From: An information entropy-based risk assessment method for multiple-media gathering pipelines
First level | Second level | Weight | Description |
---|---|---|---|
Design | Pipeline strength | Safety design factor (34) | \(\frac{\textrm{Actual}\ \textrm{wall}\ \textrm{thickness}}{\textrm{Design}\ \textrm{wall}\ \textrm{thickness}}\): >1.8 (0); 1.61~1.8 (3.5); 1.41~1.6 (7); 1.20~1.4 (14); 1.1~1.20 (21); 1.0~1.1 (28); <1 (34) |
Water hammer | Elevation change (9) | Gently topography (0); Design pressure - MAOP > Maximum elevation pressure (4); Design pressure - MAOP < Maximum elevation pressure (9) | |
Protective (6) | Slow closing device (2); Pressure relief valve (3); Buffer tank (5); Operating procedures for preventing water hammer (6) | ||
Integrity assurance | Usage time (10) | 0~5years (2), 5~15 years (4), 15~20 years (6), 20~25 years (8), >25 years (10). | |
Inspection time (7) | <1 year (1); 1~2 years (2); 2~3 years (3); 3~4 years (4); > 4 years (7) | ||
Welding quality | Welding level (10) | Strictly follow the operation procedure, i.e., high quality (2); According to the operation procedure, i.e., average quality (6); Random welding, i.e., poor quality (10) | |
Inspection rate (10) | 100% (2); 80%~100% (6); 60%~80% (8); <60% (10) | ||
Backfill quality | Backfill depth (8) | >76.2 cm (2); 7.62~76.2cm (4); <7.62cm or uncovered (8). | |
Backfilling method (6) | Both process and method are correct (2); Process is correct but the method is incrorrect (4); Both backfill process and method are incorrect (5); None (6). | ||
Total | Â | 100 |