darkroom ventalatoin

[ShannonG]

Sorry if this has been posted before ,i searched but couldn't find what i needed.

We sealed the deal on my new studio and will be there for several years to come.Ive completed most of the darkroom area with new drainage,insulation and water filtration. Now that my 1 year trial period to see if the facility works my needs is over (and it works verry well) Now im ready to put more money into my darkroom. So now im needing ventilation. The room is 12 feet by 24 feet (or so) what do you folks recommend for a fan,fan housing. The ones that are light safe and that i can close up during winter months. The usual chemicals are not that bad,but im starting to get into some alternative techniques to ware air exchange would be a good idea.
Thanks for sharing your experiences.
Shannon

[gleaf]

Check out Kodak's document. J314
It was written for commercial processor facilities.
Ilford has one as well.
http://www.kodak.com/global/en/corp/.../pdfs/J314.pdf







http://www.kodak.com/global/en/corp/.../pdfs/J314.pdf

[ShannonG]

Thanks for the PDF,its very helpful. I was thinking of getting this unit
http://www.emsdiasum.com/microscopy/...phic/fans.aspx
Does anyone have experience with this particular unit.I would like it to mount flush to the wall.,al so is this one light tight?
Thanks again
S

[jeroldharter]

If you want a simple option, find the quietest, higher volume bathroom fan (check out Panasonic). Put the fan in a corner of the 24' wall. On the opposite corner, put a lightproof Doran louver for intake air. That should suffice for most circumstances.

If you want the quietest standard household fan, get the type where the fan motor is up by the roof rather than integrated with the ceiling fixture.

Also, be mindful of return air volumes. A 12 x 24 x 10 room has 2800 cubic feet of air. So determine how often you want the air exchanged in your room and get a corresponding fan. But that removed air has to be replaced with other air from your house or else the fan is sucking a vacuum.

An ounce of prevention: single tray processing is a great method for reducing fumes. It sounds screwy if you are used to using a series of trays, but once you get used to it the process is intuitive and I think preferable. You need plastic beakers of the proper volumes (2500 and 5000ml worked well for me, from US Plastics). I rarely turned on the fan, even with selenium toning. Certainly if you use brown toner or similar chemicals, the fan is a must.

[Ken Lee]

If you place the air exit over your head, the fumes have to pass by your nose before the leave the room. If you place the exit over the trays, the fumes leave before they affect you.

You might find this page helpful: http://www.eepjon.com/VentHoods.html

I can personally recommend Jon Edwards and his work.

[Taija71A]

____

Shannon... In addition to the 'above cited' excellent HVAC posts by Jerold and Ken... Hopefully, some of the following information -- Will also perhaps? be of further interest or even some assistance to you...

The simplest method used to calculate 'Ventilation Air Requirements' for a Darkroom... Is based upon the complete number of 'Changes of Air' -- That *you* require per hour.


Note:
Although some organizations may recommend as little as six (6) Air Changes per hour... If Possible, ten to twelve (10-12) Air Changes per hour -- Would be a good 'Minimum' Design Specification.

With 10-12 Air Changes per hour, the amount of air entering and leaving your Darkroom... Will totally replace the air in your Darkroom (*In approx. every 5-6 minutes)! *This figure of course... Depends upon your Volume of 'Make-up Air' or 'Fresh Air Intake' (as per Jerold's comment above).

Also, your quantity of 'Make-up Air' or 'Fresh Air Intake'... Should always be equal to at least 90% of your air -- 'That is Exhausted'.
--
Therefore, in order to Determine the Airflow Rate (CFM) required to adequately ventilate your Darkroom:


1). Calculate the Room Volume of your Darkroom.
2). Using the Air Change Rate Equations... You will be able to easily calculate the size required for your Exhaust Air Fan or Total Air Volume Requirement.

Air Change Rate Equations:

CFM (Exhaust Fan Size) = AC (*Perhaps use a figure of 10-12 as per above) x Room Volume / 60

or

AC = CFM (Existing Fan Size) x 60 / Room Volume

Where...

AC = Number of Air Changes per Hour.
CFM = Airflow Rate (Cubic Feet per Minute).
Room Volume = (Width x Length x Height) = ft3 (cubic feet).

--
Shannon, if you should have any additional questions or concerns... Please feel free to PM me -- Okay? Thank-you!
--
Best regards,

-Tim.
________

[lab black]

I soundly agree with Ken's suggestion to explore the Edwards ventillation system. In addition, when I built my darkroom, I was given an excellent suggestion to install ventillation, approximately six inches above the floor, in case of an acid spill on the ground. There happens to be a current listing on Ebay for some vents that have become quite difficult to locate;
Ebay listing
"Darkroom air vents, 4 in."

Best of luck.

[lenser]

Shannon,

Kodaks' old publication "Photolab Design" (K-13) offers this page including an illustration of a design drawing airflow across the trays and out through what is essentially a sink wide slit at the top of the back splash just above the trays. I'm planning on this set up being connected to a high flow bathroom vent fan in my next darkroom.

[Tin Can]

I recently installed one of these. http://www.westsidewholesale.com/pan...fv-30nlf1.html I chose an all metal Panasonic for longevity as I built it into the wall, removeable by Sawzall.

Perhaps slightly undersized for my room, but I had outside vent diameter limitations to 6" pipe. It's a condo. I had to beg.

I find it sufficient for how I carefully use it and made it pull off the back of my main 10' sink with adjustable vent pipe drops.

If I use something nasty I can work directly under a hood with full flow. My fresh air make up comes from across the room, 18" off the floor, from a roof vent. I put furnace filters over the make up air intakes.

I wouldn't want much more airflow or I lose too much heat or AC.

[ROL]

I have a 12" Doran light proof exhaust fan over my sink. It's more than capable of handling my 11'x20'x9' space. I put it on a bathroom style variable sped rheostat, to help control the noise. It's so noisy, I only use it at full draw when necessary. One thing to think about is where the exchange air will be coming from (I installed a passive vent in the ceiling opposite the exhaust, ported to the outside).