[gow589]

I need to seek a non combustional fan to evacuate the garage as I Pint. We have a granger which should be an excellent source. Any suggestions on fans considered non-combustional?

[302 Z28]

The least expensive method is to use some regular cheap box fans and use them to blow air into the garage through some filters. Those fans have inductance motors and as such do not generate sparks when operating. I would not however use them inside a paint booth or garage where they would be exposed to flammable vapors. The on-off switch is not intrinsically safe and is a source of ignition when either turning the fan on or off.

Vince

[gow589]

Anyone ever actually heard of an un-vented spray booth igniting?

[Polish Painter]

I have been using regular cheap box fans for 18 years . Put them in the garage windows to pull air out of the garage.

Use to put the cheap blue filters behind them , right in front of the motor.
Have not done that in years. Start them before spraying and turn them off after completion.

May not be the safest choice .

[Irelands child]

I've been using the 1050cfm version of this fan with the optional variable speed control. TEFC motor.

http://www.greenhousemegastore.com/T...ctinfo/FA-VFT/

Depending on the size of area you are using, you probably wont need to run it at full speed. I ran at about 2/3rs speed in a 12x20 foot garage. Full speed will pass too much air across the painted surface, and in some cases drying too quick along with pulling any dirt into your fresh paint. I even ended up with a crude deflector to move the air differently.

My (now disassembled) paint booth:



The filter:



And what isn't in my lungs - and with a low overspray gun:



Dave W

[gow589]

I love the detail you have gone through to do so, but is that fan a non-combustional fan? What constitutes a non combustional fan?

[302 Z28]

Originally Posted by gow589

I love the detail you have gone through to do so, but is that fan a non-combustional fan? What constitutes a non combustional fan?

TEFC (totally enclosed fan cooled) is by definition an intrinsically safe motor.

FWIW, just because no one has ever heard of a paint booth explosion is no reason to discount the possibility.

Vince

[Irelands child]

Originally Posted by 302 Z28

TEFC (totally enclosed fan cooled) is by definition an intrinsically safe motor.

FWIW, just because no one has ever heard of a paint booth explosion is no reason to discount the possibility.

Vince

Thanks Vince - I had written a similar response about TEFC motors - and Earthlink went down just as I posted

Dave W

[gow589]

Originally Posted by 302 Z28

FWIW, just because no one has ever heard of a paint booth explosion is no reason to discount the possibility.

Vince

Somehow I knew that would be the next thing posted.

[cyclopsblown34]

TEFC motors are not approved as explosion proof motors. Explosion proof motors are based on TEFC enclosures but they ahve to meet certain classifications in order to certified as such. Use of a basic TEFC motor in an exhaust fan does not meet explosion resistance guidelines for a combustible spray and the motor manufacturer is not allowed/or will not recommend a motor for an explosion proof motor, it is up to the end user to specify which motor. Check out Baldor.com for their explosion proof motors as standard items and what they are good for. I'm a Baldor distributor and have been down this road a few times with customers, it is frustrating as can be. An engineer from the customer usually gets involved in the XP motor selection and specification process.

[DanTwoLakes]

Originally Posted by 302 Z28

TEFC (totally enclosed fan cooled) is by definition an intrinsically safe motor.

FWIW, just because no one has ever heard of a paint booth explosion is no reason to discount the possibility.

Vince

As someone who has been to two electric motor factory schools, I'd like to add my 2 cents. A TEFC motor is just that, it is not rated for hazardous conditions, but Vince is right that it is basically safe because it is totally enclosed. It offers no protection against extremely volatile dust or fumes, nor is it adequate in a situation where it would be exposed to high pressure washing. In that case you would need a washdown duty motor.

What you are looking for is an explosion proof motor. Those are used where dust or fumes may ignite. I think that using an explosion proof motor would be overkill and you wouldn't like the price, either.

[DanTwoLakes]

Sorry,......I posted before I read the post before mine. One of the he two factory schools I went to was the Baldor school, and cyclopsblown34 is right on the button.

[DanTwoLakes]

Originally Posted by Irelands child

I've been using the 1050cfm version of this fan with the optional variable speed control. TEFC motor.



Dave W

The motor for this fan is totally enclosed, but it is not fan cooled, it is air over.

[302 Z28]

I should clarify, I misspoke when I said the motor is "intrinsically safe". The proper definition of "Intrinsically Safe" is as follows.

" Intrinsically Safe Circuit: A circuit in which any spark or thermal effect, produced either normally or in specified fault conditions, is incapable of causing ignition of a mixture of flammable or combustable material in air in the mixture's most easily ignited concentration.

Therefore, Intrinsically safe means that an apparatus, such as a temperature transmitter is not capable of causing an explosion. Explosion proof means that should an explosion occur, it will be contained within an enclosure. "

Explosion proof is whole nother level of protection that is far and away more expensive than most of us home hobbyists can afford.

In a potentially explosive atmosphere we need to not only worry about creating sparks, we also need to consider the surface temperature of any operating device. If a devices surface temperature exceeds the auto ignition point of the atmosphere it is being exposed to then the potential of an explosion is high.

Vince

[TubeTek]

Here's a typical spray booth fan http://www.grainger.com/Grainger/items/7F927?Pid=search They use aluminum blades for spark resistance, and the TEFC motor is mounted out of the airstream. The belt is typically inside a steel tube running from the outer housing of the fan down to the shaft. They wouldn't pass muster as explosion proof, but they do have a sort of maze type path any spark from the motor would have to pass thru to get to the airstream.

Real no kiddin explosion proof components are more expensive than you even guess. Motors are bad enough, but motor starters in explosion proof enclosures will make the motors look cheap. A little section of flex conduit at the motor, made to comply with explosion proof requirements, can cost a few hundred bucks by itself.

We used to do some work that required all explosion proof components, but it was at a site that did things like loading tracer rounds, making solid rocket fuels, etc. Because of the extreme cost, no one uses explosion proof stuff if there's any other possible way to get the job done safely.