Re: Low Water Pressure and Water Pipe Size
Posted by Tony Conner on October 11, 2001 at 20:49:19:
In response to Re: Low Water Pressure and Water Pipe Size
Flow (gallons per minute or GPM) in a given pipe depends on the pressure drop from end to end. The greater the pressure drop, the more GPM. However, if you have a low pressure at the inlet of the pipe, you haven't got very much pressure drop to work with. To get the same GPM with a lower pressure drop, you'll need a larger pipe.

The nozzles won't add any pressure. That's where the water pressure falls to zero PSI (atmospheric). The flow through a given nozzle is ruled by the same pressure drop factor as the pipe. The outlet pressure is zero, and the nozzle will have a hole in it of a set size, so the greater the water pressure at the nozzle inlet, the more water it will pass.

The bottom line is - if you have low inlet pressure to your sprinklers, you'll need larger pipe to supply them.

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