Replies

1. 
   HowardAcheson | Jul 17, 2005 12:40am | #1

   If you are not spraying, you do not need an explosion proof fan.  If you can live and breathe in the area, it is not explosive. 

   However, if you have concerns, just put a fan in a window blowing in and open a window on the other side of the shop.  The fan is in fresh air if it is blowing in.  No chance of explosion.

   Howie.........
1. 
   mikegagne | Jul 17, 2005 09:26am | #2

   just put a fan in a window blowing in and open a window on the other side of the shop.I would like to suggest you reverse this advice- blow the air out and open the window on the other side of the shop. Pressurizing the room with the fan blowing in could cause the fumes to migrate to the other parts of the house. Creating a negative pressure situation in your basement will draw fresh air into the room and exhaust the fumes with no one else noticing anything. Aloha, mike

1. 
   HowardAcheson | Jul 17, 2005 08:32pm | #3

   You are, of course, correct.  I suggested blowing in if he wanted to alleviate his concerns about the remote possibility of a fume caused explosion. 

   Howie.........

   Edited 7/17/2005 9:08 pm ET by Howie

2. 
   WillGeorge | Jul 20, 2005 06:29pm | #4

   Just me so check with a expert... explosion proof fans..

   Will NOT work.. Just one item... EVERYTHING electrical/fire related must be explosin' proof!

1. 
   mudman | Jul 20, 2005 08:12pm | #5

   That is a good point. All the large fans I've ever seen use brushless motors, so there are no sparks there. Really the "explosion proof" rating has more tho do with the blades and housing. Steel blades scraping the housing could create a spark, so they are made of aluminum or other sparkless alloys. Explosion proof fans are only margionally more safe than regular fans. I am no minimising the importance of using properly rated equipment, it is an issue to consider. However unless the whole room is explosion proof (fixtures, switches, air compressor, HVLP turbine) there is no point in an explosion proof fan. I know that my HPLV turbine switch sparks every time I turn it on. Also the cantact switches on a air compressor are open to the air. The more pratical approach is to have as much fresh air circulation as possible to dilute the fumes to a safe level.

   Mikeplease excuse my spelling.

1. 
   Elcoholic | Jul 21, 2005 08:05am | #6

   There's some confusion here about explosion proof motors and fans.  I don't know about fans, but do know about motors.  There's 3 basic types of induction motor constructions Open, TEFC and Explosion Proof.  Most single phase induction motors are arc producing because of the starting switch.  3 phase motors don't have a starting switch so are non-arcing.  TEFC motors are sealed and can be used in Division II hazardous areas.  Oversimplifying a bit, Div II areas are those where a combustable substance may come into contact as a result of a failure, such as a blown gasket.  Explosion proof motors are very, very expensive.  Like Explosion Proof conduit fittings, E.P. motors are designed that if there's electrical ignition of the combustable substance inside the motor it has to contain the gasses and allow them to escape in a controlled fashion allowing the gases to cool below the ignition temperature of the surrounding atmosphere.  EP motors are used in Division I areas where the flammable atmosphere is a normal part of the operating process and not a result of a failure.John O'Connell - JKO Handcrafted Woodworking

   The more things change ...

   We trained hard, but it seemed that every time we were beginning to form up into teams, we would be reorganized.  I was to learn later in life that we tend to meet any new situation by reorganizing; and a wonderful method it can be for creating the illusion of progress while producing confusion, inefficiency, and demoralization.

   Petronious Arbiter, 210 BC

1. 
   mudman | Jul 21, 2005 07:32pm | #7

   I forgot about the centrifigul switch. That would be a potiential ignition source. TEFC motors are pretty well sealed, but very few fans use TEFC motors. Most use cheaper regular open induction motors.

   Mikeplease excuse my spelling.

3. 
   Walker1 | Jul 22, 2005 05:37am | #8

          What you are looking for is called an air over motor. The difference is the motor is sealed so the air flows over it. A regular motor draws air through it to assist in cooling,which would also draw in fumes that would build up and ruin the motor. And increase the fire hazard. This is not an explosion proof motor. That's a different motor, and you don't need it. The air over motors generally cost around 50% more than a regular one.

            Try to find a elec. motor supplier who has experience with small exhaust fans.They will be able to help you find a good cage, and help select the right blade for your purpose eg. what size 13,14,15?,what pitch, how many blades ,3,4,5?

            It's a bit of leg work, but taking this route should get you exactly what you need, for about 1/3 the cost. And if any of the three components ever needs replaced,   It's cheap and easy.

              Good Luck.                Walker1

       Edit, Unless you're spraying; this would be overkill.

   
   

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   Edited 7/21/2005 10:44 pm ET by Walker1