Viscous Liquids - Friction Loss vs. Viscosity and Flow

Friction loss in steel pipes for fluides with various viscosities are indicated in the diagrams below.

Note that kinematic viscosity SSU 32 (1 centiStokes) equals viscosity of water at normal room temperature. Kinematic viscosity SSU 2000 (440 centiStokes) equals SAE 140 Gear Oil.

• Viscosity and Specific Gravity of common Liquids

• 1 psi/ft = 27.7 inH₂O/ft = 22.6 kPa/m
• 1 gpm = 0.23 m³/h

Pipe Size 1/2"

Pipe Size 3/4"

Pipe Size 1"

• 1 psi/ft = 27.7 inH₂O/ft = 22.6 kPa/m
• 1 gpm = 0.23 m³/h

Pipe Size 1 1/4"

Pipe Size 1 1/2"

Pipe Size 2"

Pipe Size 2 1/2"

Pipe Size 3"

Pipe Size 4"

• 1 psi/ft = 27.7 inH₂O/ft = 22.6 kPa/m
• 1 gpm = 0.23 m³/h