【Safety Management and Standardization of Special Equipment】Which pressure vessels are not governed by the Regulations on Fixed Pressure Vessels? ——Interpretation of 1.5 items and nine categories of exempt equipment

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Ensure proper safety management of special equipment; standardization ensures safety. [Special Equipment Safety Management and Standardization] – Comprehensive summary post! Constantly being updated – feel free to communicate! ! ! https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5718553 (Source: Haichuan Chemical Industry Forum (Hua Haichuan Liu hcbbs)). Everyone is welcome to participate in the discussions. --------------------------------------------------------- In the world of pressure vessels, there is a clear red line – the \"Safety Technical Supervision Regulations for Fixed Pressure Vessels\" (TSG 21-2016, abbreviated as \"Fixed Pressure Vessel Regulations\") which defines the scope of its application. Those within the red line must be subject to strict supervision ； Beyond the red line, there are different reasons for each. Today, we will take a look at the nine types of equipment that are explicitly excluded under Article 1.5 of the Fixed Capacity Regulations – to find out what they are, where they are used, and why they can operate without being subject to these regulations. I. What are mobile pressure vessels, gas cylinders, and oxygen chambers? Mobile pressure vessels: movable pressure-bearing equipment such as railway tank cars, road tank trucks, and tank containers. Gas cylinders: common ones include oxygen cylinders and liquefied gas cylinders. Oxygen chambers: medical hyperbaric oxygen chambers, diving decompression chambers, etc. Purpose and principle: Mobile pressure vessels are used for transporting liquefied gases and compressed gases ； Gas cylinders are used for storing and transporting various gases ； An oxygen chamber increases the pressure inside it, thereby raising blood oxygen levels, and is used to treat hypoxic diseases, decompression sickness, and other conditions. Execution standards: Mobile pressure vessels: TSG R0005 \"Regulations on Safety Technical Inspections of Mobile Pressure Vessels\"; Gas cylinders: TSG 23 \"Regulations on Safety Techniques for Gas Cylinders\"; Oxygen chambers: GB/T 19284 \"Medical Oxygen Compression Chambers\", etc. Why are they not included in the \"Regulations on Fixed Pressure Vessels\"? Because they are “too liquid.” The full name of the “Fixed Pressure Vessels Regulations” is the Regulations for Fixed Pressure Vessels, which are specifically designed for equipment that does not move. Mobile devices have their own separate regulatory system, with each having its own “registration record”. II. What are military equipment, nuclear facilities, aerospace vehicles, railway locomotives, marine facilities and ships, as well as pressure vessels used in underground mines? This is a list of \"special industries,\" including: Military equipment: tanks, pressure systems on warships. Nuclear facilities: pressure vessels in nuclear reactors. Aerospace vehicles: rocket fuel storage tanks, aircraft hydraulic systems. Railway locomotives: boilers and gas tanks on locomotives. Offshore facilities: pressure vessels on offshore platforms. Ships: marine boilers, pressure tanks. Underground mines: air compressor storage tanks underground, etc. Purpose and principle: Each has its own purpose, but they all share the common feature of being part of a larger system that serves specific industry needs. Implementation standards: Different industries have their own standards; for example, nuclear facilities adhere to nuclear safety regulations, while military industries follow the GJB national military standards. Why not include it in the Solid Waste Regulations? Article 100 of the Special Equipment Safety Law explicitly stipulates: “The supervision and management of the safety of special equipment used in military equipment, nuclear facilities, and aerospace vehicles are not governed by this Law.” ”-7 These areas either relate to **security** or already have stricter industry regulatory frameworks, and therefore are not included in the scope of regulation for general consumer equipment. III. What are containers with a normal operating working pressure of less than 0.1 MPa? It refers to those containers whose pressure is below 0.1 MPa (approximately equal to 1 atmosphere) under normal operation, including some devices that are subjected to pressure briefly during feeding or discharging. Purpose and principle: Such containers are commonly used for storage at atmospheric pressure and reactions under atmospheric pressure. Although pressure may be experienced momentarily during feeding or discharging, the pressure is low under normal operating conditions, so the risk is limited. Why not include it in the Solid Waste Regulations? The first item in the scope of application of the Fixed Volume Regulations is “operating pressure greater than or equal to 0.1 MPa”-1. If the pressure is below this threshold, it falls outside the definition of a \"pressure vessel\" and therefore is not subject to regulation. IV. What is a pressure chamber that forms an integral part of, or serves as a component in, mechanical equipment with rotational or reciprocating motion? Including pump casings, compressor housings, turbine housings, hydraulic cylinders, paper machine rolls, etc. Purpose and principle: Pump casing: Houses the impeller and directs fluid flow. Compressor housing: Houses the compression mechanism and withstands the pressures during compression. Hydraulic cylinder: Converts hydraulic energy into mechanical energy to drive the piston. Paper machine rolls: Pressure rollers used in the papermaking process. Compliance standards: These components generally comply with their respective product standards. Why not include it in the Solid Waste Regulations? They are “part of the machine,” not separate pressure vessels. GB 150-1998 \"Steel Pressure Vessels\" explicitly stipulates that it is not applicable to \"pressure vessels that form an integral part or serve as components in mechanical equipment with rotational or reciprocating motion\"-3. The Fixed Volume Regulations also adopt this principle, treating them as components of mechanical equipment rather than separate containers. V. What are plate heat exchangers, spiral plate heat exchangers, air-cooled heat exchangers, and cooling coils? Plate heat exchangers: Composed of a series of metal plates stacked together, with channels formed between the plates for heat exchange. Spiral plate heat exchangers: Made by rolling two parallel steel plates into a spiral shape, creating two spiral channels. Air-cooled heat exchangers: Air-cooling devices that use air as the cooling medium. Cooling coils: Cooling systems made up of arranged tubes, commonly found in cold storage facilities. Purpose and principle: All of these are devices used for heat exchange, but they differ in terms of structure. Plate and spiral plate types are compact with high heat transfer efficiency ； Air-cooled type is suitable for water-scarce areas ； Cooling exhaust pipes are commonly used in refrigeration systems. Execution standards: Plate heat exchangers: GB/T 29466-2023 \"Plate Heat Exchanger Units\" and other standards; Spiral plate heat exchangers: NB/T 47048 \"Spiral Plate Heat Exchangers\"; Air-cooled heat exchangers: NB/T 47007-2018 \"Air-Cooled Heat Exchangers\". Why are they not included in the \"Solid and Liquid Equipment Regulations\"? Although these heat exchangers may be able to withstand pressure, they have a special structure, and their failure mode is usually \"leakage\" rather than \"explosion\"; their risk characteristics differ from those of conventional pressure vessels. As early as in the 2010 version of the \"Regulations on Safety Inspection of Pressure Vessels,\" \"shellless coil exchangers, corrugated plate exchangers, air-cooled exchangers, and cooling tubes\" were included in the categories that are not covered by these regulations. VI. What are steam heating coils in atmospheric-pressure vessels and tubular heating furnaces in process equipment? Steam heating coil: A coil installed inside a pressure-free container, through which steam is passed to heat the material. Tubular heating furnace: A device in which furnace tubes are arranged within the furnace chamber, with the flame directly heating the material inside the tubes. Purpose and principle: The heating coil is used for indirect heating of pressure-free storage tanks and reaction tanks ； Tubular heating furnaces are core heating equipment in oil refining and chemical processing units, such as atmospheric and vacuum distillation furnaces, delayed coking furnaces, and hydrogenation reaction feed furnaces, etc. -5. Execution standards: Tubular heating furnaces shall comply with industry standards such as SH/T 3036 \"Flame Heating Furnaces for General Oil Refining Plants\" and Q/SY 06508.2 \"Technical Specifications for Industrial Furnaces in Oil Refining and Chemical Engineering\". Why not include it in the Solid Waste Regulations? Although the heating coil is subject to pressure, it is attached to a container at atmospheric pressure, so the risks are relatively controllable ； Tubular heating furnaces are part of the category of \"process equipment\"; they are devices that are directly heated by flames, and they have their own set of industry standards – they are not regulated as conventional pressure vessels. VII. What are fully enclosed combined electrical apparatuses specifically used in the power industry (such as capacitor pressure vessels)? Fully enclosed switchgear used in power systems is filled with insulating gas (such as SF6) inside, and its enclosure can withstand pressure. Purpose and principle: It is used for the control and protection of high-voltage power systems. It combines circuit breakers, isolating switches, grounding switches, transformers, etc. within a sealed metal enclosure filled with high-voltage insulating gas, offering a compact design and high reliability. Execution standards: Adhere to industry standards for electricity, such as GB 7674 \"Gas-insulated metal-enclosed switchgear with a rated voltage of 72.5 kV and above\" and others. Why not include it in the Solid Waste Regulations? This is specialized equipment for the power industry, with a well-established set of industry standards; it falls under the category of electrical equipment and is not regulated as a pressure vessel. VIII. What are tire vulcanizing machines and pressure-resistant rubber molds used in the rubber industry? Tire vulcanizing machine: A specialized device used for vulcanizing tires; it uses heat and pressure to vulcanize the raw rubber. Rubber mold: A mold that is used to vulcanize rubber products. Purpose and principle: The tire vulcanizing machine places the raw tire inside the mold, and through heat and pressure, the rubber is vulcanized to form a finished tire with elasticity and strength. The inside of the mold is subjected to high pressure to ensure precise product shape and size. Execution standards: Adhere to the industry standards for rubber machinery, such as HG/T 3229 \"Testing Methods for Tire Vulcanizing Machines\", etc. Why not include it in the Solid Waste Regulations? This is specialized process equipment for the rubber industry; although it can withstand pressure, it belongs to mechanical equipment rather than a separate pressure vessel, and there are specific industry standards that govern it. IX. What are plastic pressure vessels without reinforcement? A pressure vessel made entirely of plastic, without any reinforcement such as fiber reinforcement. Purpose and principle: It is used in applications with high corrosion requirements but low pressure, such as certain chemical storage tanks and water treatment equipment. Implementation standards: Different product types are subject to different national standards; why aren’t they included in the “Solid Waste Regulations”? The Fixed Capacity Regulations are primarily aimed at metal pressure vessels. The material properties, aging patterns, and failure modes of plastic containers differ significantly from those of metal containers, and they are mostly used in low-pressure applications; therefore, they are not included within the scope of regulation for special equipment. Conclusion: After reviewing these nine types of equipment, you may notice a pattern: the scope of application of the \"Fixed Capacity Regulations\" follows the principle of \"risk-based approach and specialized responsibility assignment.\" It could be due to different risk characteristics (such as the tendency of heat exchangers to leak), existing specific regulations (such as those for gas cylinders and mobile containers), industry-specific conditions (such as in the military or nuclear sectors), parameters that do not meet standards (such as pressure below 0.1 MPa), or special structural features (such as machine components) – each case has its own rationale and corresponding \"exemption“. Understanding these exceptions helps us to more accurately determine the regulatory boundaries for pressure vessels, and it also makes it clear that the safety regulation of special equipment is by no means a one-size-fits-all approach; rather, it involves detailed risk management.