I. Unlicensed Operation and Illegal Work
1. Unauthorized Installation or Modification Without Special Equipment Production or Permit For example, in 2025, Zhang, an employee of a food company in Anqiu, Shandong, installed pressure vessels and pipelines without a business license or special equipment production permit. He was investigated and fined 100,000 yuan by the market supervision department. This behavior not only violates Article 18 of the "Special Equipment Safety Law of the People's Republic of China," but also creates hidden dangers such as insufficient structural strength and welding defects due to a lack of professional construction standards.
2. Using Unlicensed Personnel for Special Equipment Operations A hardware factory in Changle County was ordered to rectify and was punished for arranging forklifts to be operated by personnel without forklift operation permits. Similarly, pressure vessel operation must be performed by personnel holding corresponding qualifications such as R1 or R2, and the phenomena of "temporary workers filling in" or "boiler operators also operating" must be eliminated.
II. Malfunctioning or Neglected Management of Safety Accessories
1. Uncalibrated Safety Valves, Damaged Seals, or Blocked Discharge Pipes Safety valves are the last line of defense against overpressure. 1. If pressure gauges are not calibrated for a long period (they should be calibrated annually), rusted and unable to release pressure, or if the discharge pipe is bent and affects pressure relief, the pressure will continue to rise until an explosion occurs.
2. Pressure gauges not calibrated on time, with incorrect range, or malfunctioning pointers. Pressure gauges need to be calibrated every six months, and the range should be 1.5 to 3 times the working pressure. If the instrument is inaccurate, operators cannot determine the true pressure, which can easily lead to misjudgment of the situation.
3. Rupture discs and emergency shut-off devices not replaced or tested regularly. Especially in containers containing flammable or toxic media, these devices must remain sensitive and reliable; otherwise, rapid isolation cannot be achieved in the event of an accident.
III. Violations of operating procedures and loss of parameter control
1. Operating with faulty safety interlock devices. In 2020, a company in Jinan experienced a safety interlock failure in its autoclave. The operator continued to pressurize, ultimately causing the autoclave lid to slip and steam to leak, resulting in two deaths. Any abnormality in protective devices should prompt immediate shutdown; "taking chances" is strictly prohibited.
2. Rapid pressure and temperature increases cause thermal stress damage. Rapid loading can lead to excessive temperature differences between the inner and outer walls of the container, generating significant thermal stress. Prolonged exposure to this can accelerate fatigue crack formation. The pressure increase rate should be controlled (e.g., ≤0.3 MPa/min), especially for high- or low-temperature containers, where slow operation is necessary.
3. Frequent or large fluctuations in operating pressure/temperature. Drastic fluctuations in pressure and temperature can induce alternating stress, reducing the fatigue resistance of materials and causing significant damage to pipes, welds, and other components.
IV. Inadequate equipment condition checks.
1. Failure to inspect for defects before commissioning. Ignoring issues such as deformation, corrosion, bulges, and cracks in the container, or overlooking leaks at flanges and sealing surfaces, can lead to sudden rupture during operation.
2. Failure to confirm the chemical composition and compatibility of the medium. Incorrect filling or introduction of incompatible media (e.g., oxygen and grease) can trigger violent reactions or even explosions. 3. Failure to purge or test oxygen content before entering confined spaces: Entering a container for cleaning without effectively isolating the gas source and analyzing oxygen content greatly increases the risk of asphyxiation.
V. Improper Maintenance and Emergency Response
1. Removing bolts or tightening fasteners under pressure: Forcing operation while the container is still pressurized can cause bolts to break, flanges to fly off, resulting in serious mechanical injuries.
2. Failure to establish an emergency shutdown mechanism: Failure to immediately cut off power, depressurize, and evacuate personnel in cases of overheating, overpressure, leakage, or abnormal noise delays response.
3. Neglecting regular inspections and corrosion monitoring: Approximately 60% of pressure vessel accidents are related to lack of maintenance. Failure to conduct timely internal and external inspections, wall thickness measurements, and non-destructive testing makes it difficult to detect hidden defects.
VI. Lax Implementation of Management Systems
1. Failure to register for use or establish technical files: According to regulations, pressure vessels should obtain a "Special Equipment Use Registration Certificate" within 30 days of being put into use and establish a complete file including design, manufacturing, inspection, and accident records.
2. Failure to establish operating procedures or implement the "two-ticket, three-system" approach: The lack of standardized operating procedures easily leads to misoperation. Start-up and shutdown procedures, parameter control ranges, and abnormal handling measures should be clearly defined.
3. Failure to conduct emergency drills and safety training: Operators lack the ability to respond to emergencies, often resorting to blind rescue efforts in the event of an accident, thus increasing casualties.
