Black powder storage???

[Longknife]

I have been reading the thread about making black powder but decided a LONG time ago that the risk was just not worth it. We all have and use black powder and storeing it is enough of a worry for me! Here is an incident that happened recently, in my home town and it causes me to worry. This building was especially designed for Black powder storage, no electricity, about 9:00 PM when no one was present, and It BLEW? I just wonder what would make that happen???

http://www.thetelegraph.com/news/hanley_23928___article.html/fire_industries.html

 

[Mad Monk]

The big question here is if black powder was the only thing being stored in the building?  Did the building have electric lights installed in the storage area.

Keep in mind that heat, and only heat, will ignite black powder.

The only documented incidents of black powder igniting without any "outside" ignition source involved the storage of black powder in a damp or wet state.  There is a U.S. Bureau Of Mines paper on this dating back to WWII.
In some blasting work they make the powder damp and then tamp it in the blast hole.  This reduces any shattering effect on the rock around the blast hole.

The paper went into the damp powder undergoing chemical reaction that evilves heat.  With large amounts stored in a shed the heat is not dissapated.  When the temperature of the powder gets up around the boiling point of water the sulfur begins to turn to a gas and becomes highly reactive in the powder.  These evolves even more heat.  Eventually the ignition temperature is reached and then the mass ignites. 

In this scenario the entire mass of powder is being heated slowly so almost the entire mass reaches the ignition temperature at the same time.  The resulting explosion mimics detonation of the mass.  Remember than BP is not a true detonating explosive because it is a compounded explosive incapable of reaching detonation velocities within the mass of powder.  But under the circumstances described it will mimic true detonation in explosive effect.

This is simply impossible when one is dealing with a few cans of powder.  it can only happen in a large mass.

If you try to reproduce this with just a few cans the rising gas pressure within the can simply blows the caps off the cans or splits the seam in the side of the can.  Then once open to the atmosphere any sulfur vapors produced simply are carried away in the air.

Generally,  When stored black powder goes up it is because there was a malfunction in any electrical wiring in the building or some very sensitive explosive or detonators were stored with it.

With our cans or plastic bottles you are supposed to store them outside of the house.  Not inside the house.  Stored in an ATF approved magazine away from an occupied dwelling.

Storage temperature should not exceed 150 F.  If you heat black powder slowly, once the temperature of the powder reaches 180 F a small portion of the sulfur begins to go from the solid state to the gaseous state without going through the liquid phase.  In the solid state the sulfur is relative inactive.  But in the gaseous state the sulfur can become highly reactive and "attack" the potassium nitrate.  In doing so this creates/evolves heat.  If the heat is not removed then this chemical change process becomes a self-accelerating decomposition reaction which evolves even more heat.

If the powder is stored wet it may not need an outside heat source to begin this reaction.  And by wet I mean several percent of moisture in the powder, not the fractions of a percent or around a percent as might be commonly seen in black powder.


E. Ogre

[William Worth]

How much wet/damp powder does it take to reach "critical mass"? 

[Mad Monk]

According to the report it involved several thousand pounds of black powder.  Moisture content was roughly 2.5%.

E. Ogre

[William Worth]

Do I assume correctly, that if one were to check their powder and it was generating it's own heat, that the solution would be to spread it out and ventilate it? 

[Mad Monk]

Do I assume correctly, that if one were to check their powder and it was generating it's own heat, that the solution would be to spread it out and ventilate it? 

I have never heard of it doing this in the amounts we deal with.

I have had 25 pounds at a time in my steel magazine out bacvk in 100 degree heat and never had it begin to release heat.  It is just something we would never see.  Especially when packed in one pound cans or even in 25 pound boxes.

E. Ogre

[Roger Fisher]

Gasoline more dangerous than black!

[Daryl]

We have a friend who is much more dangerous than black powder -  so, we keep him as a friend

[RichardW]

Not too long ago I was looking at a few cans of powder in the basement. Thinking about safety and maybe storing it in the barn.  Then I looked at the 250-gallon fuel oil tank in the corner and decided the powder was not a big-hitter when it came to blowing-up the house.

Sometimes it is hard to sort fact from fiction when using and storing black powder. Some posts on this website have helped to that extent.  I do not push my luck and keep my powder away from heat, open flame, electrical current, out of the hot sun, and of course, I keep my powder dry.   I consider myself fortunate not to have any powder related mishaps in over 35 years of BP shooting.

[Roger Fisher]

Not too long ago I was looking at a few cans of powder in the basement. Thinking about safety and maybe storing it in the barn.  Then I looked at the 250-gallon fuel oil tank in the corner and decided the powder was not a big-hitter when it came to blowing-up the house.

Sometimes it is hard to sort fact from fiction when using and storing black powder. Some posts on this website have helped to that extent.  I do not push my luck and keep my powder away from heat, open flame, electrical current, out of the hot sun, and of course, I keep my powder dry.   I consider myself fortunate not to have any powder related mishaps in over 35 years of BP shooting.

I have a care about gasoline in the house - won't happen!

Short story regards a dwelling fire.  2 metal 1 lb cans of black stuck up in the basement rafters.  (fire started in basement) One can alongside foor joist split open and the powder was consumed from the heat.  The can on the opposite side of the joist was scorched; but that was the extent of it.   

[William Worth]

I've often wondered, just how well did the powder magazines in the forts do.  I can understand the need to bury it for protection from enemy fire, but was powder deterioration in the magazine a frequent problem? 

[Mad Monk]

The magazines were vented as far as I had been able to learn.  Also you simply did not site them in/on swampy ground.

Over at Harrisburg, PA there is a historical site with the old powder magazine restored.

Keep in mind that up until after the Civil War they pacvked the powder in wooden kegs.  If you visit the old Du Pont plant to the North of Wilmington, DE you will see the keg shop restored with all of the tools.

One of the main things with the powder kegs was that the wood used to make the kegs had to be properly aged and dry.

During the Civil War Du Pont made some military musket powder at the plant near Wilkes-Barre.  Won't even try to spell the name of the place but we go through there often.  They could not get this powder to pass the proof test and Lammot Du Pont thought that they might have used green wood to make the kegs.  Meaning the green wood would dry, shrink and not protect the powder from damp air.

You will see in old writings where periodically they would pull the kegs of powder out of the magazine and roll them around on the ground and then stack them back in the magazine.  This was done because the powder was not graphite coated which would allow the powder grains to begin to fuse together forming clumps.  This is classic behavior with crystalline materials.  In this case potassium nitrate as the crystalline material.

In one of Allen Eckert's early books he describes an incident that happened on Sullivan's march up into New York to punish the Indians who were raiding down into this area besides New York settlements.
A wagon hauling their powder overturned while fording a stream.  The powder kegs were recovered.  Any that cracked open while in the water were simply discarded.  Those that survived undamaged were opened.  The powder spread out on flat rocks.  Then the powder was repacked in the kegs.
Some assume that this was to dry the powder.  Not so.  They had to dry the kegs.  If you were to store the powder in kegs that had gotten a good dunking the moisture would within a period of time migrate through the wood and into the powder.  They had to dry the kegs to insure the powder would stay dry for the remainder of their journey.

Usually they did not worry about lightning strike on trees near a magazine.  It might charge the ground around the magazine but there would not be the heat generated flash and boom as when the charge passes through the air.  But one old source comments that St. Elmo's Fire is another matter entirely.  This might have come off sailing ships where it was more common than on land.

E. Ogre