Installation of flame arresters in chemical plants

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1. “Code for pressure piping – Industrial piping – Part 6: Safety protection” (GB/T 20801.6-2020): 5.2 Flame arresters. Flame arresters shall be installed on the following equipment and piping systems: (1) Atmospheric-pressure storage tanks for flammable liquids; vents, breather valves, their inlets and outlets, as well as gas interconnecting pipes of low-temperature storage tanks for liquid hydrocarbons, LNG, etc； (2) Combustion inlets such as torches, incinerators, and oxidizers ； (3) Presence of continuous ignition sources and inlet/outlet ports for mechanical equipment such as fans, vacuum pumps, and compressors in Zone 0 ； (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 the main gas pipelines ； (6) Gas and vapor outlets of parallel equipment or systems used for processing 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) Piping 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 should be installed. It is advisable to set up systems for monitoring the concentration of incoming gas and triggering interlocks at 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 protective 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 At the vents or breather valves, or vapor connection pipes of atmospheric storage tanks for Class A-B, Class B, and Class C-A flammable liquids, as well as cryogenic storage tanks for liquefied hydrocarbons, liquefied natural gas, etc ；     2 Inlets for combustible gases, vapors, or fuel gases in combustion equipment such as burners and oxidation furnaces ；     3 Inlets and outlets for mechanical equipment such as fans, vacuum pumps, compressors, etc., used for transporting explosive gases ；     4 Gas displacement/return pipelines for tankers and tank trucks used for transporting 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 The gas and vapor outlets of individual units or systems such as parallel equipment systems for processing flammable chemicals and reactors, flammable solvent recovery systems, flammable gas or vapor recovery systems, and flammable waste gas treatment systems, as well as the inlets of collective manifolds leading to treatment equipment such as incinerators, oxidation furnaces, and activated carbon adsorption tanks where ignition sources may exist ；     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 pipeline 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 pipelines carrying such media into these factories shall not exceed DN40. Insulated piping should be used, or 100% non-destructive testing of the pipelines shall be carried out. In addition, necessary monitoring instruments as well as interlock systems for emergency exhaust and feed cut-off shall be installed.     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 ； For storage tanks containing Class A and Class B liquids that are purged with nitrogen or other gases, emergency pressure relief devices shall also be installed. 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 shall be installed on the pipes connecting to the storage tank, the loading dip pipe, 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 should incorporate measures to prevent excessive high or low system pressure. 5.1.6 The selection of pipeline flame arresters shall comply with the following provisions: 1 The type and technical safety level of pipeline 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 detonation. 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) Earth-covered horizontal storage tanks for storing Class A-B and Class 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 0°C or lower, the vent valves and flame arresters shall have anti-freezing functions or anti-freezing measures shall be taken. When the material may crystallize at ambient temperature, the breather 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 The 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 manifold of the online combustible gas 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 flame arrestors. 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 arrestors, the following storage tanks shall be equipped with fire arrestors: a) Fixed-roof storage tanks holding Class A, B, and C oils, which shall have fire arrestors installed on their vent pipes or breathing valves ； b) Flame arresters shall be installed on pipes that are in constant communication 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 breathing valve and flame arrester should be equipped with anti-freezing measures ； When there is a possibility of crystallization or self-polymerization of materials at ambient temperature, the breather valve and flame arrester should be equipped with measures to prevent such 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 vents in the vapor space of storage tanks or containers containing explosive gases; c) Branch pipes of vapor interconnecting pipelines between Type A-B and Type B liquid storage tanks, and collection manifolds for oil vapor discharge pipes at the tops of 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 should be installed as close as possible to the tanks, containers, or equipment. 9. “Safety Technical Supervision Regulations for Pressure Piping” (TSG D0001-2009): Article 130 Flame arresters shall be installed on the following vent or exhaust pipes: (1) Direct vent pipes of storage tanks containing materials with a flash point less than or equal to 43°C, or where the maximum operating pressure of the material is higher than or equal to its flash point (including vent pipes equipped with breather valves) ； (II) Vent main for online analyzers of combustible gases ； (III) Exhaust pipes of internal combustion engines in explosive hazard areas. Article 131: A pipe flame arrester shall generally be installed at a designated location in the piping system in any of the following situations: (1) Piping that transports mixed gases capable of causing deflagration or detonation ； (II) Gas pipelines that transport gases capable of self-decomposing to cause explosions and leading to flame spread ； (III) Pipelines for reduced-pressure combustible gases connected to open-flame equipment (in special cases, a water seal device may be installed) ； (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 put 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 placed 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 fire-blocking performance of flame arresters shall comply with the provisions of GB/T 13347. 12. \"Technical Specifications for the Treatment of Industrial Organic Waste Gases 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.