I replied the other day but I see it didn't post or got lost... Anyway, I don't take many thing personally so don't worry about that. All I wanted to do was clarify things.
That's true but a "flammable atmosphere" is different from a flammable solid. Things like gasoline fumes, LPG/NG, acetylene, MEK and so forth are either gas or gas emitting and it's the gas the mixes easily with the ambient air making for the "flammable atmosphere. An internal combustion engine when properly operating contains a "flammable atmosphere" in the cylinder on the compression stroke, it's that flammable atmosphere that is easily ignited by the spark from the sparkplug. Black Powder is a solid which means it takes a whole lot more heat to get it going than can normally be produced by human ESD.
there is a real risk that filling or emptying an FIBC will generate enough static electricity to cause and incendiary discharge.
FIBC's are quite unique in that more often than not, they're made from non/low-conductive material and being filled with a non/low-conductive material. When you combine the two especially in case where the FIBC is being filled/emptied, it is possible to generate ESD potentials of 100kv or more considering that a typical FIBC has about 64 cubic feet of storage volume and a total volume of 112-144 cubic feet, that's a lot of area for dust to build up in and a lot of surface area on the FIBC. The larger the contained volume and the larger the surface area, often around 160 square feet for a typical FIBC, the higher the ESD potential can become especially when combined with materials that promote ESD generation. The potential for a dust explosion caused by ESD when filling/emptying FIBC's is very real but it all depends upon the size of the dust particles and their flammability rating. The maximum temperature and duration of an ESD must be sufficient to cause ignition of the dust. As said before, one cannot compare typical human-source ESD to that produced by such conditions as filling/emptying an FIBC. The issue of a "painful" human-source ESD isn't a factor in determining the actual voltage & amperage flow because the felt pain is directly proportional to the point at which the arc originated such that nerve ends are at the surface of the skin, the nerves run on electrical impulses and any electrical disruption within the nerves can cause enhanced sensation of discomfort. Anyone who has gone through an EMG/nerve conduction test can attest to the fact that even the very low voltage and amperage used for such tests can vary anywhere from a mild sensation to severe pain despite the fact that no damage is being done by the electrical current.
A typical human-source ESD is far less than the 13,000-17,000 volts a Piezo-electric generator puts out (the little push/twist button igniter on your BBQ grill). The typical painful loud snap of a human ESD generates an arc length less than 0.050" or about 6,000 volts. Humans also have a considerably lower capacitance value than something like FIBC because the human body is electrically conductive which means the amount of amperage released in a human-source ESD is way below the available potential in an FIBC thus greatly limiting the amount of heat the ESD arc can produce and subsequently transfer to a flammable solid.
I'm not trying to beat a dead horse here but it is pertinent to make the distinction between the ESD potential of a human verses that of something like an FIBC. To try making that kind of stretch would be the same as trying to make the stretch between a little portable generator and a nuclear power plant generator, both generate electricity but one is a whole lot bigger. As I said before, I'm not discounting the fact that ESD is a concern that should be addressed but I am making that point that black powder is no where near as sensitive to ESD as some claim it to be ... if that was the case, how could so many black powder manufacturers get away with packaging the product in plastic containers?
I'm also one to push safety and ESD mitigation is definitely something people should address and to do so the facts must be presented. One doesn't want to cover a reloading bench with plastic like vinyl or Formica nor should wood be coated with polyurethane or other synthetic paint/finish because it creates the same conditions as any other plastic type covering. Same as having an unfinished wood or concrete floor as opposed to wall-to-wall carpet, plastic seat coverings, plastic trays/containers and so forth.