Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You and Your Team.

Learn More →

UNDERGROUND PIPELINE PROTECTION FRENCH PRACTICE

UNDERGROUND PIPELINE PROTECTION FRENCH PRACTICE UNDERGROUND PIPELINE PROTECTION FRENCH PRACTICE I T is before, and not after, the con­ defects thus found must be repaired A comprehensive monograph on struction of a pipeline that decisions on the spot. Particular care must be the topical problem of the pro­ should be made concerning the degree taken in zones with very humid or tection of underground pipelines of corrosion protection required. Such aggressive soil, or where strong stray against corrosion has been con­ a decision must, of course, be based currents are present. on the merits of the case. To find the tributed by J. Vincent-Genod, Cathodic protection most economic method in the given an engineer of the French circumstances, it may be necessary to However good a protective coating 'Societe des Transports Petro- carry out a preliminary survey, the may be, it can never be adequate to liers par Pipe-Line,' to the May cost of which would be negligible prevent corrosion entirely. But if it is 1955 issue of the French journal, compared with the capital values at combined with cathodic protection, stake. Travaux, which is mainly de­ the combined protection afforded can be very effective indeed. Generally speaking, a distinction voted to oil pipeline construc­ must be made between external and A considerable pool of experience tion. The following is a brief internal corrosion. Whilst the latter is now available on cathodic pro­ summary of that monograph. might be fought by adding special tection. Having selected the most inhibitors to the corrosive medium economic local current supplies, the concerned, external corrosion calls for next step is to choose the location of it is possible to estimate the rate of two types of protective measures which the protection points in accordance corrosion to be expected on each might be used jointly or separately: with their theoretical range and certain section of the proposed pipeline, and protective coatings (i.e. passive pro­ local conditions. thus to decide on the preventive tection), and cathodic protection (i.e. Where low-tension current is cheaply measures to be taken. active protection). available, the most economic method of cathodic protection is the use of Protective coatings Preliminary survey rectifiers. According to the quality of the insulation, the rectifiers must, The preliminary survey must in­ If circumstances call for the passive for a 12-in. pipeline, be spaced at clude all the potentially relevant protection of the pipeline by protective distances varying between 15 and 60 factors, i.e. the nature of the soil, the coating, a further choice must be made miles. An important part of the cost presence or absence of stray currents, between the several different types of of such a rectifier station is incurred etc. Survey methods include the coatings available for this specific in the earthing device which is also taking of soil samples, the investiga­ purpose. Most of them have a mere responsible for the highest energy tion of moisture conditions and the insulating function; others also act as consumption of the whole circuit. In measurement of soil resistance by inhibitors. recent American practice, metallic means of electrodes or by means of For economic reasons the coatings earthing devices have been replaced Schlumberger's quadripole method. most generally used for underground by carbon anodes which have a longer This method, which is generally pre­ pipelines are of the bituminous type service life. The rectifiers are com­ ferred by the specialist engineers of which have good dielectric properties bined with transformers from which the French company, consists of but may have to be specially treated the required voltage can be obtained. setting up a direct current between to obtain the necessary hardness and two electrodes situated at a given elasticity, important properties which Where a current supply is not distance from each other and measur­ must be regularly ascertained by available it may be possible to use ing the difference in the potential appropriate tests. These coatings magnesium anodes, a method which is thereby created between two other might be applied to the pipes prior to, also recommended where the section electrodes situated at given distances or at the time of, the laying of the of pipeline to be protected is so short between the two first. The survey pipeline, i.e. either in the workshop or that the installation of a rectifier also comprises the measurement of on the site. Given good workmanship, equipment would be uneconomic. pR values and the polarisation of the there is little to choose between these Special problems are encountered steel. two methods, but in situ application where a pipeline must be protected is usually more economic, as the choice against strong stray currents. In that In a study of possible sources of of the coating need, in this case, not case, special drainage devices may have corrosion, such as stray currents, be influenced by considerations con­ to be provided, e.g. in the vicinity of particular attention must be paid to cerning the mechanical protection of sub-stations of electrified railways. It direct current conductors with little the pipes during the transport. is sometimes difficult to determine the or no insulation against the soil (e.g. most suitable out of several alternative the rails of d.c. electrified railways; Where pipes are treated in advance, solutions because the electric potential electrolytic corrosion is particularly the coating must be carefully checked of the railway tracks may vary greatly active near railway sub-stations). A before the pipe is finally lowered into in terms of time and distance. The survey of this kind can be costly, but the trench. This can be done by drainage circuit may have to be con­ it may be simplified to a certain means of a special instrument, known trolled by automatically acting polarised extent by an expert interpretation of as the 'electric brush'; this is essen­ relays or equivalent devices to guard soil resistance data and geographical tially an electrode to which a high against the setting up of harmful data. voltage is applied which flashes over currents. where the coating is defective. Any With the aid of all this information, August 1955 CORROSION TECHNOLOGY 253 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Anti-Corrosion Methods and Materials Emerald Publishing

UNDERGROUND PIPELINE PROTECTION FRENCH PRACTICE

Anti-Corrosion Methods and Materials , Volume 2 (8): 1 – Aug 1, 1955

Loading next page...
 
/lp/emerald-publishing/underground-pipeline-protection-french-practice-IKt551wew5
Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0003-5599
DOI
10.1108/eb019090
Publisher site
See Article on Publisher Site

Abstract

UNDERGROUND PIPELINE PROTECTION FRENCH PRACTICE I T is before, and not after, the con­ defects thus found must be repaired A comprehensive monograph on struction of a pipeline that decisions on the spot. Particular care must be the topical problem of the pro­ should be made concerning the degree taken in zones with very humid or tection of underground pipelines of corrosion protection required. Such aggressive soil, or where strong stray against corrosion has been con­ a decision must, of course, be based currents are present. on the merits of the case. To find the tributed by J. Vincent-Genod, Cathodic protection most economic method in the given an engineer of the French circumstances, it may be necessary to However good a protective coating 'Societe des Transports Petro- carry out a preliminary survey, the may be, it can never be adequate to liers par Pipe-Line,' to the May cost of which would be negligible prevent corrosion entirely. But if it is 1955 issue of the French journal, compared with the capital values at combined with cathodic protection, stake. Travaux, which is mainly de­ the combined protection afforded can be very effective indeed. Generally speaking, a distinction voted to oil pipeline construc­ must be made between external and A considerable pool of experience tion. The following is a brief internal corrosion. Whilst the latter is now available on cathodic pro­ summary of that monograph. might be fought by adding special tection. Having selected the most inhibitors to the corrosive medium economic local current supplies, the concerned, external corrosion calls for next step is to choose the location of it is possible to estimate the rate of two types of protective measures which the protection points in accordance corrosion to be expected on each might be used jointly or separately: with their theoretical range and certain section of the proposed pipeline, and protective coatings (i.e. passive pro­ local conditions. thus to decide on the preventive tection), and cathodic protection (i.e. Where low-tension current is cheaply measures to be taken. active protection). available, the most economic method of cathodic protection is the use of Protective coatings Preliminary survey rectifiers. According to the quality of the insulation, the rectifiers must, The preliminary survey must in­ If circumstances call for the passive for a 12-in. pipeline, be spaced at clude all the potentially relevant protection of the pipeline by protective distances varying between 15 and 60 factors, i.e. the nature of the soil, the coating, a further choice must be made miles. An important part of the cost presence or absence of stray currents, between the several different types of of such a rectifier station is incurred etc. Survey methods include the coatings available for this specific in the earthing device which is also taking of soil samples, the investiga­ purpose. Most of them have a mere responsible for the highest energy tion of moisture conditions and the insulating function; others also act as consumption of the whole circuit. In measurement of soil resistance by inhibitors. recent American practice, metallic means of electrodes or by means of For economic reasons the coatings earthing devices have been replaced Schlumberger's quadripole method. most generally used for underground by carbon anodes which have a longer This method, which is generally pre­ pipelines are of the bituminous type service life. The rectifiers are com­ ferred by the specialist engineers of which have good dielectric properties bined with transformers from which the French company, consists of but may have to be specially treated the required voltage can be obtained. setting up a direct current between to obtain the necessary hardness and two electrodes situated at a given elasticity, important properties which Where a current supply is not distance from each other and measur­ must be regularly ascertained by available it may be possible to use ing the difference in the potential appropriate tests. These coatings magnesium anodes, a method which is thereby created between two other might be applied to the pipes prior to, also recommended where the section electrodes situated at given distances or at the time of, the laying of the of pipeline to be protected is so short between the two first. The survey pipeline, i.e. either in the workshop or that the installation of a rectifier also comprises the measurement of on the site. Given good workmanship, equipment would be uneconomic. pR values and the polarisation of the there is little to choose between these Special problems are encountered steel. two methods, but in situ application where a pipeline must be protected is usually more economic, as the choice against strong stray currents. In that In a study of possible sources of of the coating need, in this case, not case, special drainage devices may have corrosion, such as stray currents, be influenced by considerations con­ to be provided, e.g. in the vicinity of particular attention must be paid to cerning the mechanical protection of sub-stations of electrified railways. It direct current conductors with little the pipes during the transport. is sometimes difficult to determine the or no insulation against the soil (e.g. most suitable out of several alternative the rails of d.c. electrified railways; Where pipes are treated in advance, solutions because the electric potential electrolytic corrosion is particularly the coating must be carefully checked of the railway tracks may vary greatly active near railway sub-stations). A before the pipe is finally lowered into in terms of time and distance. The survey of this kind can be costly, but the trench. This can be done by drainage circuit may have to be con­ it may be simplified to a certain means of a special instrument, known trolled by automatically acting polarised extent by an expert interpretation of as the 'electric brush'; this is essen­ relays or equivalent devices to guard soil resistance data and geographical tially an electrode to which a high against the setting up of harmful data. voltage is applied which flashes over currents. where the coating is defective. Any With the aid of all this information, August 1955 CORROSION TECHNOLOGY 253

Journal

Anti-Corrosion Methods and MaterialsEmerald Publishing

Published: Aug 1, 1955

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$499/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month