Pipeline Leak Detection using Acoustic Emission
Aerial, river, road and railway bed crossings
of pumping and compressor stations, gas distributing stations
Cracks, lack of penetration, under-cuts,
inclusions, edge displacements in butt welding
Testing is performed during operating conditions
Inspection of whole structure
Inspection of areas not possible with other NDT techniques
Minimum access to surface for sensors mounting
Distant location of flaws
efficient method of testing
Sensitive to growing defects, i.e. most dangerous flaws are detected
Questions for Practical Applications
What is the minimum leak to be detectable?
Depending on the type of fluid, the pressure difference across the
defect, the size of the defect and the instrument. Minimum 0.3 ml/sec
was reported. Generally,
ml/sec for liquid or 10-20
ml/sec for gas is more practical.
2. What is the optimum space between two sensors for leak detection?
Depending on materials under test, the leak rate, the type of fluid, the
pressure difference across the defect, the size of the defect and the
instrument. There is a trade off
the detectable leak rate and the space. Maximum
was reported. 50 – 125m
3. What is the frequency bandwidth which is suitable for leak detection?
Generally, the frequency of the leak noise has a character of wide
bandwidth. The sensors with the resonant frequency between 30 - 400 KHz
were frequently used.
4. How efficient for underground pipeline leak detection?
is not unusual.