Anyone use Edwards Engineering local exhaust vent hoods?

[lena_tsakmaki]

Hello all

Does anybody use Edwards Engineering vent hoods for local exhaust

ventilation?If yes then:

What length,for what size sink

What CFM blower for what size darkroom

and my main question

How noisy is it.It might be difficult to make objective noise level

judgments if you don't have an SPL meter but how does it compare to a

Doran fan, a quiet dishwasher like a Bosch or the average clothes

drier.Also is the blower in the darkroom or an attic above it.

Is the noise mainly from the motor or is there a lot of hissing sound

from the air entering the vent.

And last where is your intake placed and is it passive.

 

I hope there is someone out there that uses these vent hoods because

I would like someones first hand opinion before I consider ordering

one.

 

Thanks

Lena Tsakmaki

[michael_kravit]

I just finished designing a 450 Square Foot darkroom for a platinum printer. We designed and installed the Edwards exhaust system. There are many considerations that you must take into account. If you exhaust the amount of air necessary to make the Edwards system work efficiently, you will have to provide an equal amount of make up air.

 

Call Jon Edwards, give him the length of your sink and size of your darkroom. He will then run the numbers and give you the size of the exhaust fan you will need.

 

If you are in a warm climate and you will be airconditioning the darkroom, you will have to install unit(s) that will provide enough cooling to account for the exhaust air loss.

 

My suggestion is to hire a local mechanical engineer. have him design and balance your system needs with economic concerns.

 

Mike

 

Michael J. Kravit, AIA

Architect

[michael_kravit]

I forgot to answer your other questions.

 

1. You want the fans located outside the darkroom as yes, they are noisy. In teh attic, or roof mounted would be better.

 

2. If you remotely mount the exhaust fans you will still experience some fan noise and will also hear some exhaust noise turbulence noise depending on the size of fan and cfm flow. Jon can give you more info on this.

 

3. This is an expensive system. As this facility is in S. Florida, we had a 3.5 ton cooling load. When we added in the exhaust calculation, we determined that we would need a 10 ton a/c unit to cool the darkroom.

 

Mike

[michael_kravit]

The exhaust system and a/c increase cost the client roughly $12,000.

 

Mike

[lena_tsakmaki]

Mike

Thank you for your responce.I already talked with Jon a couple of days ago.His suggestion was 4 feet hood for 8 feet sink and a 400 cfm blower.My furnace blower (the noise of which gets on my nerves) is 79cfm, that's why I wanted the real life experience info of someone that might have a similar system.The blower retailer does not give db info and I was unable to find a website for the manufacturer(Dayton).

Jon doesn't have db info either but he told me they are noisy.If I had a db figure I could estimate how much the noise will drop if I place it in the attic.

I think hiring a mechanical engineer would be too much for this project.This is my first darkroom and I am enclosing an 11x7 area in my garage.Since we might relocate in a couple of years I'm trying not to make a huge investment into things that I won't be able to move to another darkroom.And the weather doesn't get extremely hot in the summer (I live in the San Francisco bay area) so I won't install a/c intially.Thanks for your info.

Lena

[david_lazarus]

Try a duct booster fan, you should be able to fine one online. About 400cfm should be enough. I have a 150 now in my 6x9 darkroom and I have a/c ducted in. I have no problems with smells.

I have a air inlet under the sink channeled though the walls for a light trap. If you need more help please let me know. I am a A/C contractor.

David.

[ralph_barker]

For a quasi-temporary installation, I think I'd concur with David's suggestion - try using some combination of inexpensive, light-baffled intake and exhaust units. You could, for example, locate a conventional exhaust fan external to the darkroom, and connect it to the baffled darkroom exhaust vent with drier-vent hose to minimize the noise. Locating the exhaust vent near the fixer end of the sink will also help minimize fumes. You will get some heat build-up in a relatively small space, so consider ways of locating the air intake (again, light-baffled) such that you're pulling in cool air. You might also want to think about some form of filtration on the air intake as a means of minimizing dust.

 

Note, too, that a 400cfm system is moving a fair amount of air. That system would completely replace the air in your space in about a minute and a half. That sort of air movement might be overkill for your needs.

[wayne_crider4]

Dayton's motors and exhaust ventilation is handled by Grainger. Their a

wholesale outfit to business's. Their catalog should have just about any info

you need concerning exhaust.

 

I don't know what your using to develop, but you might try going to less

hazardous chemicals. Xtol, TS4 and TF4. If your planning on a 8ft sink I've got

to believe your doing alot of production. If not are you overbuilding? 8ft sinks

in stainless (if this is the case) ain't cheap even used. Especially 3 or 4

compartment ones, or are you building one out of fibreglass? If your setting up

16x20 trays all you really need is a wash sink and for that amount a larger

than normal fart fan would probably do. I'm a mechanical contractor btw.

[lena_tsakmaki]

Thanks for the answers everyone.

David I might email you with future questions since you offered to help.

Wayne,Grainger(the first place I checked) does not have decibel info.

I am already using xtol(in the combi tank-not open tray)and Dektol,no intension in getting into Amidol,PMK.But I need to get a really good ventilation in order to eliminate future photo-chemical sensitivities, since I'm sensitive to lots of things and my printing sessions are 8+ hours long.

The sink will be coated plywood and I think 8ft is the bare minimum since it fits only 5 11x14 trays.I wish I had the space to put another 3ft sink for washing.

Thanks again.

Lena

[tom_oldfield1]

I am building a darkroom and was stalled for several weeks over the ventilation problem. Found that Panasonic makes ventilation units that go inline with flexible ducts. I installed the 440cfm unit with 8" ducts. It is in the attic and very quiet. I reversed their plan and use it to insert air into the darkroom through what should be a return air with a hepa filter. The vent is along the back of the sink. Not done yet, but this seems to work very well. The units can be purchased at local HVAC suppliers.

[kelly_flanigan1]

Place the exhaust vent where the chemicals and trays are. Then place a blower which pressurizes the darkroom; thru a decent large 3m Brand micron level Filtrete ® filter. Then make sure one has doors that are closed.<BR><BR> The pressurized filtered air then will exhaust thru a non powered vent; above the trays and chemical areas. A small blower can be used near the chemicals; but it needs to be only 1/3 the size/cfm of the main darkroom blower. <BR><BR>This method radically reduces dust drawn into the darkroom; since it is slightly pressurized. Any cracks below doors; etc will then move dust out of the darkroom. Using an exhaust fan only draws dust into the darkroom; where it collects on the enlargers; and everything else. Designing it like a cleanroom will reduce dust buildup; and radically reduce dust getting on customers work; etc. Many clean rooms,better designed darkrooms, ball bearing assembly areas; etc use this pressurized method; with the chemical vapors being allowed to flow out; thru a defined vent. <BR><BR>The older darkroom books mention this pressurized method; some are many decades old. Howard Hughes had a car that was positively pressurized; with a giant filter in the trunk; I think it was from the late 1940's.<BR><BR>With a postive pressure system; the blower can be in another room; with the noise confined to that area. It also can be tapped off a standard AC/heat duct; with a helper blower before the 3M filtrete ® micron filter. One can use standard Dwyer Magnehelic® pressure gages; which measure to fraction of an inch of water; to see how much the darkroom is pressurized. A static pressure tube is placed one in darkroom; one on the blower side.<BR><BR>The "non pressurized" method seems to be popular; for those who like cheap solutions; and dont mind a system that actually draws dust into ones darkroom. A cheaper fix for this is to at least provide a controlled entrance for air; thru a decent micron level filter. A door can be replaced; and a standard 20x30" filter; and a light trap placed. Here at least some of the air will be filtered; but alot of dust will still enter thru cracks in other areas.