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 instant-off potential shall be measured by a rapid response instrument. Immediate action shall be taken if positive changes in pipeline potential occur after energizing the transformer-rectifier. The number of measurements should be based on local soil conditions. This section of the The connections of cables to the pipeline shall be designed to ensure adequate mechanical strength and electrical continuity and to prevent damage to the pipe at the point of connection.
NOTE Metallic casings only provide temporary borehole stabilization, as the metal will be consumed by the d. Typical examples where this could occur include excessively negative potentials 5. Adobe is a trademark of Adobe Systems Incorporated.
The need for, and the type of, CP for thermally-insulated pipelines shall be subject to an additional evaluation taking into account the following. As an alternative to the protection potentials given above, a minimum of mV of cathodic polarization between the pipeline surface and a reference electrode contacting the electrolyte may be used.
Monitoring stations and distribution boxes should be provided with lockable access doors or caps, as applicable. Monitoring stations and distribution boxes shall be accessible during all seasons and shall be designed and located to minimize vandalism or accidental damage. In these cases, alternative criteria shall be verified and applied. Where an alternative is offered, any variations from this part of ISO should be identified.
Alternative corrosion control methods should be considered in such cases. When corrosion potential measurements are carried out, all temporary CP systems shall be disconnected and the pipeline shall be fully depolarized see Figure A. As a general guide a potential difference of less than mV may be regarded as inconclusive.
ISO – Standards Australia
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. Locations where high-voltage a.
Drainage stations Measure drain-point potential and the current at least monthly Connections to foreign pipelines Measure current flow at least annually Bonding devices and grounding systems Measure electrical continuity at least annually Safety and protection devices Measure settings and function at least annually At monitoring stations Measure instant-off potentials annually a Less frequent measurements may be considered based on results of specialized surveys see By applying a direct current to the pipeline in the same manner as CP, a voltage gradient is established in the soil due to the passage of current to the bare steel at coating defects.
If electrical safety-earthing is required, this shall be made compatible with the CP system by installing polarization cells or diode circuits, suitably specified and rated for the purpose, in the earthing circuit or by installing separate earthing zinc or galvanized steel electrodes, buried in low-resistivity backfill and not in direct electrical continuity with other earthing systems. Once the CP system has been energized and set at the design value, the rectifier output voltage and the current output should be recorded.
The pipe-to-soil potential shall be measured to verify CP effectiveness using the protection criteria in 5. All cables shall be separately terminated in a single monitoring station with facilities to install direct or resistive bonds and surge arrestors. Table 4 — Routine functional checking frequencies Item Action Frequency Impressed-current station Check that the operation and condition of the transformer-rectifier unit is satisfactory and record the output voltage and current every one to three months depending on operational conditions such as lightning, stray currents, construction activities.
Welded steel pipes and fittings for water, sewage and medium pressure gas You may be interested in this related standard Gas appliance safety – Audit workbook You may be interested in this related standard. Add to Alert PDF. This shall be done by installing permanent bonds across the high-resistance mechanical connectors, using suitable attachment methods.
The readings might not reflect the potential at the pipe-to-soil interface. Deep-well groundbeds should be provided with adequate vent pipes to prevent gas blocking between anodes and the conductive backfill. After installation of the cable-to-pipe connection, the coating shall be repaired using a suitable coating material.
Proceed to Checkout Continue Shopping. On-land pipelines This document has been re-assessed by the committee, and judged to still be up to date.
The type and frequencies of further specialized surveys will depend on factors such as suspected coating deterioration, effects of elevated temperatures, construction activities, interference currents, etc. For galvanic-anode systems, the following shall apply. If this is impossible, then the likely consequences with regard to safety shall be assessed. Jso electrical connections shall be encapsulated or coated using a material which is compatible with the pipeline coating.
All cables shall be identified by colour-coding or tags.