Pumping - Pressure Loss Calculations

Question 1

What are four factors affecting pressure loss?

Answer 1

Internal diameter of hose

Output flow of water

Height in metres above or below the water source

Length in hoseline

Question 2

What are two main reasons for pressure loss in hose lines?

Answer 2

Frictional loss

Effects of gravity when working above the water source or pump

Question 3

A loss of pressure due to friction is governed by the following laws which are?

Answer 3

The longer the hoselines, the greater the frictional loss

Pressure loss is directly proportional to the square of the flow rate

If the flow rate through the hose is doubled, the pressure loss due to friction will increase by a factor of four

Pressure loss is inversely proportional to the hose diameter

Question 4

How much pressure is lost due to gravity?

Answer 4

0.1 bar per metre

Each floor level is roughly 3m = 0.3 bar

Question 5

What are some practical considerations to overcome pressure loss?

Answer 5

Adding 1 bar to every 45mm hose

Adding 0.2 bar to every 70mm hose

Pressure loss less than 0.5 can be ignored, higher than 0.5 can be rounded up

Adding 0.3 bar to every floor level