Galaxy,

Everyone called it a standpipe but that would have been too simple. There is a float assembly in each tank which "should" stop the dump at 3500 pounds in each tank which Boeing figured would give you 45 minutes in the pattern. There were notes in all the training materials at AA for F/Es to expect this system to fail in the sim if the Captain said to "Dump to the standpipes."

RMP,

If you're dumping, you're having a bad day. Do you really want to add running out of fuel on top of that?

Some planes do have override pumps that work during dump but some planes just use the regular pumps.

What good is a flow meter in the dump line going to do, you're looking for a number on the fuel panel if if you don't have a "fuel remaining" setting on the dump control.

How a shutoff valve would accelerate the dump is, ah, a CNN talking head answer.