To select the right pipe diameter for your system: 
consider the flow rate (CFM) and length of your piping. Keep in mind that larger pipe sizes increase airflow but also raise costs.

Tailor your air system to your tools, compressor power, and building layout. For optimal flow rate, create a loop system starting from the compressor and circling back. This setup boosts flow, reduces pressure drop, and allows for smaller lines.

The port size on your compressor tank doesn't dictate pipe size; it's determined by piping length and compressor CFM. Remember, air restriction occurs over long distances with small pipes.

Key points:
air flow decreases with distance from the compressor, longer piping requires larger diameters, larger pipes enhance airflow but add to costs, and reducing pipe size at the end of a run hampers flow without benefits.