Notice on Strengthening the Safety Management of High-Temperature and High-Pressure Pipelines and Pressure Vessels to Prevent Explosions of Pressure Equipment

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This post was last edited by Zhizhi Ming on 2016-8-24 08:14. Notice on Strengthening the Safety Management of High-Temperature and High-Pressure Pipelines and Pressure Vessels to Prevent Explosions of Pressure Equipment, Guodian Jisheng [2016] No. 244. On August 11, 2016, during the commissioning phase of the thermal power project at Madian Gangshi Power Generation Co., Ltd. in Dangyang City, Hubei Province, a high-pressure steam pipeline ruptured, resulting in steam leakage and severe casualties as a consequence of the accident. All units must thoroughly learn from the lessons of these accidents, and effectively strengthen the management of pressure-bearing equipment such as pressure vessels and high-temperature, high-pressure pipelines, in order to prevent similar incidents from occurring. I. Strictly control the quality of equipment. All units should strengthen source control by conducting a comprehensive inspection of the material quality, manufacturing standards, and installation quality of pressure-bearing equipment in use, especially those high-temperature and high-pressure pipelines as well as pressure vessels that have been put into operation recently. Thoroughly examine key stages such as procurement and supply, quality inspection, and construction acceptance, and verify relevant documents and materials (including relevant contracts, import customs declarations, inspection and quarantine certificates for incoming goods, inspection reports issued by the entry/exit inspection and quarantine authorities, quality certification documents from manufacturers, quality certification documents from piping manufacturers, construction acceptance documents, and technical supervision documents). Pressure equipment that lacks complete documentation, whose material or specifications do not meet standards, or whose performance is poor according to safety and quality assessments must be replaced immediately to completely eliminate potential safety hazards. II. Strengthen supervision and inspection. All units must carry out proper technical supervision work. In addition to undergoing the safety performance inspections of pressure vessels by the relevant authorities as required, all pressure-bearing equipment such as high-temperature and high-pressure pipelines should be subject to regular inspections in accordance with established procedures (including visual inspections, weld flaw detection, wall thickness measurement, hardness testing, and metallographic analysis). In particular, attention should be paid to checking for thermal fatigue on the inner surface near the steam inlet, as well as erosion and corrosion in the sections of the heater drain pipes. During equipment maintenance, special attention is paid to checking for defects that could cause leakage in pressure-bearing components due to expansion and mechanical factors. After the installation or replacement of equipment, heat treatment and weld inspection must be carried out in accordance with specifications. Regularly calibrate safety doors (valves) and pressure gauges as required to ensure accurate readings and reliable operation. Before being put into use, boiler and pressure vessels must undergo registration procedures as required and obtain a permit for use. III. Strengthen operation and maintenance. Strengthen the control of boiler load and water level to prevent overheating due to water shortage, as well as sudden pressure increases caused by a drop in load. Strengthen water treatment supervision to ensure the quality of steam and water, prevent corrosion and scaling, and enhance regular blowdown of boilers to maintain smooth operation in all circulation circuits. Strengthen the inspection of the tubes outside the furnace; for phenomena such as tube system vibration, water hammer, restricted expansion, and insulation detachment, the causes should be carefully analyzed and measures taken promptly. If there is steam or water leakage from the tubes outside the furnace, it is necessary to identify the cause as soon as possible and take appropriate actions; if isolation from the system is not possible, the furnace should be shut down immediately. Proper technical training and accident scenario planning should be carried out to enhance the operational skills of staff and their ability to handle abnormal situations, thereby ensuring that no pressure spikes in the system occur as a result of mistakes or improper operations. IV. Ensure personal safety. Operators conducting on-site inspections must wear appropriate safety protective equipment as required, and no one shall stay for long periods in areas with weak pressure resistance such as boiler manholes, expansion joints connecting the furnace, and explosion-proof doors. During the operation of the boiler, welding operations on pressure-bearing components are not permitted, nor are repairs to seal leaks while the boiler is under pressure. The boiler safety valves, PCV valves, and vent valves shall be calibrated; when conducting pressure tests on the pressure-bearing components, relevant safety measures must be established and strictly implemented.