AWWA Pipeline Integrity and Testing 2 — Questions and Answers
Question 1: What is the primary purpose of a hydrostatic pressure test on a new water main?
- To flush sediment from the pipe
- To verify the pipeline can withstand operating pressure without leakage (Correct answer)
- To disinfect the interior pipe surface
- To measure flow velocity under normal conditions
Correct answer: To verify the pipeline can withstand operating pressure without leakage
Hydrostatic pressure testing confirms that joints, fittings, and pipe walls can sustain pressure without failure or excessive leakage.
Question 2: According to AWWA C600, what is the typical test pressure for a newly installed ductile iron water main rated at 150 psi working pressure?
- 150 psi
- 200 psi
- 225 psi (Correct answer)
- 300 psi
Correct answer: 225 psi
AWWA C600 specifies a test pressure of 1.5 times the rated working pressure, so a 150 psi main is tested at 225 psi.
Question 3: Which inspection method uses a camera-equipped device inserted into a pipe to visually assess internal condition?
- Acoustic emission testing
- Closed-circuit television (CCTV) inspection (Correct answer)
- Magnetic flux leakage (MFL) scanning
- Ground-penetrating radar (GPR)
Correct answer: Closed-circuit television (CCTV) inspection
CCTV inspection deploys a motorized camera through the pipe interior to identify cracks, corrosion, joint offsets, and debris.
Question 4: What does an abnormally high allowable leakage value during a pressure test most likely indicate?
- The pipe material is highly porous
- There are leaking joints or cracks in the tested segment (Correct answer)
- The pressure gauge is reading too low
- The test duration was insufficient
Correct answer: There are leaking joints or cracks in the tested segment
Excessive leakage beyond the AWWA-allowed limit signals physical defects such as failed joints, cracked pipe, or faulty fittings in the test section.
Question 5: In pipeline integrity management, what is a 'cathodic protection survey' used to evaluate?
- Disinfection byproduct levels in the water
- The effectiveness of corrosion protection on metallic pipelines (Correct answer)
- Sediment accumulation inside the pipe
- Water hammer pressure transients
Correct answer: The effectiveness of corrosion protection on metallic pipelines
Cathodic protection surveys measure pipe-to-soil potential to determine whether the impressed current or sacrificial anode system is adequately protecting the metal from corrosion.
Question 6: Which destructive testing method involves removing a short pipe sample from service to test its physical properties in a laboratory?
- Coupon sampling (Correct answer)
- Acoustic leak detection
- Hydrostatic proof testing
- Electromagnetic testing
Correct answer: Coupon sampling
Coupon sampling cuts out a section of in-service pipe so engineers can measure wall thickness, tensile strength, and degree of corrosion in a laboratory.
Question 7: What is the AWWA-recommended minimum duration for a hydrostatic acceptance test on a new water main?
- 15 minutes
- 1 hour
- 2 hours (Correct answer)
- 4 hours
Correct answer: 2 hours
AWWA C600 requires the pressure test to be maintained for a minimum of 2 hours while leakage is measured against allowable limits.
AWWA Pipeline Integrity and Testing 2
What is the primary purpose of a hydrostatic pressure test on a new water main?