Darkroom design question

Hello all,

I am in the beginning process of building my darkroom and I have gone over all the darkroom portraits and have really got some awesome ideas and inspiration. The only thing is my darkroom is going to be a bit different and I was wondering if someone may help me. I will be taking over most of the laundry room ( after much talk with my wife lol) and in the corner of my dark room will be the hot water tank and furnace. The area that they take up will be 6 feet x 5 feet I am placing my sink on the opposite wall and will be about 7 to 9 feet away from the furnace. My biggest concern is blowing myself up LOL does anyone know if this will cause any problems for me down the line? it's the chemicals and pilot light that I am most concerned about. The actual room will be 9 feet by 10 feet with a square of 5x6 that I can not use. I plan on having two dry counters and the sink I will add a formal plan if anyone needs it. I just have to draw it up.

Thank you all,

Tim

There is nothing in normal B&W chemicals that will be combustible to my knowledge. My concern is for your safety. Being a darkroom, you will be in a small and enclosed (and sealed) area. Unless you have a forced ventilation, you may actually suffer from lack of oxygen and if that should ever happen, you will not be the one to be able to tell it. Plus, incomplete combustion, if that should happen will leave you with carbon monoxide which is odorless. Pilot light is always on but full-on burn will come on from time to time and that will consume good amount of oxygen. Maybe chemists among APUG membership can give you a quantitative answer but that will be my concern.

Tim- My darkroom also houses my hot water tank and furnace. My sink is about 10 feet away from them, and my enlarger/dry side is about 8 feet away. The pilot light is behind the furnace, so it's not in eyesight of my work area, and the glow doesn't reach the work area (that should be a concern for you). It's been like this for 19 years. Haven't blown myself up, yet...

To be on the safe side, consider installing a Carbon Monoxide Detector.

+1 on the CO dectector.
Unless you're planning on doing wet plate work no B&W chemistry or materials are particularly dangerous near things like water heaters or boilers.
But the water heater does need adequate combustion air both for its operation and for the flue to vent properly, so you'll want to make sure your ventilation is good. You may need to put some sort of baffle in front of it so that it doesn't make unwanted illumination.

paul_c5x4 said:

To be on the safe side, consider installing a Carbon Monoxide Detector.

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I completely concur. This is good advice for anyone with any combustion appliances in their home as well as those with no combustion appliances but an attached garage.

Important point: those widely available carbon monoxide detectors you'll find in home stores, etc. are all UL listed. While UL listing is usually a good thing, in my opinion it's bad for carbon monoxide detectors. The standard those ubiquitous detectors are certified to was written more to satisfy the agencies that must respond to 911 calls rather than to provide optimum human protection. Compliant detectors don't alarm at all until substantial levels of carbon dioxide are present and, even then, only after a long delay. All this to preclude so-called "false alarms." Long-term low-level carbon monoxide poisoning is insidious and, in my opinion, much more common that one might think. The medical community probably wastes a lot of time chasing other explanations for the symptoms it causes.

In my home, I've installed a carbon monoxide detector that sounds immediately when very low levels are present. It's more expensive and the chemical detection element has a fixed service life, therefore requiring replacement after five years, but I think my life and health are worth the cost. Here's a place that sells the brand I have:

A note on my calendar reminds me to order a new one every five years. Exact appearance of CO Experts units have changed (and, based on the linked page, will be changing again), but that's the one I'll get next time too. Spending hours in a darkroom that also contains a gas-fired water heater and furnace is far too great a risk without this kind of protection.

The most combustable chemical I can think of to be used in a photo-lab is Iso-propanol. And even this is not actually common.

As indicated above ventilation is a must for every photo-lab. Occupational standards for photo-labs give minimun rates of turn-over of the room-air-volume.

Do you think that ventilation for the darkroom and for the water heater could go hand in hand?

In other words, could the draw up the flue be used to pull out any vapors from photo chemistry? If that is true, then all you would need is to provide enough incoming fresh air to keep the water heater happy. Right?

(Combustible vapors notwithstanding but, for traditional photo chemistry, this should not be an issue.)

I'd consider closing off the furnace & hot water heater and installing an air inlet in addition to the fan.

A heater typically runs irregular, and even then the air volume sucked in may be quite small. I would not base a photo-lab ventilation on it.
The standard lab ventilation would be in the magnitute of complete turn-overs per hour. Furthermore a proprietory ventilation could exhaust fumes at their place of origin.

I think I understand what you're saying but the reason I thought of a common exhaust is because I was wondering whether an air extractor might cause a reverse draw down the flue and, therefore, a buildup of combustion products inside the room.

This was (and often still is) a concern for cinema projection rooms. The draw from the carbon arc lamp or xenon lamp had to be exhausted out of the room. (Soot and cancer causing combustion products from carbon arcs, ozone from xenon lamps and just plain heat extraction to keep the lamphouse from melting down.) The problem is that, unless you have air inlets to balance the pressure, you can end up with a reverse draw situation where air comes IN through non-operational stacks or else you will have negative pressure in the room. I have seen projection booths where the balancing fans stopped working and you couldn't open the doors to the room without a fight!

So, my thought was to have a common vent, up the flue, with enough inlet air to balance the pressure in the space to keep the exhaust gas from the heater from backing up into the room.

What do you think?

A good point! I forgot about that.

The best way to avoid that is to give a lab its own fresh-air intake at least of the size of the exhaust. However that could mean getting too cold air in. Aside of an airheater or heat-recuperator, the other way would be to get the "fresh" air in by many "leaks" from the rest of the house. Preheated so to say. But if this doesn't work correctly a drain on that heater system might be produced, and exhaust from that may come in.

Don't forget that the flames in heating units also emit light.

Thank you ALL!! Yes I will put a carbon alarm in the room! good idea. I just wanted to hear from people who may have had this issue. I was going to use two bathroom fans over my sink. Venting right outside to keep the fumes down.

Tim

Panasonic brand bathroom fans cost more but they are whisper quiet. You might want to do that since you'll be working in that room for hours at a time.

Putting an exhaust fan in a furnace room with normal flues on the appliances is a really bad idea. Unless you have positive pressure make up air into that room, you could backdraft both flues with your fan. Now if you have high efficient furnace and hot water tank with outside air supplied for combustion, you would be ok.

Bob-D659 said:

Putting an exhaust fan in a furnace room with normal flues on the appliances is a really bad idea. Unless you have positive pressure make up air into that room, you could backdraft both flues with your fan. Now if you have high efficient furnace and hot water tank with outside air supplied for combustion, you would be ok.

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Yes Both my furnace and water tank is high efficient and I found out last night that my furnace has a electric start! (stupid I know just never has a reason to know until now) so with that being said. Do you think a bathroom fan is going to be ok?

Thanks

In order for you all to see what I am talking about I added a few photos from this weekends demo. I taped out the door in one photo as I will be entering the darkroom from my office. I also taped out the floor where the new wall will go. As you can see it is adding some extra space as the little room I opened up had white pain on the floor. The new wall will be my wet side and I was thinking of a L shaped counter to work to my sink. As you can see the water and furnace takes up a bit of room and I REALLY wish they were some where else. Oh well I will work around them!
Thanks
Tim

Your furnace is ok, but the hw tank is a normal convection flue, so you really should have positive pressure air into the room.

Worker 11811 said:

Do you think that ventilation for the darkroom and for the water heater could go hand in hand?

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Depends on how old the furnace/boiler is.

I don't know about the regulations in Canada and the US but here, a boiler will either be a balanced flue or a fan assisted flue. In both cases, the flue is two co-axial pipes. Fresh air is drawn in around the outside and hot flue gases escape via the inside pipe.

The whole of the combustion area is sealed from the room so if the gas is burning incorrectly and putting out CO or CO2, it will all be vented and will not enter the room.

Also, any combustable gases within the room will not come into contact with the burner so will not ignite.

However, if you have an old burner/furnace then this might not be the case.


Steve.

laser said:

Don't forget that the flames in heating units also emit light.

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As do luminous watches... apparently!


Steve.

It would be a very good idea to use positive ventilation - knock a hole in an internal wall and install a fan to push the air into the room instead of pulling it out. This is better for dust too because you can filter the air going into the room from the rest of the house.

What would be the disadvantages of positive pressure ventilation?
One could be that lab air is pressed into other rooms. Any more?

Without it, the flue gases from the existing hot water tank would be drawn into the room by the exhaust fan instead of going up the chimney. All that is needed is a fan of the same cfm rating as the exhaust fan, and they both should be on the same power switch.

Bob-D659 said:

Without it, the flue gases from the existing hot water tank would be drawn into the room by the exhaust fan instead of going up the chimney.

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we need to know if the burner is sealed to the room or if it draws its air from the room in order to make a statement to that effect.


Steve.