[Awalker]

Looper, I have worked in the gas industry for 15years and PSI means as much as orifice size. For each orifice size you will get a certain amount of btus per pound of pressure. So if I wanted to get a certain amount of btus I could use a small orifice size and higher pressure or a larger orifice size and lower pressure. There is a chart around here somewhere with the btu rating and pressures of various orifices. Volume (your flow rate), and pressure are inversley related to one another as per the ideal gas laws, so pressure does mean something! The main reason I see people putting 1/8" or 1/16" orifices in blown burners is that the burners are adjustable by installing either a needle valve upstream or adjusting the pressure regulator upstream to change the flow rate of the burner for their desired characteristics. I have also heard more variable fuel usage reports from people with blown burners for that very reason, they just have them adjusted to use too much fuel. A well designed forced air burner won't explode with the forced air stops either. Now if you are running to rich and you stop of the air supply the flame will want to exit the forge looking for air to burn but it won't explode because it is already on fire.
Also, just a point to ponder, how many people have changed to blown forges, then gone back to atmospheric?