BS EN 15280:2013
$167.15
Evaluation of a.c. corrosion likelihood of buried pipelines applicable to cathodically protected pipelines
| Published By | Publication Date | Number of Pages |
| BSI | 2013 | 42 |
This European Standard is applicable toburied cathodically protected metallic structures that are influenced by a.c. traction systems and/or a.c. power lines.
In this document, a buried pipeline (or structure) is a buried or immersed pipeline (or structure), as defined in EN 12954.
In the presence of a.c. interference, the protection criteria given in EN 12954:2001, Table 1, are not sufficient to demonstrate that the steel is being protected against corrosion.
This European Standard provides limits, measurement procedures, mitigation measures and information to deal with long term a.c. interference for a.c voltages at frequencies between 16,7 Hz and 60 Hz and the evaluation of a.c. corrosion likelihood.
This European Standard deals with the possibility of a.c. corrosion of metallic pipelines due to a.c. interferences caused by inductive, conductive or capacitive coupling with a.c. power systems and the maximum tolerable limits of these interference effects. It takes into account the fact that this is a long-term effect, which occurs during normal operating conditionsof the a.c. power system.
This European Standard does not cover the safety issues associated with a.c. voltageson pipelines. These are covered in national standards and regulations (seeEN 50443).
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | Contents Page |
| 6 | Foreword |
| 7 | 1 Scope 2 Normative references 3 Terms and definitions |
| 10 | 4 Cathodic protection personnel competence |
| 11 | 5 Assessment of the a.c. influence 5.1 General 5.2 Assessment of the level of interference |
| 12 | 6 Evaluation of the likelihood of a.c. corrosion 6.1 Prerequisite 6.1.1 General 6.1.2 A.c. voltage on the structure |
| 13 | 6.2 A.c. and d.c. current density 6.2.1 General 6.2.2 A.c. current density 6.2.3 High cathodic d.c. current density 6.2.4 Low cathodic d.c. current density |
| 14 | 6.2.5 Current ratio “Ia.c./Id.c. ” 6.2.6 Soil resistivity 6.3 Corrosion rate 6.4 Pipeline coatings 6.5 Evaluation of the metal loss 7 Acceptable interference levels |
| 15 | 8 Measurement techniques 8.1 Measurements 8.1.1 General 8.1.2 Selection of test sites |
| 16 | 8.1.3 Selection of measurement parameter 8.1.4 Sampling rate for the recording of interference levels 8.1.5 Accuracy of measuring equipment 8.1.6 Installation of coupons or probes to calculate current densities 8.2 D.c. potential measurements |
| 17 | 8.3 A.c. voltage measurements 8.4 Measurements on coupons and probes 8.4.1 Installation of coupons or probes 8.4.2 Current measurements |
| 18 | 8.4.3 Corrosion rate measurements |
| 19 | 8.5 Pipeline metal loss techniques 9 Mitigation measures 9.1 General 9.2 Construction measures 9.2.1 Modification of bedding material 9.2.2 Installation of isolating joints 9.2.3 Installation of mitigation wires |
| 20 | 9.2.4 Optimisation of pipeline and/or powerline route 9.2.5 Power line or pipeline construction 9.3 Operation measures 9.3.1 Earthing 9.3.1.1 General 9.3.1.2 Direct earthing 9.3.1.3 Indirect earthing of the pipeline via d.c. decoupling devices |
| 21 | 9.3.1.4 A.c. compensation method 9.3.2 Adjustment of cathodic protection level 9.3.3 Repair of coating defects 10 Commissioning 10.1 Commissioning |
| 22 | 10.2 Preliminary checking 10.2.1 General 10.2.2 Start up |
| 23 | 10.2.3 Verification of effectiveness 10.2.4 Installation and commissioning documents 11 Monitoring and maintenance |
| 25 | Annex A (informative) Simplified description of the a.c. corrosion phenomenon A.1 Cathodically protected pipeline A.2 Cathodically protected pipeline with a.c. voltage A.2.1 Description of the phenomena |
| 26 | A.2.2 Reduction of the a.c. corrosion rate |
| 27 | Annex B (informative) Coupons and probes B.1 Use and sizes of coupons and probes B.1.1 Use of coupons or probes B.1.2 Sizes of coupons or probes B.2 Installation of buried coupons and probes B.2.1 General B.2.2 Before installing the coupon or probe |
| 28 | B.2.3 Installation of the buried coupon or probe |
| 29 | B.3 ER probes principles B.3.1 Assessment of the corrosion using the electrical resistance (ER) probe technique B.3.1.1 General theory |
| 30 | B.3.1.2 Mathematical development to determine Vcorr B.3.1.3 Vcorr assessment |
| 31 | B.3.1.4 Specific recommendation for ER probe B.3.2 ER probe application in the field B.4 Perforation probes |
| 33 | Annex C (informative) Coulometric oxidation |
| 34 | Annex D (informative) Influence of soil characteristics on the a.c. corrosion process D.1 Influence of electrical parameters D.2 Influence of the electrochemical process D.3 Influence of alkaline ions and cations |
| 35 | Annex E (informative) Other criteria that have been used in the presence of a.c. influence E.1 General E.2 ON-potential approach E.2.1 General E.2.2 More negative (Eon) cathodic protection level E.2.3 Less negative (Eon) cathodic protection level |
| 36 | E.2.4 Criteria |
| 38 | Annex F (informative) Parameters to take into account to choose a d.c. decoupling device F.1 General aspects to be taken into account F.2 Electrical parameters |
| 39 | Annex G (informative) Method to determine the reference electrode location to remote earth |
| 40 | Bibliography |
