Max GPM thru 2.5 and 3 inch hard suction at draft?

[38ff 250]

All,

Im trying to find what the maximum GPM you can get thru a 2.5 and 3 inch hard suction hose at draft, no matter what size the pump is. I know there are more variables like feet of head, friction loss, etc, but there must be some rule of thumb. For example, the rule of thumb for 6 inch hose is no matter how large your pump is, with 1 6 inch hard suction the most you'll ever get out of it is approximately 1500 GPM. If you add a 2nd 6 inch off a 2nd intake, you can easily get 2000 GPM or more. I need the same info for both 2.5 and 3 inch hard suction.

Thanks!

Edited July 16, 2011 by 38ff

[antiquefirelt 994]

All,

Im trying to find what the maximum GPM you can get thru a 2.5 and 3 inch hard suction hose at draft, no matter what size the pump is. I know there are more variables like feet of head, friction loss, etc, but there must be some rule of thumb. For example, the rule of thumb for 6 inch hose is no matter how large your pump is, with 1 6 inch hard suction the most you'll ever get out of it is approximately 1500 GPM. If you add a 2nd 6 inch off a 2nd intake, you can easily get 2000 GPM or more. I need the same info for both 2.5 and 3 inch hard suction.

Thanks!

Best to just do the evolution. Pump set ups vary enough and are sometimes "optimized" sometimes downgraded, that the actual numbers are probably less standard than one might think. It's a good chance to explain why FL on the intake side at draft may be a significant factor vs. the same small number on the discharge side or from a positive water source?

Edited July 16, 2011 by antiquefirelt

[batt. 12 12]

The way I learned it from a good pump operator. He always told me he does it like this, for a 2 1/2 in max flow is 250GPM, 5 in 500GPM etc etc

[Bnechis 3,961]

The way I learned it from a good pump operator. He always told me he does it like this, for a 2 1/2 in max flow is 250GPM, 5 in 500GPM etc etc

If it was this simple.....The charts for suction hose include, hose diameter, hose length. lift hight, Altitude and pump capacity.

I don't know what the numbers for 2 1/2" is, but I do know of depts. that use a 3" squrrel tail suction to support a 250gpm attack (so it must move at least that much in the real world and at 5,000 ft above sea level).

NFPA charts show:

4" at 500gpm max of 10 ft lift.

5" at 1,000gpm max of 10 ft lift.

6" at 1,500gpm max of 10 ft lift.