Spray Booth Light

[Leigh Betsch]

I curtained off a section of my shop for a spray booth this week. It is 5 ft wide by 12 ft long with plastic strip curtain for a wall between it and the rest of the shop. I have a window in one end and exhaust fan to the outside in the other end. I have a 12' stainless steel table with shelves under the top to put stuff on inside the booth. Overall it seems to work very well. But, I need a light. I have 4ft 2 bulb sealed fluorescence lights in the rest of the shop. These were installed by the previous owner and appear to be a wash down type if light. My question is should I relocate one or two of these lights to the new finishing room, should I look for an explosion proof light, halogen, or go with an incandescent fixture or two. What type of light would be the best to have when viewing and matching colors?

[Matt Meiser]

I basically have an open-face booth and in there I just have three 2-bulb covered fixtures, one on each side and one on the top. I used the full-spectrum bulbs in them to get the best color reproduction I can.

[Jack Lindsey]

Paint spray booths are classified as Hazardous locations by the National Electrical Code and are subject to very strict requirements to prevent explosion of gasses or vapors that are present. They are a Class 1, Division 1 location and lighting equipment used in them must be labeled as approved for that classification. The purpose is to prevent an explosion or fire that could damage your shop and/or inflict bodily harm on you.

Class 1 Div 1 fixtures are built like a battleship and are somewhat expensive. A regular fixture can be used, however, if it is located outside of the classified area. This is accomplished in many commercial paint booths that are located inside buildings by cutting holes in the roof, placing a sealed glass barrier over the hole, and mounting the fixture over the glass but outside the booth. That keeps the fixture outside of the classified location. Note that I am not telling you how to light the booth, I'm simply giving you some background on paint spray booth lighting.

I suggest you talk to your local electrical inspector and ask him for his ideas on how light your paint spraying area. Due to the potential for explosion or fire if a non-approved fixture is used I highly recommend that you take out a building permit and have the installation inspected to assure that it meets code.

As far as lamp selection goes, GE makes a lamp especially for color matching called a Chroma 50.

[Leigh Betsch]

Thanks for the help. The class 1 div 1 lights are going to get spendy. If I limit myself to just water base and the occasional rattle can of paint or laquer would I still need class 1 div 1 lights? Right now I use a halogen light stand and shine it throught the plastic curtain from behind me, which causes shadows.
Any thought on how much wattage to put in a 5 x 12 x 8 curtained off finishing room with all white walls and ceiling? Can you ever have too much light?

[Matt Meiser]

Leigh, this is a hobby shop, right?

[Leigh Betsch]

Hobby, absolutely I could never make money doing this!

[Matt Meiser]

You have to make your own decisions, but hobbyists and homeowners have worked for years in garage and basement shops using things like window fans or no fans for ventilation and whatever lighting they had with a lot nastier chemicals than you are talking about spraying.

What did you use for a fan? If its not explosion proof, then what's the point of putting in explosion proof lighting?

[Leigh Betsch]

:) Matt, I don't have an explosion proof fan right now but thinking ahead if I want to get into spraying solvent finishes I would at least already have the right lighting and just need to replace the fan. I'm using a thru the wall Dayton fan.

Like most things I do I tend to figure out how to do them right and then make some compromises along the way so I can afford them. So once I know more I can at least try to get it right. Someplace along the learning curve I will reach a solution that I believe to be practical for my application.

I've still got some more learning to do to determine if flood lighting is better than florescent strip lights. I might be able to put recessed floods in the ceiling and cover with a glass lens.

Right now I'm still leaning toward relocating a couple of my existing light fixtures, buy a couple of Chroma 50 bulbs, if my ballasts are right, and sticking to water born finishes. I'm not sure how many fixtures to move so if anyone has rule of thumb for watts per sq ft or some guidance I would appreciate it.

[Faust M. Ruggiero]

Leigh,
Jack is absolutely right about the code and sealed lights. The fact is, as part time wood workers we have a tendency to take chances with a lot of stuff that would never pass code if we were inspected. The reality is we are somewhat limited by our pocketbooks. I think we have to use our heads. If you are spraying water based liquids you can take a few chances others, who spray solvent based chemicals cannot, eg. using a fan without an explosion proof motor. Make sure the air movement meets accepted of CFM for the spray area and if your air stream goes through the motor, collect the overspray in arrestor filters.
I take few chances. One that I do take is with lights. I do not use explosion proof lights. I never allow fumes to build up in the booth. The fan goes on prior to spraying and stays on until the fumes are cleared. Prior to shutting down the fan I shut down the lights. I spray at the end of the day so I can leave the shop almost immediately after shutting down. I am particularly careful not to let fumes collect in the main part of the shop where a mundane thing like a thermostat can create an arc.
I am not telling you to ignore laws made for our protection but I also know if you haven't laid down the $350 for an explosion proof motor you will probably not spring for a couple $400 plus light fixtures. Just don't allow fumes of any kind to build up in the booth and don't spray solvents with a fan powered by a non-explosion proof motor.
fmr

[Tony Bilello]

Short and sweet......you cant have enough lights.
Take a look at a local body shop. They usually mount their fluorescent lights vertically every 1 1/2 to 2 feet. As for color matching, the best thing to do is to make a sample piece, go out in the daylight/sunlight and make your match there.
I am a big proponent of safety so if you could afford the explosion proof lights and fans get them. If not, do as someone suggested earlier and mount the lights outside the booth shooting through a sealed 'window'.
As for the fans, any good exhause fans should work providing you are not creating a dense cloud of explosive or flamable vapors. I spray lacquer within 6 feet of a butane heater with fairly large flames. I am not concerned as long as I am not creating a cloud. Ventillation is everything. Explosions are caused by the explosive/flamable vapors reaching a particular lower limit of saturation of the air in the room. THAT, is the important thing and very important it is.
So, how big is your shop including height? How well is it ventillated? How quickly can you move vapors from your booth out of the shop and into the open air? Is there enough ventillation for 4 smokers to smoke in your booth and still have relatively clean air?

[Garth Keel]

I always take the position that if what I'm doing is dangerous or not to code, if anything happens that will give my homeowners insurance a gift-wrapped bullet-solid reason to deny any claim. But maybe I think the glass is half empty. If you can't trust your insurance company, who can you trust? They are in business to help, right? :confused:

[Jack Lindsey]

Leigh -

As a lighting professional I have to advise staying within the code, which means explosion proof fixtures if flammable or explosive vapors are present, however I think Faust, Tony, and Garth have provided some valuable insight. I really suggest you talk to your local building inspector, and have the installation inspected and approved. As Garth stated, an insurance company can deny payment if you have a problem and there is no record of a permit and inspection.

As far as the number of fixtures goes I would use two 2 lamp fixtures due to the length of the space.

[Leigh Betsch]

Jack, two lamp 4 footers or 8 footers?

I understand pretty much where every one is coming from. I wouldn't expect a professional to advise anything but code.

[Jack Lindsey]

Two 2 lamp 4' or one 2 lamp 8'. About the same light either way. Thanks for understanding where I'm coming from.

[phil harold]

for finishing I prefer to have a bare bulb a few inches above the surface the finish is being applied
you can see the finish better with the light at that angle

[Faust M. Ruggiero]

Leigh,
I find that an overhead light in the spray booth is not good, even if it is super bright. I do have one but it is not my only light source. I like to be able to adjust light to the project I am spraying. For instance, if I am spraying a table top mounted at a 45 degree angle (to fit in the spray area), overhead light is OK. I have an 8' hi output fixture mounted on the ceiling. My booth has curtain walls and ceiling I can slide closed when I spray and push out of the way when I am not. The ceiling has a clear vinyl panel and the light shines through the vinyl.
However, if I were spraying a table top laying horizontally, the overhead light would actually cause a glare that would keep me from seeing the spray pattern as well as I like. Then I shut off the overhead and turn on quartz work lights on movable tripods. I would set the location and height of the light to cast a glancing light across the table surface. I keep these lights upstream of the airflow so the spray really never touches them. I've seen lights as simple as the aluminum reflector lights with the squeeze clip mounted to whatever, just so you have enough of them in the right place.
If you mount small projects on a turntable, you set the lights before you start spraying then spin the project as you spray so the lights are always upstream and effective.
fmr

[Leigh Betsch]

Right now I'm using a halogen task lighting that I shine in through the plastic curtain. I think a task light will always be necessary so I can see the finish better. I'm only spraying waterborn but I can see that I'll want to spray alcohol based shellac at some time, so I'm keeping my eyes open for a used explosion proof fan and lights. Is there an explosion proof task light?

[Glen Butler]

In my spray booth it was important for me to have an explosion proof fan because all the volatile stuff was flying past it. As for lighting there is constantly clean air blowing past them. Even with out a fan the chances of an explosion are so small. Incandescent lights with as hot as they get are not capable of triggering an explosion. Add a fan to the mix so the flammable gases cannot even get to the fixtures, there really is no danger. You are probably more likely to get struck by lightening.

The problem is that you have one freak accident and legislation comes out to protect that situation. Bureaucrats have more time than common sense or field experience and it still important to protect that .00001% especially in a work environment.

[Gerry Werth]

[QUOTE= But, I need a light. I have 4ft 2 bulb sealed fluorescence lights in the rest of the shop. These were installed by the previous owner and appear to be a wash down type if light. My question is should I relocate one or two of these lights to the new finishing room, should I look for an explosion proof light, halogen, or go with an incandescent fixture or two. What type of light would be the best to have when viewing and matching colors?[/QUOTE]

Move at least two of those 4' sealed flourescent fixtures in your booth, and put in 6500K or 7000K bulbs. The higher the K temp, the closer to natural sunlight, which is the best light for color matching, run seeking, coverage determining light.

[Jack Lindsey]

The higher the K temp, the closer to natural sunlight, which is the best light for color matching, run seeking, coverage determining light.

Not exactly. Sunlight varies from about 2000K at sunrise to about 10000K at noon on a summer day in Denver. For color matching I'd use a Chroma 50 which is specifically designed for that purpose.