How was the quality of the pipeline repair? A comprehensive analysis of the quality assurance system for the repair project. In the fields of pipeline transportation such as oil, natural gas, and water supply, if a pipeline leaks or ruptures, it will not only lead to waste of resources and environmental pollution, but also may cause serious safety accidents. Pipeline emergency repair, as the emergency response system for dealing with pipeline emergencies, its quality directly affects the long-term safe operation of the pipeline and public safety. So, how is the quality of pipeline emergency repair? This article will comprehensively analyze the quality guarantee mechanism of pipeline emergency repair projects from multiple dimensions such as quality standard system, process control, quality assurance of key links, inspection and acceptance, and technological innovation. I. Standard System for Pipeline Repair Quality The quality of pipeline emergency repairs is primarily based on a well-established standard system. China has already established a repair quality standard system covering both oil and gas pipelines as well as municipal water supply and drainage pipelines. In the field of oil and gas pipelines, the newly revised SY/T 7033-2024 "Technical Specifications for Failure Repair of Steel Oil and Gas Pipelines" was officially implemented on March 24, 2025. This standard was drafted by leading enterprises in the industry such as the Northern Pipeline Co., Ltd. of National Pipeline Group and China Petroleum Pipeline Bureau Engineering Co., Ltd., providing unified technical specifications for oil and gas pipeline repair. At the same time, GB 50369-2014 "Construction and Acceptance Specifications for Long-Distance Oil and Gas Pipelines" has clearly stipulated requirements for handling pipeline defects. For example, when the depth of scratches on the steel pipe surface is less than or equal to 5% of the nominal wall thickness, grinding treatment can be carried out; when it is greater than 5%, grinding treatment is required and the wall thickness must be confirmed. In the field of municipal water supply and drainage, T/UNP 794-2025 "Technical Regulations for Non-Digging Repair of Municipal Water Supply and Drainage Pipelines" has been implemented since July 2025. It is applicable to circular pipelines with diameters ranging from DN150 to DN3000 and covers quality inspection and acceptance standards for various repair technologies such as in-situ curing method and pipeline lining method. In addition, GB 50268 "Code for Construction and Acceptance of Water Supply and Drainage Pipelines" is the basic basis for emergency repair and acceptance of water supply pipelines. These standards constitute the "legal bottom line" for the quality of pipeline emergency repairs, and the repair units must strictly adhere to them. II. Quality Control During Emergency Repair Process High-quality emergency repairs stem from the quality control throughout the entire process. Modern pipeline emergency repairs have shifted from the simplistic "temporary leak sealing" model to a systematic and standardized quality control system. Preliminary investigation and assessment Repair quality begins with accurate problem diagnosis. In a case of a DN2400 large-diameter water supply pipe top-penetration repair, due to the pipe being buried approximately 10 meters deep and located beneath a fast lane, traditional leak detection techniques could not be used. The repair team adopted the Sahara II pipeline detection new technology. This technology is based on acoustic non-destructive condition assessment detection technology and can detect and locate the leakage point of the pipeline through sound wave signals without affecting the normal operation of the pipeline network. Through spectral analysis and synchronous sound monitoring, the leakage point was finally accurately located, providing a reliable basis for subsequent repairs. 2. The entire process quality supervision chain For the emergency repair projects of sewage pipelines and pumping stations, due to their characteristics of high urgency and strict technical requirements, the modern quality control system has established a complete quality supervision chain covering the entire process from fault diagnosis, scheme formulation to on-site construction. This includes: · Material quality control and on-site inspection: Strictly control the quality of emergency materials such as pipes and seals · Standardized key process operations: Strengthening the standardized procedures for non-intrusive pipeline repair and rapid replacement of pump station equipment · Image recording of concealed works: Implement image-based recording and multi-party verification for concealed sections such as foundation pit excavation, pipe connections, waterproofing and anti-corrosion work. 3. Closed-loop management mechanism Through the closed-loop management of "inspection - rectification - re-inspection", the main responsibilities of all participating parties are effectively implemented, ensuring that the emergency project can be handled quickly while maintaining high quality and durability. III. Quality Assurance of Key Stages The quality of pipeline emergency repairs depends on the meticulous control of every key step. Welding quality assurance Welding is the most crucial and dangerous part in pipeline emergency repairs. In a case of pipeline emergency repair, the maintenance was carried out using manual arc welding technology. Considering the particularity of the on-site emergency repair, the welding process parameters were systematically optimized. Specifically, this included: · Select the E7016 low-hydrogen type welding rod, which has excellent toughness and crack resistance. Strictly implement the API1104 standard Adopt a segmented emergency repair plan, combined with prefabricated welding technology and multi-layer multi-pass welding method. For the arc burn marks on the oil pipeline, they can be repaired by grinding with a grinding wheel or by welding. However, the thickness after the repair must not be less than the minimum thickness allowed by the material standard. 2. Quality Assurance Measures In pressure-sealing operations, the sealing quality directly determines the success or failure of the emergency repair. When using mechanical sealing devices for pipeline rupture repairs, it is necessary to cooperate with a Roots pump to drain the oil and establish an oil seal wall. For the repair of oil theft holes, a pressure-sealing device can be used, and the diameter of the wooden plug needs to match the pipeline pressure. It is worth noting that the "Technical Regulations for Pipeline Repair Operations of the Hafu Joint" being formulated by the China Foundry Association will systematically stipulate the applicable scope, selection, pre-operation preparations, installation steps, and acceptance of construction operations for Hafu joints (which can be quickly repaired without stopping the flow). This will provide unified technical guidance for the quality of Hafu joint repair operations. 3. Pipeline Cutting and Assembly The pipe cutting process requires the removal of the anti-corrosion coating on both sides by 500mm each. For high-pressure pipes with a design pressure greater than 6.4 MPa, mechanical cutting should be used to ensure a smooth cut. The alignment accuracy of the pipe sections after replacement directly affects the welding quality.