dpb, good idea about the union. Thank you.

Ed, thank you for the further input.

Now here's a question that you folks feel free to inform me qualifies for the dumbest post of the month:

I see the gas line pressure is low, like 1 psi at most. Would it be damned foolish to replace this pipe without turning off the gas? I think the horizontal force on the pipe that I would be "fighting" when threading would be on the order of Pi*(0.5 inch)^2 * 1 psi =~ 1 pound.