I'm putting a valve and union in the gas drop to feed my water heater. I need the union there because the pipe is in the way of pulling the water heater out. It will be located above the top of the water heater so it will clear when removed. I also need to align the outlet of the tee down below that feeds the gas valve. It would be free hanging. Pipes also feed furnace, so some vibration is present. I figure that a pipe flange could be bolted to the floor and a nipple attached with a coupling to the bottom of the drip leg (cap removed), but the coupling would have to be blocked inside, sort of like two caps end to end. Does such a fitting exist? Is it easily accessible? Other ideas to accomplish the same thing, supporting this vertical drop of pipe?