IA Pumping Systems & Pump Selection

Question 1

Total Dynamic Head (TDH) in a pump system is the sum of which components?

Accepted Answer

Static head + friction losses + velocity head + pressure head at discharge

Answer

TDH = static head + friction head losses + velocity head + any pressure required at the point of delivery, representing total energy the pump must supply.

Question 2

On a centrifugal pump curve, what is the 'best efficiency point' (BEP)?

Accepted Answer

The point on the pump curve where the pump operates at its highest efficiency

Answer

The BEP is the flow and head combination where the centrifugal pump converts the most shaft power into hydraulic energy with minimal losses.

Question 3

Cavitation in a centrifugal pump is caused by:

Accepted Answer

Low suction pressure causing liquid to vaporize inside the pump

Answer

When suction pressure drops below the liquid's vapor pressure, bubbles form and collapse violently inside the pump, causing noise, vibration, and impeller damage.

Question 4

Net Positive Suction Head Available (NPSHa) must always be:

Accepted Answer

Greater than NPSHr (required) to prevent cavitation

Answer

NPSHa must exceed NPSHr by at least 2–3 feet of safety margin to ensure the pump does not cavitate.

Question 5

Which type of pump is most commonly used in municipal and agricultural irrigation mainline applications?

Accepted Answer

Centrifugal pump

Answer

Centrifugal pumps are the most widely used irrigation pump type due to their high flow capacity, reliability, and suitability for clean water service.

IA - Irrigation Association Certification Practice Test

IA - Irrigation Association Certification Practice Test

IA Pumping Systems & Pump Selection