Piping Piping Inspection and Testing

Question 1

What is the most common NDE method used for measuring remaining wall thickness of in-service piping?

Accepted Answer

Ultrasonic Testing (UT) with thickness gauge

Answer

Radiographic Testing (RT)

Answer

Magnetic Particle Testing (MT)

Answer

Visual Inspection (VT)

Question 2

What is 'injection point corrosion' in process piping?

Accepted Answer

Localized and often severe corrosion at or near a point where chemicals are injected into a pipe

Answer

Corrosion caused by oxygen injection into steam systems

Answer

Internal corrosion in fire water injection lines

Answer

Corrosion due to cathodic protection current injection

Question 3

What is 'pitting corrosion' and why is it particularly dangerous in piping?

Accepted Answer

Localized attack creating small deep holes that can penetrate the pipe wall without significant weight loss or obvious external signs

Answer

Uniform corrosion affecting large pipe surface areas equally

Answer

Erosion damage from high-velocity fluid impingement

Answer

Corrosion occurring only on pipe external surfaces

Question 4

What is the purpose of an acoustic emission (AE) test on piping?

Accepted Answer

To detect and locate active crack growth, leaks, or structural defects by listening for stress wave emissions during pressurization

Answer

To measure the sound level inside operating pipelines

Answer

To verify pipe insulation sound attenuation

Answer

To check for cavitation in pump suction piping

Question 5

What is the 'remaining life' calculation used in piping inspection programs?

Accepted Answer

Estimated time until the pipe wall reaches minimum required thickness based on measured corrosion rate

Answer

Time until next scheduled maintenance shutdown

Answer

The number of pressure cycles remaining before fatigue failure

Answer

Calendar time since the pipe was last replaced

Question 6

What type of corrosion mechanism causes damage specifically in the heat-affected zones of welds in sensitized stainless steel?

Accepted Answer

Intergranular corrosion (weld decay)

Answer

Uniform corrosion

Answer

Erosion corrosion

Answer

Galvanic corrosion