Installation of flame arresters in chemical processing units

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Code for Pressure Piping – Industrial Piping, Part 6: Safety Protection (GB/T 20801.6-2020) 5.2 Installation of flame arrestors: Flame arrestors shall be installed in the following equipment and piping systems: (1) Atmospheric storage tanks for flammable liquids, as well as the vents and inlet/outlet ports of low-temperature storage tanks containing liquid hydrocarbons, LNG, etc., and the pipes connecting them to the atmosphere； (2) Combustion inlets such as torches, incinerators, and oxidizers ； (3) Inlets and outlets for mechanical equipment such as fans, vacuum pumps, and compressors in Zone 0, with a continuous ignition source ； (4) Vent valves of terminal stations, tankers, and tank trucks for loading and unloading flammable liquids or gases, as well as gas main pipes ； (5) Breather valves of intermediate gas storage tanks in biogas systems, sewage treatment systems, and landfill gas systems, as well as gas main pipes ； (6) Gas and vapor outlets of parallel equipment or systems used in the processing of flammable chemicals, as well as the inlets to collectors that lead to torches, incinerators, oxidizers, activated carbon adsorption tanks, and other treatment devices ； (7) Exports from reactors or containers that may undergo uncontrolled exothermic reactions, spontaneous combustion, or self-decomposition to the atmosphere or to containers that cannot withstand explosive pressures ； (8) Pipeline systems for transporting explosive gases and vapors that may explode or detonate ； (9) Vent main for online combustible gas analysis equipment ； The exhaust manifold of internal combustion engines entering hazardous areas with explosive gas atmospheres. 2. \"Fire Protection Standards for Engineering Design of Fine Chemical Enterprises\" (GB 51283-2020): 5.1.5 When waste gas containing volatile organic compounds is treated using waste gas treatment facilities such as thermal oxidation furnaces, a high-temperature interlock protection system for the combustion chamber and an overpressure relief device for the combustion chamber shall be installed. It is advisable to install a system for monitoring the concentration of incoming gas and to implement interlocks for high concentrations, as well as flame arresters and relief devices in the waste gas pipelines. 5.4.4 The fuel gas pipelines heated by heat transfer oil furnaces shall be equipped with the following protection measures: 1 Install a low-pressure alarm system and a low-low pressure interlock shutdown system ；     2 Install a flame arrester between the fuel gas control valve and the heat transfer oil furnace. 5.7.7 Flame arresters shall be installed on non-electrical equipment in the following potentially explosive environments: 1 Vent openings or breathing valves of atmospheric-pressure storage tanks for flammable liquids of Class A, B, and C A, as well as low-temperature storage tanks for liquefied hydrocarbons, liquefied natural gas, etc., or the gas connection pipes ；     2 Inlets for combustible gases, vapors, or fuel gases in combustion equipment such as incinerators and oxidizers ；     3 Inlets and outlets for mechanical equipment such as fans, vacuum pumps, and compressors used to transport explosive gases ；     4 Gas displacement/return pipelines for tankers and tank trucks used for loading and unloading flammable chemicals ；     5 At the vent valves of the intermediate gas storage tanks in biogas systems, sewage treatment systems, and landfill gas systems, or before their gas branch pipes connect to the main pipeline ；     6 Gas and vapor outlets of individual pieces of equipment or systems, such as parallelly connected equipment systems comprising reactors for processing flammable chemicals, flammable solvent recovery systems, flammable gas or vapor recovery systems, and flammable waste gas treatment systems; and the inlets of collection manifolds leading to treatment equipment like incinerators, oxidizers, and activated carbon adsorption tanks where there may be ignition sources ；     7 Reactors or containers in which uncontrolled exothermic reactions, spontaneous combustion reactions, or self-decomposition reactions may occur, generating flammable gases or vapors, up to the outlet of the container or to the atmosphere if it cannot withstand explosive pressures ；     8 Vent main for online analysis equipment of flammable gases or vapors. 7.2.10 The piping design in the pharmaceutical industry shall also comply with the following requirements: 1 When it is necessary to use Class A or Class B media in factories of Class C or lower, the diameter of the pipes carrying such media into these factories shall not exceed DN40. Transfer shall be carried out using jacketed pipes, or 100% non-destructive testing of the pipes shall be conducted, along with the installation of necessary monitoring instruments as well as interlock systems for emergency ventilation and feed cut-off.     2 When the exhaust branch pipes of various workshops or production facilities are connected to the main pipe and sent to the exhaust gas treatment system, a flame arrestor should be installed at the connection point between the branch pipe and the main pipe. 3. \"Code for Fire Protection Design of Petrochemical Enterprises (2018 Edition)\\" (GB50160-2008): 6.2.19 Fixed-roof tanks storing Class A B and Class B liquids shall be equipped with flame arresters and vent valves ； Storage tanks for Class A B and Class C liquids that use nitrogen or other gases for gas sealing should also be equipped with emergency pressure relief devices. 7.2.12 When the pipeline pressure before the fuel gas control valve of the heating furnace is equal to or less than 0.4 MPa (gauge), and there are no low-pressure automatic protection instruments, a flame arrester shall be installed between each fuel gas control valve and the heating furnace. 4. The \"Technical Standards for Oil and Gas Recovery Facilities\" (GB/T 50759-2022) stipulate that 5.1.3 The oil and gas collection system shall be designed appropriately based on factors such as the properties of the oil and gas in the storage or loading systems, as well as the operating temperature and pressure. It shall also comply with the following requirements: 1. It shall be hermetically connected to storage tanks, tank trucks, and ships ；     2 Detonation-type flame arresters should be installed on the pipes connecting to the storage tank, the loading arm, and the vapor arm ；     3 The condensate should be collected in a sealed manner and must not be discharged on-site ；     4 The oil and gas collection system shall incorporate measures to prevent the system pressure from becoming excessively high or low. 5.1.6 The selection of pipe flame arresters shall comply with the following provisions: 1 The type and technical safety level of pipe flame arresters shall be determined based on the flame propagation speed of the medium, the maximum test safety clearance value of the medium under actual operating conditions, and the installation location ；     2 The selection of flame arrestors shall comply with the provisions of 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 prone to clogging due to polymerization, crystallization, etc., pressure monitoring should be installed at both ends of the pipeline flame arrester, and measures to prevent clogging should be taken. 5.1.7 The breather valve of the storage tank shall be equipped with a flame arrester, which shall be of the type resistant to burning and deflagration. 5. \"Code for Design of Tank Areas in Petrochemical Storage and Transportation Systems\" (SH/T 3007-2014): 5.1.9 Flame arresters shall be installed on the vent pipes or breathing valves leading to the atmosphere of the following storage tanks: a) Fixed-roof storage tanks and above-ground horizontal storage tanks used for storing liquids of Class A, B, and C ；     b) Horizontal buried tanks for storing Class A and B liquids ；     c) Tanks of the sealing and protection system filled with nitrogen or other inert gases ；     d) Central vent on the roof of the internal floating roof tank. 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 shall have anti-freezing functions or anti-freezing measures shall 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. 6. \"Installation of Flame Arresters\" (HG/T 20570.19-1995): 3.0.1 Installation of vent flame arresters; 3.0.1.1 Installation of flame arresters in oil storage tanks shall be carried out in accordance with the \"Design Code for Oil Depots\" (GBJ74-84). 3.0.1.2 For storage tanks (and tank trucks) containing 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 In pipelines that transport explosive mixtures capable of deflagration or detonation (taking possible accident scenarios into account), pipeline flame arresters shall be installed at the inlet of the receiving equipment. 3.0.2.2 For pipes transporting gaseous materials that can decompose explosively on their own and cause flame propagation (such as acetylene), a pipe 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. 7. The \"Safety Technical Specifications for Vertical Cylindrical Welded Steel Storage Tanks\" (AQ 3053-2015) stipulate that in 12.2.4 Fire arresters, the following storage tanks shall be equipped with fire arresters: a) Fixed-roof storage tanks holding Class A, B, and C oils, which shall have fire arresters installed on their vent pipes or breathing valves ； b) Flame arresters shall be installed on pipes that are in frequent contact with the atmosphere on storage tanks equipped with gas sealing. When the lowest average monthly minimum temperature in the tank construction area is below 0°C, the vent valves and flame arresters should be equipped with anti-freezing measures ； When the material is prone to crystallization or self-polymerization at ambient temperature, the vent valve and flame arrester should be equipped with measures to prevent crystallization or self-polymerization. 8. The \"Standards for Selection, Inspection, and Acceptance of Flame Arresters for Petrochemical and Oil Pipeline Systems\" (SH/T3413-2019) stipulate that: 5.0.1 Where there is a possibility of the presence of explosive mixtures and no other means 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 pipes in the gas space of storage tanks or containers containing explosive gases: c) Branch pipes of the gas connection pipes between storage tanks holding Class A B and Class B liquids, as well as the collection pipes for oil and gas emission from the tops of the storage tanks ； d) The main oil and gas emission (or recovery) pipes and branch pipes of the loading and unloading facilities. 6.2.12 For the oil and gas collection piping systems at the top of storage tanks, as well as the main pipes and branch pipes of the oil and gas emission (or recovery) systems for loading and unloading facilities, flame arresters of the stable deflagration type should be used, and these flame arresters ought to be installed near the tanks, containers, or equipment. 9. \"Regulations on Safety Technical Inspections of Pressure Pipelines\" (TSG D0001-2009): Article 130: A vent flame arrester shall be installed on the following vent or discharge pipelines: (1) The direct vent pipes of storage tanks whose flash point is 43°C or lower, or whose maximum operating pressure is equal to or higher than their flash point (including vent pipes equipped with breather valves) ； (II) Vent main for online combustible gas analysis equipment ； (III) Exhaust pipes of internal combustion engines in explosive hazard areas. Article 131: Pipe flame arresters shall generally be installed at designated locations in pipeline systems in any of the following circumstances: (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. 10. According to Article 4.4.9 of the \"Technical Regulations for Safe Use of Hydrogen\" (GB4962-2008), check valves should be installed between hydrogen pipelines and the devices and equipment connected to them. Effective isolation measures should be in place at the valves located at the boundaries between these systems, in order to prevent external flames from the devices and equipment from backflowing into the hydrogen system. When hydrogen is used for welding, cutting, as fuel, or as a shielding gas, a flame arrester should be installed on the branch pipe of each hydrogen-using device (set). 8.2 A flame arrester should be installed on the hydrogen exhaust pipe, and the flame arrester shall be located at the pipe outlet. 11. According to 6.5.5.4 of the \"Technical Guidelines for Air Pollution Control Engineering\" (HJ2000-2010), a flame arrester should be installed behind the filter and in front of the thermal combustion chamber or regenerative chamber. The flame-retardant performance of the flame arrester shall comply with the provisions of GB/T13347. 12. \"Technical Specifications for the Treatment of Industrial Organic Waste Gas by Adsorption Method\" (HJ2026-2013) 6.5.2 Fire arresters (fire dampers) shall be installed in the piping system between the treatment system and the main production equipment; the performance of these fire arresters shall comply with the requirements specified in GB13347.