Yes and it can be schedule 80 and schedule 120
I don't think 6 inch pipe is available in schedule 30.
What schedule pipe?
No
Schedule 10 , 40 and 120
8 inch schedule 40 pipe has a cross sectional area of 0.0583 square feet
YES there is
250 PSI WELDED
.165"
What schedule 10 ,20, 40, 80, 120????
XXh in piping is a determination of the wall thickness of the pipe. XXh stands for double extra heavy (or double extra strong) under an old standard measuring system. It has the thickest pipe wall of any other. The actual thickness is dependent on the nominal pipe diameter. Present determination of wall thicknesses of pipes is called schedules. Schedule 10 pipe is the thinnest while schedule 160 is the thickest. Heavy pipe is slightly thicker than today's sch. 40 pipe, extra heavy slightly thicker than sch. 80 pipe, and double extra heavy is slightly thicker than today's sch. 160 pipe. XXh pipe is no longer in use commercially and has been replaced with schedule 160 pipe, XXh Brass or Bronze pipe is forged or molded from bronze, rather than Iron or steel. Some wall thicknesses of double extra strong pipes are: 1/2 inch nom. dia. = 0.294 inch thick 3/4 inch nom. dia. = 0.308 inch thick 1 inch nom. dia. = 0. 358 inch thick 1 1/4 inch nom. dia. = 0.382 inch thick 1 1/2 inch nom. dia. = 0.400 inch thick 2 inch nom. dia. = 0.436 inch thick
http://www.ipspipe.com/Documents/Spec/Pipe_pressure_rating.pdf
Schedule 40 PVC pipe. Legal in all residential and up to 3 story commercial applications.