CLEAN WATER SERVICES TECHNIQUES FOR EVALUATING FORCE MAIN CORROSION PROBLEMS

Transcription

1 CLEAN WATER SERVICES TECHNIQUES FOR EVALUATING FORCE MAIN CORROSION PROBLEMS PNCWA 2012 Annual Conference & Exhibition October Boise, ID Presented by: Mike Kebbe, P.E., Clean Water Services Acknowledgements: Nate Cullen, Clean Water Services Steve Kebbe, Clean Water Services CJ Baxter, Clean Water Services Scott Woodbury, Clean Water Services Jim Helton, Murray, Smith & Associates, Inc. Susan Gierga, Murray, Smith & Associates, Inc.

2 Presentation Overview Background Project Development Outcome Questions Twin 24-Inch Pipelines

3 Project Background Routine Maintenance found this Prevention Develop Priority List

4 Priority List Categories Categories: Risk Impact Cost

5 Priority List Category Factors Risk Factors: Age Stress Magnitude (PVC) Soil Corrosivity Failure History

6 Priority List Category Factors Impact Factors: Pipe Size Pipe Length Accessibility Redundancy

7 Priority List Category Factors Cost Factors: Replacement

8 Priority List Risk Factors: Age Stress Magnitude (PVC) Soil Corrosivity Failure History Impact Factors: Pipe Size Pipe Length Accessibility Redundancy Cost Factors: Replacement Scoring Criteria

9 Priority List Risk Scoring Identifier Risk Factors Weight of Risk Factor Potential Score Scoring Criteria A Age B1 Stress Magnitude (PVC) B2 Soil Corrosivity (DI) C Failure History yrs yrs >50 yrs Force Main Reuse Line <25% <50% 25% - 50% 50-75% >50% >75% mildly corrosive moderately corrosive highly corrosive 0 failures 1 failure >1 failure

10 Priority List Impact Scoring Identifier Impact Factors Weight of Impact Factor Potential Score Scoring Criteria D Pipe Size 2 1 < 8" 4 8" - 16" 9 > 16" E Pipe Length 1 1 <1,000' 4 1,000' to 10,000' 9 > 10,000' F Access 1 1 No issues 4 Moderate difficulty may have bores or vegetated land to consider. 9 Seasonally in-accessible, deep bores, wetlands etc. G Redundancy 2 1 Reuse pipe 4 Two pipes 9 One pipe

11 Priority List Cost Calculating Cost Factors: Replacement - $/LF based on pipe diameter

12 Priority List Impact Factors: Pipe Size Pipe Length Accessibility Redundancy Risk Factors: Age Stress Magnitude (PVC) Soil Corrosivity Failure History Cost Factors: Replacement Scoring Criteria

13 Priority List Based on Risk Risk Factor Weight C (Failure History) A B1 B2 Risk No. Force Main/Reuse Line (Age) (Stress*) (Corrosivity*) Score Gaston (Reach No. 1 - Station 0+00 to 20+00) King City Reuse (85th Ave to Alderbrook) Summerfield Reuse (85th to Alderbrook) King City Reuse (Alderbrook to King City) Cipole Beaverton Cornelius Rock Creek Ranch (Highlands) Childs Saum Creek Sherwood Pine Lodge South Bull Mountain Borland Gaston (Reach No. 2 - Station to ) Aloha #3 - # Banks Jackson Bottom Pipeline Risk Ranking

14 Priority List Based on Impact D (Pipe Size) E (Pipe Length) Impact Factor Weight F (Accessibility) G (Redundancy) Impact Score Impact Ranking No. Force Main/Reuse Line North Plains Aloha #3 - # Twin 24s # Sherwood River Road 18" Gaston (Reach No. 2 - Station to ) Gaston (Reach No. 3 - Station to ) Dawson Creek Cipole Orchard Hill Gaston (Reach No. 1 - Station 0+00 to 20+00) WQL Pleasant View West Union Cross Creek River Road 10" Lower Tualatin # Lower Tualatin #

15 Priority List Based on Risk x Impact x Cost No. Force Main/Reuse Line Risk Score Risk Impact Ranking Score Impact Ranking Risk x Impact Risk x Impact Ranking Cost of Replacement, Risk x Impact $1,000,000s x Cost Risk x Impact x Cost Ranking 29 Twin 24s # $ Aloha #3 - # $ North Plains $ Banks $ Gaston (Reach No. 2 - Station to ) $ Dawson Creek $ Gaston (Reach No. 3 - Station to ) $ Oak Village $ King City Reuse (Alderbrook to King 7 City) $ Gaston (Reach No. 1 - Station 0+00 to ) $ Sherwood $ Cipole $ King City Reuse (85th Ave to 5 Alderbrook) $ Cornelius $

16 Priority List Questions, comments & suggestions?