730 likes | 912 Views
“THE OFTEN FORGOTTEN UNDERGROUND WORLD”. UNMARKED SEWER THREATS. AGA Distribution Construction Maintenance Committee Mike Kemper, NPL Construction Company September 16, 2008. Core Business : The safe installation & maintenance of reliable energy distribution systems Over 500 crews
E N D
UNMARKED SEWER THREATS AGA Distribution Construction Maintenance Committee Mike Kemper, NPL Construction Company September 16, 2008
Core Business: The safe installation & maintenance of reliable energy distribution systems Over 500 crews Over 2500 employees Operate in 20 states One of the largest users of One-Call Centers in U.S WHO IS NPL? Safety. Quality. Best Cost.
CUSTOMER BASE • CNP • DEA • MERC • GMG • Nicor • EAS NVP ATO • BKH • BGE • SWG • STR • NI Peoples • NI • WGL • XEL • DUK • SWG • KGS • SWG • KGS • UNS • SWG • ONG • APS • SWG • AGL • SWG • ATO • ATO SOCAL SRP • CPS Safety. Quality. Best Cost.
Who’s responsible for marking? Sewer Main Lateral to mains connection Installed line House City street Property line DO WE HAVE A PROBLEM? What could happen?
Sewer Lateral Old Gas Service Line New Gas Main
MADILL, OK 1/2/2007 OK Natural Gas line was installed in 1992
Headline:March 13, 2006Woman, Granddaughters Barely Escape Explosion
MIDDLETOWN, OHIO 3/16/2006 • After seeing bubbles in the water and smelling the natural gas, the plumber told a grandmother and her three grandchildren to get out of the home immediately. • March 18, 2006 Middletown Journal
ODDS OF GETTING A HOLE-IN-ONE 1 in 12,000
MINNESOTA • 27 cross bores reported to the Minnesota Public Utilities Commission in a 6 month time period.
PALO ALTO, CA • 4 blocks inspected • 24 cross bores found
ANOTHER PROJECT • 11,000 sewer laterals inspected • 250 cross bores identified • 2% were cross bores
ANOTHER CITY • Just over 400 gas cross bores discovered over 200 miles of sewer main lines • One cross bore located at a school • Averaged 2 cross bores per mile • The utility mailed notices to over 50,000 residences asking them to first call a special phone number if they had a sewer backup.
AND ANOTHER CITY • Averaged 3 cross bores per mile of sewer main • One cross bore • located at a • hospital
CGA CONFERENCEMARCH, 2008 • “How many of you have experienced Crossbores?” • 2/3 of attendees raised their hands • CGA’s Locating Sewer Service Laterals Committee reached a stalemate and closed the initiative. The team, however, believes this is an important issue and does not want to be satisfied with the status quo. Best Practices Task Group re-formed this fall.
“The Use of Trenchless Excavation Equipment in Relation to the Marking of Underground Facilities” 2008
ARE OWNERS/OPERATORS YOU WORK FOR REQUIRED TO MARK THEIR FACILITIES?
Most states already require some level of locating by the sewer owner/operator States need to enforce sewer locating laws In the meantime … LEGISLATION STATUS Safety. Quality. Best Cost.
Reduction of risk can be achieved with the use of relatively new technology and policies for both new installations and legacy installations. NOW WHAT DO WE DO? Safety. Quality. Best Cost.
How important is the issue of unmarked sewer lines to your business? • Average importance: 9.26(10 = high; 1 = low) • 40 responses from major trenchless contractors in the US
HAVE YOU EVER HAD TO PAY ANY CLAIMS AS A RESULT OF DAMAGING AN UNMARKED LINE?
BE SMART. PROTECT YOURSELF. Lack of Information
One major utility’s standard Duke’s policies NPL’s Policy 22 at www.gonpl.com CBSA’s Guidelines for Identification of Legacy Cross Bores AVAILABLE Safety. Quality. Best Cost.
ONE LDC’s STANDARD • Verification is required using any or all: • Check manholes for depth and direction • Fish tape with Sonde transmitter • Excavate 1’ > depth of lateral near start and end of bore • GPR, if it works • Camera before/after bore • Pre and post construction door hangers
DUKE’S POLICIES • Pre-Construction: Required pre-locating before • any excavation • Post Camera: Required to audit that there are no • crossbores before ANY GAS UP • Contract line items to pre-locate (often via camera) • and post-camera all sewer mains and laterals, • services and storm drains • NPL completed 600 of almost 10,000 NPL Bore • Cards in 2007
CAMERA METHODOLOGY • Trunk line with jump-off push camera’s from house to street. Safety. Quality. Best Cost.
Guidelines for locating prior to and verification post construction Sample Legacy Inspection Contract Equipment manufacturers – notices Sample ordinances Requiring Drain Cleaner training Requiring Accessibility to Sewer Maps LITERATURE UNDER DEVELOPMENT Safety. Quality. Best Cost.
Educate local plumbers, rental stores, mobile home park owners … to look before they root; Find installed problems …before they find us. LEGACY SOLUTIONS Safety. Quality. Best Cost.
A CASE STUDY • An inspection program to inspect sewer mains and laterals for possible cross bores • 4 priorities identified: • Mobile Home Parks • Multi-Family • Schools • Hospitals
4 METHODS USED • Maps and Recordsreview eliminated • Wherever evidence of open trench installation (documented and field) • Facilities installed after no blind bore policy began • Electronic separation • Electronically locate depth and run of sewer lateral and gas service/main • Separation greater than 18” required • Video past intersection point • Used ProPipe and Orbit to complete pilot • Dig and Inspect • As needed Safety. Quality. Best Cost.
VIDEO INSPECTION TECHNOLOGY • ProPipe mainline lateral launcher • 8” and larger diameter lines • Self propelled • Capable of inspecting 1600’ (800’ each direction) of sewer main and 80’ of any sewer service along the way • Audio and video capable Safety. Quality. Best Cost.
VIDEO INSPECTION TECHNOLOGY • ProPipe hand operated camera • Typically used on lines 6” and smaller • Range 200ft • Audio and video capable Safety. Quality. Best Cost.
2004 PILOT • Started in August, 2004 • Late in 2004 a committee was formed to develop program protocol company wide • 13,612 inspections in 2004 • 4 cross bores discovered Safety. Quality. Best Cost.