Guidelines for Leak Detection of Atmospheric Pressure Vertical Cylindrical Welded Steel Storage Tanks

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In January 2024, the group standard \"Guidelines for Leak Detection of Atmospheric Pressure Vertical Cylindrical Welded Steel Storage Tanks\" (T/CCSAS 046-2023), prepared by organizations such as Sinopec Safety Engineering Research Institute Co., Ltd. under the auspices of the China Chemical Safety Association, was released and put into use. The media stored in atmospheric pressure vertical cylindrical welded steel storage tanks (referred to as atmospheric pressure tanks) are often flammable, explosive, toxic, and harmful, and the storage volumes are generally large; any leakage can lead to serious consequences. Storage tanks in our country often experience extended service life, posing a high risk of leakage. The application of advanced tank leakage monitoring technologies to take corrective actions at the early stage of tank leakage helps improve the safety and reliability of tank facilities. Abroad, particularly in the United States, standards such as NFPA 329 \"Recommended Practices for Controlling Releases of Flammable and Combustible Liquids and Gases\" and API Publ 340 \"Methods for Preventing and Detecting Liquid Leaks at Aboveground Storage Facilities\" have established a comprehensive and detailed technical framework for preventing and controlling tank leaks, covering technical standards, detection methods, control measures, and more. At present, China has accumulated some experience in leak detection for storage tanks. There are numerous methods for leak detection, but no unified and systematic guidelines for carrying out such detections have been established. The application of these detection methods as well as their standardized implementation lack relevant standard guidelines. This standard takes into account domestic and international technical standards, advanced experiences, and recommended practices for tank leakage detection. It outlines the procedures for detecting leaks in atmospheric pressure tanks as well as the technical requirements for the entire implementation process, including general requirements, preparations before testing, on-site testing, result analysis and evaluation, and reporting. It also specifies the detailed requirements for determining testing locations, selecting testing methods, and formulating monitoring plans, thereby providing valuable guidance for standardizing tank leakage detection operations. This standard includes 12 appendices that detail the scope of application, advantages and disadvantages, as well as the specific testing procedures for leak detection methods applicable to atmospheric-pressure storage tanks used for storing petroleum, petrochemical products, and other similar liquids. These methods include visual inspection, volumetric measurement, bubble test under pressure, bubble test under vacuum, foundation drilling for leak detection, leak detection using a layer on the foundation, tracer gas detection, acoustic emission detection, use of pre-installed detection elements in the foundation, resistance-based leak detection, magnetic particle testing, penetrant testing, magnetic flux leakage detection, infrared thermal imaging detection, and ultrasonic testing as supplementary methods. The standard specifies the testing instruments and equipment required for each method, the basic conditions for testing, the testing procedures, as well as the requirements for evaluating and determining test results. The \"Guidelines for Leak Detection of Atmospheric Pressure Vertical Cylindrical Welded Steel Storage Tanks\" can assist enterprises and testing service organizations in systematically applying efficient tank leak detection techniques to carry out thorough inspections. By enabling the detection of leaks at an early stage, before they spread, effective measures can be taken, which is of great significance for ensuring the safety of chemicals in China and protecting the environment.