Periodic inspection of pressure pipelines refers to the conformity verification activity carried out by legally qualified inspection agencies and inspectors, in accordance with relevant national laws, regulations, safety technical specifications, and technical standards, following specified cycles and inspection methods, to assess the safety status of pipelines. Its core objective is to timely identify potential safety hazards that may arise during long-term operation, such as corrosion, wear, fatigue, material degradation, and propagation of welding defects, to scientifically evaluate the current safety status of pipelines, and to propose targeted corrective and maintenance recommendations, ensuring that pipelines remain in a safe and controllable operating condition, thereby preventing safety accidents at the source.
Testing Products
Refers to in-service pressure pipeline systems and associated components that, as defined by regulatory standards, require periodic safety performance verification. This covers:
DD2 Public Pipelines: Gas pipelines, thermal pipelines (heating networks)
DD3 Industrial Pipelines: Process pipelines, power pipelines, refrigeration pipelines
Testing Items
Macroscopic (Visual) Inspection:
Visual inspection, using tools when necessary, of pipeline structure, geometric dimensions, surface conditions (e.g., cracks, corrosion, leaks, deformation), as well as welded joints, anti-corrosion coatings, and thermal insulation layers.
Wall Thickness Measurement:
Ultrasonic thickness measurement is generally used for wall thickness determination of pressure pipelines.
Safety Accessory Inspection:
Mainly includes safety valves, rupture discs, and safety interlock devices for quick-opening pressure vessels.
Surface Defect Detection:
Using test methods specified in NB/T 47013.
Buried Defect Detection:
Using radiographic or ultrasonic testing methods; when these cannot be performed on-site, other effective test methods may be used.
Material Analysis:
Depending on the specific circumstances, analysis can be performed using chemical analysis, spectroscopic analysis, hardness testing, metallographic analysis, etc., as required.
Pressure Strength Check:
Performed following the requirements of relevant pipeline design standards.
Stress Analysis:
Conducted when deemed necessary by inspectors or the user.
Pressure Test:
If there is doubt about the safety condition of a pipeline during the periodic inspection, a pressure test shall be conducted.
Leak Test:
For pipelines conveying media classified as extremely hazardous or highly hazardous, or where zero leakage is required by design, a leak test shall be conducted.
Testing Standards
Law of the People’s Republic of China on Safety of Special Equipment
Regulation on Safety Supervision of Special Equipment (State Council Order No. 549)
Safety Technology Supervision Regulation for Pressure Pipelines – Industrial Pipelines (TSG D0001-2009)
Periodic Inspection Regulation for Pressure Pipelines – Industrial Pipelines (TSG D7005-2018)
Periodic Inspection Regulation for Pressure Pipelines – Public Pipelines (TSG D7004-2010)
Non-destructive Testing of Pressure Equipment (NB/T 47013-2015)
Pressure Piping Code – Industrial Piping (GB/T 20801.1~6-2020)
Pressure Piping Code – Public Piping (GB/T 38942-2020)
Service Advantages
In the field of periodic inspection of pressure pipelines, our organization provides full-process, high-quality inspection services for clients across various industries, leveraging a comprehensive qualification system, a professional technical team, and an efficient service model. Our core strengths can be summarized in the following five dimensions, fully meeting the needs of equipment safe operation and enterprise production:
I. Comprehensive Qualification System:
We have obtained a Class B Testing Institution Certificate assessed by the China Special Equipment Inspection Association, and a Special Equipment Class A B1 Inspection Institution Approval Certificate issued by the Shaanxi Provincial Administration for Market Regulation. We are qualified to conduct periodic inspections of pressure pipelines (DD2 public pipelines: gas pipelines, thermal pipelines; DD3 industrial pipelines: process pipelines, power pipelines, refrigeration pipelines). We also possess NDT capabilities including RT (including DR), UT, MT, PT, TOFD, PAUT, and ECT.
II. Professional Technical Team:
Our team brings together many industry elites deeply engaged in the field of special equipment inspection and testing, including several senior special equipment inspection experts and young technical leaders. We have dozens of special equipment inspectors and over one hundred NDT personnel, relying on profound professional knowledge and practical experience to provide clients with an exceptional service experience.
III. Advanced Equipment and Methods:
We are equipped with internationally leading testing equipment, totaling over 280 sets, including X-ray flaw detectors, pipe crawlers, digital ultrasonic flaw detectors, phased array ultrasonic flaw detectors, TOFD ultrasonic flaw detectors, DR digital radiography detectors, eddy current detectors, spectrometers, buried pipeline coating detection systems (PCMX), underground pipeline locators (RD8200), close-interval potential (CIPS) survey systems, direct current voltage gradient (DCVG) testing systems, and electronically controlled high-definition endoscopes.
IV. Broad Business Coverage:
Our projects span petrochemical refining, chemical plant installations, coal chemical projects (coal-to-liquid, coal-to-gas, coal-to-methanol, etc.), long-distance transmission pipelines and surface gathering projects (oil and gas transmission), urban pipeline network projects (heating networks, natural gas networks), gas filling station/LPG station pipeline projects, storage projects (spherical tanks, storage tanks, cryogenic tanks), power plant projects, food/pharmaceutical/cement/glass processing/fertilizer/gas manufacturing/military manufacturing plant projects, as well as hotel/hospital projects with self-provided boilers.
The scope of work for the above projects includes third-party or fourth-party NDT and periodic inspection of pressure vessels/pipelines for new construction, repair and maintenance, and in-service inspections. Based on client needs, we also conduct specialized inspections and tests on metallic materials, including spectroscopic analysis (chemical element analysis), hardness testing, metallographic examination, wall thickness measurement, mechanical property testing, and physical property testing. Additionally, we perform annual inspections of pressure pipelines/pressure vessels within the scope of our special equipment inspection authorization, as well as commissioned inspections for equipment exceeding their design service life.
V. Extensive Geographic Coverage:
Our company's service projects cover multiple provinces and autonomous regions, including Shaanxi, Gansu, Ningxia, Inner Mongolia, and Xinjiang.
