GB/T 21246-2020Measurement method for cathodic protection parameters of buried steel pipelines (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 21246-2007 "Method for Measuring Cathodic Protection Parameters of Buried Steel Pipelines", and is in line with GB/T 21246-2007 The main technical changes are as follows.

---Added the potential value and temperature coefficient of silver chloride reference electrode and common reference electrode (see 4.3.3, 2007 edition 4.3.3);

---Detailed requirements for power-off potential measurement (see 5.3, 5.3 of the 2007 edition);

---Added the requirement of current synchronization verification in close interval potential measurement (see 5.4.2);

---Modified the name and applicability of cathodic polarization potential and diagram (see 5.6, 2007 edition 5.6);

--- Supplement the installation and test piece requirements of the polarization probe method (see 5.7, 5.9 in the 2007 edition);

---Added soil pipe method (see 5.8);

---Added the current loop method (see 7.3);

---Modified the requirements of megohmmeter method measuring instrument (see 8.1.2, 9.1.2 in 2007 edition);

--- Refined the content of the electric potential method for testing the insulation performance of insulating joints (flanges) (see 8.2, 9.2 of the 2007 edition);

---Insulation joint (flange) insulation performance test adds voltage method and power current loop method (see 8.3 and 8.5);

---Increase the corrosion rate measurement (see Chapter 11);

---Deleted the positioning of the anode zone of the pipeline (see 5.10 of the 2007 edition);

--- Deleted the resistivity of the outer anti-corrosion coating of the pipeline (see Chapter 8 of the 2007 edition);

---Deleted the ground leak detection of the outer anti-corrosion layer of the pipeline (see Chapter 12 of the 2007 edition).

1 Scope

This standard specifies on-site measurement methods for cathodic protection parameters of buried steel pipelines on land.

This standard is applicable to the field measurement of cathodic protection parameters of buried steel oil, gas and water pipelines on land.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this document. For undated references, the latest version (including all amendments) applies to this document.

JJG124 ammeter, voltmeter, power meter and resistance meter

JJG366 Ground Resistance Meter Verification Regulation

JJG622 Insulation Resistance Meter (Megger) Verification Regulation

JJF1587 Digital Multimeter Calibration Specification

SY/T 0029 Technical Specification for Application of Buried Steel Inspection Sheet

3 Terms and definitions

The following terms and definitions apply to this document.