AWWA Equipment and Tools Knowledge 3

Question 1

A mag-drive (magnetic drive) pump is typically selected when:

Accepted Answer

Leakage of pumped fluid must be completely prevented

Answer

Magnetic drive pumps use a magnetic coupling instead of a shaft seal, eliminating leakage paths — critical for hazardous or ultrapure fluids.

Question 2

What is the primary purpose of a suction lift limitation of approximately 25 feet for centrifugal pumps?

Accepted Answer

Atmospheric pressure limits the vacuum that can lift water

Answer

Standard atmospheric pressure (~14.7 psi) can support approximately 33.9 feet of water column, so practical suction lift is limited to about 25 feet to avoid cavitation.

Question 3

When testing a fire hydrant, a pitot gauge is used to measure:

Accepted Answer

Velocity pressure of water flowing from the outlet

Answer

A pitot gauge inserted into the flowing stream from a hydrant nozzle measures velocity pressure, which is used to calculate flow rate.

Question 4

In water treatment, a backwash cycle on a rapid sand filter is triggered when:

Accepted Answer

The head loss across the filter reaches a predetermined level

Answer

Rapid sand filters are backwashed when head loss (pressure drop) across the filter media reaches the design limit, indicating media is clogged.

Question 5

What is the function of a corporation stop (corp stop) in a water service connection?

Accepted Answer

Provide a tapped connection and shutoff directly on the water main

Answer

A corporation stop is a small valve tapped directly into the distribution main, forming the starting point of the customer service connection.

(AWWA) American Water Works Association Practice Test

(AWWA) American Water Works Association Practice Test

AWWA Equipment and Tools Knowledge 3