(1) Calculation of pipeline operating parameter
The calculation formula of pipeline operating parameter is similar to that of damage parameter, and it is just needed to substitute n as the number of functional defects of the pipeline.
(2) Calculation of pipeline functional defect parameter
The calculation formula of pipeline functional defect parameter G is similar to that of structural defect parameter F; compare the pipeline operating parameters and select the bigger one.
(3) Calculation of functional defect density
The calculation formula of pipeline functional defect density YM is similar to that of structural defect density SM, and the larger the density value is, the more the defects are.
(4) Calculation of pipeline functional defect
The determination of functional defect level of the pipeline shall conform to the provisions of Table 3.1.4-1. The functional defect type evaluation of the pipeline shall be determined according to Table 3.1.4-2.
Table 3.1.4-1 Contrast Table for Functional Defect Level Evaluation of Pipeline
| Level |
Defect Parameter G |
Description of Damage Condition |
| Ⅰ |
G≤1 |
No or slight impact, the pipeline operation is basically unaffected |
| Ⅱ |
1 |
The flow in pipeline is to a certain extent blocked, but the operation is not affected much |
| Ⅲ |
3 |
The flow in pipeline is seriously blocked, the operation is significantly affected |
| Ⅳ |
G>6 |
The flow in pipeline is very seriously blocked, soon or it has already caused the paralysis of operation |
Table 3.1.4-2 Reference Table for Functional Defect Type Evaluation of Pipeline
| Defect Density YM |
<0.1 |
0.1~0.5 |
>0.5 |
| Functional Defect Type of Pipeline |
Local defect |
Partial or whole defect |
Whole defect |
(5) Calculation of pipeline maintenance index
The pipeline maintenance index is an index which indicates the urgency of pipeline rehabilitation and is confirmed after the structural defect level of pipeline is determined and the pipeline importance and environmental factors are considered. If the pipeline has defects and many pipelines need to be maintained, under the condition of limited maintenance capacity and heavy tasks of maintenance team, the pipeline rehabilitation plan shall be worked out according to the severity of defects, degree of impact of defects on the service area, and urgency of defects. The pipeline functional defect only involves the affected degree of internal operating condition of the pipeline, and is unrelated to the condition of soils in which the pipeline is buried. The pipeline maintenance index shall be calculated according to the following formula:
MI = 0.8×G + 0.15×K + 0.05×E
Wherein: MI——Pipeline maintenance index;
K——Regional importance parameter, determined according to the provisions of Table 3.1.3-3;
E——Pipeline importance parameter, determined according to the provisions of Table 3.1.3-4;
The maintenance level shall be determined according to the maintenance index, and the higher the level is, the larger the urgency is. The pipeline maintenance level shall be determined according to the provisions of Table 3.1.4-3.
Table 3.1.4-3 Pipeline Maintenance Level Division
| Level |
Maintenance Index MI |
Maintenance Suggestions and Instructions |
| Ⅰ |
MI≤1 |
No obvious defects to be processed |
| Ⅱ |
1＜MI≤4 |
No need for immediate processing, but should arrange a treatment plan |
| Ⅲ |
4＜MI≤7 |
It should be handled as soon as possible after comprehensive consideration, which is based on the underlying data |
| Ⅳ |
MI＞7 |
The water delivery function is seriously affected and should be processed immediately |
