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FELL
Electro-Scan One-step Sewer Leak Detection & Location |
| Comparison of Sewer Evaluation Tools |
Most cost effective pipe defect location test detects all types of potential leakage faults - joints, service connections and cracks whether actively flowing or not at the time of the test |
Best
Property
Property
|
Flow
Monitoring |
TV Inspection |
Pressure
Testing |
Smoke Testing |
Electro-Scanner |
|
Test Rate(ft/day) |
Months to Years |
2,000 to 3,000 |
1,000 to 2,000 |
5,000 to 10,000 |
3,000 to 4,000 |
|
Interpretation
Rate (ft/day) |
Highly variable |
4,000 to 6,000 |
10,000 to 20,000 |
10,000 to 20,000 |
16,000 to 20,000 |
|
Cost per
foot*1 |
$0.15 to $0.30 |
$3.00 to $5.00 |
$4.00 to $5.00 |
$0.25 to $0.35 |
$1.00 to $2.00 |
|
Capital Cost |
$40,000 |
$100,000+ Dedicated vehicle |
$10,000 + TV for Joint testing |
$2,000 |
$25,000 to $40,000 |
|
Pipe Type |
All |
All -low flow |
6 to 30 inch |
6 to 30 inch |
3 to 60 inch including
laterals Non-conducting*2 |
|
Conditions
Required for Field Test Scheduling |
Requires measurement of
dry weather and storm events |
Leaks must be active.
(pipe below ground water level or during storm event) |
Pipe cannot be surcharged |
Pipe above ground water
level. Months of dry weather prior to testing. No wind. |
None |
|
Pipe
Preparation |
Hydraulic analysis and
installation of monitors |
Clean, Empty No flow for 30 minutes.
May require bypass pumping |
No Roots or Grease. No flow for 60 minutes.
May require bypass pumping |
Isolate pipe section
Resident and emergency services notification |
Partial Surcharge for 10 minutes |
|
Portability*3 |
High |
Low |
Low |
High |
High |
|
Output Data*4 |
Quantitative |
Qualitative |
Quantitative |
Qualitative |
Quantitative |
|
Defect/Leak Detection |
All active leaks Cannot detect pipe defects
that are potential leaks. |
Leaks flowing at time of
test. Structural potential leak defects.*5 Cannot detect potential
leak joint defects. |
All pipe potential leak
defects*5 except lateral connection from main.
Characterization of defects depends on test setup. |
Some defects |
All potential pipe leak
defects.*5 Characterization of defects as structural, joint
or lateral connection. |
|
Defect/Leak
size measurement. |
Infiltration measurement
for weather events captured |
Descriptive estimate of
active leaks |
Pass/Fail |
Descriptive estimate of
defects |
Amplitude of current trace
related to size of defect |
|
Location
Accuracy |
Within 1,000 to 15,000 ft |
Within inches |
No TV: within 300 feet With TV: within inches |
Highly variable |
Within inches |
|
Data
reliability, consistency and repeatability |
Moderate: Dependant on time period
and weather events captured |
Moderate: Dependant on experience of
operator and interpreter. Joint leaks must be active. |
Moderate: Depends on placement of
plugs and test setup. |
Low: Highly dependant on
surface and soil type/condition |
High: Independent of soil type
and ground water level |
|
QA Testing*6 |
High |
Moderate |
Moderate |
Low |
High |
|
Field Crew
Training |
Weeks Specialist |
Months Specialist |
Weeks Specialist |
Days Maintenance Crew |
Days Maintenance Crew |
|
Interpretation
Training |
Specialist Professional |
Specialist Technician |
Technician |
Technician |
Technician |
Notes:
1.
Cost per foot is based on
typical contractor rates and
includes pipe preparation, field testing, interpretation and reporting
2.
Non-conducting Pipe Types
include: VCP, RCP, ACP, Plastic,
CIPP
3.
Portability: Ability to
test in limited access areas such as
backyard easements.
4.
Output Data
Quantitative: Numeric
output
readily incorporated into GIS, databases and summary tables for
condition
assessment and grading
Qualitative: Descriptive
output difficult to incorporate into GIS, databases and summary tables
for
condition assessment and grading.
Highly dependant on
judgment
and experience of test operator/interpreter
5.
Potential leak defects:
Pipe structural, service lateral
connection and joint defects that will allow infiltration or
exfiltration.
Liquid flow through the defect may or may not be occurring at the time
of the
test.
6.
QA Testing: The
effectiveness of the test to assure that the
rehabilitation method has repaired the pipe defects.
Metrotech
Corporation, 488 Tasman Drive, Sunnyvale, CA 94089. Ph: (408) 734-1400