The Secret Is in the Pipe

The Secret Is in the Pipe

There’s no such thing as too large a compressed air line.

A common error we see in compressed air systems, in addition to poor piping practice, is line sizes too small for the desired air flow.

This isn’t limited to the interconnecting piping from compressor discharge to dryer to header. It also applies to the distribution lines conveying air to production areas and within the equipment found there. Undersized piping restricts the flow and reduces the discharge pressure, thereby robbing the user of expensive compressed air power. Small piping exacerbates poor piping practices by increasing velocity—and turbulence—induced backpressure.

Pipe size and layout design are the most important variables in moving air from the compressor to the point of use. Poor systems not only consume significant energy dollars, but also degrade productivity and quality. How does one properly size compressed air piping for the job at hand? You could ask the pipefitter, but the answer probably will be, “What we always do”, and often that’s way off base. Another approach is matching the discharge connection of the upstream piece of equipment (filter, dryer, regulator or compressor). Well, a 150-hp, two-stage, reciprocating, double-acting, water-cooled compressor delivers about 750 cfm at 100 psig through a 6″ port. But most 150-hp rotary-screw compressors, on the other hand, deliver the same volume and pressure through a 2″ or 3″ connection.