take a back seat to the number of house hold accidents.
Curt

geauxpez · Apr 24, 2007

bdial said:
You might be able to add a powered vent to the water heater just to make sure. It's mounted on the heater's flue and comes on whenever the burner is operating. When you get to replacement time, you can investigate sealed units that use no room air at all.

It's a fairly new unit, so at this point the less I spend on that the better.

juan · Apr 24, 2007

How long will you be performing an operation that requires the dark? Will you really be inside long enough to need extra ventilation?

For instance, you don't say what format you shoot, but suppose you want to develop a roll of film. You shut up the darkroom for maybe 10-minutes at most to load the tank. Then open the door to actually develop the film, and you'll have plenty of ventilation. Printing is the same - expose a print, develop it and fix it - maybe 15-minutes at most - then open the door for a few minutes to allow for ventilation.

I do all of my work in a bathroom with no ventilation at all other than the door. I have to work in spurts, but I've never had a problem.
juan

Photo Engineer · Apr 24, 2007

Actually, CO dectectors (carbon monoxide) are available for about $25 US here and work quite well. You may want to test things with one of these detectors. We have had one in our home for years.

PE

Sal Santamaura · Apr 24, 2007

UL listed CO detectors commonly sold in the US are reportedly not so good. Claims have been made that they are slow responding and have high thresholds, allegedly as a result of the UL standard being established that way to avoid numerous 911 calls. This thread

http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=275636&_#Message275636

talks about two fast responding detectors. I have the CO Experts unit in my home.

geauxpez · Apr 24, 2007

juan said:
How long will you be performing an operation that requires the dark? Will you really be inside long enough to need extra ventilation?

For instance, you don't say what format you shoot, but suppose you want to develop a roll of film. You shut up the darkroom for maybe 10-minutes at most to load the tank. Then open the door to actually develop the film, and you'll have plenty of ventilation. Printing is the same - expose a print, develop it and fix it - maybe 15-minutes at most - then open the door for a few minutes to allow for ventilation.

I do all of my work in a bathroom with no ventilation at all other than the door. I have to work in spurts, but I've never had a problem.
juan

Processing film is not really an issue...once I get the reel(s) loaded, I have no problem leaving a door open & right now I use a changing bag. As for printing, I usually work on that for 2 or 3 hours at a time. I like to keep things closed so that my eyes don't have to re-adjust every time. I already have a vent fan and two other sources of fresh air (one opening to the outside & one that opens into the house proper). I forgot that there's a window in the door that opens into the house -- I can open that as well and put a large curtain over the door so air can still come in through the window.

Thanks for the additional pointers, though.

gr82bart · Apr 24, 2007

Separate your darkroom from the hot water heater if you can, positive pressure, high air change rate and a CO2 detector.

Regards, Art.

Curt · Apr 24, 2007

I have a pellet stove in my shop in the garage, which is a separate room in the garage with no ventilation or a small amount of fresh air from a door, and I have a First Alert smoke detector next to it and above the stove. It doesn't go off unless I open the door and let the chamber with smoke pour out. So I open the door if I need to restart the stove. It also has an LED window that gives the level. Taking the precautions of a clean flue and shut offs are necessary with gas of course. Here we have earthquake shut offs at the entrance.

Helen B · Apr 24, 2007

Of course you could do it the traditional way and take a canary into the bathroom with you instead of one of those fresh-fangled CO detectors. All you would have to work out was how to see when it falls off its perch. Maybe there's a market for genetically modified canaries with slightly phosphorescent plumage.

Avoiding carbon monoxide

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