After reading my post from last week on pit foaming safety, Dr Jay Harmon, extension ag engineer at Iowa State University asked me about spark ignition furnaces.
Thanks Jay for catching what I missed. According to LBWhite, their spark ignition furnace will try to light 3 times before it locks out for failure to light, even if the gas is turned off. This is a potential ignition source when foam from manure storage pits is knocked down (broken) that I overlooked.
If you have a spark ignition furnace before you begin to break up the foam, turn off the electric circuit to the furnace or unplug the furnace so it does not try to light if the controller calls for heat in the room.
As I wrote last week, to reduce/prevent the risk of explosion from methane accumulation as a result of breaking of the foam ‘bubbles’, all sources of potential gas ignition must be turned off. While pilot lights on furnaces are the most obvious sources, spark ignitors are just as likely to cause an explosion under the right circumstances.