Complexities in Locating Deep Utilities - MISS DIG System ...€¦ · Complexities in Locating Deep Utilities Michigan Utility Coordination Conference January 20th, 2016. Project

Complexities in Locating Deep Utilities

Michigan Utility Coordination Conference

January 20th, 2016

Project Design Phase

•Advance utility relocations

•Deep utility relocations may be problematic during construction

•Excavators need to expose utilities prior to excavation

MISS DIG UNDERGROUND FACILITY DAMAGE PREVENTION AND SAFETY ACT

Act 174 of 2013

effective April 1, 2014

Act 174 of 2013

460.725 Duty of excavator to provide dig notice to notification system; contents of notice; validity of ticket; compliance with procedures and requirements; exposure of facility; notice requirements; excavation using power equipment.

Act 174 of 2013 excerpt

460.725

Sec. 5. (5) . . . before blasting or excavating . . . an excavator shall expose all marked facilities . . . If conditions make complete exposure of the facility impractical, an excavator shall consult with the facility owner or facility operator to reach agreement on how to protect the facility . . .

Act 174 of 2013

460.725

Sec. 5. (8) An excavator shall provide notification to the notification system requesting additional assistance if the location of a marked facility within the approximate location cannot be determined.

Act 174 of 2013

460.723 Definitions.

Sec. 3. (a) "Additional assistance" means a response by a facility owner or facility operator to a request made by an excavator during business hours, for help in locating a facility.

Act 174 of 2013

460.727 Marking facility location; positive response; additional assistance of facility owner or operator upon request by excavator; damage to facility; emergency response; construction of new facility.

Act 174 of 2013 excerpt

460.725

Sec. 7. (5) . . . facility owner or facility operator shall provide additional assistance to an excavator . . .

Act 174 of 2013

460.723 Definitions.

Sec. 3. (a) "Additional assistance" means a response by a facility owner or facility operator to a request made by an excavator during business hours, for help in locating a facility.

Act 174 of 2013

•Act is silent on the responsibilities of an Excavator or Utility Owner if “agreement” is not reached

•Could impact a Roadway Owner’s project schedule• Roadway Owner may need to provide resolution • MDOT Case Example

Jefferson Bridge over RR cut

Reroute of 12 ducts, 4 Subtransmission and 2 distribution circuits due to bridge demo (4 bore shots)

DTE ”As-Built”

DTE “As-Built”

Day 1 After Being Contacted by Construction Contractor

DTE markings on the wall placed previously by DTE Contractor while boring under the Railroad Bed are in Pink

Day 1 after Miss Dig “re-located” facilities

Miss Dig Markings near identical to construction marks

Day 2: DTE Contractor, Miss Dig, and Construction Contractor meet to relocate

DTE Contractor uses “Sonde” to locate all “empty” duct bundles. (Note close proximity to Casing bore)

Miss Dig uses connection to our facilities for more accurate reading

Day 2Resulting location from Contractor “Sonde”

DTE Contractor locates all “empty ducts, marks and labels them for drawing with depths

Shows approximate Width and Location of facilities

Numbers correspond with Duct numbering on “As-built”

“As-Built” detail with Field Notes

Drawing was provided to Contractor as reference for remaining Casings to be completed (One for East Side and one for West side of Railroad Bed) after Sonde locating

Locating Deep Utilities

Vacuum Excavation Vehicles

Typical Depth under Ideal Conditions;15’ to 20’

Typical Depth under Ideal Conditions; 10’ to 12’

Radiodetection 400Multi-Frequency512Hz 8KHz 33Khz 65KHz

Low Medium

Metrotech 810Single Frequency

83KHzHigh

Subsite 950Multi-Frequency512Hz 1Khz 8KHz 29Khz 80KHz

Low Medium High

Metrotech 9890xtMulti-Frequency982Hz 9.8KHz 82KHz

Low High

Metrotech 530Single Frequency

332KHzHigh

Rycom 8876Dual Frequency815Hz 82KHzLow High

PipehornSingle Frequency

480 KHzVery High

3M Dynatel 2250Multi-Frequency5772Hz 8Khz 33KHz 133Khz

Low Medium High

Primary Geophysical Methods – Designating Equipment

Pipe & Cable Locators

Electromagnetic Tools

• VIVAX Loc-150Tx

Limitations of Pipe and Cable Locating Devices (Electromagnetic)

Nonconductive Utilities: Equipment relies on the transmission of an electrical signal along a continuous conductive (metallic) conduit. Nonconductive utilities (e.g. fibers without metallic sheathing) cannot be identified with these tools.

Poor Soil Conditions: Highly conductive soils (e.g. saturated clay) can render the use of lower frequencies ineffective. Conversely, extremely nonconductive soils (e.g. dry sand) can make it difficult to establish a sufficient ground connection to complete the necessary circuit.

Utility Congestion: Higher frequencies are susceptible to interference via “bleed over” to adjacent metallic conductors (utilities) in areas of high utility congestion. Extremely congested areas can sometimes make utility designating very challenging.

Excessive Utility Depths: All equipment has a threshold after which a signal cannot be detected. The depth of this threshold depends on soil conductivity, utility composition, transmitter power output, and the specific design of the piece of equipment.

Non-Tonable Utilities

Detectable fiberglass duct rodders (multi-duct and sub-duct systems)

Beacons \ Sondes and Camera systems (non-tonables)

Sewer Lines

Empty Conduits

Gyroscopic Utility Mapping

10-11 JAN 2012