29 Difference Analysis of Acoustic Emission Testing …
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Table 29.2 Recommended service period in different companies
Grade
Description
Recommended service period
PetroChina Pipeline
Company
Company B
Company C
A
Very minor/no damage
5 years
4 years
4 years
B
Minor damage
3 years
3 years
2 years
C
Intermediate damage
2 years
2 years
1 year
D
Active damage
Require internal
inspection in 1 year
1 year
0.5 year
E
Highly active damage
Internal inspection
immediately
0.5 year
Require internal
inspection
So we should use the reasonable method of data evaluation to divide the number
of AE grade so as to provide practical maintenance advice for tank owners.
29.2.2.4 Recommended Service Period is Inconsistent
The recommended service period is inconsistent. There are three different recommended service period obtained from the published papers [1, 2, 7], as shown in
Table 29.2.
So we should consider the basis theory of recommended service period for tank
re-inspection in the future.
29.3 Conclusion
1. Height setting of liquid level, data acquisition time, data processing method and
so on can affect the accuracy of AE inspection of the tank floor.
2. Reliable AE evaluation can be a reality if the inspectors had a lot of experiences,
and the suitable data analysis method and data acquisition methods were adopted.
3. Comparing between AE in-service inspection and non-destructive testing on
aboveground storage tank floors will make AE testing more and more accurate
in the future.
4. It is important to summarize the scientific and reasonable practices of AE testing
in the petroleum industry, and to form a unified standard on data acquisition and
data evaluation in order to promote the application of AE on tank floor evaluation.