DETECTIONDETECTIONProfessionalProfessional

Issue 3 A publication of SENSIT Technologies

DAMAGE PREVENTION

UTILITY LOCATING:EM, GPR AND ULTRA-TRAC APL

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3

Welcome to 2016! Wow, it seems like just yesterday we were working to finish 2015. Last year was a fantastic year for SENSIT Technologies and I am truly grateful to both our long time, loyal customers as well as the many new ones that were introduced to SENSIT products last year. Everyone at SENSIT knows the importance of their job and how it ultimately can effect yours. I also know that regardless of every effort to build perfect products, there can still be surprises. Our dedicated team in Customer and Technical Services are ready to answer questions and provide product and application support. Equally important, they constantly communicate the trends they hear from you to our engineering team. This process insures continuous improvement to meet our objective of zero defects.

2016 looks to be another exciting year at SENSIT Technologies. We are adding resources toward the development of new innovative products as well as reviewing our legacy products to improve your field experience. Since last fall, we added four new engineers to our global staff as well as hired a new Director of Engineering, Kurt Stefans. These new resources will enable us to meet the pace of changes in deployable technologies for the future.

Another recent hire is Adam Zeciri who is SENSIT’s new Product Manager for our growing Locating Products business. Adam brings more than 15 years of experience in underground utility locating and certifying utility and contractor locate personnel. Significant enhancements have recently been made to our Ultra-Trac APL (acoustic pipe locator). Adam will assist clients in understanding how to implement this unique product to find untraceable underground piping systems. He is also responsible for the feature article in this edition which compares the different technologies available today to locate underground utilities.

Thank you again for your business and taking the time to read Detection Professional. We hope you find the information valuable. Please free to send this edition to others and of course, let us know if you have any suggestions or comments.

All the best,

J. Scott KleppePresident and Chief Executive Officer

J. Scott KleppePresident and Chief Executive Officer

President’s Message

4 DETECTION PROFESSIONAL • Issue 3

Utility Locating: EM, GPR and ULTRA-TRAC APL

Feature Article

Introduction to Utility LocatingNo matter the technology used to locate buried pipes and cables today, there is no single tool that can do it all. Just as a carpenter’s tool box consists of application-based tools like the hammer, chisel and screwdriver, the role of the utility locator also calls for more than one tool to be effective in the field. To fully understand what sets these different tools apart and when a specific tool should be selected over another, one must first understand the applications and limitations of currently available locating equipment.

Today, the most commonly used methods to locate buried infrastructure are electro-magnetic (EM), ground penetrating radar (GPR), and acoustic. This article will highlight the technical limitations of each technology and in the process, what sets the Sensit Ultra-Trac Acoustic Pipe Locator apart as a truly essential tool for the locator’s toolbox.

Electromagnetic Utility LocatorsIn 1931, Gerhard Fischer invented the first handheld utility locator for commercial use, to primarily locate buried metallic pipes and cables. Electro-magnetic (EM) pipe and cable locators use electricity to create a magnetic field to trace the path of buried metallic pipes and cables. EM locators can only detect metallic pipes, cables and wire. They are commonly called conventional locators, due to their wide spread popularity and use. Conventional EM utility locators have 2 main parts: the transmitter and the receiver. The transmitter functions as a miniature power plant and is used to transmit alternating current to energize a metallic pipe, cable or wire. The byproduct of alternating current flowing on a metallic conductor is a magnetic field that may be detected by the receiver.

EM Limitations - Other metal present near the target line will cause

distortion, causing error in the reading. This could be anything metallic; such as a parallel utility line, a metal building or a vehicle.- EM locating equipment can only be used to locate metallic utilities. It cannot be used to find non-metallic lines unless a tracer wire is present (for plastic or concrete-asbestos pipe, for example) and is metallically continuous.- EM locating equipment cannot tell what type of utility is being located. The operator must verify the utility type by either potholing or tracing the utility line structure to structure.

Ground Penetrating RadarThe first large-scale application for Radio Detection and Ranging (RADAR) was used during World War II by the British and American military, to detect electromagnetic pulses reflected by aircraft. Ground Penetrating Radar (GPR) was first used to determine the depth of a glacier in Austria in 1929. Today, despite its common limitations due to soil conditions, modern use of GPR to locate buried utilities has increased in popularity, due to the ability to find both metallic and non-metallic lines.

Environmental FactorsThe dielectric constant of the media or substrate being scanned determines the amount of signal that is absorbed by the substrate through attenuation. Because soil type determines this factor, soil conditions must be optimal for GPR to work. Soil moisture content greatly affects the GPR signal; in general, dry soil is better than wet. Also known as permittivity, the dielectric constant is frequency dependent for GPR. The higher the frequency, the better the resolution with shallower depth penetration. Conversely, the lower the frequency, the better the depth penetration with lower resolution. The size and material of the target line will also impact the ability to be seen using GPR.

The soil type and moisture content definitely matter for GPR to successfully locate buried pipes. Ranked from best to worst: Air, solid ice, rock, sand, silt,

and finally clay. As shown in the map below, most areas of the United States do not have optimal soil conditions for the effective deployment of GPR.

GPR Limitations- Soil type plays a major role in the ability to find pipes and cables using GPR.- The greater the depth, the greater the target utility size needs to be; smaller pipes and cables will not be found using GPR.- Certain types of pipe materials simply cannot be seen by GPR in any soil type, at any depth.- GPR cannot tell the type or material of the buried utility line. Must be verified by potholing or tracing the utility line structure to structure.

PineBluff

LittleRock

FortSmith

Fayetteville

Yuma

Tucson

Phoenix

San Jose

SanFrancisco

SanDiego

Sacramento

LosAngeles

Fresno

Pueblo

Longmont

Greeley

FortCollins

Denver

ColoradoSprings

Boulder

WaterburyNewHaven

Danbury

Bristol

Bridgeport

Wilmington

Dover

Tampa

Orlando

Miami

Jacksonville

Fort

Lauderdale

Macon

Atlanta

Albany

WaterlooSiouxCity

Omaha

IowaCity

Dubuque

DesMoines Davenport

CedarRapids

Pocatello

IdahoFalls

BoiseCity

Rockford

Chicago

TerreHaute

Muncie

Indianapolis

FortWayne

Evansville

Bloomington

Anderson

Wichita

Topeka

St.Joseph

Lawrence

Owensboro

LouisvilleLexington

Huntington

Shreveport

NewOrleans

Monroe

LakeCharles

Lafayette

BatonRouge

Alexandria

Worcester

Springfield

New Bedford

LowellLawrence

BrocktonBoston

Baltimore

Portland

Lewiston

Bangor

ToledoSouth Bend

LansingGrandRapids

Flint

Detroit

AnnArbor

St.Cloud

Rochester

Minneapolis

La Crosse

GrandForks

FargoDuluth

Springfield

St.Louis

KansasCity

Columbia

Pascagoula

Jackson

Hattiesburg

Biloxi

Missoula

GreatFalls

Billings

Winston-

Salem Raleigh

High Point

Fayetteville

Durham

Charlotte

Bismarck

Portsmouth

Manchester

Trenton

Santa Fe

LasCruces

Albuquerque

Reno

LasVegas

Rochester

NewYork

Buffalo

Wheeling

ParkersburgDayton

Columbus

Cleveland

Cincinnati

Akron

Tulsa

OklahomaCity

Lawton

Salem

Medford

Eugene

PittsburghPhiladelphia

Providence

Newport

Sumter

Spartanburg RockHill

Greenville

Columbia

Charleston

SiouxFalls

RapidCity

Nashville

Memphis

Knoxville

JohnsonCity

Jackson

Clarksville

Chattanooga

SanAntonio

Lubbock

Houston

El Paso

Dallas

CorpusChristi

Austin

SaltLakeCityProvo

Ogden

Logan

Washington

DC

Roanoke

Richmond

NorfolkLynchburg

Burlington

Yakima

Tacoma

Spokane

Seattle

Portland

Bellingham

Sheboygan

Racine

Oshkosh

MilwaukeeMadison

KenoshaJanesville

GreenBay

EauClaire

Appleton

Charleston

Cheyenne

Casper

Tuscaloosa

Montgomery

Mobile

Huntsville

Gadsden

Dothan

Decatur

Columbus

Birmingham

Lincoln

WY

WI

WV

WA

VA

VT

UT

TX

TN

SD

SC

RI

PA

OR

OK

OH

ND

NC

NY

NM

NJ

NH

NV NE

MT

MO

MS

MN

MI

MA

MD

ME

LA

KY

KS

IA

IN

IL

ID

GA

FL

DE

CT

CO

CA

ARAZ

AL

Ground-Penetrating Radar Suitability Map

HAWAII

PUERTO RICO &U.S. VIRGIN ISLANDS0 50 100 150 200 25025

Kilometers0 50 100 150 20025

Kilometers

0 10 20 30 405

Kilometers

USDA-NRCS. 2009. Ground Penetrating Radar Suitability - US (map). Using ArcGIS, Version 9.2 (Environmental Systems Research Institute, Inc., Redlands, Ca.). National Soil Survey Center, Lincoln, Nebraska. Scale 1:1,500,000. Map projection for continental U.S. using Albers Equal Area, North American Datum 1983 (NAD83). Map projection for Hawaii using Hawaii State Plane NAD83. Map projection for Puerto Rico and U.S. Virgin Islands NAD83. USDA-NRCS. 2008. Digital General Soils Map (GSM) version 2. Continental United States, Hawaii, Puerto Rico and U.S. Virgin Islands. Soil Data Mart Source (http://soildatamart.nrcs.usda.gov). December 2008 edition. Soil Survey Staff. 2009. NSSC DATA – Ground Penetrating Radar Suitability Index (GPRSI) [data file] - National Soil Information System (Evaluation Draft - 02/2009). USDA Natural Resource Conservation Service, National Soil Survey Center, Lincoln, Nebraska. (http://soils.usda.gov). Current State and Equivalent, TIGER/Line 2008 (cartographic boundary file, tl_2008_us_state.zip). 2008. U.S. Census Bureau. Available FTP: ftp://ftp2.census.gov/geo/tiger/TIGER2008/. [Accessed on February 20, 2009] Urban Areas (generalized cartographic boundary file, ua99_d00_shp.zip ). 2000. U.S. Census Bureau. Available FTP: http://www.census.gov/geo/cob/bdy/ua/ua00shp/. [Accessed on February 20, 2009] USGS. Analytical Hillshade computed from 1 kilometer National Elevation Dataset (NEDS) using the following parameters: 315 degrees altitude, 45 degrees azimuth, and z factor 1x. Prepared by USDA-NRCS-NSSC, Lincoln, NE.

Water

Not Digitized

International Border

State Line

Interstate Highway

1 Very High

Not Rated

6 Unsuited

5 Very Low

4 Low

3 Moderate

2 High

GPR Index

Urban Areas

Large Water Body

The majority of the United States offers moderate to low GPR feasibility.

Source: USDA-NRCS. 2009. Ground Penetrating Radar Suitability - US (Map).

PineBluff

LittleRock

FortSmith

Fayetteville

Yuma

Tucson

Phoenix

San Jose

SanFrancisco

SanDiego

Sacramento

LosAngeles

Fresno

Pueblo

Longmont

Greeley

FortCollins

Denver

ColoradoSprings

Boulder

WaterburyNewHaven

Danbury

Bristol

Bridgeport

Wilmington

Dover

Tampa

Orlando

Miami

Jacksonville

Fort

Lauderdale

Macon

Atlanta

Albany

WaterlooSiouxCity

Omaha

IowaCity

Dubuque

DesMoines Davenport

CedarRapids

Pocatello

IdahoFalls

BoiseCity

Rockford

Chicago

TerreHaute

Muncie

Indianapolis

FortWayne

Evansville

Bloomington

Anderson

Wichita

Topeka

St.Joseph

Lawrence

Owensboro

LouisvilleLexington

Huntington

Shreveport

NewOrleans

Monroe

LakeCharles

Lafayette

BatonRouge

Alexandria

Worcester

Springfield

New Bedford

LowellLawrence

BrocktonBoston

Baltimore

Portland

Lewiston

Bangor

ToledoSouth Bend

LansingGrandRapids

Flint

Detroit

AnnArbor

St.Cloud

Rochester

Minneapolis

La Crosse

GrandForks

FargoDuluth

Springfield

St.Louis

KansasCity

Columbia

Pascagoula

Jackson

Hattiesburg

Biloxi

Missoula

GreatFalls

Billings

Winston-

Salem Raleigh

High Point

Fayetteville

Durham

Charlotte

Bismarck

Portsmouth

Manchester

Trenton

Santa Fe

LasCruces

Albuquerque

Reno

LasVegas

Rochester

NewYork

Buffalo

Wheeling

ParkersburgDayton

Columbus

Cleveland

Cincinnati

Akron

Tulsa

OklahomaCity

Lawton

Salem

Medford

Eugene

PittsburghPhiladelphia

Providence

Newport

Sumter

Spartanburg RockHill

Greenville

Columbia

Charleston

SiouxFalls

RapidCity

Nashville

Memphis

Knoxville

JohnsonCity

Jackson

Clarksville

Chattanooga

SanAntonio

Lubbock

Houston

El Paso

Dallas

CorpusChristi

Austin

SaltLakeCityProvo

Ogden

Logan

Washington

DC

Roanoke

Richmond

NorfolkLynchburg

Burlington

Yakima

Tacoma

Spokane

Seattle

Portland

Bellingham

Sheboygan

Racine

Oshkosh

MilwaukeeMadison

KenoshaJanesville

GreenBay

EauClaire

Appleton

Charleston

Cheyenne

Casper

Tuscaloosa

Montgomery

Mobile

Huntsville

Gadsden

Dothan

Decatur

Columbus

Birmingham

Lincoln

WY

WI

WV

WA

VA

VT

UT

TX

TN

SD

SC

RI

PA

OR

OK

OH

ND

NC

NY

NM

NJ

NH

NV NE

MT

MO

MS

MN

MI

MA

MD

ME

LA

KY

KS

IA

IN

IL

ID

GA

FL

DE

CT

CO

CA

ARAZ

AL

Ground-Penetrating Radar Suitability Map

HAWAII

PUERTO RICO &U.S. VIRGIN ISLANDS0 50 100 150 200 25025

Kilometers0 50 100 150 20025

Kilometers

0 10 20 30 405

Kilometers

USDA-NRCS. 2009. Ground Penetrating Radar Suitability - US (map). Using ArcGIS, Version 9.2 (Environmental Systems Research Institute, Inc., Redlands, Ca.). National Soil Survey Center, Lincoln, Nebraska. Scale 1:1,500,000. Map projection for continental U.S. using Albers Equal Area, North American Datum 1983 (NAD83). Map projection for Hawaii using Hawaii State Plane NAD83. Map projection for Puerto Rico and U.S. Virgin Islands NAD83. USDA-NRCS. 2008. Digital General Soils Map (GSM) version 2. Continental United States, Hawaii, Puerto Rico and U.S. Virgin Islands. Soil Data Mart Source (http://soildatamart.nrcs.usda.gov). December 2008 edition. Soil Survey Staff. 2009. NSSC DATA – Ground Penetrating Radar Suitability Index (GPRSI) [data file] - National Soil Information System (Evaluation Draft - 02/2009). USDA Natural Resource Conservation Service, National Soil Survey Center, Lincoln, Nebraska. (http://soils.usda.gov). Current State and Equivalent, TIGER/Line 2008 (cartographic boundary file, tl_2008_us_state.zip). 2008. U.S. Census Bureau. Available FTP: ftp://ftp2.census.gov/geo/tiger/TIGER2008/. [Accessed on February 20, 2009] Urban Areas (generalized cartographic boundary file, ua99_d00_shp.zip ). 2000. U.S. Census Bureau. Available FTP: http://www.census.gov/geo/cob/bdy/ua/ua00shp/. [Accessed on February 20, 2009] USGS. Analytical Hillshade computed from 1 kilometer National Elevation Dataset (NEDS) using the following parameters: 315 degrees altitude, 45 degrees azimuth, and z factor 1x. Prepared by USDA-NRCS-NSSC, Lincoln, NE.

Water

Not Digitized

International Border

State Line

Interstate Highway

1 Very High

Not Rated

6 Unsuited

5 Very Low

4 Low

3 Moderate

2 High

GPR Index

Urban Areas

Large Water Body

5

Continued on next page

6 DETECTION PROFESSIONAL • Issue 3

Acoustic Pipe Locator (APL)Originally invented by Gas Technology Institute (GTI), SENSIT Technologies acquired the rights for commercialization and production in 2011. Since the first APL rolled off SENSIT’s production line, many advancements have been made based on input from end users. The latest advancement is the incorporation of a Windows-based tablet to create 3-D image maps of scan data. The APL can be used to find metallic and non-metallic pipes, in any soil type, to depths to 30 feet.

SENSIT Technologies ULTRA-TRAC® Acoustic Pipe Locator (APL) provides an alternative and supplemental method of locating buried pipes. The APL transmits and receives acoustic sound waves and then looks for differences in acoustic impedance in the soil caused by pipes, cables, ducts and other buried infrastructure using a process known as impedance mismatch. The APL is able to locate buried utilities, regardless of material type, broken tracer wire and soil conditions.

The chassis, or foot of the unit, houses the battery, electronic components and send-and-receive sensors. Located near the front of the chassis, the actuator sends a series of sound waves, or ‘pings’ into the ground. To the rear of the chassis, dual matched accelerometers receive the sound waves once they have been reflected from a buried pipe, cable, or duct.

How APL WorksWith the push of the APL’s scan button, twenty-four pings are delivered into the ground at a single location, known as a slice. A series of slices is known as a scan. A scan must consist of at least 5 slices,

to allow internal software to calculate the location of a buried utility line. A pattern will emerge in the survey, identifying the possible location of a buried pipe. The tablet displays this information to the operator on-the-fly in 3-D. Survey data can also be stored for use as a client deliverable, emailed to a supervisor for verification, or stored for record keeping purposes.

APL Limitations- As with GPR and EM, the operator should have a ballpark idea of where the scan should be taken based on system knowledge and surface indicators- As with EM and GPR, the APL cannot tell what type of facility is being located. The operator must verify the utility type by potholing or tracing the utility line structure to structure.

Obstacle (Pipe)

Re�ective Wave Transmitted Wave

Ground Surface

Continued: Utility Locating: EM, GPR and ULTRA-TRAC APL

ConclusionGiven their inherent limitations, a toolbox consisting solely of conventional EM and GPR locating equipment simply cannot find everything on their own, unless the target utility is metallic, or has an unbroken tracer wire for EM, or soil conditions are optimal for the use of GPR. As the USGS soil map shows, in the contiguous United States, optimal soil conditions for effective use of GPR are few and far between. Pairing EM equipment with the APL enables the end user to find both metallic and non-metallic utilities, in a broad range of soil types.

The Sensit APL provides the operator with an essential tool to locate metallic and non-metallic pipes, cables and ducts, regardless of broken tracer wire and soil type. Its ease of operation, coupled with the ability to display and store scan data in 3-D, makes the APL an excellent choice for anyone trying to find buried pipes, cables and ducts. Utility locators, engineers, surveyors, energy companies and municipalities alike, are currently deploying acoustic locating technology with the Sensit APL.

Find out more at GasLeakSensors.com or call us at 1-219-465-2700 to schedule a demo.

7

About the Author

Since 1999, Adam has been mapping and locating subsurface utilities in North America. Utilizing conventional land surveying, GPS/RTK, thermal imaging (IR), subsurface and concrete scanning via ground penetrating radar (GPR), electromagnetic induction (EMI), conventional electromagnetic locating (EM), acoustic locating and SPAR utility surveying technologies, Adam has located and mapped buried infrastructure in the United States.

He has trained utility locators in EM and GPR since 2007 and instructed locator certification courses since 2009. In addition, Adam has supervised and trained gas leak survey, utility locating, infrastructure mapping, corrosion, utility construction and gas leak repair field crews. He recently trained and qualified operators in over 29 different gas construction, maintenance and repair tasks as a senior technical instructor and OQ evaluator.

Adam ZeciriProduct Manager Utility LocatingSENSIT Technologies

This contour map, known as ScanView, can be viewed after every scan to better understand the ground profile. Though a single scan is not an adequate search, it can provide important insight based on the strength of the reflected sound waves.

The APL’s state-of-the-art 3D Pipe Mapping feature allows users to stack several scans together to obtain a 3D map of the underground topography. This 3D map, including axis control and an interpolation feature, improves resolution and provides quicker and more accurate analysis of the surveyed area.

8 DETECTION PROFESSIONAL • Issue 3

Damage PreventionCase Study

The ClientA Natural Gas utility company with 12,000 miles of natural gas pipelines, serving over 500,000 customers in the western United States.

The ChallengeLocating a 3” PVC natural gas pipeline acquired from a railroad company. The line had received several hits from third parties near the survey area.

The client needed to find and mark the line to avoid future incidents. Traditional locating equipment failed to find the line, as no tracer had been used during installation.

Gas Line Locating with ULTRA-TRAC (APL) Acoustic Pipe Locator

SENSIT SolutionULTRA-TRAC® APL was deployed to the survey site. With the assistance of the client, we conducted an acoustic locator survey, in a series of eight foot scans.

To collect the most accurate data for the survey, sixteen acoustic readings were used for each scan. Each “pipe found reading” was marked with white paint

ResultsAfter completing a full series of scans covering a 32x23’ grid area, a pattern developed at 60”, along with an area known to contain fiber optic line. The client used a vacuum excavator to verify the natural gas line location.

ConclusionAs a result of this success and recognizing the savings they could realize through continued deployment of the APL, the client purchased one unit and expressed interest in several more.

Case Study

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ULTRA-TRAC® APL is easy to use and locates systems in minutes. The locator works on asphalt, concrete, grass, gravel and soil and finds all types of pipe; metallic, concrete, and plastic.

3D Pipe Mapping Software allows users to access and view a comprehensive collection of data in a graphical format to clearly identify piping systems.

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Founded in 2000, CGA is committed to saving lives and preventing damage to underground infrastructure by promoting effective damage prevention practices. CGA brings together all stakeholders in the industry with a shared responsibility for reducing damage to underground facilities in North America.

Participants in CGA include: excavators, locators, road builders, railroads, public works, one call, electric utilities, telecommunications companies, oil and gas distribution and transmission, state regulators, insurance companies, emergency services, and equipment manufacturers.

The CGA provides a forum where these stakeholders can share information and work together to enhance safety, protect underground facilities, and address all aspects of damage prevention. Through

its leadership, CGA is making significant, measurable progress in creating a

damage prevention culture across North America.

SENSIT Technologies actively participates in CGA events and forums and is viewed as a technology leader in the community through its development of the Ultra-Trac APL (acoustic pipe locator) and Ultra-Trac MJL

(metallic joint locator).

Damage PreventionAwareness

SENSIT Technologies is a proud member of the Common Ground Alliance. CGA is an association comprising approximately 1,500 members

covering every facet of the underground utility industry.

The 811 Logo is a registered trademark of the Common Ground Alliance.

10 DETECTION PROFESSIONAL • Issue 3

APWA UNIFORM COLOR CODE*Each color identifies a specific type of utility.

Proposed Excavation

Temporary Survey Markings

Electric Power Lines, Cables, Conduit and Lighting Cables

Gas, Oil, Steam, Petroleum or Gaseous Materials

Communication, Alarm or Signal Lines, Cables or Conduit

Potable Water

Reclaimed Water, Irrigation and Slurry Lines

Sewers and Drain Lines

WHITE

ORANGE

YELLOW

PINK

RED

BLUE

PURPLE

GREEN

*These colors are close approximations of the industry standard.

11