What are the best practices and standards for ERT quality assurance and control?

1 What is ERT QA/QC?

ERT QA/QC refers to the systematic processes and procedures that aim to verify and improve the quality of ERT data acquisition, processing, and interpretation. ERT QA/QC involves checking the integrity and functionality of the ERT equipment, calibrating and validating the ERT measurements, correcting and filtering the ERT data, and evaluating and verifying the ERT images. ERT QA/QC can help to identify and eliminate errors, noise, artifacts, and uncertainties that may affect the ERT results.

2 Why is ERT QA/QC important?

ERT QA/QC is important because it can enhance the confidence and credibility of ERT results. ERT results can be influenced by various factors, such as the electrical properties and geometry of the target, the configuration and arrangement of the electrodes, the injection and measurement methods, the environmental conditions, and the data processing and inversion algorithms. ERT QA/QC can help to assess and minimize the impact of these factors on the ERT results. ERT QA/QC can also help to optimize the design and performance of the ERT system, to ensure the repeatability and reproducibility of the ERT results, and to comply with the relevant standards and regulations.

3 How to perform ERT QA/QC?

There is no definitive method for performing ERT QA/QC, as different applications and objectives may require different approaches and criteria. However, some general steps and guidelines for ERT QA/QC include checking the equipment for any damage, malfunction, or contamination before data acquisition, monitoring and recording parameters during data collection, and inspecting and analyzing the data after the acquisition. Additionally, choose an appropriate electrode configuration and arrangement that suits the target and the measurement objective; use a suitable electrode material, size, and shape to reduce contact resistance; apply a sufficient and stable current or voltage to the electrodes; use a consistent data acquisition protocol; collect enough data points to cover the target area; compare ERT measurements with other methods; use appropriate data correction and filtering techniques; select an inversion algorithm that matches the data characteristics; adjust inversion parameters to obtain a stable image; and evaluate the quality of the image using quantitative or qualitative indicators.

4 What are some ERT QA/QC standards?

There are some existing standards and guidelines that provide recommendations and specifications for ERT QA/QC. For example, the ASTM E2907/E2907M-13 standard covers the general principles and procedures for ERT of metallic pipes and tubes. The ASTM D6431-18 standard describes the methods and equipment for ERT of soil and rock masses. The ISO 17405:2016 standard defines the terms and requirements for ERT of concrete structures. The IEEE Std 1671.2-2012 standard establishes the framework and methodology for ERT of microelectronic devices. These standards can serve as references and benchmarks for ERT QA/QC, but they may not cover all aspects or scenarios of ERT applications.

5 How to improve ERT QA/QC?

Continuously improving ERT QA/QC is essential and can be done by following the best practices and standards applicable to your application, staying up-to-date with the latest developments and innovations in ERT technology, performing regular maintenance and calibration of the ERT equipment, conducting periodic audits and assessments of the ERT QA/QC system, seeking feedback from other ERT experts and users, participating in training and education programs, and sharing your experiences with the ERT community.