1. Sewer Line Crossbore Program
Dan Woehrle Manager, Gas System Engineering
June 13, 2013

2. St. Paul Incident
Contractor pierced gas main while working to unclog sewer line - February 1, 2010
Gas ignited and fire quickly spread
Contractor and homeowner escaped
Home destroyed, contractor treated & released
Excavated and found 2” gas main in conflict with 6’ clay tile sewer lateral
Ordered by MNOPS to develop a plan.

3. Xcel Energy’s Plan Improve Construction Practices
Legacy System Program
Public/Contractor Awareness Program
Customer Call-in Process

4. Improve Construction Practices
Revised construction procedures for installation of natural gas pipe company wide
Implemented new practices
Confirm sewers are clear when new gas pipe is installed underground
Seven approved methods for confirming no conflicts
Never create another conflict
Document cleared premises on as-built and in GIS

5. Improve Construction Practices
Clearing Methods Used
Televising Method (43%)
Maps and Record Method (32%)
Open Trench Method (22%)
Exposed Sewer Method (1%)
Sonde Method (1%)
Relative Elevation Method (<1%)
Inserting Method (<1%)

6. Legacy System Program Locations prioritized based on a risk ranking
High Priority Premises (schools, churches, hospitals, nursing homes)
Year of install
Elevation change from street to foundation
Location of gas main compared to sewer main
Previous conflict locations

7. Legacy System Program Project to Date
Using both mainline technology and premise out technology
98,000+ premises inspected
1600 miles of main
125 conflicts identified

8. Public/Contractor Awareness
Increase awareness of the hazards associated with gas/sewer conflicts
Plumbing and sewer cleaning contractors
Equipment rental companies
Customers
Safety DVD
Bill inserts, advertisements, news media, online
“Call Before You Clear”

9. CallBeforeYouClear.com

10. Customer/Plumber Requests
Ask all customers/plumbers to call before they clear
We will review our records and determine if an in-sewer camera inspection is necessary. The premise may have been cleared previously
Camera contractors on standby to go to any location in our service territory
No cost to customer or plumber
26 conflicts identified via call-in process

12. Summary Natural gas system is safe unless disturbed
Prevention through expanded communications, updated construction practices
Never create another conflict
Continue to investigate as requested by customers, plumbers or sewer contractors
On-going legacy inspection program

13. Questions?