Soil corrosivity condition index for buried steel pipeline

External corrosion is common threat on underground pipeline structures resulting bad impact on human, environment and financial. Researches show that the identification of soil corrosivity level may be determined by the location conditions and suitability of pipeline structures installation. Current...

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Main Author: Mohamad Nazim, Fatimah Aqilah
Format: Thesis
Language:English
Published: 2014
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Online Access:http://eprints.utm.my/id/eprint/77656/1/FatimahAqilahMohamadMFKA20151.pdf
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spelling my-utm-ep.776562018-06-26T07:49:53Z Soil corrosivity condition index for buried steel pipeline 2014-12 Mohamad Nazim, Fatimah Aqilah TA Engineering (General). Civil engineering (General) External corrosion is common threat on underground pipeline structures resulting bad impact on human, environment and financial. Researches show that the identification of soil corrosivity level may be determined by the location conditions and suitability of pipeline structures installation. Currently, there is no guideline to assess the condition of site corrosivity by rank or index system for soil conditions in Malaysia. The index system, referring to site corrosivity may provide an early indication on the potential structural damages subjected by soil corrosion prior to pipeline installation and to assess the possible failures of damaged pipeline. This research focuses on the development of soil corrosivity condition index based on soil parameters and site characteristics evaluation for pipeline structure installation and maintenance work purposes. A total of 207 carbon steel coupons originated from X- 70 metal type were installed in site A, B, C, D and E located at peninsular Malaysia for a period of 18 months. The buried coupons were retrieved every 3-months to monitor the corrosion rate by metal loss product coupled with measurement of the soil parameters including Soil Resistivity (Res), Moisture content (Mc), pH, Sulphide (SO4), Sulphate (SO3), Chloride (Cl) and site characteristics information including Soil Type (ST), Water Access (WA) and Disturbance Factor (DF). The results of corrosion rates and soil parameters were analyzed by using statistical method through normality, hypothesis and outlier’s detection test, and the corrosion rates were classified into three categories: crmax, cravg and crmed. The site corrosivity conditions were designed by the classification of four corrosivity percentage levels with 0% as the worst condition and 100% as the best condition namely as “not corrosive” for 76-100%, “mildly corrosive” for 51-75%, “corrosive” for 26-50% and “very corrosive” for 0-25%. A number of six (6) soil parameters and three (3) site characteristic indexes were designed within 0-10, where 0 represent the worst condition and 10 points represent the best condition. The equation model of site corrosivity condition percentage was finally designed along with the weighing factor considerations. The collected data of soil parameters and site characteristics were applied into the model equation to compare the accuracy of designed indices with the existing corrosion rate data. Based on the comparison, the results show that the soil corrosivity condition index proposed model is identical to crmax data and approximately similar to cravg and crmed data for every site. The results also show that site B and C are identified as the most corrosive sites compared to site A, D and E. In conclusion, the proposed index system can assist pipeline operators in selecting the most suitable sites for pipeline installation by considering the level of soil corrosivity, hence, minimising the unnecessary corrosion protection on buried pipeline. 2014-12 Thesis http://eprints.utm.my/id/eprint/77656/ http://eprints.utm.my/id/eprint/77656/1/FatimahAqilahMohamadMFKA20151.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:106760 masters Universiti Teknologi Malaysia, Faculty of Civil Engineering Faculty of Civil Engineering
institution Universiti Teknologi Malaysia
collection UTM Institutional Repository
language English
topic TA Engineering (General)
Civil engineering (General)
spellingShingle TA Engineering (General)
Civil engineering (General)
Mohamad Nazim, Fatimah Aqilah
Soil corrosivity condition index for buried steel pipeline
description External corrosion is common threat on underground pipeline structures resulting bad impact on human, environment and financial. Researches show that the identification of soil corrosivity level may be determined by the location conditions and suitability of pipeline structures installation. Currently, there is no guideline to assess the condition of site corrosivity by rank or index system for soil conditions in Malaysia. The index system, referring to site corrosivity may provide an early indication on the potential structural damages subjected by soil corrosion prior to pipeline installation and to assess the possible failures of damaged pipeline. This research focuses on the development of soil corrosivity condition index based on soil parameters and site characteristics evaluation for pipeline structure installation and maintenance work purposes. A total of 207 carbon steel coupons originated from X- 70 metal type were installed in site A, B, C, D and E located at peninsular Malaysia for a period of 18 months. The buried coupons were retrieved every 3-months to monitor the corrosion rate by metal loss product coupled with measurement of the soil parameters including Soil Resistivity (Res), Moisture content (Mc), pH, Sulphide (SO4), Sulphate (SO3), Chloride (Cl) and site characteristics information including Soil Type (ST), Water Access (WA) and Disturbance Factor (DF). The results of corrosion rates and soil parameters were analyzed by using statistical method through normality, hypothesis and outlier’s detection test, and the corrosion rates were classified into three categories: crmax, cravg and crmed. The site corrosivity conditions were designed by the classification of four corrosivity percentage levels with 0% as the worst condition and 100% as the best condition namely as “not corrosive” for 76-100%, “mildly corrosive” for 51-75%, “corrosive” for 26-50% and “very corrosive” for 0-25%. A number of six (6) soil parameters and three (3) site characteristic indexes were designed within 0-10, where 0 represent the worst condition and 10 points represent the best condition. The equation model of site corrosivity condition percentage was finally designed along with the weighing factor considerations. The collected data of soil parameters and site characteristics were applied into the model equation to compare the accuracy of designed indices with the existing corrosion rate data. Based on the comparison, the results show that the soil corrosivity condition index proposed model is identical to crmax data and approximately similar to cravg and crmed data for every site. The results also show that site B and C are identified as the most corrosive sites compared to site A, D and E. In conclusion, the proposed index system can assist pipeline operators in selecting the most suitable sites for pipeline installation by considering the level of soil corrosivity, hence, minimising the unnecessary corrosion protection on buried pipeline.
format Thesis
qualification_level Master's degree
author Mohamad Nazim, Fatimah Aqilah
author_facet Mohamad Nazim, Fatimah Aqilah
author_sort Mohamad Nazim, Fatimah Aqilah
title Soil corrosivity condition index for buried steel pipeline
title_short Soil corrosivity condition index for buried steel pipeline
title_full Soil corrosivity condition index for buried steel pipeline
title_fullStr Soil corrosivity condition index for buried steel pipeline
title_full_unstemmed Soil corrosivity condition index for buried steel pipeline
title_sort soil corrosivity condition index for buried steel pipeline
granting_institution Universiti Teknologi Malaysia, Faculty of Civil Engineering
granting_department Faculty of Civil Engineering
publishDate 2014
url http://eprints.utm.my/id/eprint/77656/1/FatimahAqilahMohamadMFKA20151.pdf
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