Pump piping is an ongoing challenge and a source of problems for many.

In this question, the writer talks about the discharge side of the pump, and this area tends to be less dangerous than the inlet side of the pump.

For multiple pumps discharging into a common header, a number of concepts are worthy of consideration.

1.  The size of the discharge piping from each pump must be increased immediately by at least one size from the pump nozzle. This means that the pipe size will already have increased before it reaches the discharge header.

2.  The eventual size of the discharge header should be capable of ensuring that the flow velocity within the header does not exceed 10 feet/second at any point in the header.

3.  The connection of the pump discharge line to the header should be such that the flow combination minimizes the turbulence in the header. In other words the connections should not be at right angles, but rather angled into the flow in the same direction of the flow.