Negative Suction

It depends on the specific pump/impeller/speed/design.

Have a look at the data sheet.

The theoretical maximum suction lift for water is 33.9 feet or 10.33272 meters.
From a practical standpoint, in consideration of the friction loss of the piping, the altitude of the station, etc. normally the maximum lift for any pump is approximately 25 ft or 7.62 meters.

http://www.pumps-in-stock.com/pump_theory_basics.html

Regards Woody

Suction lift varies with the NPSH capability of the pump at the operating point.

This requirement is subtracted from the nominal 33.9' (at sea level) available.

In addition you need to subtract suction pipe losses and entry losses.

If it is higher than sea level, the lift available will be further reduced.

Dear friend,

NEGATIVE SUCTION HEAD depends upon the following.

1. Mean Sea Level. 2. Density/Sp.Gravity of the Liquid. 3. Temperature of the Liquid.

4. Frictional Losses on account of Flow/Velocity/Friction Factor.

DHAYANANDHAN.S