How do you calculate the size of the header when connecting four 3" NPS nozzles?

To determine the appropriate size of the header when connecting multiple nozzles, the key principle revolves around maintaining adequate flow and pressure within the piping system. In this case, when connecting four 3" NPS (Nominal Pipe Size) nozzles, the total flow capacity that must be managed is critical.

First, we need to consider the combined flow area of the four 3" nozzles. The cross-sectional area of a 3" pipe can be calculated using the formula for the area of a circle (A = πd²/4), where d is the diameter in inches. The area of one 3" NPS nozzle would be approximately 7.07 square inches. Therefore, the total flow area for four nozzles would be about 28.28 square inches.

When sizing the header, it is essential to ensure that the inner diameter of the header is sufficient to provide a flow area equal to or greater than that of the combined nozzles. For practical and code compliance reasons, larger pipe sizes often account for potential flow losses and ensure optimal performance.

Typical practice suggests that to accommodate the flow from multiple 3" NPS nozzles, a header size larger than the combined areas also needs