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Yet Another Explosion Proof Fan Quesion


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earlier we called grainger asking about this explosion proof fan. She said a paint booth would need one of these.

this thread says that first fan is okay for a paint booth.

Anyone care to spread any light on the situation? I wan't to be safe but I don't want to spend $500 if I don't have to.

I'm spraying in a 12' x 6' x 7' room and I'm going to be spraying nitro.

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This is the one I'm getting.I'm buying a "spray booth" fan from grainger in a bit. The motor isn't rated as "explosion proof," though. I thinks its rating is hazardous location(which I believe is close to explosion proofe. It really doesn't matter though, because the motor will never see a bit of the oversray or gasses from the spray booth. It has a bolt flange on each side. I'm bolting it to the wall of the spray booth. I plan to put a set of furnace filters on the booth side of the fan, and one on the outside of the fan. Notice that it's about the same price as the one you want, but pulls about double the air. IMHO, it's worth taking the extra effort to isolate the motor from the spray booth if you can get double the cfm for the same price.

peace,

russ

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No it is not an explosion proof motor. Will it exhaust the space-yes, will it run and most likely work-yes, Is the motor rated for that use-NO. So will it cause a fire or explosion-maybe(it is better than some choices, but not correct). The big difference in explosion proof motors is the housing and the way it is sealed up, and if it does produce an internal explosion they are designed to allow for the release of pressure(at least enough for them not to become a pipe bomb). So the question is do you want to pay a few hundred more for a safer installion or just take your chances. I am sure you are dealing with similar issues with the light fixtures you are choosing, unless you have placed them outside the sealed space. Good luck with your booth, and be safe. I can't wait to see more of your finish work.

Peace,Rich

P.S. Russ is on the right track- Get it out of the environment. Hazardous location may not mean explosion proof. Dust or flyings (even if just collecting) in a space is enough to classify an area as hazardous. If you get it out of the classified space your going to remove most of the potential for trouble (very very smart).

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Jeremy mentions that he uses a furnace fan.

for exhaust, I used a Furnace motor and fan. It is isolated in that the motor of course is outside of the ducting and the fan is belt drive with sealed bearings.

is that something like this?

Hazardous location may not mean explosion proof. Dust or flyings (even if just collecting) in a space is enough to classify an area as hazardous. If you get it out of the classified space your going to remove most of the potential for trouble (very very smart).

I'm prety sure that furnace fan would get the motor out of the way of the fumes. My question is will the belt and or bearings in there or whatever cause an explosion?

What kind of furnace fan are you talking about Jeremy?

Edited by Godin SD
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P.S. Russ is on the right track- Get it out of the environment. Hazardous location may not mean explosion proof. Dust or flyings (even if just collecting) in a space is enough to classify an area as hazardous. If you get it out of the classified space your going to remove most of the potential for trouble (very very smart).

+1

In the electrical world (I work for a contractor) we try to avoid placing electrical devices (motors, switches, light fixtures etc.) within a hazardous-rated area whenever possible... less expensive installation and safer.

If you have access to a copy of the National Electrical Code, look up Article 516, Spray Application, Dipping, and Coating Processes:

If you have an enclosed booth, the space 3' from any opening is considered a Class I, Division 2 area (inside the booth itself is Class I Div 1). If you keep your fan motor and any other electrical devices out of this area, then they don't need to be hazardous location-rated (aka "explosion-proof"). The fan itself, though, should be rated for spray booth usage, i.e. non-ferrous, non-sparking blades, etc. Don't forget to ground any metallic surfaces within the booth and ductwork.

Have fun, and be safe :D

Mike

P.S. - if you are just converting a room into a spray booth, then that's another thing... you'd have to upgrade any existing switches, light fixtures, and wiring in the room to Class I Div 1. Not for the faint-hearted. Use an enclosed spray booth.

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There are some serious things to consider when setting up an area that is “explosion proof”.

Is the fan motor going to be exposed to the fumes/vapors? If yes then it must be explosion proof.

How are you lighting the area? This must also be explosion proof along with the switches.

You need to look at how the chemicals/paints are moving in the spray lines and how you transfer the chemicals.. This will create a static charge and can ignite in an explosive area.

This is a very serious issue and needs to be taken seriously. I work in Industrial Safety and have read many fatal reports of people burning up when the atmosphere that they are working in explodes.

All of the safety rules and laws out there are written in the blood of others. Don’t end up a statistic.

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What I'm doing is converting a shed(new) into a spray booth. All I'm doing is putting sealed light fixtures in with all sealed wiring(obviously the light switch will be external to the booth), bolting the fan I mentioned to the exterior(along with removable furnace filters), grounding the building, and installing air hose fittings and fresh air supply fittings on the wall. I'm currently bidding on a hobbyair system on ebay. This certainly burns a hole in your pocket...but you feel good knowing you'll be safe.

peace,

russ

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What I'm doing is converting a shed(new) into a spray booth. All I'm doing is putting sealed light fixtures in with all sealed wiring(obviously the light switch will be external to the booth), bolting the fan I mentioned to the exterior(along with removable furnace filters), grounding the building, and installing air hose fittings and fresh air supply fittings on the wall. I'm currently bidding on a hobbyair system on ebay. This certainly burns a hole in your pocket...but you feel good knowing you'll be safe.

peace,

russ

Thats exactly what I'm doing.

I had an electrition over yesterday to hook up the lights and he told me everything I'd need to do to get the lights explosion proof. There will be no switches in the room so I don't have to worry about that.

The fan situation is the only thing I have any questions about.

Does anyone know if that furnace fan will work?

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Anyone watch mythbusers? The bug bomb one? They had a hell of a time getting it to ignite and had to use excessive amounts of the propellant to get it to go. Draw your own conclusions with this.....

This being said it all depends on your local laws and your own nerves to what you do.

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I can't agree with you more guitarguy. It's really unlikely that you're going to have an explosion. However, you cannot deny that it's possible. That said, I'd rather spend a few extra bucks to ensure it never happens, than take the risk of it probably not happening. I've sprayed two part urethane clears, epoxy primers, etc in my garage with lights that are definitely not explosion proof and open outlets on all of the walls. I never had any mishaps. I've just decided it isn't worth the risk anymore. I plan to be spraying a lot of this stuff in the future, and I want it to have no ill effects on me whatsoever. That said, Godin, have you looked into positive pressure fresh air supplies? Hobbyair makes the cheapest ones I can find. If you're planning on spraying two parts, that needs to be up at the top of the list with the fan that won't blow you up. :D

peace,

russ

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I'm deffinitly NOT going to be spraying anything worse than nitrocellulose. No two part polys without a full body suit and fresh air system for me :D I wan't to be smart enough to play these guitars after I'm done with them :D

I think with a good ventilation fan a regular resperator rated for nitro will be sufficent.

I'm putting the exhost fan right underneath the guitar/whatever I'm spraying so it should pull the fumes away prety efficently.

BTW I remember seeing that episode of mythbusters. I love that show.

Edited by Godin SD
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Anyone watch mythbusers? The bug bomb one? They had a hell of a time getting it to ignite and had to use excessive amounts of the propellant to get it to go. Draw your own conclusions with this.....

This being said it all depends on your local laws and your own nerves to what you do.

These safety rules are written for good reasons. The bulk of the codes are created after fires or bad things happen. It is hard enough to understand what set of circumstances happened to create the fires, electricutions, explosions etc... That is why we should try to follow codes. Some things just won't occur to you, but they can happen. It's like the guy who digs a hole and it it burries him almost chest high as it caves in. It didn't seem like a big deal, until he can't get out and dies from asphyiation.

Godin- The electrician that came out told you how to "get the lights explosion proof". Do you mean how to seal them out from the space? I am only asking because you can't make a regular light fixture "explosion proof".

It seems like we are using explosion proof a lot to describe lights and motors. It is really hard to create fixtures, motors and devices that meet the explosion proof rating. The devices will have threaded hubs, special machined seals (not usually gasketed, that is for a different hazardous type of environment). Most of the devices are in cast housings. The conduits that feed these devices need to have special seal offs as they enter the hazardous space (this is to prevent the conduit from becoming a pipe bomb if vapors collect in the pipe). As mentioned above we try to get the electrical components out of these environments. It is safer and much cheaper to keep them out.

I think you are getting some solid advise from several of the people posting, and it sounds like you are paying close attention to how you build. It should turn out well.

Peace,Rich

P.S. Who do you work for Mike? I work for Dynalectric in Portland Or.

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Do you mean how to seal them out from the space?

Yes. All the lights will be sealed and there will be no outlets or switches in the room.

Cool, I was imagining the guy told you to seal up the fixture itself and keep it in the booth (which would be bad). Sounds like your booth is gonna be sweet. I will have to build a booth in my shed one of these days. I am using waterbased right now, but it would be nice to shoot some Nitro and maybe Poly. Maybe you can post up some pictures after you are done (maybe even a little tutorial, I am sure a lot of people are thinking about building a booth).

Peace,Rich

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Lets put this in perspective here....

An areosol laquer is no less flamable than 2 part poly. (yet we use aerosol's in enclosed spaces such as a garage on a regular basis)

Flamable and explosive are two very different things

If the fan is doing it's job there shouldn't be hardly any solvents in the air, they should be gone as soon as they are sprayed.

With hardly any solvent in the air if there is an ignition it will be much like putting a lighter in front of a spray can. Flamable....not explosive.

But like others are saying extra safe can't hurt.

and wear your seatbelt when you do a run to pick up paint. If you're going to get hurt a car accident is more likely.

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For lighting, I'm constructing an airtight lexan box that runs the length of the sealing. It will butt up against the ceiling and one wall. It will house 2, 4 bulb, fluorescent light fixtures. The power wires will be run out through the wall and all power lines for the booth will be run external to the booth in weather resistant conduit. Does that sound sufficiently safe, rich? Essentially, the light fixures and all associated wires would be isolated from any fumes withing the booth, but would still be in the shed itself. That's really not much different from guys who put plexi over holes in the wall and butt light fixtures against that.

Oh...and I think most people would notice any type of clearcoat building up in the room(at which point they'd open the doors to the booth) if the fan died...that stuff isn't exactly clear when it's airborne.

peace,

russ

Edited by thegarehanman
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Then one day your fan dies on you and you don't notice it until the room is full of nitro fumes... then the loose socket on your fluorescent shop light arcs just a tiny bit... the ensuing events might do a little more than singe your eyebrows.  :D

That's some perspective for ya  :D

You should check that first! before even spraying anying....and once you walked in your booth you will feel no air flow....you would know this if you spray in a booth regularly.

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Lets put this in perspective here....

An areosol laquer is no less flamable than 2 part poly. (yet we use aerosol's in enclosed spaces such as a garage on a regular basis)

Flamable and explosive are two very different things

If the fan is doing it's job there shouldn't be hardly any solvents in the air, they should be gone as soon as they are sprayed.

With hardly any solvent in the air if there is an ignition it will be much like putting a lighter in front of a spray can. Flamable....not explosive.

But like others are saying extra safe can't hurt.

and wear your seatbelt when you do a run to pick up paint. If you're going to get hurt a car accident is more likely.

Look, this is a space dedicated for this task. None of us are going to be able to tell if a space is class 1 div. 1 without knowing more about the space and what is being used for. The fact is you are probably right that not much will happen when the fan is going and pulling the vapors out (then again I don't know). The problems occur because you have the potential to create an explosive environment or have enough vapor to flash. Lets say you spray and close up the booth for the day after the booth has been used for a while. The fan is off and the paint is drying, you go back the next day to work in the booth and turn on the light. The circuit arcs a bit ignighting the vapors that have collected overnight. If you sprayed something once or twice in your garage, you hopefully don't have as much residual paint, hopefully it is a larger space and hopefully it doesn't allow vapors that collect to flash. Then again hopefully a fire never occurs, possibly ignighting propane stored in your garage, or the gas can for the lawn mower.

Personally I think it would be foolish to ignor the fact that it is a potential hazard, or to say well normally it shouldn't do anything. It's what happens under the right conditions, given what the space is used for. Obviously Godin is taking the needed precautions to minimize that potential(very smart IMO).

Peace,Rich

Peace,Rich

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And here we have proper operation of a booth. The fan should never be shut off while something is in the booth.

I'm kinda being the devil's advocate here, so I'll shut up. lol. If I stop posting on this forum I've been blown up..... I'll take my chances.

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:D Sorry Russ, Not ignoring you man. I typed my responce up just as I was leaving work. I didn't even see your post before I posted. The only issue with sealing the lexan up and putting fixtures in the "box" is if somehow that seal fails a little and vapors collect(effectively trapping them, and allowing them to build up). A small breather(not suction) would allow the negative pressure in the space to pull fresh air out of the lexan box if somehow the seal failed. I think if your walls are sealed reasonably well wireing in the walls shouldn't hurt (just make sure you get the same effect as with the lexan "breather", don't allow vapors to get trapped in the wall.). A paint booth is obviously not like an oil tanker or gas station, you just need to prevent the collection of vapor. That is between the spray area and the area outside the spray area that will have the electrical devices.

Peace,Rich

GuitarGuy,

I'll take my chances.
Good luck, I surely hope nothing ever goes wrong, but then again like Murphy's law says- Everything that can go wrong, never goes wrong.... B) . I do understand what you are saying though.

I don't suppose I should mention that areas were dust(saw dust) is thick enough in the air(to flash), or collects is classified as a hazardous location by the NEC. Yes, they make "dust tight" motors. :D I think I will avoid that subject, till I feel like taking some abuse.

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I don't suppose I should mention that areas were dust(saw dust) is thick enough in the air(to flash), or collects is classified as a hazardous location by the NEC. Yes, they make "dust tight" motors. :D  I think I will avoid that subject, till I feel like taking some abuse.

Heard that, Flower mills fall into that category as well. It is the least hazardous on the list. And... the mythbusters tried it and couldnt get it to go. They got a little ignition but noting that didnt put itself out. Might mention as well that everything they got to burn/explode required an open flame to get it to go. Food for thought.

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I don't suppose I should mention that areas were dust(saw dust) is thick enough in the air(to flash), or collects is classified as a hazardous location by the NEC. Yes, they make "dust tight" motors. :D  I think I will avoid that subject, till I feel like taking some abuse.

Heard that, Flower mills fall into that category as well. It is the least hazardous on the list. And... the mythbusters tried it and couldnt get it to go. They got a little ignition but noting that didnt put itself out. Might mention as well that everything they got to burn/explode required an open flame to get it to go. Food for thought.

I think mythbusters needs to explain how these things just can't happen to the people killed or injured when these things happen.

examples

OSHA

Kinda informative

Those are just links I found from a quick search. I have had this stuff drilled in my head for years, because it relates directly to my job. Most of the documented incidents that drive these codes relate to larger industrial work places, but the codes apply to any space that the hazards exist. It takes the right mix of air and fuel then and ignition source. The idea is to use common sense and make it hard for that proper mix to happen(thus no problem). I guess it is what it is, and there is no real point in going much further. Godin and Russ are building with safety in mind.

Peace,Rich

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You speak as if i don't believe you. I do! Its just this proper mixture is insanely hard to come by in a booth that is used once or twice a month. Or somewhere that has a typical film of dust. I think were arguing a moot point here as well.

YES IT IS POSSIBLE! .....there I said it. :D

But me winning the lottery is just as likely!

For the record they said it was plausable....obviously by the evidence too numerous to count it is confirmed.

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