We as a club have all permits and inspections to meet the Ohio laws for blackpowder storage.
We have a powder magazine which is metal but just recently the inspector has informed us that we have to line the entire inside with wood. Our guess is this will help reduce the shrapnel effect in the event of an explosion.
Also in your earlier post you mentioned putting all your cans in plastic bags. It has been my experience that first, the sealed bags can create their own dampness in changing conditions, and second I have seen these bags develope a great deal of static at times. Depending on the grade of powder this could be a hazard. The advice I have been given is that the cans by themselves in a dry storage will last a very long time. I know of one club member that has shot 35+ year old powder with no problems.
Curious when you referenced 'inspectors' if you mean some sort of Ohio State inspectors, what inspectors, etc.
The little metal storage magazine I referenced is one like is sold by the Maine Powder House, etc...nothing as large as what you store at your club I'm sure.
Interesting about the wood lining being used to reduce shrapnel...I've read stories of wooden sailing ships that commented flying wooden splinters being blasted apart by cannon balls hitting the timbers was the most devastating cause of death and injury to the sailors...go figure.
Yes, whenever I bag-seal the cans from a new case, I take them out of the cardboard shipping carton, leave everything sitting around for a couple days in the house to completely let any moisture dry out and stabilize the temperature, then I bag them 3 cans to a gallon size freezer ziploc, pressing the air out, etc.
I order Goex by the case, shoot a can a month, so the longest any cans stay in plastic is only a couple years...so far there's never been a hint of moisture.
But to be honest, I'm not sure I'll bother wasting my time doing the ziploc thing on my next case anyway...go through it too fast...and stored in the house it's in a climate controlled environment anyway.
PS: I've seen some pretty convincing experiments during the past couple years supporting the claim that static does NOT set off BP after all...have you seen those?