[Bill Eveland]

Correct , going under ground it would be better to use the galvanized, I was referring to what I was using above ground, black pipe is what we have here at our shop and have never had any problems.
We have a drain at each fitting tee for drainage.
When setting in the pipe in the ground , I would set it at a slight slope to drain back in the house and have a low point made and install a ball valve to drain the condensation out .