STANDARD. ISO. First edition. Petroleum and natural gas industries —. Cathodic protection of pipeline transportation systems —. Part 1. Purchase your copy of BS EN ISO as a PDF download or hard copy directly from the official BSI Shop. All BSI British Standards. STANDARD. ܚ. ISO. First edition. an Petroleum and natural gas industries -. Cathodic protection of pipeline transportation systems
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Where an alternative is offered, any variations from this part of ISO should be identified. Reference number ISO There are a 51589-1 of measurements that can be isi out to determine the effectiveness of an installed isolating joint or isolating flange kit, as described in A.
Thus, the potential measurement with the reference electrode at the ground surface will include a contribution from the IR drop. An increase in the recorded potential difference can indicate a coating defect or a metallic 155589-1 in close proximity to the pipe.
J is the design electric current density for bare steel, expressed in milliamperes per square metre; Fc is the coating breakdown factor, dimensionless; r is the outer radius of the pipeline, expressed in metres; L is the length of pipeline, expressed in metres. Measurements of potential are iao versus distance, from which features can be identified by changes in potential caused by local variations in CP current density.
For buried pipelines, the isoo measured against the reference electrode shall be measured, generally within 1 s after the protective current is switched off. Automatic current control alone shall not be used for iwo current flow where soil moisture or other variations near the pipeline can cause potential variations.
The monitoring plan shall include at least the following: Key 1 IR Drop 2 polarization 3 rectifier on 4 corrosion potential 5 instant-on potential 6 depolarization 7 rectifier off 8 on potential 9 instant-off potential 10 depolarized potential corrosion potential X Time 15859-1 Structure-to-electrolyte potential, mV Figure A. If the pipeline is transporting any fluids that are electrically conductive, the isolating joints shall be internally coated on the cathodic most expected negative potential side, for a length sufficient to avoid interference-current corrosion.
Generally, the monitoring stations should be installed above the pipeline. Use of continuous conductive polymer anodes should be considered, particularly for very high resistivity soils surrounding the pipeline. Your Alert Profile lists the documents that will be monitored. There are complementary techniques which can be used to give a more accurate assessment of the effectiveness of the CP.
External corrosion control in general is covered by Io The galvanic anodes should be attached to the pipeline via a cable in a monitoring station. The instant-off potential shall be measured by a rapid response instrument. In case of low soil resistivity, jso a. These earthing systems can be constructed using a wide variety of electrodes galvanized steel, zinc, magnesium, etc.
Current density requirements also depend upon the oxygen content jso resistivity of the soil. As a general guide a potential difference of less than mV may be regarded as inconclusive. The location of compensation devices shall be carefully considered. This standard is also available to be included in Standards Subscriptions. Where the protective coating is in good condition, the current will attenuate at a constant rate, which depends upon coating properties.
ISO – Standards Australia
The potential gradients caused by coating defects will then be the mean values of the potentials between the reference electrodes at locations 2 and 3 and at points 2 and 4arranged symmetrically with the distance, L, in Figure D. All cables shall be terminated in a monitoring station. Where thermite welding is used, the welding procedure shall ensure that any copper penetration into the pipeline material is less than 1 mm and that the local pipeline hardness remains within the pipe specification.
After installation of the cable-to-pipe connection, the coating shall be repaired using a suitable coating material. To minimize the IR drop, the reference electrode should be placed as close to the pipe as possible. A detailed cable-to-pipeline connection procedure shall be included in the CP design.
For non-metallic casings and coated steel casings, if usedCP should be provided to the pipeline inside the casing by installing galvanic anodes or impressed-current polymer anodes along the bottom of the pipe, together with a reference electrode inside the casing.
Alternative corrosion control methods should be considered in such cases. In accordance with Adobe’s licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing.
Making transverse readings with one electrode located at the epicentre of the coating defect, anodic and cathodic characteristics can be determined. The need for, and the type of, CP for thermally-insulated pipelines shall be subject 155891 an additional evaluation taking into account the following.
Subscription pricing is determined by: Cathodic protection of the carrier pipe within the casing can be improved by earthing the casing using steel earthing rod s.
All cables shall be separately terminated in a single monitoring station with facilities to install direct or resistive bonds and surge arrestors. Safety-earthing and instrument-earthing shall be mutually compatible with the CP system. Annex A gives details of the measurements.
These jso shall be carried out with the CP systems both in operation and de-energized. NOTE 2 Possible effects associated with a. Ieo downloading this file, parties accept therein the responsibility of not infringing Adobe’s licensing policy. Please first log in with a verified email before subscribing to alerts. Locations where high-voltage a.
This section of the A further objective can be to collect data for optimization of future CP designs. Normally, all large coating defects can iiso identified if measurements are made at intervals of 5 m along the pipeline. Results provided by the remote monitoring system should be periodically checked against manually recorded data to ensure 15589- the remote monitoring system is functioning correctly.
Addition of water to the groundbed may help to reduce the groundbed resistance to previous levels. Current attenuation surveys are based on the assumption that when an a.