Darkroom ductwork/ventilation/plumbing

[BetterSense]

In my house I have an 8x10 foot closet that I want to darkroomify. It buts directly up to a bathroom. On the other side of the wall from this closet, there is a bathroom with a shower/tub combo installed (with tile) directly on the other side of the wall from the closet. If I wanted to get real destructive, I could just tear that wall out and combine the closet and bathroom into a darkroom, but that approach lacks WAF.

The problem with the closet is there is no ducting into it, no plumbing, and no ventilation. The bathroom, on the other hand, has a duct in the ceiling and also has an exhaust fan in the ceiling.

My plan is to put a "T" into the ductwork going into the bathroom ceiling A/C duct, and run that it into the closet ceiling. This will cut the air going to each by 1/2, but I can have adjustable ceiling vents to close one room or the other off room off.

Then I will install a bathroom exhaust fan in the ceiling of the closet and "T" that into the same vent the bathroom exhaust fan goes too. The bathroom ceiling fans I have looked at all have 1-way valves installed in them so this should be enough to prevent crossover (no point in venting the darkroom fumes into the bathroom or vice versa).

For plumbing, I suppose if I cut a hole in the drywall in the proximity of faucet-side of the tub/shower combo that is installed on the other side of the wall, I will be able to see the plumbing and tap into both the drain and the hot/cold lines for my darkroom sink.

I'm not a plumber, HVAC person, or electrician, but those are my thoughts. Do you think it's worth approaching?

[Henry Ambrose]

Sounds like a good plan in general. The size will be very nice for a "big enough" darkroom - just about perfect for one person. Put a 24-30" deep 10 foot sink on one wall and 10 foot counter for enlargers on the other, leaving about 3 1/2 to 4 feet in the middle to walk in. Makes a very efficient space.

[WayneStevenson]

Your first plan would be to verify where your fans are bringing the air. Not all bathroom vents actually vent to the outside. Poor workmanship may have left them venting into walls, ceilings, attics, etc. Which may be fine for humidity (maybe), but not for chemical exhaust.

There is no way to ensure duct work is air-tight without you having seen it, or havng been the one who installed it. No easy verifying that the air you're exhausting into it, is all coming out at the end. And no way to ensure the added air pressure of another fan pushing throuh it isn't going to cause disconnects. Most ducts I have seen are just mashed together without any tape or anything.

Aim for 6 air changes per hour, or 1 air change per 10 minutes. This is Kodak's recommendation for their B&W chemicals. GOOD bathroom fans will give you 70 - 90CFM. So a good one should take care of your room size no problem.

But also remember that technically, if you're exhausting 80CFM of air, you need to really be bring in 80CFM of fresh air to replace it.....

But also ask yourself how anal you are about your health. If you're not worried, don't take it so seriously. If you are, do it right. Then you have absolultely no worries.

[WayneStevenson]

And you should be pretty spot on with your thoughts of the plumbing. Nothing to it really. If you're not farmiliar with plumbing, as long as you can sucessfully turn off water into your house, you'll be fine as the worst that can happen, is leaky plumbing.

Likely you have copper plumbed so you'll need to solder with a torch. Ensure you use pluming solder (lead-free). You can get compression fittings which make things easier for you, but solder and copper really is the way to go. Unless you go PEX. But the costs raise quite a bit going that route. And you have to marry the copper into the PEX. And if you're renting the crimper, you have to make sure everything is nice and dry before returning it because problems always happen after everything has closed down.

Drain is a little more complicated. Could be a P trap on there. Though might be below where you can see / have access to. Could be encased in concrete. So many different ways it could have done. Most I doubt woud not be worth the trouble.

I bring my water into and out of my darkroom with large kitty litter pails. Also have a water cooler / heater I use when I need a good supply. Been thinking about plumbing a bottle for it so it's a constant supply. But the more I use, the more I have to bring out. Toyed with the idea of using a water pump to bring it out of my darkroom, but not really worth the effort.

[John Jarosz]

Think about resale of the house. I'm sure you'll want to take the darkroom with you when you leave. Construct the plumbing so that you can valve off the water feed, unscrew the drain connection and replace it with a cap. It would help if the means for disconnecting or valving is inside the wall so you can just put drywall or some kind of panel over the hole to cover it.

It sounds like you've thought this thru OK.

john

[BetterSense]

I figured I would install a 14x14 plumbing access panel in the wall (under the proposed sink) and simply leave the cover off of it while my sink is installed. When I remove the sink, I should be able to cap the pipes and just put the acesss panel cover on.

I think the hot/cold water shouldn't be a problem but I don't know what tub drains look like so I might have some surprises; the bathroom is on the second story and the tub drain could be too down close to the subfloor to tap into easily.

Speaking of resale value, if I put in a big darkroom sink, don't I need some kind of backsplash guard? Otherwise the back would just be drywall.

[Colin Graham]

I did something very similar to a spare bedroom that shared the plumbing wall with a bathroom. Pulled water from the tub and connected the waste line under the house, past the tub's p-trap.

You will also need a vent to let the sink drain properly- that might be difficult to tap into an existing one, but if running a new one out through the roof is impractical, you can use a studor vent (http://www.studor.com/mini-vent.htm) that attaches to the waste line after the sink's p-trap with a t-fitting.

Panasonic (http://www.panasonic.com/business/building-products/ventilation-systems/products/whisper-green-lite.asp) makes excellent bath fans. The whisper green line are very quiet and efficient- you can run them all day and not get noise fatigue. That's good advice about checking the ducting- better to add a new dedicated duct, too many bends reduce the CFM dramatically, and it's true most houses just have the ends of the exhaust ducts laying in the attic insulation or jammed into a bird block. Also, most bath fan dampers don't seal very well, so with the pressure differential you might force exhaust odors into any areas that share the same ductwork. A darkroom can add a lot of moisture vapor to a modern supertight house, so the bath fan is as much for air moisture control as exhausting odors, or mold can become a problem quickly.

I used a sheet of thin plywood laminated with formica for a backsplash, screwing the top of it to wall studs and caulking the bottom to the sink. Should be easy to remove without too much damage, just putty a few screw holes.

[Henry Ambrose]

You can install vents in the wall to let air flow through. Use the stud cavity as a duct -- one "return air" grill goes at the top of the wall opening to one side and the other at the bottom opening to the other room. Or put a dark vent straight through the wall. Either is easy to fix if you move by replacing with a piece of drywall. This might be better later on than a dark vent through a door. Drywall is cheaper and easier to fix.

I'd consider a new fan and vent for the darkroom as others have suggested. Place the air intake above the sink and away from the source of incoming air. What you want is clean air coming from behind/beside you and replacing the dirty air that's being pulled off the sink. Clean air flowing past you.

And as long as we're being critical of venting practices, you don't want either the bath or darkroom vent emptying into your attic. Not even if code allows. Vent through the roof and outdoors. Down side there is another piercing of the roof but better overall if done right.

[BetterSense]

Well there is already a through-the-roof stack from the bathroom vent; I figured I would "T" into that vent in the attic and share the through-roof pipe. It's unlikely I would need to run both the bathroom vent fan and the darkroom vent fan at the same time.

[Drew Wiley]

Best to position the fan duct where it pulls the air from the back of the sink, or up from
that area, rather than across your face. If your exhaust fan will accept a variable speed control that is very useful, so you can adjust the air as needed. 80cfm is a bare
minimum - if it is rainy or humid outside, you need something which will push against
to hydrostatic pressure, and the more kinks and corrugations you have in the ductwork, the more air friction will be involved too. Make-up air is essential, so you'll
also need a light-tight air intake. For drains etc be sure to use plastic pipe like ABS,
since metal connections can be corroded by many darkroom chem.

[ic-racer]

It sounds doable to me. In this thread I share my experience tapping into my home's water supply. Just for 'piece of mind' I pressurized the house's water system with 40 psi compressed air and painted all the sweated joints with soap water to test for leaks before restoring the water supply to the house.

http://www.apug.org/forums/forum43/71585-its-copper-me.html

[Louie Powell]

An 8x10 foot space would make a very nice darkroom. My thoughts:

1. Ventilation - this is very important. If you don't have fresh air in the darkroom, you will tire far more quickly and be much less creative. The best approach to ventilation is to force air to flow INTO the darkroom. In photography, dust is your enemy The best way to manage dust is to force filtered air into the darkroom, and then allow it to exhaust on its own. If the air pressure inside the darkroom is slightly greater than the pressure outside, you won't have dust entering through the unavoidable spaces around receptacles, doors, etc. A related problem is noise - if the ambient noise level is too great, that also becomes a factor that leads to premature tiring. Most bathroom ventilator fans are too noisy. I found that Radio Shack has a 120v computer-style 'muffin fan' that is reasonably quiet and that works very well in a darkroom. And if you can mount the fan outside the darkroom and duct air in, it is totally silent. Other than the bathroom, what other spaces surround the 'closet' you are converting to a bathroom? Unless you are into sulfide toning, the airborne effluent from a darkroom aren't all that noxious and you may be able to get away with simply letting the air flow where it will. But if you are concerned, you could always put a simple vent to an attic, basement or even outdoors.

2. Plumbing - going through the wall adjacent to the shower should expose hot and cold water supply lines that you can tap into. Unless your house is fairly new, the piping will likely be copper. Copper pipe is traditionally soldered, but in some markets you can find compression fittings that can be used in retrofits. The extension into the darkroom can be copper, welded plastic (CPVC) or PEX (with compression fittings). Be aware that opening that wall may not expose drain lines. The drain from a shower is in the floor underneath the shower. If you can get access to the area under the bathroom, you should be able to tap into the shower drain. About the only scenario I can think of where opening the wall behind the shower would expose a drain is if that wall contains a vent from the shower drain - there should be a vent from the shower drain, but it doesn't have to be in the same wall as the supply lines.

3. Electrical - think about how many receptacles you think you will need, and then install twice that number. They are cheap to install when you are constructing the darkroom, but harder and more expensive to add later. And treat the darkroom like a bathroom - make sure that the receptacles are on a GFI. Your life may depend on it. Also, think about including a master switch that turns everything in the darkroom on or off at one time.

[BetterSense]

The darkroom space is in the northeast corner of the second story of the house. Above it is attic, below it is a guess bedroom with double closets (possible plumbing space). To the south is a bathroom; to the west is my project/hobby room.

I previously worked in my apartment's 5x7 foot walk-in with no water, no ventilation, and the only outlet was an adapter I put in the light socket in the ceiling. The biggest problem was that it was hot, there was no ventilation and no running water or drain. I don't have a problem with fumes from silver gelatin, but I would like to be covered for color and bleaching I guess. So I'm looking at putting in the bathroom ceiling fan, I can put in an A/C duct into the ceiling, and now yall have given me the idea to install a stud-space dark-vent from my hobby room into the darkroom. The bathroom ceiling fan would be the most expensive and the hardest since I would have to run wires. If I put a stud-space vent from the hobby room into the darkroom and run an A/C duct into the ceiling of the darkroom that may be sufficient.

[Henry Ambrose]

snipped a whole bunch......

If I put a stud-space vent from the hobby room into the darkroom and run an A/C duct into the ceiling of the darkroom that may be sufficient.



I've done this several times now and it works well. Its nice to have your darkroom being constantly heated and cooled. Your stuff keeps better and its always comfortable to go in and start work.

As long as we're "perfecting" your darkroom, you might think about installing a remote fan that is mounted in the attic and sucks out of the darkroom. A little more expensive and a bit more trouble but the noise reduction would be nice. As with another poster, I'm pretty sensitive to fan noise as well.

You might also think about a combination shelf/hood over the sink. Its a great place to put the things you use frequently and a hood really helps control the fumes. Make it about 16" deep and about head high with the air extraction built into it. A trough turned upside down, if you will.

[BetterSense]

As long as we're "perfecting" your darkroom, you might think about installing a remote fan that is mounted in the attic and sucks out of the darkroom. A little more expensive and a bit more trouble but the noise reduction would be nice.

That might be a good way to go. I only thought about bathroom fan because it's kind of a similar application to a bathroom fan, but I know that I will almost never run a bathroom fan unless it's literally silent or I just need to clean fumes out temporarily. And actually, I suppose a darkroom fan can exhaust right into the attic without causing an problems. It doesn't seem like in really needs piped out; I have those tornado-style roof vents in my attic.

[Drew Wiley]

Pulling air is always more efficient than pushing it. Using an attic-mounted or external
fan is a much better option - quieter, better fan life, better air exchange - but also
distinctly more expensive. I have a huge exterior mounted squirrel-cage fan on my
lab, and in a new bathroom a Panasonic attic-mounted one which I have to be careful
to remember to turn off because I can't even hear the thing running - and its around
350CFM.

[WayneStevenson]

I keep reading about ventilation at the sink. But realistically, you want your ventilation where your biggest fume release would be occuring. Which would be where your developing trays or print processor is going to be.

[Henry Ambrose]

I keep reading about ventilation at the sink. But realistically, you want your ventilation where your biggest fume release would be occuring. Which would be where your developing trays or print processor is going to be.

Which for someone with a nice long sink is in the sink. I'm writing about a "sink" that's essentially a big long (8 or 10') tray about a foot deep in front and 18-24" at the rear with a drain in the middle. A big sink containing trays with chemicals and a print or film washer.

[jp]

If you are going to be wiring up for fans, you should install an outlet or a couple of outlets on your ceiling for safelights. Mine are on a switched outlet so I can turn them on/off from the wall. Other people like pull strings. But either way you need electricity for them. This should be easy/cheap to do while wiring up a fan.

Plenty of wall outlets is good too. You may need plenty of outlets. I have hooked initially up 2 enlargers and a timer, but have added a small lamp for dim working light while coating paper for alt process, and a hair dryer for drying alt process paper or testing drydown on silver paper. I also plug in an air cleaner sometimes too.

[Nacio Jan Brown]

Louie Powell is right on about having positive pressure in your darkroom. With a fan sucking air out you will get dust-laden air drawn into the room every time you open the door. To get positive pressure in my darkroom I used a "room-to-room" fan I got from Grainger. Its air supply is filtered through a 12"x24" pleated furnace filter in a simple housing I made. The air supply is indoor air and hence heated. High on a wall above the sink I installed a light-tight passive vent through which the air can exit. On tying into a drain line be sure you have a p-trap somewhere between your sink drain and the drain line itself. Without this you will get sewer gasses coming up out of the sink drain. I disagree with the person who said you would need a vent to get the sink to drain properly. The US has incredibly(!) complex codes for vents. Other countries don't even require them--and their sinks somehow drain. If you do choose to have venting the easiest code-compliant type to install will be what is called an "island vent." Using such a vent eliminates the need to tie in to a vent line that goes up through the roof. A Studor vent will also work, and is easier still, although they are not code compliant in some jurisdictions. Me, I'd start with nothing and see whether there was a problem. Last, you might consider just working in a darkroom without running water. I worked as a professional photographer for some years in such a darkroom. I brought two-quart plastic juice pitchers in with the mixed chemicals for the trays. To avoid having to carry trays of chemicals out, which is tough to do without frequent spills, I dumped the trays into a plastic office waste basket at the end of each session. The print washer was in the laundry room. I developed film in the laundry room after loading it in the dark. Not elegant but I never missed running water at all while I was making prints. Let us know what you come up with and how it works for you. njb

[Drew Wiley]

Nacio - did you use Tide in you laundry room print washer?

[BetterSense]

I finally got brave enough to cut a hole in the drywall on the other side of the tub...there are the two hot-and-cold 5/8 copper lines hanging right there for the taking. The only question I have is how to tap into them. I could cut them, but I'm scratching my head over how I would insert an T-fitting, since they don't look very flexible.

The tub drain goes straight down into the floor and I can't see it, but running right down through the exterior wall where I CAN see is what looks like 2" white CPVC that also heads down into the floor. I could cut it, install one of those flexible boot-T-fittings, and that could be my sink drain, but I don't know where it goes. I can only assume it eventually ends up in the sewer but for all I know it could be a vent for something else and really cause problems if I dump water down it.

[jp]

sharkbite.com makes products you can use to reliably tap copper pipes. I think either Home depot or lowes carries it.

The 2" pipe is probably a vent and I don't think vents are intended to be used for that; there's probably some rule against it, but I'm not a plumber.

I'd recommend a pro plumber. If you've done all the busting of drywall, they should be able to come and do their work in an hour or so. The risk is a leak that causes thousands of dollars in damage such as a mold problem or water damaged rooms.

[BetterSense]

I've done plenty of pipe-joining before, but I just have limited experience designing plumbing or reverse-engineering existing plumbing when you can't even see through the walls.

[Henry Ambrose]

You can cut the copper with a shorty cutter and then tin the parts, slip the Ts in place and sweat it all together. This assumes you have enough give in the lines to push them apart enough. Or the Sharkbite things work. They're expensive but way cheaper than a plumber.

Don't tie into the tub vent for a drain. It runs to the tub drain but also the vent in the tub at the stopper handle. The tub drain is underneath the tub (duh) and you might get to it from the ceiling below.

You -can- tie your new vent into the tub vent line. A vent will make the sink drain better with large volumes of water. A trickle won't matter but emptying the print washer or cleaning up will.

You might need to go through the ceiling below to get to a good place to tie into a drain. I'd pick the sink drain or it may be that you have a trunk or collector for the bath available.

Slow down, have a seat and look at/imagine where the waste water goes from the bathroom. Is there another bath, laundry room or kitchen underneath? They all tie in to a drain. Figure out what makes sense and maybe cut a little hole or two to prove your imagining. That will help you figure a way to tie in.

[Nacio Jan Brown]

Nacio - did you use Tide in you laundry room print washer?
Woolite, actually. Tide is too harsh.

[BetterSense]

Here is a picture of the plumbing. I'm still not sure if I can use the vertical white pipe as my sink drain. From what I've read, using a vent as a drain can be done (it's called a wet vent) but only under certain circumstances with good results.


http://www.chazmiller.com/images/qluming.jpg

[Merg Ross]

Can't you tie into the tub waste line; it looks like it is vented. I don't think using the soil stack would be a good idea. Perhaps I am not understanding the problem.

[BetterSense]

Can't you tie into the tub waste line; it looks like it is vented.

I can't get to the tub waste line; it runs right down into the floor as you can see in the picture. I don't know that the white pipe on the left is a vent line, but seeing as there's nothing higher that drains I can only assume that it is.

[Merg Ross]

I can't get to the tub waste line; it runs right down into the floor as you can see in the picture. I don't know that the white pipe on the left is a vent line, but seeing as there's nothing higher that drains I can only assume that it is.
That appears to be the soil stack (vent) that you could use to wet vent your waste line. Be sure to include the "P" trap. I think that would work, but check with a plumber first. Looks like a fun project once the mechanical systems are taken care of. Good luck!

[Pawlowski6132]

How high are the ceilings?

[R Shaffer]

Here is a picture of the plumbing. I'm still not sure if I can use the vertical white pipe as my sink drain. From what I've read, using a vent as a drain can be done (it's called a wet vent) but only under certain circumstances with good results.


http://www.chazmiller.com/images/qluming.jpg

If you google 'wet vent' you will see diagrams of how to tie a a drain line into vent. The access looks really tight to use the water lines for the tub.

[Jerzy Pawlowski]

...
I bring my water into and out of my darkroom with large kitty litter pails. Also have a water cooler / heater I use when I need a good supply. Been thinking about plumbing a bottle for it so it's a constant supply. But the more I use, the more I have to bring out. Toyed with the idea of using a water pump to bring it out of my darkroom, but not really worth the effort.

Hi Wayne,
My darkroom is separated from any water services by a corridor. Since it is basement my choice was working in concrete floor, water in/out by hand, or pump. Bringing water by copper pipes is not a problem, for water out I have installed pump. Pipe (1 1/4") goes over ceiling to laundry room, I did not bother connecting outfall to sewer pipe, my pipe empties simply to laundry room sink. It works like a charm, I stopped even noticing water running from time to time. Cost is not great, pump around $100, garbage container (must be with relatively flat bottom), and time for gluing pipes.

[BetterSense]

I did a little writeup of how the plumbing project went. I'm now building my darkroom sink. Next priority is ductwork and venting followed by electric.

http://www.chazmiller.com/projects/plumbing.html