Issue 1:Principles, definitions, scope of application, and classification levels of TSG 31-2025 “Safety Technical Regulations for Industrial Pipelines”

I. Date of publication and implementation

1. Release date: September 22, 2025

2. Implementation:January 1, 2026

3. Explanation of Permissions: State Administration for Market Regulation

4. Repeal of the regulation:

"Regulations on Safety Technical Supervision of Pressure Pipelines — Industrial Pipelines" (TSG D0001-2009)

"Rules for Periodic Inspection of Pressure Pipelines — Industrial Pipelines" (TSG D7005-2018)

II. Principles for Formulation

1. TSG 31-2025 “Industrial Pipeline Safety Technical Regulations”, abbreviated as “...”Industrial regulations”;

In accordance with the "Special Equipment Safety Law of the People's Republic of China", the "Regulations on the Safety Supervision of Special Equipment", and the "Catalogue of Special Equipment", and based on safety technical specifications such as TSG D0001-2009, the "Rules for the Supervision and Inspection of Pressure Pipelines", and the "Rules for the Periodic Inspection of Pressure Pipelines – Industrial Pipelines", it is necessary to merge and clarify the logical relationships, unify the relevant requirements, and further establish comprehensive safety technical specifications specifically for industrial pipelines;

3. Adjusted the administrative licensing regulations pertaining to various aspects; incorporated the basic safety requirements for industrial pipelines outlined in relevant documents in recent years, and made necessary adjustments to address issues that were identified during the implementation process;

4. The scope of application for industrial pipelines was further clarified, and specific safety technical requirements were added for power pipelines, refrigeration pipelines, non-metallic pipelines, high-pressure pipelines, as well as airport fuel supply pipelines;

5. Add requirements related to supervision and inspection, and clarify the scope of manufacturing supervision and inspection as well as installation supervision and inspection.

6. It is necessary to clarify the coordination between reference standards and safety technical specifications. Relevant national or industry standards should be directly cited, so as to avoid duplicate stipulations regarding technical details and other aspects. (It is essential for practitioners to thoroughly study the knowledge related to these standards and apply it in practice.)

III. Definition of pressure pipelines

Pressure pipelines refer to tubular devices that utilize certain pressures to transport gases or liquids. These pipelines are defined as those with a working pressure of 0.1 MPa (gauge pressure) or higher, transporting gases, liquefied gases, steam, or flammable, explosive, toxic, corrosive substances, or liquids whose working temperature is 100°C or higher at standard pressure, and whose nominal diameter is 50 mm or larger. This definition does not apply to pipelines and equipment with a nominal diameter of less than 150 mm and a working pressure of less than 1.6 MPa (gauge pressure), which are used to transport non-toxic, non-flammable, and non-corrosive gases. The safety supervision and management of oil and gas pipelines shall also be carried out in accordance with laws and regulations such as the "Work Safety Law" and the "Oil and Gas Pipeline Protection Law".

<Excerpted from Announcement No. 114 of 2014, "Catalogue of Special Equipment">

IV. Scope of Application

1. Industrial pipelines that meet the definition in the “Catalogue of Special Equipment” and simultaneously satisfy the following conditions:

1) The working pressure must be ≥0.1 Mpa (gauge pressure) and must not exceed 100 Mpa (Note 1).

2) The nominal diameter is ≥50 mm;

3) The medium being transported is gas, liquefied gas, steam, or a liquid that is flammable, explosive, toxic, corrosive, and/or whose operating temperature is equal to or higher than its standard boiling point.

2. Industrial pipelines (hereinafter referred to as pipelines) include process pipelines belonging to process equipment, auxiliary equipment, and utility systems within boundary areas (Note 2); they also include power pipelines used in thermal power plants to transport steam and steam-water mixtures, as well as refrigeration pipelines.

Note 1:***Pipelines with a working pressure of 42 Mpa or higher are collectively referred to in these regulations as high-pressure pipelines.

Note 2:Generally, isolation valves serve as the demarcation point between industrial pipelines, long-distance pipelines, and public pipelines. Within oil and gas transmission stations, the boundary between process pipelines and main pipelines is usually determined by the inlet and outlet isolation valves; alternatively, this boundary can be established by the pipeline operator itself.

3. Special Provisions:

1) The process pipelines within oil and gas transmission stations in long-distance pipeline systems, as well as the airport fuel supply pipelines (Note 3), shall be constructed in accordance with these regulations;

2) Low-temperature insulation pipes, pipes inside cold storage containers (including those inside low-temperature pump enclosures), sleeved pipes, pipes inside mother-and-child tanks, as well as other sections of pipes or pipe systems that are concealed in structure or are not suitable for disassembly and inspection during their service life must comply with the provisions of these regulations.

Note 3:The airport fuel supply pipelines include those connecting the airport fuel tanks and those used for refueling on the runway.

4. Scope of non-applicability

1) Pipelines for military equipment and nuclear facilities;

2) Pipelines in offshore facilities and underground mines;

3) Special pipelines on mobile devices, such as those used in railway locomotives, automobiles, ships, aerospace vehicles, etc.;

4) Pipelines for the exploration, development, and extraction of petroleum, natural gas, geothermal energy, etc., as well as pipelines for the collection and transportation of oil and gas in oil and gas fields;

5) Pipelines with a nominal diameter of less than 150 mm and a working pressure of less than 1.6 Mpa (gauge pressure), used for transporting non-toxic, non-flammable, and non-corrosive gases (excluding liquefied gases, steam, and oxygen);

6) Pipelines to which the equipment itself is connectedNote 4) 。

Note 4: Internal pipelines of pumps and compressors (except for the pipes connecting multiple stages on-site), as well as the external pipe connections of such equipment; likewise, this applies to internal pipelines of steam turbines, gas turbines, internal combustion engines, refrigeration units, quick-freezing devices, and other equipment used for transporting or processing fluids.

V. Definition of the scope of the pipeline system

The pipelines covered by these regulations include pipeline components, pipeline supports, connectors, mechanical safety interlock devices, and instruments.

1. Pipeline components refer to parts that are used to connect or assemble into a sealed pressure pipeline system. These components include pressure pipeline elements, safety devices, as well as pipe fittings made of non-ferrous metals (or their alloys), cast pipe fittings, flexible joints, pressure-resistant hoses, fasteners, low-temperature insulation pipes, directly buried jacket pipes, sight glasses, and throttling devices used in pipelines (such as orifice plates), etc. (Note 5);

2. Pipe supports, including hangers, spring-loaded supports, diagonal tie rods, counterweights, adjustable bolts, support rods, chains, guide rails, saddles, bases, rollers, brackets, sliding supports, lifting lugs, pipe hangers, clamping rings, pipe clamps, U-shaped clips, and clamping plates, etc.;

3. Connection joints, including those between pipeline components, the joints that connect pipelines to equipment or devices (such as welds, flanges, seals, and fasteners), as well as the joints that connect pipelines to non-compressed components;

4. Mechanical safety interlocking devices and instruments.

Note 5:

1) Pressure pipeline components include pipes, fittings, valves, flanges, compensators, sealing elements, as well as special components for pressure pipelines. Special components for pressure pipelines refer to anti-corrosion components and combined devices made up of these components. Combined devices are those that consist of pipes, fittings, valves, flanges, compensators, sealing elements, etc., combined together through welding, flange connections, or other methods to perform a specific function. Examples include gas pressure regulating devices, temperature and pressure reducing devices, flame arresters, flow meters (with their enclosures) (Note 6), and prefabricated pipe sections manufactured in factories (Note 7);

2) Safety accessories refer to safety valves, rupture disc devices, and emergency shut-off valves used on pipelines.

Note 6:A flowmeter “housing” refers to the casing made of pipes, rolled tubes, castings, forgings, flanges, pipe fittings, etc., which is manufactured through mechanical processing or welding in order to withstand the pressure of the medium inside the flowmeter.

Note 7: Prefabricated pipe segments in a factory setting refer to pipe components that are manufactured by the manufacturer in a factory according to the constructiondesign drawings. These components are assembled by welding or flanging pressure pipe parts together before being shipped out. Examples include manifold assemblies, filters, separators, condensate tanks, strainers, mixers, buffers, ball transfer tanks, insulating joints, and manifolds. This definition does not include pipe prefabrication that takes place at the construction site.

VI. Classification of pipeline grades

1. Principles of division:

Classification is based on design pressure, design temperature, the toxicity of the medium, its corrosiveness, and its fire hazards.

2. Classification method: Divided into GC1, GC2, and GCD levels.

1) GC1 level

Process pipelines that transport media classified as Acute Toxic Hazard Category 1, Acute Toxic Hazard Category 2 gases, or Acute Toxic Hazard Category 2 liquids whose operating temperatures exceed their standard boiling points, as specified in GB/T 42594 “Guidelines for the Classification of Media Hazards in Pressure Equipment”;

Process pipelines that transport flammable gases of Category 1 and Category 2 as specified in GB/T 42594 (including chemically unstable gases of Category A and Category B), as well as flammable liquids of Category 1 and Category 2, and whose design pressure is greater than or equal to 4.0 Mpa;

Process pipelines that transport fluid media, and for which the design pressure is greater than or equal to 10.0 Mpa, or for which the design pressure is greater than or equal to 4.0 Mpa and the design temperature is greater than or equal to 400°C.

2) GC2 level

Process pipelines and refrigeration pipelines other than those classified as GC1 grade.

3) GCD level

Power pipelines.

3. For detailed classification, please refer to Appendix A “Classification of Industrial Pipelines Based on the Toxicity, Corrosiveness, and Fire Hazard of Their Contents.”