1
Implementing and Managing
a Large Water Utility’s
Underground Corrosion-Control Program
Danny J. Klopfer, P.E. Infrastructure Planning Mgr.
515-283-8754
E-mail: [email protected]
Jeff Schramuk NACE CP Specialist #7695
630-235-1559
www.cpsolutionsinc.net
2
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
Topics to be Covered
3
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
4
*Source: State of the Industry
Report 2011, Journal AWWA,
103:10, Oct-2011, pp. 42-54.
State of the Water Industry – Year 2011
“The ticking time bomb
related to failing
infrastructure – it is
just a matter of time
and will affect every
community in the U.S.”
5
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
6
“A water utility’s asset management
plan is an optimization process that
attempts to meet the competing
objectives of cost minimization and
reliability maximization.”
*Source: Rubin, S.J., A Call for Reliability Standards, Journal AWWA, (Jan-2011)
Asset Management: A Real-World Definition
7
Asset Management – The Core Framework
*Source: U.S. EPA. Asset Management: A Best Practices Guide. EPA 816-F-08-014, (Apr-2008)
Water Utility Asset
Management
5. What is the long-term funding
strategy?
1. What is the current state of your assets?
2. What level of sustainable service is
required?
3. Which assets are critical to
sustainability?
4. What are the minimum life cycle
costs?
8
Asset Management – The Questions to Ask
*Source: U.S. EPA. Asset Management: A Best Practices Guide. EPA 816-F-08-014, (Apr-2008)
Water Utility Asset
Management
5. What is the long-term funding
strategy?
1. What is the current state of your assets?
2. What level of sustainable service is
required?
3. Which assets are critical to
sustainability?
4. What are the minimum life cycle
costs?
1. Know what is owned,
where is it located, and
assess its condition
2. Understand water
main performance and
regulatory standards
3. Determine critical
assets and evaluate
their risk of failure
4. Know costs of
continual asset repairs
versus replacement
5. Evaluate capital
expense funds versus
current rate structures
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Risk = (Consequences of Failure) x (Likelihood of Failure)
Assess the Risk of a Water Main Failure
10
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
11
Anodic Area
(Metal Loss)
DC Current
Cathodic
Area
(Protected)
Anodes & Cathodes on a Buried Metallic Pipe
12
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
13
Corrosion of Prestressing Wires on Concrete Cylinder Pipe
14
Are Pipeline Coatings/Tape-Wrap Always Effective?
15
Ductile Iron Water Pipe – Reduced Wall Thickness
3/8” thick (Pressure Class 150)
16
Loose Polyethylene Wrapping
17
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
18
Corrosion occurs where DC current
discharges from the metal to the electrolyte.
The objective is to allow your water main to
receive DC current (be cathodic) from an
expendable anode placed in the soil.
How Cathodic Protection Works
19
Cathodic Protection System Types – Sacrificial Anodes
Sacrificial Anode: DC current
is obtained from more active
metal anodes connected
directly to the structure
20
Sacrificial Anode
Coating Defect
Connection to Pipe
Grade
Sacrificial Anode Installation
21
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
22
521 miles out of
1380 miles* has
already reached its
life expectancy
*includes approximately 380 miles of non-metallic pipe used for a rural water distribution system
Des Moines Water Works – An Overview
620 miles out of
1380 miles* will
reach its life
expectancy by 2020
DMWW Summary Stats
23
Decade CIP DIP PVC PCCP WSP ACC Totals1800-1899 169,857 0 0 0 0 0 169,857
1900-1909 161,104 0 0 0 0 0 161,104
1910-1919 359,560 0 0 0 0 0 359,560
1920-1929 614,331 0 0 0 0 0 614,331
1930-1939 415,976 0 0 0 2,184 0 418,160
1940-1949 300,535 0 0 0 0 0 300,535
1950-1959 902,326 0 0 32,984 1,549 0 936,859
1960-1969 461,458 16,158 0 1,507 2,435 25,228 506,785
1970-1979 99,503 212,809 917,893 61,528 10 0 1,291,743
1980-1989 0 59,573 709,463 77,686 165 0 846,887
1990-1999 0 64,439 947,996 99,988 75 0 1,112,498
2000-2009 0 95,644 416,006 67,752 4,857 0 584,259
Total (ft.) 3484649 448622 2991358 341445 11275 25228 7302577
Total (mi.) 660.0 85.0 566.5 64.7 2.1 4.8 1383.1
Pipe Material Installed by the Des Moines Water Works by Decade (ft.)
DMWW – Water Main Pipe Installation History
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DMWW’s Long-Term Main Break Data (1994-2011)
After 2007 there are approx. 30 annual breaks per 100 miles pipe (excluding rural water system)
0
50
100
150
200
250
300
350
400
Nu
mb
er
of
Bre
ak
s
Year
Total Main Breaks - Trends
25
DMWW’s More Recent Main Break Data (2004-2011)
0
50
100
150
200
250
300
350
400
Nu
mb
er
of
Bre
aks
Year
Total Main Breaks - Trends
Reduce Number of Broken Water Mains
Extend Service Life of Water Mains
Reduce Operating Costs of Water Mains
DMWW – Anode Retrofit Program Purpose
27
The ARP Objective Site Selection Model Considers:
Number of pipe failures
Pipe material/age/diameter
Pipe condition
Ease of anode installation
Soil characteristics
Traffic disruption
Excavation/restoration costs
Implementing DMMW’s Anode Retrofit Program
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Typical Anode Retrofit Installation Method
Years 2004 – 2008 Connection Methods
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Years 2004 – 2005: Stud Welding
Years 2006 – 2008: Pin Brazing
Neither Work on Pit Cast Iron Pipe!
Exothermic Weld Connection and Hardware
Year 2008+: Exothermic Welding
Exothermic Welds Can Be Used On:
• Pit-Cast Iron Pipe
• Spin-Cast Iron Pipe
• Ductile Iron Pipe
Keyhole to Pipe & Wire Connection
32
Installation in Paved Roadways – Asphalt or Concrete
33
DMWW Main Break Comparison – ARP vs. No-ARP
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
Cu
mu
lati
ve S
um
Mai
n B
reak
s
Year
No-ARP(1985-ARPYear)
With ARP(ARP Year-2012)
Log. (No-ARP (1985-ARP Year))
Log. (WithARP (ARPYear-2012))
34
DMWW Economics - Water Mains Installed w/ARP
0.0%
2.0%
4.0%
6.0%
8.0%
10.0%
12.0%
14.0%
$8.00
$9.00
$10.00
$11.00
$12.00
$13.00
$14.00
$15.00
AR
P C
ost
vs.
Ne
w P
ipe
(%
)
AR
P U
nit
Co
st (
$/f
t)
ARP Installation Year
35
ARP installed on 82,370 feet of 6” to 16” water mains
Total ARP Installation Cost = $1,028,838
Main Break Cost (over 25 years) w/o ARP = $3,975,561
Cost of New Mains would have been >$10 Million
A 25-year service life extension is expected
An average reduction of 90% in water main breaks
DMWW Anode Retrofit Program: 2004-2011 Summary
36
Over the estimated 25-Year Effective Service Life*
of the
Anode Retrofit Program…
Anode Retrofit Program vs. Pipe Replacement
$44,255 Annualized Savings
Anode Retrofit Program vs. Main Break Repairs
$99,752 Annualized Savings
*After the initial anode installation, CP anodes must be replaced 3 times over the replacement pipe life
DMWW Economic Analysis: 2004-2011 Summary
37
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
38
What’s Your Biggest Cost to Repair a Main Break?
39
Do I really want to
re-excavate this hole for
another water main break?
The Biggest Cost is for the Excavation & Restoration!
Install a sacrificial CP anode
while the water main repair
excavation is already open!
40
Anode Installation and Connection Method
41
Document all leak and main break repairs as
recommended by Water Research Foundation
(formerly AWWA Research Foundation)
Install a sacrificial anode every time the water
main is exposed for repairs or tapping
Utilize water main failure data as a portion of
your Asset Management System
*Source: Research Applications, Proven Utility Benefits, Paper #8, AwwaRF, August 1995.
AWWA WRF Recommendations for Water Utilities
42
Average Cost of a Main Break
>$5,000*
Cost of CP Anode & Connection Device
Less than $200!
Cathodic Protection Is Proactively Inexpensive
*For comparison, the average cost for each main break in Des Moines, IA was $5,372 in 2011
Consider the cost of repairing a water main break
versus the cost of
installing a sacrificial anode during the pipe repair…
43
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
44
DMWW – WTM Corrosion Control Criteria
The DMWW considers corrosion protection as
part of its design analysis for the following types
of pipe materials used for new water mains:
Prestressed Concrete Cylinder Pipe (AWWA
C304/C301)
Ductile Iron Pipe (AWWA C110)
Welded Steel Pipe (AWWA C200)
45
The CP system will extend the life of the new
water transmission main by at least 25 years at
a cost that is much less than…
Pipe repairs or,
Main replacement or,
The potentially more significant (but incalculable) indirect
costs that could occur as a result of a service disruption
to a key facility that the water main serves.
Why Install CP on a Water Transmission Main?
46
Sacrificial Anodes Installed in the Pipe Trench
47
Post Mounted Test Station Terminal Board
48
What is the additional
cost of installing
cathodic protection on
a new water
transmission main?
Economics of the CP Installation
49
In general, the total initial cost to install a CP system
should be less than 3-5% of the total construction cost
of the water main.
When expressed over the 25-year life expectancy of
the CP system, the annual cost is ≤0.20%.
Economics of the CP Installation
The effectiveness of any CP system is highly dependent upon the quality of
any coating and or wrapping system applied to the external pipe surface.
Higher quality pipe coatings will reduce the cost of the cathodic protection.
50
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
51
So What Have We Missed?
Anode Retrofit Program
Anodes at Main Breaks
CP for New Large Water
Transmission Mains
CP for Smaller Metallic
Water Distribution Mains!
52
Corrosion Problems Facing Water Utilities
Water Infrastructure Asset Management
Definitions and Terminology
Pipe Materials and Anti-Corrosion Coatings/Barriers
DMWW Cathodic Protection Projects
CP Anode Retrofit Program for Existing Distribution Mains
CP Anodes at Water Main Breaks
CP for New Water Transmission Mains
CP for Small Diameter Distribution Mains
Cathodic Protection Operation & Maintenance
53
Why Bother to Collect Corrosion Control O&M Data?
54
DC Potential
Measurement
DC Current
Measurement
Note: Calibration
Sticker on Meter
CP Performance Can Be Easily Verified
55
Do You Have Any Questions?
Danny J. Klopfer, P.E. Infrastructure Planning Mgr.
515-283-8754
E-mail: [email protected]
Jeff Schramuk NACE CP Specialist #7695
630-235-1559
www.cpsolutionsinc.net
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