For what it's worth, my understanding is most hot plate/magnetic stirrers in common use in organic chemistry labs are not explosion proof/approved for hazardous locations.   They are potential ignition sources when used with flammable solvents, but when operated in properly functioning fume hoods, the solvent vapors are swept away at a sufficient rate such that the ignition sources don't typically  encounter vapor concentrations in the flammable (> LEL) range.   I'm not saying that's a good policy, but I believe it is why (along with the use of reflux condensers)  there isn't an epidemic of fires when flammable liquids are used with these devices. 

What is your policy on heating or mixing flammable liquids with non-explosion proof, not spark proof stirrer hot plates?

 

Tom Bialke, MSPH, CIH

Mgr. Research Safety and Compliance

Kent State University