I had a small fire in my reacotor, only because my dad left the heater element on while he was draining some bio out of the reactor, can you say DUH! Had to dump a bucket of water on it to get it to go out.
dumping water on a diesel fire is a good way to spread the fire you were incredibly lucky. i don't have the space to process or i would be doing it, however for those of you who do, you have to remember you are manufacturing "diesel fuel". its supposed to burn really well, and the process involves heat so you really should have large fire extinguisher handy, depending on the size of the operation i would say at least a 10 pounder or even a 50. when fire strikes you're not going to wish for a smaller cheaper extinguisher. many of you who are processing also are involved in other stuff in the shop grinding welding cutting torches hopefully not to near your bd plant but still all good reasons to get good fire suppression devices
BioDiesel is a Class B fuel. Use a Dry Chemical fire extinguisher. Even with a dry chem you can spread the fire by pushing the fuel around with the pressure of the extinguisher. Try deflecting it off something.
Be careful of using a CO2 extinguisher in confined spaces it displaces oxygen. CO2 also has a cooling effect and can bring the tempuarature of the fuel below the ignition temp.