Server maintenance is scheduled for Saturday, December 21st between 6am-10am CST.

During that time, parts of our website will be affected until maintenance is completed. Thank you for your patience.

Menu
Search
Filters
Close
Menu

Instant-Off Potentials Underestimate Cathodic Protection Levels on Pipelines

Picture for Instant-Off Potentials Underestimate Cathodic Protection Levels on Pipelines
Available for download

Cathodic protection (CP) is used to prevent external corrosion on underground pipelines. The effectiveness of CP is commonly evaluated by measuring the DC potential (voltage) of the pipeline with respect to a reference electrode located on the surface of the earth above the pipeline. Criteria used to interpret pipeline potential measurements are given by Section 6 of NACE SP-0169-2013 “Control of External Corrosion on Underground or Submerged Metallic Piping Systems.

Product Number: 51323-19083-SG
Author: Peter Haas
Publication Date: 2023
$0.00
$20.00
$20.00

The criteria and methods given by AMPP/NACE SP0169 and TM0497 rely heavily on the use of Instant-Off potential measurements to assess cathodic protection levels on pipelines. Despite wide acceptance of these standards, there is little or no data to demonstrate that an Instant-Off potential accurately represents the polarized potential that exists across the metal/electrolyte interface of a pipeline under normal operating conditions. This paper summarizes laboratory testing that was conducted to demonstrate the accuracy of Instant-Off potentials. Test results show that Instant-Off potentials significantly underestimate pipeline polarized potentials. Examples are given where the reliance on Instant-Off potentials can lead to pipeline damage.

The criteria and methods given by AMPP/NACE SP0169 and TM0497 rely heavily on the use of Instant-Off potential measurements to assess cathodic protection levels on pipelines. Despite wide acceptance of these standards, there is little or no data to demonstrate that an Instant-Off potential accurately represents the polarized potential that exists across the metal/electrolyte interface of a pipeline under normal operating conditions. This paper summarizes laboratory testing that was conducted to demonstrate the accuracy of Instant-Off potentials. Test results show that Instant-Off potentials significantly underestimate pipeline polarized potentials. Examples are given where the reliance on Instant-Off potentials can lead to pipeline damage.

Product tags
Also Purchased
Picture for 07036 PRACTICAL CONSIDERATIONS FOR UPPER LIMITS OF CATHODIC PROTECTION
Available for download

07036 PRACTICAL CONSIDERATIONS FOR UPPER LIMITS OF CATHODIC PROTECTION

Product Number: 51300-07036-SG
ISBN: 07036 2007 CP
Author: Ernest Klechka, Steven F. Daily, and Kevin C. Garrity
Publication Date: 2007
$20.00

This paper reviews the concerns of applying excessive levels of cathodic protection current to pipelines and the need for establishing an upper potential limit. Coating disbondment, hydrogen induced stress cracks, stress corrosion cracking, hard spots and the problems associated with measurement of a true polarized pipe-to-electrolyte potential are addressed.
Picture for 06163 CATHODIC PROTECTION OF PIPELINES
Available for download

06163 CATHODIC PROTECTION OF PIPELINES IN HIGH RESISTIVITY SOILS AND THE EFFECT OF SEASONAL CHANGES

Product Number: 51300-06163-SG
ISBN: 06163 2006 CP
Author: Fraser King, Greg Van Boven, P, Nichols, Rod Reid, Kurt Lawson and Neil Thompson
Publication Date: 2006
$20.00

The effect of seasonal changes on the protection of pipelines in high-resistivity soil. The nature and magnitude of the seasonal fluctuations. Corrosion rates are low even when compliance with a given CP criterion cannot be demonstrated.
Picture for 07118 Chemistry and Corrosion Rates under Pipeline Disbonded Coatings With or Without Cathodic Prote
Available for download

07118 Chemistry and Corrosion Rates under Pipeline Disbonded Coatings With or Without Cathodic Protection

Product Number: 51300-07118-SG
ISBN: 07118 2007 CP
Author: Fengmei Song and Narasi Sridhar
Publication Date: 2007
$20.00

The transport of dissolved O2, and that of dissolved carbon dioxide (CO2) if present, into the disbonded region through holiday can be key to determining the disbonded corrosion rate. The evolution of chemistry in the disbonded region and the transient behavior of corrosion potential and rate in the disbonded region are investigated and reported in this work.
Categories
Industry
Recently viewed
Popular tags
View all

Association for Materials Protection and Performance

© AMPP All Rights Reserved.
Membership Terms of Content Use
Contact Customer Support