Industry

Application

NPSH Margin
(use whichever is the greater value)

Petroleum / hydrocarbon process

Typical, except vertical canned pumps

1.1 ratio or 1.0 m (3.3 ft)

Chemical process

Typical

1.1 to 1.2 ratio or 0.6 m (2.0 ft) to 1.0 m (3.3 ft)

Electric power generation

Circulating / cooling water

1.0 m (3.3 ft)

Boiler feed < 250 kW/stage

1.3 ratio

Water

Typical, stainless steel or aluminum-bronze impeller, < 75 kW/stage

1.1 ratio or 1.5 m (4.9 ft) minimum

Building services

Typical for pumps in open systems (not pressurized)

1.0 ratio up to a 1.1 ratio or
0.6 m (2.0 ft)

General

Often a standard catalog pump

1.1 ratio or 1.0 m (3.3 ft)