by "firkin" you are referring to the volume, right? That's about 10 or 11 gallons.
What kind of connectors does it have on it for tapping it? sanke, like a keg of bud would have, or is it something weird/special?
At 10 gallons in size, it would make a good boil kettle, mash tun or liquor tank if you cut the top out.