This standard specifies the category and definition, basic regulations, gas stations and facilities, gas metal pipelines, electrical systems and electronic systems of urban gas lightning protection. This standard applies to the lightning protection design and construction of new, modified and expanded urban gas, and the lightning protection of existing urban gas systems can be implemented as a reference. This standard does not apply to the design of gas installations on marine and inland ships, railway vehicles, vehicles and other means of transportation. QX/T 109-2009 Technical Specification for Lightning Protection of Urban Gas QX/T109-2009 Standard Download Decompression Password: www.bzxz.net
This standard specifies the category and definition, basic regulations, gas stations and facilities, gas metal pipelines, electrical systems and electronic systems of urban gas lightning protection. This standard applies to the lightning protection design and construction of new, modified and expanded urban gas, and the lightning protection of existing urban gas systems can be implemented as a reference. This standard does not apply to the design of gas installations on marine and inland ships, railway vehicles, vehicles and other means of transportation.

Meteorological Industry Standard of the People's Republic of China
Technical Specifications for Lightning Protection of City Gas
Technical Specifications for Lightning Protection of City GasPublished
People's Republic of China
Meteorological Industry Standard
Technical Specifications for Lightning Protection of City Gas
QXT1092009
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Normative reference documents
Terms and definitions
Basic provisions
Gas stations and facilities
Gas metal pipelines
Electrical system
Electronic system
Appendix A Informative appendix
Appendix B Informative appendix
Appendix C Informative appendix
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Classification and scope of explosion hazard areas in power supply areas of gas transmission and distribution systems Classification of fire hazards produced
Classification and scope of explosion hazard areas in power supply areas of liquefied petroleum gas stations 2009
Appendices A, B and C of this standard are informative appendices. This standard is proposed by the National Technical Committee for Standardization of Meteorological Disaster Prevention and Mitigation SACTC345. This standard is under the jurisdiction of the National Technical Committee for Standardization of Meteorological Disaster Prevention and Mitigation SACTC345. The main drafting unit of this standard is Chongqing Lightning Protection Center. Chen Hong, Liu Jun, Li Jianping
The main drafters of this standard are Li Jiaqi, Li Liangfu, Qin Binquan, Ren Yan, QX T 109
1 Scope
Technical specification for lightning protection of urban gas
QXT1092
This standard specifies the terms and definitions of urban gas lightning protection, basic provisions, gas stations and facilities, gas metal pipelines, electrical systems and electronic systems, etc.
This standard is applicable to the lightning protection design and construction of new, rebuilt and expanded urban gas, and the lightning protection of existing urban gas systems can be implemented as a reference
This standard is not applicable to the design of gas installations on marine and inland waterway ships, railway vehicles, automobiles and other means of transportation. Note: In this standard, gas storage tanks include gas storage cabinets
Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all references with dates, all subsequent amendments do not include errata or revisions. The latest versions of these documents are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced documents, the latest versions shall apply to this standard. GB50057 Code for Lightning Protection Design of Buildings
GB50058 Code for Design of Electrical Installations in Explosive and Fire Hazardous Environments HGJ281990 Code for Design of Electrostatic Grounding for Chemical Enterprises 3 Terms and Definitions
The following terms and definitions apply to this standard
Town gas citygas
Combustible gas of a public nature supplied to various types of users such as residents, commerce, industry, production, heating, ventilation and air conditioning through a transmission and distribution system from regional gas sources in cities, towns or settlements and meeting the gas quality requirements of this standard. Town gas generally includes natural gas, liquefied petroleum gas, artificial coal Gas and new composite gas 3.2
Low-pressure gas holder lowpressuregasholder Working pressure gauge pressure is below 1OkPa Gas holders that store gas by volume change are divided into wet gas holders and dry gas holders
High-pressure gas holder highpressuregasholder Fixed-volume gas holder
Working pressure gauge pressure is greater than 0.4MPa Gas holders that store gas by pressure change 3.4
Pressure regulating device regulatordevice
Reduces higher gas pressure to required lower pressure High-pressure unit general term includes pressure regulator and its ancillary equipment 3.5
Pressure regulating station regulatorstation
Regulator main snow number good master|| tt||QXT109
Regulator box regulator box
Place the regulator in a special box near the gas-using structure. It is responsible for regulating the pressure. It includes the regulator and the box. The suspended and underground boxes are called regulator boxes. The floor-standing boxes are called regulator cabinets. 3.7
Introduction pipe service pipe
The main valve between the outdoor gas distribution branch pipe and the user's indoor gas inlet pipe. When there is no main valve, it refers to the pipeline 1m above the indoor ground. 3.8
Pipeline concealment piping embedment
The pipeline is directly buried in the wall and ground
Pipeline concealment piping concealment
The pipeline is laid in the decorative layer of the pipe trench in the ceiling of the pipeline well. 3.1 0
Gas stationgasstation
Gate station storage and distribution stationCNG filling stationCNG storage and distribution stationCNG bottle group supply stationLNG supply baseGasification stationMixing stationBottled supply station, etc. are called gas station3.11
Gas transmission and distribution systemgastransportationsystemThe urban gas transmission and distribution system is generally composed of gate station gas pipeline networkgas storage facilitiespressure regulating facilitiesmanagement facilitiesmonitoring system, etc.3.12
Lightning protection zonelightningprotectionzoneThe areas where the electromagnetic environment of lightning needs to be regulated and controlled3.13
Lightning protection devicelightningprotectionsystemLightning arresterDown conductorgrounding deviceSurge protector and Total of other connecting conductors 3.14
Down-conductorsystem
Metallic conductor connecting lightning arrester and grounding device 3.15
Earth-terminationsystemThe total of grounding body and grounding wirewwW.bzxz.Net
Basic provisions
4.1 Lightning protection for urban gas should be based on lightning disaster risk assessment and reasonable site selection, functional zoning and pipeline network layout in combination with the characteristics of urban gas to ensure safety, reliability, advanced technology and economic rationality. 4.2 Lightning protection design for urban gas should be based on the following contents: National and local lightning protection laws, regulations, normative documents and lightning protection technical standards Lightning disaster risk assessment report and related materials Local resources
4.4 Urban gas operators Daily inspection, maintenance and repair of lightning protection devices should be done well. QXT109
4.5 If a lightning disaster occurs in urban gas, the management unit should promptly report it to the local meteorological authority, assist in the investigation of lightning disasters and make rectifications in a timely manner.
5 Gas stations and facilities
5.1 General provisions
5.1.1 The lightning protection design of buildings with explosion hazards such as gas storage tanks and bottled sales warehouses in gas stations should comply with the relevant provisions of GB50057. The classification is shown in Appendix A and Appendix B.
5.1.2 The electrical explosion-proof level in the explosive environment should comply with the design provisions of GB50058 for the zoning. See Appendix C for the design provisions of the zoning. Equipment pipelines and pipeline branches in the station area that may cause static electricity hazards should take anti-static grounding measures and comply with the provisions of HGJ28.5. 1.3 The distance between the open-air process equipment and buildings in the gas tank area of ​​the station and between the buildings and structures outside the station shall meet the requirements of lightning protection safety distance.
5.1.4 The buildings where the electrical and electronic system equipment are located shall be designed for direct lightning protection according to the requirements of GB50057. 5.1.5 In a building, the grounding of electrical equipment and the grounding of electronic system equipment should adopt a common grounding system, and the grounding resistance value should be the minimum value.
5.2 Tank area
5.2.1 The independent lightning rod overhead lightning conductor network erected in the tank area shall be placed in the LPZ0 area. 5.2.2 When the thickness of the tank roof is greater than or equal to 4mm, the roof can be used as a lightning rod. If the thickness of the tank roof is less than 4mm, a direct lightning protection device should be installed.
5.2.3 Floating roof tanks. Floating roof tanks should not be equipped with lightning rods directly on the tank body. Instead, the floating roof and the tank body should be electrically connected with two wires. The connecting wires of floating roof tanks should be soft copper stranded wires with a cross-sectional area of ​​not less than 25 mm2. For internal floating roof tanks, the connecting wires of steel floats should be soft copper stranded wires with a cross-sectional area of ​​not less than 16 mm. The connecting wires of aluminum floats should be stainless steel wire ropes with a diameter of not less than 1.8 mm.
5.2.4 Steel storage tanks must be grounded for lightning protection. The distance between grounding points along the perimeter of the tank should not be greater than 30 m, and there should be no less than 2 grounding points. 5.2.5 Steel storage tanks The impulse grounding resistance of the lightning protection grounding device should not be greater than 10. When the steel storage tank is only grounded for lightning protection, the grounding resistance should not be greater than 30.
5.2.6 The metal components such as the flange on the top of the tank in the tank area should be reliably electrically connected to the tank body. The flange connected with no less than 5 bolts may not be bridged in a non-corrosive environment. The metal components on the top of the discharge tower should also be reliably electrically connected to the discharge tower. 5.2.7 When the cathodic corrosion protection of underground liquefied petroleum gas tanks takes the following measures, it is no longer necessary to set up lightning protection and anti-static grounding devices separately: When the sacrificial anode method is used for cathodic corrosion protection of liquefied petroleum gas tanks The grounding resistance of the sacrificial anode should not be greater than 10. The cross-sectional area of ​​the copper core connection between the anode and the storage tank should not be less than 16mm
When the forced current method is used for cathodic corrosion protection of liquefied petroleum gas tanks, the grounding electrode must be a zinc rod or a magnesium-zinc composite rod. The grounding resistance should not be greater than 10. The cross-sectional area of ​​the copper core connection between the grounding electrode and the storage tank should not be less than 16mm5.3 Voltage regulation and metering area
5.3.1 The impact grounding resistance value of the voltage regulating station should not be greater than 10. Voltage regulating stations located in open areas and voltage regulating stations using elevated telemetry antennas should be equipped with lightning protection devices separately
5.3 .2 When the gas metal pipelines inside and outside the pressure regulating station are insulated, the pressure regulating device must be grounded. The grounding resistance should be less than 105.3.3 The equipment in the pressure regulating station should be placed in the LPZOB area. 6 Gas Metal Pipeline
6.1 General Provisions
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6.1.2 Grounding devices should be installed at the beginning, end, branch and straight section of the overhead gas metal pipeline every 200m300m. The impulse grounding resistance should not be greater than 30. The grounding point should be set at the fixed pipe pier. The pipeline within 100m from the building should be installed every 2 6.1.3 The inlet and outlet of the gas pipelines in and out of civil buildings, the outdoor roof pipes, the vertical pipes, the discharge pipes, the inlet pipes and the gas equipment should all be equipped with lightning protection and electrostatic grounding devices.
6.2 Gas metal pipelines should not be laid on the roof. When the actual conditions cannot be met, the gas metal pipelines can be laid on the roof, but the following requirements should be met.
a. The gas facilities such as the roof gas metal pipeline, the discharge pipe, the exhaust pipe, the boiler, etc. should be installed within the protection range of the lightning arrester and away from the eaves, corners, ridges and other places of the building that are easily affected by lightning. b. The roof vent pipe and smoke exhaust pipe should be equipped with flame arresters and connected to the roof lightning protection device as close as possible. c. The roof gas metal pipe and the lightning protection net belt should be connected by metal wires at least at two locations, and the spacing between the connection points should not be greater than 30m. When the horizontal and vertical clearance between the roof gas metal pipe and the lightning protection net belt is less than 100mm, it should also be connected by wires. d. The metal jumper wire between the roof gas pipe and the lightning protection net can be made of round steel or flat steel. The diameter of the round steel should not be less than 8mm, the cross-sectional area of ​​the flat steel should not be less than 48mm2, and its thickness should not be less than 4mm. Round steel is preferred. e. When the gas metal pipe When the pipeline enters LPZ1 from LPZO, an insulating flange or steel-plastic joint shall be installed. The pipes at both ends of the insulating flange or steel-plastic joint shall be grounded nearby. The grounding resistance shall not be less than 106.3 Metal gas risers on the exterior wall of buildings
6.3.1 When the building user branch pipe is connected to the metal gas riser on the exterior wall, an insulating flange or steel-plastic joint shall be installed. The pipes at both ends of the insulating flange or steel-plastic joint shall be grounded nearby. The grounding resistance shall not be less than 106.3.2 Metal gas pipelines laid vertically along the exterior wall shall be reliably connected to the lightning protection device of the building at intervals of no more than 12m. .4 Gas metal pipelines introduced into the station
6.4.1 Overhead gas metal pipelines entering and exiting the station should be grounded outside the station. 6.4.2 When the gas metal pipeline is introduced into the station by ground introduction, the electrical insulation device should be installed after the introduction pipe comes out of the outdoor ground and before it passes through the wall to the house. The clamp is installed on the indoor gas metal pipeline and then connected to the main equipotential connection box through the equipotential connection line. If the combination of insulating flange and external discharge gap is used, it should be installed after the indoor gas main valve. The gas metal pipelines at both ends of the insulating flange are connected by the discharge gap. 6.5 Others
6.5.1 The metal jumper wire buried underground should be hot-dip galvanized round steel with a diameter of not less than 10mm. 6.5.2 When the transition resistance of the joints of elbows, valves, flanges, etc. connected by threaded connections of gas metal pipelines is greater than 0.03, the joints should be connected by metal wires.
7 Electrical system
7.1 General provisions
7.1.1 The low-voltage distribution lines of urban gas systems should be laid in metal armored cables or sheathed cables through steel pipes and buried in various lightning protection areas. At the junction of the partitions, the metal sheath or outer steel pipe of the cable should be connected to the equipotential connection belt. It is strictly forbidden to cross the station through the overhead line. When it is difficult to use buried cables for the entire line, overhead lines can be used. A section of metal armored cable or sheathed cable should be used to pass through the steel pipe and directly buried underground. The buried length should be no less than 15m. 7.1.2 The metal sheath of the cable or the metal protective pipe of the cable in the power distribution system of the station should be grounded at both ends. According to the requirements of GB50057, a multi-level surge protector should be installed, preferably three levels. The surge protector should have explosion-proof function and be compatible with the resistance of the protected equipment. 7.2 The grounding trunk line in the station should be connected to the grounding device in different directions and at least two locations. 7.3 The grounding device of the electrical equipment in the station should be set separately from the grounding device of the independent lightning rod. The distance between them should be not less than 3m. The grounding resistance value should be QXT109. 7.4 The metal casing of all electrical equipment in the station should be grounded. Electrical equipment other than lighting fixtures should use a special grounding wire. If the grounding wire is laid in the same protective tube as the phase line, it should have the same The metal sheath of other insulated metal pipelines and cables can only be used as auxiliary grounding wires, and the grounding resistance value should be less than 47.5. The lighting fixtures in the station can use the metal pipeline system with reliable electrical connection as the grounding wire, but the metal pipeline that transports flammable substances cannot be used.
Electronic system
8.1 General provisions
8.1.1 When the outdoor signal transmission line of the urban gas system is a metal wire, it is advisable to use a shielded cable or a metal pipeline for underground laying. At the entrance, the metal sheath of the cable or the outer metal pipe should be connected to the total equipotential bonding belt. When it is difficult to use buried cables for the entire line, overhead lines can be used and a section of metal armored cable or sheathed cable can be directly buried in a steel pipe. The buried length should not be less than 15m. 8.1.2 Cables of electronic systems in stations should be installed with SPDs at the interfaces of each lightning protection zone. 8.2 Metal conductors such as metal shielding layers and metal pipes of communication lines, data lines, control cables, etc. should be connected to the same potential at the interfaces of each lightning protection zone when entering and exiting buildings and electronic system rooms. 8.3 Electronic system equipment such as monitoring instrument probes in stations should be placed in LPZ0B area, and their wiring cables should be shielded. Shielded cable or steel pipe protection and grounding treatment
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A.1 Overview
Appendix A
Informative Appendix
Classification and scope of explosion hazard areas in power supply places in production areas of gas transmission and distribution systems This appendix is ​​applicable to gas with relative density of operating medium less than or equal to 0.75 and gas with relative density greater than 0.75. The classification and scope of explosion hazard areas should comply with the relevant provisions of Appendix B of this specification. A.2 Classification and scope of explosion hazard areas in power supply places in production areas of gas transmission and distribution systems The division shall comply with the following provisions: A.2.1 The release sources of all places in the production area of ​​the gas transmission and distribution system belong to the second-level release sources. Places with second-level release sources can be divided into Zone 2. A few places with poor ventilation can be divided into Zone 1. The division of the areas should comply with the provisions of the following typical examples: 1. The explosion hazard zone level and range of fixed-volume gas storage tanks installed in the open air are divided as shown in Figure A.1. The center is the outlet of the release pipe of the safety relief valve of the storage tank. When the height of the outlet is greater than 4.5m from the ground, the radius is 3m and the top is 5m. When the height of the outlet is less than or equal to 4.5m from the ground, the radius is 5m. The distance from the pipe mouth to the pipe mouth is 7.5m, and the range from the pipe mouth to the ground is zone 2. The radius from the bottom of the tank to the ground is not less than 4.5m, which is zone 2. The discharge pipe mouth of the high-pressure tank
Outdoor floor-
Figure A, 1. The explosion hazard zone level and range division of fixed-volume gas storage tanks installed outdoors 2. The explosion hazard zone level and range division of low-pressure gas storage tanks installed outdoors are shown in Figures A.2a and A.2b. The space above the piston or rubber sealing membrane inside the dry gas storage tank is zone 1. The space within 4.5m outside the tank wall of the gas storage tank is measured from the discharge pipe mouth to the top of the tank 7.5m is Zone 2
3 The explosion hazard zone between the valves of the inlet and outlet pipes of the low-pressure gas storage tank is divided into the following levels and ranges: See Figure A.3 The space inside the valve room is Zone 1 The range within 4.5m of the outer wall of the valve room and the range within 7.5m of the roof measured from the outlet of the vent pipe is Zone 2 4 The explosion hazard zone levels and ranges of the well-ventilated compressor room, pressure regulating room, metering room and other production rooms are divided into the following levels and ranges: See Figure A.4 The interior of the building and the outer wall of the building The range within 4.5m of the roof measured from the outlet of the vent pipe is Zone 2 5 The process device area set up in the open air The classification of explosion hazard zones is shown in Figure A.5. The area within 4.5m outside the edge of the process unit area, the outlet of the vent pipe, or 7.5m above the highest device is Zone 2. 6 The classification of explosion hazard zones for underground surge chambers and underground valve chambers is shown in Figure A.6. 7 The classification of explosion hazard zones for unmanned gas surge chambers in urban areas is shown in Figure A.7. QXT109
The space within 4.5m of the outer wall of the surge chamber building and within 7.5m above the outlet of the vent pipe is Zone 1.
A.2.2 The following power supply places can be divided into non-explosion hazardous areas: 1. Areas without release sources and no intrusion of flammable gas; 2. Areas where the highest concentration of flammable gas may not exceed 10% of the lower explosion limit; 3. Areas near equipment using open flames in the production process, such as gas boiler rooms, etc. 4. Areas of ground pipelines set up in the open air within the station. However, the valves should be determined according to the specific situation. Dry low-pressure tank piston
or rubber seal wax upper
low-pressure Qian type
outdoor floor ||tt| |Gas storage tank
Zone 2
Outdoor floor
Classification and scope of explosion hazard areas for low-pressure gas storage tanks installed outdoors Tank wall
Inside of low-pressure tank
Bottom of tank
Outdoor floor
Valve room
Classification and scope of explosion hazard areas between valves of inlet and outlet pipes of low-pressure gas storage tanks Vent pipe outlet
Outdoor floor
Compressor room, pressure regulating room, etc.
Low-pressure wet
Gas storage tank
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