Expert advice

Easy calculation of the friction loss of your pumping system.

In any pumping system, the friction loss is a combination of 3 factors:

- The friction of the water on the pipe wall;

- The flow level;

- The pipe fittings, valves or any other similar devices.

The capacity of a pump is calculated in reference to a vertical pipe installed on the pump discharge. Any horizontal pipe used in the system creates a friction loss which has to be added to the application vertical lift to calculate the total head of the system. This pipe friction loss varied with the flow and the pipe size.

The higher is the flow, the higher is the friction loss. The lower is the pipe size, the higher is the friction loss. Using a bigger pipe size is always an advantage.

The below chart describes the loss for 100' of horizontal pipe and is expressed in feet of head. The fittings are expressed in feet of head per unit.

f loss a

As an example, we will use a flow of 1200 GPH and a 1'' pipe.

So, 100' of horizontal pipe is the equivalent of 25.1' of head.

For the purpose of our example, we will consider that your system has to lift the water by 30 feet, has 4 regular elbows and 18 feet of horizontal pipe.

The elbows creates 10.8 feet of head (2,7 x 4).

Then, 18 feet of horizontal pipes at an average of 1200 GPH equals to 4.5 feet of head (25.1 x 18 / 100).

So, your total head is 45 feet (30 + 10.8 + 4.5). Refer to the capacity chart of your pump to find the real performance your pumping system will deliver, based on the configuration of your piping.

burcam rgb