What pressure level of an air compressor qualifies it as special equipment? Understand the regulatory standards in one article.

The Difference Between an Air Compressor Head and an Air Receiver Tank

Before examining whether air compressors fall under the category of special equipment, it is first necessary to clarify a core concept:The air compressor host itself is not classified as special equipment.. Relevant state authorities implement catalog-based management for special equipment; air compressors, as general-purpose mechanical equipment, are not included in the “Catalog of Special Equipment.” However, the auxiliary components integrated into air compressor systems…Gas storage tank (pressure vessel)andPressure pipelineWhen specific parameter requirements are met, they are strictly brought under the regulatory scope of special equipment.

Gas storage tanks are one of the three mandatory criteria for special equipment.

According to the “Catalogue of Special Equipment” and the “Safety Technical Supervision Regulations for Stationary Pressure Vessels,” the air receiver tank accompanying an air compressor must…Simultaneously satisfyThe following three conditions must be met for an item to be classified as special equipment (pressure vessel):

• Work stress:Maximum working pressure greater than or equal to0.1MPa(Gauge pressure).
• Volume and Dimensions:Volume greater than or equal to0.03m³ (i.e., 30 liters)and the inner diameter (for non-circular cross-sections, the maximum geometric dimension of the inner boundary of the cross-section) is greater than or equal to150mm.
• Medium in which it is contained:The contained medium is a gas, a liquefied gas, or a liquid whose maximum operating temperature is greater than or equal to its standard boiling point.

Since the medium inside an air compressor’s receiver tank is compressed air (a gas), as long as its working pressure and volume meet the aforementioned standards, it is classified as special equipment and must be subject to stringent safety supervision.

Special Administrative Provisions for Simple Pressure Vessels

In practical industrial applications, many small air compressors are equipped with “simple pressure vessels.” Although these types of gas storage tanks also fall under the scope of the special equipment catalog, they benefit from certain administrative simplification measures. Typically, simple pressure vessels must meet the requirement that their design pressure is less than or equal to 1. 6MPa, specific technical conditions such as a volume of 1,000 L or less.

For gas storage tanks that comply with the standards for simple pressure vessels, enterprises should pay attention to the following when managing them:

• No special equipment use registration is required.
• During the design service life, periodic inspections of special equipment are generally not required.
• Upon reaching its designed service life, it shall be scrapped; if continued use is required, it must undergo inspection and assessment by a qualified professional organization.

Recommendations for Enterprises on the Compliant Use of Air Compression Systems

To ensure production safety and compliance with national regulations, enterprises should undertake the following measures when procuring and operating compressed air systems:

• Verify nameplate parameters:When purchasing a gas storage tank, carefully verify the design pressure, volume, and other parameters listed on the equipment’s nameplate, and confirm whether it qualifies as a special‑purpose pressure vessel or a simple pressure vessel.
• Registration for Use:For gas storage tanks subject to routine special equipment supervision, a registration for use must be filed with the local special equipment safety supervision and administration authority prior to commissioning or within the prescribed time limit after commissioning, and a certificate of registration for use must be obtained.
• Regular Inspection and Maintenance:Apply for periodic inspections in strict accordance with the prescribed schedule, and conduct regular checks of safety valves, pressure gauges, and other safety accessories during routine operation to ensure their sensitivity and reliability.
• Establish a safety file:Establish a complete safety technical file for each gas storage tank classified as special equipment, including design documents, certificates of product quality compliance, and periodic inspection reports.