Field Verification of Gas Pipeline HCA s. John Linehan, GISP Enbridge Energy Company (US) Houston, TX 24 Feb 2009

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1 Field Verification of Gas Pipeline HCA s John Linehan, GISP Enbridge Energy Company (US) Houston, TX 24 Feb 2009

2 Purpose According to 49 CFR (c), a gas transmission must incorporate an HCA into their integrity assessment plan within one year of discovery. Assessments are not cheap! Is the HCA valid?

3 Terms HCA High Consequence Area PIR Potential Impact Radius BIHO Buildings Intended for Human Occupancy DOT Department of Transportation

4 HCA Process Is the pipeline a gas transmission line? Is the pipeline accurately mapped? Is the PIR calculated correctly? What structures or sites are within the PIR? Do these sites qualify as an HCA? Calculate the extent of the HCA. Add the HCA to the IMP and evaluate RISK.

5 HCA Determination Methods Method 1: Determined by Class DOT Class 3 or Class 4 DOT Class 1 or Class 2 where PIR > 660Ft and area contains > 20 BIHO DOT Class 1 or Class 2 where PIR contains Identified Site.

6 HCA Determination Methods Method 2: Determined by Structures and Areas Area where PIR contains 20 or more BIHO Identified Site (Church, School, Buisness, Outdoor Area, etc.)

7 Verifying Structures BIHO Abandoned, Occupied, Multi-Unit Building Type House, Apartment, Church, School, Business, Park, Outdoor area, etc People Count Occupancy of 20 or more for 50 days in a year. OR: Occupancy of 20 or more 5 days a week for 10 weeks in a year Contact Info Address, Name, Phone Location Polygon with distance to pipeline

8 Aerial Interpretation Scheduled aerial route surveys fly-over Image service Google Map, ESRI, TerraServer, Virtual Earth, etc. Aerial Interpretation cannot determine if structure is a determinant of an HCA. A site visit is necessary.

9 Drive By Employee observations Observations from local authorities Observations from service companies Follow up with on-site inspection and data collection

10 Site Visit Need location of building or site (GPS, Keymap, Alignment sheet) Standing at a known location on the pipeline, how far is it to the nearest corner of the structure? How far to the next nearest corner? Site Photograph from pipeline location to structure. Collect descriptive information about site.

11 Site Data Collection Methods Clip-board forms GPS data dictionaries Operations and Integrity Management Forms ArcPAD / ArcMobile geodatabases One Call Tickets Copy construction permits filed with local government.

12 Sample Data Collection Form

13 Mapping HCA s Digitizing structures Digitizing centerlines Digitizing HCA Areas Storing attribute information How accurate is the data?

14 Testing the HCA Is the site on a transmission pipeline? Is the population count within the rules? Is the structure or site within the PIR? Is the site currently in use? Is the site on a national list? If NO to any above, then probably not HCA.

15 Keeping Current Tracking One Call tickets May indicate future construction sites and encroachments Drive-By or Fly-Over looking for new construction or gathering areas. Local Authorities check with police and schools for local activity sites and hang-outs. Check county offices for construction permits. Review aerial or satellite imagery.

16 Thank You Questions / Comments? John Linehan, GISP Enbridge Energy Company Houston, TX john.linehan@enbridge.com

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