For a simple pressure vessel in an air compressor room with a design service life of 10 years, is it necessary to conduct inspections of the vessel during this period?

Statutory Inspection Requirements for Simple Pressure Vessels

In the air compressor room, gas storage tanks are generally classified as pressure vessels. For those that comply with the relevant national safety technical supervision regulations…Simple pressure vesselEquipment defined as such has management requirements that differ from those of ordinary pressure vessels. According to the current safety technical specifications for special equipment, simple pressure vessels, within their recommended design service life (typically 10 years),No statutory periodic inspection of the tank is required.(i.e., no need for routine annual inspections or comprehensive examinations).

Why are tank containers exempt from periodic inspections for 10 years?

The reason why simple pressure vessels are exempt from periodic inspections during their design service life is primarily due to the following factors:

• Relatively simple structureIt typically consists of basic components such as the shell, end caps, and nozzles, with no complex internal components.
• The medium has low hazard.The medium in the air receiver tank of the compressor room is predominantly compressed air, which is non-toxic and neither flammable nor explosive.
• Strict design and manufacturing standards: It has undergone rigorous supervision and inspection during the design and manufacturing stages, with a high safety margin, resulting in an extremely low probability of failure over a 10-year period under normal operating conditions.

Exemption from inspection does not equate to “exemption from oversight”: routine maintenance and verification of safety accessories.

Although the vessel itself is not subject to statutory inspection for ten years, this by no means absolves the user organization of its responsibilities. Routine safety management and the mandatory verification of safety accessories must still be strictly enforced:

• Safety Valve Calibration: The safety valve is the last line of defense against overpressure and is typically required toVerify at least once a year., ensuring that its launch pressure is accurate.
• Pressure gauge verification: Pressure gauges are used to monitor tank pressure in real time and typically requireIt shall be verified at least once every six months.and bears a valid verification‑pass label.
• Daily Wastewater Discharge and Corrosion PreventionCompressed air generated by the air compressor often contains moisture; therefore, the drain valve should be opened regularly to remove accumulated water and prevent severe internal corrosion of the tank. In addition, it is important to monitor whether the external anti-corrosion coating has peeled off.
• Daily inspectionsOperators shall regularly inspect the tank shell welds and nozzle connections for leaks, deformation, or unusual noises.

What should be done after reaching the 10-year design service life?

When a simple pressure vessel reaches its 10-year design service life, the user typically faces two options:

• Direct write-offIf the equipment is severely aged or no longer fit for continued use, it shall be scrapped, and its pressure-bearing capacity shall be compromised (e.g., by cutting holes), while simultaneously completing the deregistration procedures with the special equipment safety supervision and administration authority.
• Apply for a comprehensive inspectionIf the equipment is in good condition and is to remain in service, it must be reported to a qualified special‑equipment inspection agency prior to its expiration date.Comprehensive inspectionOnly after passing inspection may it continue to be used. However, thereafter, the equipment will no longer be exempt from inspection and must undergo regular annual inspections and comprehensive examinations in accordance with the requirements for ordinary pressure vessels.

Standardizing the management of simple pressure vessels in air compressor rooms is not only a matter of regulatory compliance but also a critical cornerstone for ensuring safe production within the enterprise.