Plastic Pipe In Construction
- Many states don't allow plastic plumbing such as PEX in taller buildings. . But PEX is allowed just about anywhere for residential construction.
- Typically schedule 20 pipe is not allowed in residential construction. . Use Schedule 40. 
- Where is ASTM D2729 used? 
- SDR 35 is between schedule 20 and 40 
- SDR=Standard diameter ratio. SDR 26 means 160 PSI - at whatever pipe diameters. Whereas schedule 40 pipe pressure will depend on size of pipe.