Code requires that all PVC DWV (drain, waste & vent) pipe used inside the structure MUST BE PVC-schedule 40 and the pipe MUST BE specifically labelled on the pipe wall as conforming to ASTM-D-2665.

All joints on the PVC must be solvent weld joints (glued) and the Glue must be specifically labelled as approved for PCV pipe.

In addition, code requires that all joints MUST BE cleaned with an approved PVC Solvent Primer before applying the glue.

You will note when buying the primer that it is made in both clear and purple dye. While both primers are the same, it is highly recommended (and required in some jurisdictions) that you use the solvent/cleaner with the purple dye so the inspector can be assured that you used the primer.

On a horizontal run the pipe must be supported within one foot of any change of direction and a hanger for each 48" of run. Metal hangers, metal wire or metal strapping is prohibited. You must use approved plastic hangers or plastic perf strapping.

Here is a side note they don't tell you in most DIY books. The pipe must be hung in such a manner that the writing on the pipe wall is clearly visible. If you happen to put a pipe with the writing against a wall or hung from a ceiling with the writing on top some hard Azz inspectors will red tag it on the premise that they cannot read the information to confirm it is the correct type of pipe.

Thanks lazypup, thats the kind of stuff I need to know.