Review of the Bureau of Reclamation's Corrosion Prevention Standards for Ductile Iron Pipe (2009) / Chapter Skim
Currently Skimming:
Appendix D: Other Considerations for Corrosion Control
Appendix D: Other Considerations for Corrosion Control
Pages 159-170
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 159... ...
. To design the pipe for a 50-year service life, the pipe thickness would be 0.45 inch Troy Stroud and James Voget, "Corrosion Control Measures for Ductile Iron Pipe," 46th Annual Appalachian Underground Corrosion Short Course (Morgantown, W.Va.: West Virginia University, 2001)
|
From page 160... ...
However, in areas with fluctuating water tables, the clean sand could become corrosive in a relatively short period of time. An alternative method to consider in reducing corrosion rates is to change the environment in the trench with the use of controlled low-strength material (CLSM)
|
From page 161... ...
McCollum, "Impressed Current Cathodic Protection of Polyethylene-Encased Ductile Iron Pipe," Paper 583 at Corrosion 93, New Orleans, La.; Graham Bell, Clifford Moore, and Scott Williams, "Development and Application of Ductile Iron Pipe Electrical Resistance Probes for Monitoring Underground External Pipeline Corrosion," NACE International Corrosion 2007 Paper 07335, Dallas, Tex.; Spickelmire, "Corrosion Control Considerations for Ductile Iron Pipe -- A Consultant's Perspective"; A.M. Horton, D
|
From page 162... ...
This is done by inserting and pulling a portable reference electrode through the plastic monitoring pipes and recording potential measurements as the reference electrode is moved. The theory is based on cathodic protection monitoring techniques first used for ground-level storage tanks, where perforated plastic monitoring pipes with portable reference electrodes were used to determine cathodic protection levels under the tank bottom. An example of this type of basic monitoring technique is shown in Figure D-1.
|
From page 163... ...
The probes were measured at regular intervals from 1982 to 1992. 11 Schiffand McCollum, "Impressed Current Cathodic Protection of Polyethylene-Encased Ductile Iron Pipe"; Horton et al., "Corrosion Control Performance Monitoring of Ductile Iron Pipe in a Severely Corrosive Tidal Muck"; Spickelmire, "Corrosion Control Considerations for Ductile Iron Pipe -- A Consultant's Perspective"; Graham E.C.
|
From page 164... ...
• According to Graham Bell in his presentation to the committee, the actual corrosion rates measured by the electrical resistance probes are most useful for comparison purposes only and "may not be an accurate measurement of the true pipe corrosion rate." According to a presentation to the committee that was based on recent test ing by the speaker, the probes that were placed on the DIP under the PE with CP
|
From page 165... ...
Mid-Dakota Rural Water Service Project The Mid-Dakota Pipeline Project in South Dakota was installed between 1996 and 2002 with approximately 262,000 lf of DIP with PE and CP. Commercially available ductile iron probes were installed along the pipeline.
|
From page 166... ...
Courtesy of Schiff Associates, Claremont, California. FIGURE D-4 Graph of probe readings at Station 1529+04 Mid-Dakota Rural Water Service (MDRWS)
|
From page 167... ...
No significant corrosion damage was found on the pipe surface. But this probe reli ability problem calls into question whether probes of this same type are providing accurate corrosion rates or are suffering from faulty manufacturing techniques.
|
From page 168... ...
The thin flat profile (Figure D-6) of the probe is designed to help prevent "tenting" of the PE, which may lead to false indications of corrosion on the ER probes and not accurately reflect the actual pipeline condition.18 17 Graham Bell et al., "Development and Application of Ductile Iron Pipe Electrical Resistance Probes for Monitoring Underground External Pipeline Corrosion." 18 Schiff Associates, Report to WEB Development Association, Electrical Resistance Probes Installed at Test Station 1459+35 (Claremont, Calif., May 11, 2006)
|
From page 169... ...
An article in the AWWA Journal in 1999 pointed out that as more-sophisticated leak and pipe corrosion evaluation techniques become available, owners and utili ties will be able to perform more evaluations of pipe condition and investigations of why failures are occurring.19 These techniques include the following: • Close-interval surveys using the most-up-to-date techniques for assessing external corrosion and correct functioning of the CP systems. These surveys should follow the External Corrosion Direct Assessment methodology devel oped by the Gas Technology Institute.20 The guide rates existing technolo gies for assessing external corrosion in cased and noncased crossings, pipes shielded by coatings, and segments with stray currents or interference from other pipelines.
|
From page 170... ...
90601 for Nondestructive Testing of Water Mains for Physical Integrity.23 The use of these intelligent in-line inspections (smart pigging) methods, such as employed previously by Colorado Springs and Calgary in their pipeline condition assessments, are a more reliable method of determining actual pipe conditions than are just random digs.24 21 Spickelmire, "Corrosion Control Considerations for Ductile Iron Pipe -- A Consultant's Perspective." 22 W.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.