What are the technical specifications for pressure pipeline installation and pressure testing?

Recently, with the continuous promotion of industrial production and urban infrastructure construction in China, pressure pipelines, as the core equipment for transporting gases, liquids and other media, have been widely used in various fields such as petrochemicals, heating and water supply, and energy transportation. The installation and pressure testing quality of pressure pipelines are directly related to the safety and stability of medium transportation. If the installation is not standardized and the pressure testing is not in place, safety hazards such as medium leakage and pipeline damage may occur. In severe cases, it may cause safety accidents such as fires and explosions, threatening the safety of personnel and property.
The technical specifications for pressure pipeline installation and pressure testing follow the core principles of "safety first, standardized construction, full process control, and precise detection", which run through the entire process of pipeline installation, pressure testing preparation, pressure testing implementation, and later acceptance. The core goal is to ensure that the installation quality of pressure pipelines meets the standards, the pressure testing is qualified, and the medium is safely and stably transported. Industry experts say that pressure pipelines belong to special equipment, and their installation and pressure testing must strictly follow relevant national safety technical regulations and industry standards. Each technical link needs to be precisely controlled, and any illegal operation may leave safety hazards. Only by strictly implementing technical specifications can pressure pipelines ensure long-term safe operation.

The technical specifications for pressure pipeline installation mainly cover three core aspects: pre installation preparation, on-site installation construction, and installation process control. Each aspect has clear specification requirements and is the foundation for ensuring installation quality.

The core of the technical specifications for the pre installation preparation stage is to do a good job in material control, scheme preparation, and personnel qualification review. The material quality of pressure pipelines is a prerequisite for installation quality, and must be strictly screened and accepted according to design requirements and TSG 31-2025 standard specifications. Core materials such as pipeline components, pipeline supports, and safety accessories need to be checked for specifications, models, quality certificates, and qualification certificates to ensure compliance with design requirements and medium transportation requirements. Among them, the pipeline components need to be tested for their pressure resistance and corrosion resistance, and the safety valves and bursting disc devices in the safety accessories must be verified and qualified before they can be used. Material storage should be standardized to avoid moisture, corrosion, and collision. Pipes and fittings of different specifications and materials should be classified and stacked, properly labeled to prevent mixing. In the "Heat Transfer into Zhengzhou" project in Henan Province, the construction team sampled and rechecked the incoming pipeline materials one by one, established a special management ledger, and prevented unqualified materials from being put into use, laying a solid foundation for installation quality.

The preparation of the construction plan should be based on the level, medium characteristics, installation environment, and geological conditions of the pressure pipeline. A special installation and construction plan should be prepared to clarify the installation process, technical parameters, quality control standards, and emergency measures. After approval, it can be put into implementation. According to the TSG 31-2025 standard, pressure pipelines are divided into three levels: GC1, GC2, and GCD. The installation requirements for different levels of pipelines vary, and GC1 level pipelines require stricter installation control measures. At the same time, installation personnel must possess corresponding qualifications, and special operation personnel must hold valid work permits before taking up their posts. The construction unit needs to provide professional training and technical disclosure to installation personnel to ensure that they master installation specifications, process points, and safety precautions. In addition, before installation, it is necessary to clean the installation site, check the performance of the construction equipment, ensure that the construction equipment meets the installation requirements, and prepare for on-site installation and construction.

The core of the technical specifications for on-site installation and construction is to control key aspects such as pipeline laying, connection, and anti-corrosion. Pipeline laying must comply with design requirements, ensure that the laying slope and direction meet specifications, and avoid bending and twisting of the pipeline. Before laying buried pipelines, the trench must be cleaned to remove debris and sharp objects. When backfilling, it is necessary to compact in layers with a compaction coefficient that meets design requirements to prevent pipeline damage under pressure. Pipeline connection is the core of installation, and commonly used welding, flange connection, and other methods must strictly follow the specifications. Welding operations require controlling welding current, voltage, welding speed, and other parameters to ensure that the weld seam is full, slag free, and crack free. In the "Heat Transfer into Zhengzhou" project in Henan Province, the construction team uses automatic welding robots for operation, combined with X-ray and ultrasonic non-destructive testing to ensure that the weld quality is not lower than the Level I standard, and the weld qualification rate reaches 100%.

The flange connection should ensure that the sealing surface is flat and clean, and the sealing element should be selected according to the characteristics of the medium. When tightening the bolts, uniform force should be applied to avoid leakage caused by uneven force; Threaded connections need to be sealed to prevent medium leakage. The anti-corrosion and insulation of pipelines must comply with regulatory requirements. Suitable anti-corrosion materials should be selected based on the characteristics of the medium and installation environment, and the coating should be uniform and leak free. Buried pipelines should be protected with anti-corrosion layers to prevent soil corrosion. The "Heat Transfer into Zhengzhou" project in Henan Province innovatively uses an internal joint coating robot to ensure uniform coating at the joint coating and improve the anti-corrosion effect of the pipeline. During the installation process, it is necessary to avoid collisions between the pipeline and other facilities, fix the pipeline properly, set up reasonable supports and hangers, and ensure stable operation of the pipeline.

The technical specifications for pressure testing of pressure pipelines are key to verifying the quality of pipeline installation, ensuring the pressure resistance and sealing performance of pipelines. It is necessary to strictly follow the full process specifications for pressure testing preparation, implementation, and acceptance. The pressure testing methods mainly include hydraulic testing, pneumatic testing, and leakage testing. The appropriate pressure testing method should be selected according to the pipeline level and medium characteristics.

The technical specifications for the preparation stage of pressure testing include pipeline inspection, preparation of test media, calibration of test equipment, etc. Before the pressure test, a comprehensive inspection of the pipeline installation quality is required to confirm that the pipeline installation meets the design requirements and installation specifications. The welds and other parts to be inspected are not painted or insulated, and temporary restraint devices have been installed on the expansion joints on the pipeline. The pressure gauge used for testing must be calibrated and qualified within its validity period, with an accuracy of not less than level 1.6. The full-scale value should be 1.5 to 2 times the maximum pressure being measured, and there should be no less than two gauges. The test medium must comply with the specifications. Clean water is preferred for hydraulic testing, and the chloride ion content in the water used for stainless steel pipeline testing should not exceed 25ppm. Dry and clean air, nitrogen, and other non flammable and non-toxic gases are used for air pressure testing. At the same time, the pipeline to be tested should be isolated from unrelated systems with blind plates, and safety valves, rupture discs, and other instrument components on the pipeline should be removed to ensure pressure testing safety.

The technical specifications for the implementation stage of pressure testing require strict control of the pressure testing pressure, pressure rise rate, and stabilization time. During hydraulic testing, the test pressure of the above ground steel pipeline that can withstand internal pressure should be 1.5 times the design pressure, and the test pressure of the buried steel pipeline should not be lower than 0.4MPa. The pressure should be slowly increased, and after reaching the test pressure, it should be stabilized for 10 minutes, then lowered to the design pressure and stabilized for 30 minutes. If there is no pressure drop or leakage, it is considered qualified. During the air pressure test, the test pressure should be 1.15 times the design pressure. Before the pressure test, a pre test of 0.2MPa should be conducted. After the pressure is increased to 50% of the test pressure and there are no abnormalities, the pressure should be gradually increased by 10%. Each level should be stabilized for 3 minutes. After reaching the test pressure, the pressure should be stabilized for 10 minutes. After reaching the design pressure, a foaming agent should be used to check for no leaks, which is considered qualified.

For pipelines transporting extremely and highly hazardous and flammable media, leakage tests must be conducted. The test must be conducted after passing the pressure test. The test pressure is the design pressure, and after stabilizing for 10 minutes, all sealing points must be checked with neutral foaming agent. If there is no leakage, it is considered qualified. During the pressure testing process, professional personnel should be arranged for on-site supervision. It is strictly prohibited to handle leakage problems under pressure. If leakage is found, it should be promptly rectified after reducing the pressure and retesting until it is qualified.

The core of the technical specifications for the pressure test acceptance stage is to keep good records of the pressure test and evaluate the results. After the pressure test is completed, detailed records of the test parameters, test process, test results, and other information should be kept to form a complete pressure test record, ensuring traceability of the construction process. For pipelines that have passed the pressure test, timely pressure relief and drainage should be carried out, temporary restraint devices should be removed, and the pipeline should be restored to its normal state; For pipelines that fail the pressure test, it is necessary to analyze the reasons and develop a special rectification plan. After the rectification is completed, the pressure test should be repeated until it is qualified before entering the next process.

The reporter learned that with the continuous expansion of the application field of pressure pipelines, their installation and pressure testing technical specifications are also continuously improving. TSG 31-2025 "Industrial Pipeline Safety Technical Regulations" will be officially implemented on January 1, 2026, further unifying the safety technical requirements of pressure pipelines and adding special specifications for power pipelines, refrigeration pipelines, etc. Industry experts remind that the installation and pressure testing of pressure pipelines is a systematic project that requires strict adherence to relevant technical specifications. Construction units need to implement a quality responsibility system, strengthen full process control, enhance professional training for construction personnel, and improve standardized operation levels. In the future, with the promotion and application of intelligent construction equipment and detection technology, the precision and standardization level of pressure pipeline installation and pressure testing will be further improved, providing strong guarantees for the safe transportation of various media and helping industrial production and high-quality development of urban infrastructure.