Technically if you hang meat in a UDS it's just like a PBC but I suppose if you set up a UDS hang to then it wouldn't be standard.
[/QUOTEActually if you hang meat in a 55 gallon drum it is not the same as a PBC. According to amazingribs.com:
"Why does the PBC use a 30 gallon drum instead of the typical 55?
Pit Barrel President, Noah Glanville explains: "We found that a 30 gallon drum provides a cooking environment that produces the better product every time. I can't explain the scientific reason for this. I can tell you we have gone through 29 different prototypes with different size drums and vent adjustments every way you can imagine."
Once again we ran this by Dr. Blonder, asking if there is any reason the smaller drum would be superior. "Absolutely makes sense." he replied, "The reason the Pit Barrel works is simple, heat rises. So you have a hot fire at the bottom, and hot air that rises to the top; which basically evens out the temperature profile to more or less constant top to bottom. Hang the meat vertically so the hot air is not blocked, and it's the perfect oven - unless there are convection cells that mess up this even profile. Imagine a really wide cooker. Hot air would rise, bump into the cooler lid, cool off and sink, forming a rotating convection cell that lowers air temp at the lid and creates unpredictable turbulence. But as you narrow the diameter of the cooker, it becomes harder and harder for air to make the turn and descend. Sounds like 30 gallons is the dividing line between stable and unstable flow."