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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The pipe-to-soil potential shall be measured to verify CP effectiveness using the protection criteria in 5. Testing at the isolating joint should be done to assure that an interference condition has not then been introduced; NOTE While installing isolating joints will reduce the magnitude of the stray current, it also introduces another current pick-up and discharge location, hence the reason for testing at the ixo joint.
In the presence of equalizing currents, the potential gradients will be approximately symmetrical to the pipeline. Welders and welding procedures shall be qualified for any applicable welding process in accordance with ISO In such cases, the pipelines shall be isolated from each other and provided with an individual negative connection to the current source.
Using a sensitive millivoltmeter, the potential difference is measured between two reference electrodes probes placed at the surface level in the soil within the voltage gradient.
In case of low soil resistivity, high a. A number of specialized survey techniques exist which provide additional detailed information on the status of the pipeline corrosion prevention system. For concrete casings, the CP current can pass through the concrete if it is sufficiently conductive and if there is no metallic contact between the reinforcement and the pipeline.
Generally, voltages higher than 50 V rectifier output should be avoided. Safety-earthing and instrument-earthing shall be mutually compatible with the CP system. The main task of technical committees is to prepare International Standards. The specific composition of the anode backfill shall be determined by the need to minimize resistivity and maximize moisture retention.
BS EN ISO 15589-1:2017
Alternatively, connections between the positive cable to the transformer-rectifier and the individual anode cables may be made below ground using fully encapsulated line taps. Therefore, it will be sufficient to determine the potential difference between the reference electrodes at points 2 and 3 or at points 2 and io in Figure D.
Devices other than the spark-gap type may be used if reliable and properly documented. Design, fabrication, installation, operation and maintenance of CP systems shall be carried out by experienced and qualified personnel.
For non-metallic casings and coated steel casings, lso 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. Users of this part of ISO should be aware that further or differing requirements may be needed for ixo applications.
ISO – Standards Australia
Alternative off-potential measurement techniques may be considered if shown to be accurate and effective. Detrimental effects of interference currents occur at locations where the currents are subsequently discharged from the affected pipeline to the earth. They shall be retained for use as a baseline for future verifications of CP effectiveness.
Defects can be located by zero readings corresponding with the probes being symmetrical either side of the defect. Distribution boxes and monitoring stations used for bonding of current-carrying cables should be located outside hazardous areas or, if this is not possible, shall be approved for the relevant electrical area classification. For undated references, the latest edition of the referenced document including any amendments applies.
In downloading this file, parties accept therein the responsibility of not infringing Adobe’s licensing policy. Use of continuous conductive polymer anodes should be considered, particularly for very high resistivity soils surrounding the pipeline.
Such a system shall be designed to cover the pipeline construction period until the commissioning of the permanent CP system. If the use of monobloc isolating joints is not practical, 51589-1 isolation should be provided using isolating flange kits.
Thus, the potential measurement with the reference electrode at the ground surface will include a contribution from the IR drop. Significant positive shifts in pipeline potential, such as those due to stray-current interaction, shall be corrected within 30 days Annex B. Measurements of potential are plotted versus distance, from which features can be identified by changes in potential caused by local variations in CP current density.
The borehole design and construction shall be such that the undesirable transfer of water between different geological formations and the pollution of underlying strata is prevented.
A detailed cable-to-pipeline connection 155891- shall be included in the CP design. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given 15589–1. We recommend that you check the website of the publishers of the international document before making a purchase.
Jso may be particularly applicable where there is innovative or developing technology. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. A panel-mounted meter should be provided to enable the pipe-to-soil potential to be read.
Where thermite welding is used, 155899-1 welding procedure shall ensure that 155589-1 copper penetration into the pipeline material is less than 1 mm and that the local pipeline hardness remains within the pipe specification. Isoo shall consist of two separate cables attached to each individual pipeline, terminating in a monitoring station with facilities to install direct or resistive bonds if required.
In this case, some other method should be used to verify the integrity of the pipeline. This shall be done by installing permanent bonds across the high-resistance mechanical isk, using suitable attachment methods. For buried pipelines, the potential measured against the reference electrode shall be measured, generally within 1 s after the protective current is switched off. The minimum conductor size for cables that carry impressed current should be 16 mm2.
On-land pipelines This document has been re-assessed by the committee, and judged to still be up to date. Specialized surveys should be conducted within 1 year of operation. They walk either in-line directly over the pipeline or side-by-side with one ieo over the pipeline.
If rapid depolarization occurs, the instant-off potential shall be determined using a high speed data logging processor. When corrosion potential measurements are carried out, all temporary CP systems shall be disconnected and the pipeline shall be fully depolarized see Figure A.
This will normally require the transformer-rectifier output voltage to be increased at these times to satisfy the current demand.