CPII Utility Systems 3 — Questions and Answers
Question 1: Which pipe material is most susceptible to corrosion in acidic soils and requires cathodic protection?
- PVC
- Ductile iron (Correct answer)
- HDPE
- Concrete pressure pipe
Correct answer: Ductile iron
Ductile iron pipe is susceptible to electrolytic and acidic soil corrosion and often requires polyethylene encasement or cathodic protection.
Question 2: A fire hydrant barrel is found cracked at the ground line during routine inspection. What is the correct disposition?
- Mark out of service and schedule repair (Correct answer)
- Continue service until the next annual inspection
- Reduce operating pressure at the hydrant
- Install a sleeve around the crack and monitor
Correct answer: Mark out of service and schedule repair
A cracked hydrant barrel is a safety hazard and must be immediately marked out of service and repaired before returning to active use.
Question 3: What is the purpose of a pressure-reducing valve (PRV) in a water distribution system?
- Increase pressure in low-pressure zones
- Prevent backflow from private services
- Reduce high inlet pressure to a safe downstream level (Correct answer)
- Relieve excess pressure caused by water hammer
Correct answer: Reduce high inlet pressure to a safe downstream level
A PRV automatically reduces high upstream pressure to a preset lower downstream pressure to protect pipes, meters, and fixtures from over-pressure damage.
Question 4: During a utility easement inspection, you find a property owner has constructed a fence across a buried gas line easement. What is the first action to take?
- Remove the fence immediately
- Document the encroachment and notify the utility owner (Correct answer)
- Issue a stop-work notice and call law enforcement
- Verify the fence has not damaged the gas line before acting
Correct answer: Document the encroachment and notify the utility owner
The inspector's role is to document encroachments and notify the responsible utility owner, who has the legal authority to pursue easement enforcement.
Question 5: What does a deflection angle greater than the manufacturer's allowable limit in a flexible pipe joint most directly risk?
- Increased friction losses in flow
- Joint separation and leakage (Correct answer)
- Reduced pipe wall thickness
- Premature corrosion at the joint
Correct answer: Joint separation and leakage
Exceeding the allowable deflection angle at a flexible joint can cause the gasket to be extruded or the joint to separate, resulting in leakage.
Question 6: Which document specifies the minimum thickness class for ductile iron pipe based on laying conditions and working pressure?
- AWWA C151/A21.51 (Correct answer)
- ASTM D3034
- AASHTO M252
- NFPA 24
Correct answer: AWWA C151/A21.51
AWWA C151/A21.51 provides the standard for ductile iron pipe thickness design based on internal pressure, external loads, and laying conditions.
Question 7: An inspector observes a utility trench being backfilled with native soil containing large rocks around a PVC sewer pipe. What concern should be raised?
- Increased buoyancy risk for the pipe
- Point loading from rocks can crush or crack the pipe (Correct answer)
- Thermal expansion of PVC will be restricted
- Groundwater infiltration will increase
Correct answer: Point loading from rocks can crush or crack the pipe
Large rocks in the pipe zone create point loads that concentrate stress on PVC pipe walls, potentially causing cracking or crushing over time.
CPII Utility Systems 3
Which pipe material is most susceptible to corrosion in acidic soils and requires cathodic protection?