Cross Bore Remediation Program NGA s 2017 Fall Operations Conference. Saadat Khan P.E. October 13 th, 2017

Transcription

1 Cross Bore Remediation Program NGA s 2017 Fall Operations Conference Saadat Khan P.E. October 13 th,

2 What is Cross Bore A cross bore is an occurrence when a gas pipe is drilled through an existing underground utility unknowingly, specifically sewer laterals. Image: callbeforeyouclear.com 2

3 Consequences Of Cross Bore Can cause backup in sewer laterals and could damage gas pipe during cleaning process that will cause gas to enter in the houses. Image: progressivepipe.com 3

4 What cause Cross Bore Why does it happen? Failure to verify sewer lateral mark outs during trenchless construction. 4

5 What cause Cross Bore (Cont.) Cross bores could happen during any trenchless process. Image: ajvac.ca 5

6 HDD Process Horizontal Directional Drilling (HDD) Process HDD Machines bore through the underground passed other utilities. The drill rod is then connected to the new gas pipe, which is pulled back through the bore opening 6

7 Camera Inspection Technology The external CCTV setup The robotic camera about to enter the sewer manhole The robotic camera inside of the sewer main, about to go up the sewer lateral The internal CCTV setup 7

8 Program The Company identified cross bore as a significant risk that need to be remediated Initiated the program in late 2015, took about 6 months to put together process and contractor in place. Company decided to inspect all known legacy and new HDD work The Company built an in-house database to record, track and pay the contractors Revised HDD procedure to mitigate future risk 8

9 Process E2E OVERALL CROSSBORE PROCESS FLOWCHART (1) Quality Assurance Evaluate HDDs Unknown number of legacy HDDs present a crossbore risk to sewer laterals Identify HDDs in system (Flowchart 2) to identify risk and inspect for crossbores (Flowcharts 3 and 4) Record results of inspection (Flowchart 5) All HDDs in system have documented mitigation of crossbore risk Damage ound? Newly installed HDDs present a crossbore risk to sewer laterals (Active construction) 9

10 Process E2E OVERALL CROSSBORE PROCESS FLOWCHART (1) Quality Assurance Evaluate HDDs Unknown number of legacy HDDs present a crossbore risk to sewer laterals Identify HDDs in system (Flowchart 2) to identify risk and inspect for crossbores (Flowcharts 3 and 4) Record results of inspection (Flowchart 5) All HDDs in system have documented mitigation of crossbore risk Damage ound? Newly installed HDDs present a crossbore risk to sewer laterals (Active construction) 10

11 Process - Identification IDENTIFICATION OF HDDs IN SYSTEM (2) Project Initiation Collect data on all mains that have relevant feature annotations, installation methods, or map text in GIS programs. Collect data on all WOs in Maximo that are labeled as being HDD. Collect data from Resource Planning on jobs that were performed using HDD. Collect data from Contractor Billing on jobs that were performed using HDD. Store all mains in ArcGIS shape files Package Preparation (Flowchart 3) When relying on map text, include all contiguous segments that share a work order or date of installation with previously identified segments. When precise location of main is not specified, append all plastic piping in area that may potentially be included. Eliminate mains with visible trench over location specified in data (unless multiple sources of data indicate HDD). 11

12 Process E2E OVERALL CROSSBORE PROCESS FLOWCHART (1) Quality Assurance Evaluate HDDs Unknown number of legacy HDDs present a crossbore risk to sewer laterals Identify HDDs in system (Flowchart 2) to identify risk and inspect for crossbores (Flowcharts 3 and 4) Record results of inspection (Flowchart 5) All HDDs in system have documented mitigation of crossbore risk Damage ound? Newly installed HDDs present a crossbore risk to sewer laterals (Active construction) 12

13 Detailed steps Basic Tasks Process Work Package PACKAGE PREPARATION FLOWCHART (3) Locate identified HDD gas mains. Identify sewer mains on same street as gas mains. Identify all buildings separated from a sewer main by a gas main Select section of legacy HDD piping that is contiguous or close together. Specify location of newly installed HDD piping (active construction). Identify locations of sewer mains based on field inspection. Identify addresses of sewer laterals at risk (and conditions for inspection, if applicable). Identify locations of gas mains on street using NRG or Small World, supplemented by field sketches and SOP sketches. Identify locations of sewer mains using Google Maps. Record addresses on inspection form. Save all supplemental sketches. Save and annotate NRG sketch. Upload complete package. Forward to Contractor for Inspection. (Flowchart 4) LEGEND Complete Path Communication 13

14 Field Ops Camera inspection contractor Gas Distribution Engineering START FINISH Process - Inspection CROSSBORE INSPECTION FLOWCHART (4) Prepare Work Package (See Flowchart 3) Push Camera Inspection YES Risk exceeds threshold? NO Complete package File records (Flowchart 5) Prepare new Work Package Perform risk evaluation of incomplete inspections by depth and location profiling Store in database as Incomplete Receive notification of damage Field Ops Supervisors and Managers with details of damage including original contractor and year of installation Store in database as Complete Project Closeout Prepare Incomplete Package and upload to dashboard NO Able to inspect all? YES Prepare Damage Package YES Damage found? Prepare Completed Package and upload to dashboard NO Receive Work Package Interface with municipality Conduct inspection Field Ops completes repair of damage LEGEND Critical Path Completion Risk 14

15 Process E2E OVERALL CROSSBORE PROCESS FLOWCHART (1) Quality Assurance Evaluate HDDs Unknown number of legacy HDDs present a crossbore risk to sewer laterals Identify HDDs in system (Flowchart 2) to identify risk and inspect for crossbores (Flowcharts 3 and 4) Record results of inspection (Flowchart 5) All HDDs in system have documented mitigation of crossbore risk Damage ound? Newly installed HDDs present a crossbore risk to sewer laterals (Active construction) 15

16 No inspection performed Process Record Retention Stakeholder requests verification All records are stored in database (see Flowchart 4) Input address or town into database query Hit Determine date and results of inspection or lack thereof Inspection performed Based on inspection ID, provide video of inspection No hit Provide rationale for determination of absence of risk and lack of need for inspection Risk is demonstrated to have been mitigated and project is demonstrated to have achieved goals. 16

17 Progress Since July of 2016, we have completed 6,353 legacy inspections across downstate NY, which resulted in finding 19 cross bores. Inspected 469 new construction jobs in NY that resulted in 2 cross bore findings. Developing alternative technologies with vendors for inspections 17

18 Public Awareness Mailers sent to homeowners whose addresses have been identified as having a crossbore risk. 18

19 Challenges Legacy HDD project identification & processing Municipalities coordination Contractor selection Resources Program tracking Unable to inspect Customer communications Public awareness 19

20 Conclusion Despite procedural changes, cross bore potential can exist. Accurate sewer lateral identification is crucial. Post camera inspection of sewer laterals will confirm whether or not cross bore exists. 20

21 Questions 21