Requirements for the layout and selection of flame arresters in pipeline accessories of the petrochemical industry

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1. Part 3 of the \"Technical Specifications for the Design of Process System Engineering – Installation of Flame Arresters\" (HG/T20570.19-95), Installation of Flame Arresters: 3.0.1.1 The installation of flame arresters in oil storage tanks shall be carried out in accordance with the provisions of the \"Design Code for Oil Depots\" (GBJ74-84). 3.0.1.2 On storage tanks (and tank trucks) for chemical oils with a flash point ≤ 43°C, a flame arrester shall be installed on their direct venting pipes (including venting pipes equipped with breather valves). 3.0.1.3 When the maximum operating temperature of the material in the storage tank (and tank truck) is greater than or equal to the flash point of that material, a flame arrester shall be installed on its direct venting pipeline (including the venting pipeline equipped with a breather valve). The maximum operating temperature must take into account factors such as changes in ambient temperature, sunlight exposure, and uncontrolled heating elements. 3.0.1.4 A flame arrester shall be installed on the vent collection pipe of the combustible gas online analysis equipment. 3.0.1.5 A flame arrester shall be installed on the exhaust pipe of internal combustion engines entering explosive hazardous areas. 3.0.1.6 Other situations where it is necessary to install a flame arrester. 3.0.2 Installation of pipeline flame arresters
3.0.2.1 For pipelines transporting explosive gas mixtures that may undergo deflagration or detonation (potential accident scenarios should be considered), a pipeline flame arrester shall be installed at the inlet of the receiving equipment. 3.0.2.2 For pipelines transporting gaseous materials that can decompose explosively on their own and cause flame propagation (such as acetylene), a pipeline flame arrester shall be installed at the inlet of the receiving equipment or at the location determined through testing to be most effective in preventing explosions. 3.0.2.3 A flame arrester or flame suppression device should be installed before the flare emission gases enter the flare tip. 3.0.2.4 Other situations where pipe flame arresters should be installed. Part 4: Selection of flame arresters ； Part 5, Precautions for installing flame arrestors. 2. Article 11.2 of the “Code for Design of Layout of Metal Pipelines in Petrochemical Industries” (SH3012-2011): Layout of flame arresters. 11.2.1 The pipeline flame arresters installed on the main fuel gas pipeline of the heating furnace should be located near the heating furnace to facilitate maintenance; the distance between these pipeline flame arresters and the burners should not exceed 12 meters. 11.2.2 The flame arrestor for the storage tank shall be installed directly on the pipe outlet at the top of the tank. 11.2.3 The flame arrester of the atmospheric vent pipeline should be installed at the end of the pipeline. 3. Article 14.6.5 of the \"Code for Design of Industrial Metal Piping (2008 Edition)\」(GB50316-2000) requires the installation of fire arrestors. 14.6.5.1 Pressure-reduced pipelines for Class B gases connected to open-flame equipment, including flare pipelines ； 14.6.5.2 When it is necessary to isolate flammable pipes (including vent pipes) from the equipment they are connected to. 4. Article 5.0.1 of the \"Standards for Selection, Inspection, and Acceptance of Flame Arresters for Petrochemical and Oil Pipelines\" (SH/T 3413-2019): Where there is a possibility of the presence of explosive mixtures and no other facilities are available to prevent the spread of flames, flame arresters shall be installed in the following pipeline systems and containers: a) Combustible gas delivery pipelines connected to burners ； b) Open vent for the gas space of storage tanks or containers containing explosive gases ； c) Branch pipes of the gas connection pipelines between Class A B and Class B liquid storage tanks, as well as the collection pipes for oil and gas emission from the top of the storage tanks ； d) The main oil and gas emission (or recovery) pipes and branch pipes of the loading and unloading facilities. Article 6.2.8: Flash arrestors installed at the ends of pipelines should preferably be deflagration-type flash arrestors. Article 6.2.10: For deflagration-type flame arresters installed in pipelines, the ratio of the distance (L) from the flange surface to potential ignition sources to the pipe diameter (D) must meet the following requirements: a) For flame arresters designated for explosion groups IIA1, IIA, IIB1, IIB2, and IIB3, L/D ≤ 50; b) For flame arresters designated for explosion groups IIB and IIC, L/D ≤ 30; c) In addition to meeting the requirements specified in paragraphs a) or b) of this standard, the distance requirements set by the manufacturer based on design and testing criteria must also be satisfied; d) Deflagration-type flame arresters shall not be used when the location of ignition sources cannot be determined. Clause 6.2.11: The required distance from the flange surface of a stable detonation-type flame arrester installed in a pipeline to a potential ignition source shall be specified by the manufacturer; when this distance cannot be met, a non-stable detonation-type flame arrester shall be selected. Article 6.2.12: Stabilized deflagration-type flame arresters shall be used for the oil and gas collection piping systems at the top of storage tanks, as well as for the main pipes and branch pipes of the oil and gas emission (or recovery) systems of loading and unloading facilities. The flame arresters should be installed as close as possible to the tanks, containers, or equipment. Article 6.2.19: Flame arresters used on the following pipelines shall have a two-way flame arrestment function: a) Branch pipelines of the gas connection pipelines between Class A and B liquid storage tanks ； b) Branch pipes of the oil and gas emission or recovery pipelines for loading and unloading facilities. 5. Article 10.6.7 of the «Code for Design of Urban Gas Supply (2020 Edition)» (GB 50028-2006): When gas combustion requires pressurized air and oxygen, safety measures must be in place to prevent air and oxygen from returning to the gas pipeline as well as to prevent backflow, and the following requirements must be met: 2 A flame arrester shall be installed between the mixing pipeline for gas, air, or oxygen and the burner; the maximum pressure in the mixing pipeline shall not exceed 0.07 MPa. 6. Article 5.1.3 of the “Technical Standards for Oil and Gas Recovery and Treatment Facilities” (GB/T 50759-2022): The oil and gas collection system shall be properly designed based on factors such as the properties of the oil and gas in the storage or loading systems, operating temperature, and operating pressure. It shall also comply with the following provisions: (2) Detonation-type flame arresters shall be installed on the pipelines connecting the storage tanks, loading arms, and vapor arms ； Article 5.1.6: The selection of pipeline flame arrestors shall comply with the following provisions: (1) The type and technical safety level of the pipeline flame arrestor shall be determined based on the flame propagation speed of the medium, the maximum test safety clearance under actual operating conditions, and the installation location; (2) The selection of flame arrestors shall conform to the current standards **“Flame Arrestors for Petroleum and Gas Pipelines” GB/T13347 and “Standards for the Selection, Inspection, and Acceptance of Flame Arrestors for Petrochemical and Petroleum Gas Pipelines” SH/T3413; (3) When used in applications where polymerization or crystallization may lead to blockages, pressure monitoring should be installed at both ends of the pipeline flame arrestor, and measures should be taken to prevent blockages ； Article 5.1.7: The breather valve of storage tanks shall be equipped with a flame arrester, which shall be of the type resistant to burning and detonation. 7. Article 5.1.9 of the “Design Code for Tank Areas in Petrochemical Storage and Transportation Systems” (SH/T 3007-2014): Flame arresters shall be installed on the vent pipes or breathing valves that lead to the atmosphere for the following storage tanks: a) Fixed-roof storage tanks and above-ground horizontal storage tanks used for storing liquids of Classes A, B, and C; b) Above-ground horizontal storage tanks covered with soil and used for storing liquids of Classes A and B; c) Storage tanks equipped with nitrogen or other inert gas sealing systems; d) The central vent pipe on the roof of internal floating-roof storage tanks. Article 5.1.10: When the average of the average temperatures in the coldest months over the years in the area where the tank is to be built is less than or equal to 0°C, the vent valves and flame arresters must have anti-freezing functions or appropriate anti-freezing measures must be taken. When the material is prone to crystallization at ambient temperature, the vent valve and flame arrester should be equipped with anti-crystallization measures. 8. Article 130 and subsequent articles of the \"Regulations on Safety Inspection of Pressure Piping – Industrial Piping\" (TSG D0001-2009) stipulate that a vent flame arrester shall be installed on venting or exhaust pipes: (1) On the direct vent pipes of storage tanks whose flash point is 43°C or lower, or whose maximum operating temperature is equal to or higher than their flash point (including vent pipes equipped with breather valves); (2) On the main vent pipe of combustible gas on-line analysis equipment; (3) On the exhaust pipes of internal combustion engines in explosion-hazardous areas. Article 131: A pipe flame arrester shall generally be installed at a designated location in the pipeline system in any of the following situations: (1) Pipelines transporting mixed gases that may undergo deflagration or detonation ； (II) Gas pipelines that transport gases capable of self-decomposing to cause explosions and facilitating the spread of flames ； (III) Pipes for compressed combustible gases connected to open-flame equipment (a water seal device may be installed in special cases) ； (IV) The exhaust pipeline before the torch tip. 9. Article 5.2 of the “Code for Pressure Piping – Industrial Piping, Part 6: Safety Protection” (GB/T20801.6-2020): Installation of flame arrestors. 5.2 Installation of flame arrestors: Flame arrestors shall be installed in the following equipment and pipeline systems: a) Vent openings and inlet/outlet ports of breathing valves of atmospheric-pressure storage tanks for flammable liquids, as well as low-temperature storage tanks for liquid hydrocarbons, LNG, etc., and the pipes connected to them; b) Inlet ports of combustion equipment such as flares, incinerators, and oxidizers; c) Inlet/outlet ports of mechanical equipment such as fans, vacuum pumps, and compressors that have continuous ignition sources and are located in Zone 0; d) Breathing valves of terminal stations for loading/unloading flammable liquids or gases, tankers, and tank trucks, as well as gas displacement and balancing pipelines; e) Breathing valves of intermediate gas storage tanks in biogas systems, sewage treatment systems, and landfill gas systems, as well as the main gas pipelines; f) Gas and vapor outlets of individual devices or systems in systems for processing flammable chemicals (such as reactors), flammable solvent recovery systems, flammable gas and vapor recovery systems, and flammable exhaust gas treatment systems, as well as the main gathering pipes leading to inlet ports of treatment equipment such as flares, incinerators, oxidizers, and activated carbon adsorption tanks; g) Outlets from reactors or containers that may experience uncontrolled exothermic reactions, spontaneous combustion, or self-decomposition, leading to the atmosphere or to containers that cannot withstand explosive pressures; h) Pipeline systems that transport explosive gases and vapors that may undergo deflagration or detonation; i) Vent pipes of on-line flammable gas analysis equipment; j) Exhaust pipes of internal combustion engines that enter hazardous areas with explosive gas environments ； Article 5.1.2: In process plants, there are numerous non-electrical equipment and piping systems that are in potentially explosive environments. A flame arrester is the main safety device for preventing explosions in non-electrical equipment; it functions to prevent explosions, stop them from spreading through pipelines, and prevent deflagration from developing into detonation. For the categories and selection of flame arrestors, refer to Appendix D.