In factory workshops, construction sites and even laboratories, silver or black compressed air pipelines crisscross like "blood vessels" in industrial production, silently conveying the source of power. However, these seemingly ordinary pipelines may have completely different identities-some are just ordinary industrial facilities, while others are listed as special equipment under strict supervision by the state. This is not a simple judgment question, but a technical and legal red line related to safety, compliance and responsibility. It is very important to clarify whether the compressed air pipeline belongs to special equipment to ensure the safety of people's lives and property and ensure the legal operation of enterprises.

I. Core Definition: Legal Standards for Special Equipment

To judge the identity of compressed air pipeline, we must first rely on the authoritative national laws and regulations. China's "Special Equipment Safety Law" and its core technical specification "Safety Technical Supervision Regulations for Fixed Pressure Vessels" (TSG 21-2016) have a clear and rigorous definition of "pressure pipeline".

According to the regulations, industrial pipelines that meet the following three conditions at the same time are classified as "pressure pipelines" within the supervision scope of special equipment:

Working pressure ≥ 0.1 MPa (gauge pressure): this is about equal to more than 1 standard atmospheric pressure. The supply pressure of most industrial compressed air systems is much higher than this value, such as 0.7 MPa and 0.8 MPa, so the pressure condition is usually the easiest to meet.

Nominal diameter ≥ 50 mm: This refers to the nominal size of the internal diameter of the pipeline. DN50 is an important dividing line. Pipes smaller than this specification, no matter how high the pressure is, are not included in the category of "pressure pipes" in special equipment for supervision in principle.

Used to transport gas medium: compressed air is a typical gas medium.

The key lies in the word "and"-the three elements of "pressure ≥0.1MPa", "diameter ≥DN50" and "conveying gas" must be met at the same time, which are indispensable. This is a hard boundary defined by laws and technical norms.

Second, common misunderstandings: which pipelines are "not" special equipment?

Based on the above standards, a large number of common compressed air pipeline application scenarios are actually not special equipment:

Gas pipe network for terminal: the terminal pipe branched from the main gas pipe of the workshop and connected to specific pneumatic tools and equipment (such as air guns, spray guns and fixtures). Its pipe diameter is usually small (such as DN15 and DN25). Although the pressure meets the requirements, it is not a special equipment because its nominal diameter is less than DN50.

Small independent system: some small laboratories, maintenance rooms or independent equipment have their own micro air compressors and their supporting pipelines. If the overall specifications of the system pipelines are less than DN50, the whole pipeline system is not regulated (but the air compressor itself may be used as a pressure vessel and needs to be judged separately).

Specific process pipeline with internal pressure always lower than 0.1MPa.

Understanding these exclusions will help enterprises focus on management priorities accurately and avoid waste of resources caused by excessive supervision.