NB/T 1001-2011Technical standard for vehicle liquefied natural gas fueling station (English PDF)

Foreword

This document was issued on 28 July 2011 by the National Energy Administration of the PRC and takes effect on 1 November 2011.

It is a NB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

In accordance with the Measures for the Administration of Standardization of Energy Sector Standards (Trial), the National Energy Administration approved the Technical standard for vehicle liquefied natural gas fueling station as a sector standard numbered NB/T 1001-2011 by Announcement No. 4 of 2011, dated 28 July 2011, to be implemented from 1 November 2011.

The code is under the management of the National Energy Administration; North China Municipal Engineering Design and Research Institute is responsible for the interpretation of its specific technical contents, and the Oil and Natural Gas Department of the National Energy Administration organized its publication and distribution by China Architecture and Building Press.

This code was drafted in accordance with the rules given in GB/T 1.1-2009 Directives for standardization - Part 1: Structure and drafting of standards.

In accordance with the Notice of the National Energy Administration on the First Batch of Energy Sector Standard Formulation (Revision) Plans for 2010 (Guoneng Keji [2010] No. 320), this code was formulated to regulate the construction of liquefied natural gas (LNG) vehicle fueling stations, unify technical requirements and achieve safety and reliability, advanced technology and economic rationality.

This code consists of 10 chapters and 2 appendices. Its main contents are: scope, normative references, terms, classification of fueling stations and site selection, general layout within the station, process facilities, fire protection facilities and water supply and drainage, electrical, buildings and structures, heating and ventilation, landscaping, and construction and acceptance.

This code was proposed by and is under the jurisdiction of the Oil and Gas Department of the National Energy Administration of the People's Republic of China.

Users are asked to summarize experience and accumulate data in the course of applying this code, and to send comments and relevant information to the drafting group of this code at the Fourth Design Institute of North China Municipal Engineering Design and Research Institute (No. 99 Qixiangtai Road, Hexi District, Tianjin, postcode 300074) for reference in future revisions.

Drafting organizations of this code: North China Municipal Engineering Design and Research Institute; Xinjiang Guanghui Shiye Gufen Youxian Gongsi; CNOOC Gas and Power Group Co., Ltd.

Chief drafters of this code: Deng Yuan, Yang Chusheng, Wu Hongsong, Du Jianmei, Chen Hailong, Ma Jingzhu, Zhang Shugang, Jiao Wei, Wang Jianjun, Gao Yonghe, Lu Fengqin, Zeng Li, Wang Lijun, Fu Yiping, Wei Hong, Yuan Shuming.

Chief reviewers of this code: Gu Anzhong, Ni Zhaopeng, Han Jun, Chen Yunyu, Deng Zhiwei, Li Jingbo, Huang Daxin, Zhang Xiaobo, Jiang Jinhua, Hao Jiandong.

1 Scope

NB/T 1001-2011 is the Chinese technical specification for liquefied natural gas vehicle fuelling stations - LNG stations, L-CNG stations that vaporise LNG to supply compressed gas, combined LNG/L-CNG stations, and stations that combine gas with conventional liquid fuels. It covers stations with storage of up to 180 cubic metres, at pressures up to 1.6 MPa for LNG and 25 MPa for L-CNG. An LNG station stores a cryogenic, flammable liquid next to a public road and dispenses it into vehicles driven by the public, so the specification is dominated by safety distances, containment of spills and the control of boil-off. It sets the general provisions and defined terms, then the classification of stations by storage capacity and the site selection and layout requirements, with the tabulated fire separation distances between tanks, dispensers, buildings, roads and neighbouring property. Process design follows - storage tanks and their insulation and pressure relief, submerged pumps, vaporisers and heaters, compressors and high-pressure storage for L-CNG, dispensers and hoses, piping and valves, the treatment of vented gas - together with the instrumentation, emergency shutdown and gas detection systems. Fire protection and water supply, electrical installation in hazardous areas, lightning and static protection, buildings and the construction, installation, testing and acceptance of the station close the specification.

1.0.1 This code specifies provisions for the design, construction and building of liquefied natural gas (LNG) vehicle fueling stations.

1.0.2 This code applies to the design, construction and acceptance of the following new, expanded and reconstructed vehicle fueling station projects with an LNG storage capacity not exceeding 180 cubic metres, an LNG working pressure not greater than 1.6 MPa and an L-CNG working pressure not greater than 25.0 MPa: 1) liquefied natural gas (LNG) fueling stations (hereinafter LNG fueling stations); 2) natural gas fueling stations in which liquefied natural gas is pressurized in the liquid state and vaporized (hereinafter L-CNG fueling stations); 3) fueling stations combining LNG and L-CNG (hereinafter LNG/L-CNG fueling stations); 4) stations combining LNG, L-CNG or LNG/L-CNG gas fueling with oil fueling (hereinafter oil and gas fueling stations).

1.0.3 In addition to this code, the design and construction of fueling stations shall comply with the relevant current mandatory national standards.

2 Normative references

The following standards are indispensable for the application of this code. For dated references, only the edition cited applies to this code. For undated references, the latest edition (including all amendments) applies to this code.

GB 150 Steel pressure vessels; GB/T 11790 General rules for cold insulation of equipment and pipes; GB/T 14976 Stainless steel seamless tubes for fluid transport; GB 18047 Compressed natural gas for vehicles; GB 18442 Cryogenic insulated pressure vessels; GB/T 19204 General characteristics of liquefied natural gas; GB/T 20368 Production, storage and handling of liquefied natural gas (LNG).

GB 50016 Code for fire protection design of buildings; GB 50019 Code for design of heating, ventilation and air conditioning; GB 50052 Code for design of power supply and distribution systems; GB 50057 Code for design of lightning protection of buildings; GB 50058 Code for design of electrical installations in explosive and fire hazardous environments; GB 50217 Code for design of cables of electric power engineering; GB 50140 Code for design of extinguisher distribution in buildings; GB 50156 Code for design and construction of automobile gasoline and gas fueling stations; GB 50191 Code for seismic design of structures.

GB 50235 Code for construction and acceptance of industrial metallic piping; GB 50236 Code for construction and acceptance of welding of field equipment and industrial piping; GB 50257 Code for construction and acceptance of electrical installations in explosive and fire hazardous environments; GB 50264 Code for design of insulation engineering of industrial equipment and pipes; GB 50126 Code for construction of insulation engineering of industrial equipment and pipes; GB 50303 Code for acceptance of construction quality of electrical installation in buildings; GB 50316 Code for design of industrial metallic piping.

GB 50484 Technical code for construction safety of petrochemical engineering; GB 50493 Code for design of combustible gas and toxic gas detection and alarm for petrochemical industry; GB 50517 Code for acceptance of construction quality of metallic piping in petrochemical engineering; HG/T 20592~20635 Steel pipe flanges, gaskets and fasteners; SH/T 3412 Selection, inspection and acceptance of metallic hoses for piping in petrochemical industry; SH/T 3521 Technical specification for instrumentation installation in petrochemical engineering; SY 0007 Code for design of corrosion control of steel pipelines and storage tanks.

TSG D0001 Safety technical supervision regulation for pressure piping - Industrial piping; TSG R0004 Safety technical supervision regulation for stationary pressure vessels; TSG ZF001 Safety technical supervision regulation for safety valves.

3 Terms

3.0.1 Liquefied natural gas (LNG): a colourless fluid in the liquid state, composed mainly of methane, which may contain small amounts of ethane, propane, nitrogen or other components normally present in natural gas.

3.0.2 Compressed natural gas (CNG): gaseous natural gas compressed to a pressure not greater than 25 MPa.

3.0.3 LNG fueling station: a dedicated site for filling LNG fuel into the on-board storage cylinders of LNG vehicles.

3.0.4 L-CNG fueling station: a dedicated site in which LNG is converted into CNG and CNG fuel is filled into the on-board storage cylinders of CNG vehicles.

3.0.5 LNG/L-CNG fueling station: general term for an LNG fueling station built jointly with an L-CNG fueling station.

3.0.6 Oil and gas fueling station: general term for a vehicle oil fueling station built jointly with a natural gas vehicle fueling station.

3.0.7 Buried LNG tank: an LNG tank installed in a tank pit, with the top of the tank 0.2 m lower than the ground elevation within a range of 4 m around it.

3.0.8 Underground LNG tank: an LNG tank installed in a tank pit, with more than half of the tank body located below the ground within a range of 4 m around it.

3.0.9 Dike: a structure used to contain LNG spilled from an LNG tank in the event of an accident.

3.0.10 Design pressure: the pressure used in the design of tanks, equipment or piping to determine the minimum permissible thickness or the physical characteristics of their components. The design pressure used to determine the thickness of any particular component includes the static head; the design pressure is determined including the static head.

3.0.11 Operating pressure: the maximum pressure that pressure vessels, piping systems and the like may reach under normal working conditions.

3.0.12 Point of transfer: the fixed connection at which LNG carried by an LNG transport vehicle is received and unloaded.

3.0.13 Station house: a building used for the management and operation of an oil and gas fueling station.

3.0.14 Fueling platform: a platform used for installing dispensers.

3.0.15 LNG (CNG) dispenser: special equipment, provided with metering and pricing devices, for filling LNG (CNG) into the on-board gas cylinders of LNG (CNG) vehicles.

3.0.16 Shut off device: a safety device giving the fueling system a self-closing function when the fueling hose is subjected to a certain external force.

3.0.17 Fueling connector: special equipment attached to the dispenser and connected to the fueling hose, used to fill LNG (CNG) into LNG (CNG) on-board cylinders.

4 Classification of fueling stations and site selection

4.1.1 The fire hazard category of a fueling station shall be Class A.

4.1.2 Tier 1 fueling stations and tier 1 oil and gas fueling stations should not be built in urban built-up areas.

4.1.3 Fueling stations and oil and gas fueling stations built in urban central areas should use buried or underground LNG tanks.

4.1.4 LNG fueling may be combined with L-CNG fueling in one station, and may also be combined with an oil fueling station.

4.1.5 No buried or underground buildings or structures (except tank areas and fire water pools) should be provided within a fueling station. Underground LNG pipe trenches in the station shall be naturally ventilated; other pipe trenches shall be filled with dry sand.

4.1.6 LNG unloading shall take place in a fixed area.

4.2.1 The classification of LNG fueling stations, L-CNG fueling stations and LNG/L-CNG fueling stations shall comply with Table 4.2.1 (V is the total LNG tank volume).

Table 4.2.1, tier 1: LNG fueling station, total LNG tank volume more than 120 and not more than 180 cubic metres, single tank not more than 60 cubic metres; L-CNG and LNG/L-CNG fueling stations, total LNG tank volume more than 120 and not more than 180 cubic metres, single tank not more than 60 cubic metres, total CNG storage volume not more than 12 cubic metres.

Table 4.2.1, tier 2: LNG fueling station, total LNG tank volume more than 60 and not more than 120 cubic metres, single tank not more than 60 cubic metres; L-CNG and LNG/L-CNG fueling stations, total LNG tank volume more than 60 and not more than 120 cubic metres, single tank not more than 60 cubic metres, total CNG storage volume not more than 9 cubic metres.

Table 4.2.1, tier 3: LNG fueling station, LNG tank volume not more than 60 cubic metres; L-CNG and LNG/L-CNG fueling stations, LNG tank volume not more than 60 cubic metres, total CNG storage volume not more than 8 cubic metres.

4.2.2 The classification of stations combining LNG, L-CNG or LNG/L-CNG fueling stations with oil fueling stations shall comply with Table 4.2.2 (V is the total volume of LNG tanks and oil tanks).

Table 4.2.2, tier 1 combined station: total LNG tank volume not more than 120 cubic metres; combined total volume of LNG tanks and oil tanks more than 150 and not more than 210 cubic metres.

Table 4.2.2, tier 2 combined station: total LNG tank volume not more than 60 cubic metres; combined total volume of LNG tanks and oil tanks more than 90 and not more than 150 cubic metres.

Table 4.2.2, tier 3 combined station: total LNG tank volume not more than 60 cubic metres; combined total volume of LNG tanks and oil tanks not more than 90 cubic metres.

Note to Table 4.2.2: the single tank volume of oil tanks shall not exceed the relevant provisions of GB 50156 Code for design and construction of automobile gasoline and gas fueling stations, and the single tank volume of LNG tanks shall not exceed the provisions of Table 4.2.1 of this code.

4.3.1 Site selection shall comply with the requirements of urban planning, traffic planning, environmental protection and fire safety, and the site shall be located where transport is convenient.

4.3.2 Fueling stations within urban built-up areas should be close to urban roads, and their distance from road intersections shall meet the requirements of the traffic authorities.

4.3.3 The fire separation distances between the LNG tanks, vent pipe outlets and LNG unloading points of a fueling station and buildings and structures outside the station shall not be less than those specified in Table 4.3.3.

Table 4.3.3, important public buildings: LNG tanks 80 m for tier 1, tier 2 and tier 3 stations; vent pipe outlets 50 m; LNG unloading points 50 m.

Table 4.3.3, locations with open flames or spark emission and civil buildings of protected object class 1: LNG tanks 35 m (tier 1), 30 m (tier 2), 25 m (tier 3); vent pipe outlets 25 m; LNG unloading points 25 m.

Table 4.3.3, civil buildings of protected object class 2: LNG tanks 25 m (tier 1), 20 m (tier 2), 16 m (tier 3); vent pipe outlets 20 m; LNG unloading points 20 m.

Table 4.3.3, civil buildings of protected object class 3: LNG tanks 18 m (tier 1), 16 m (tier 2), 14 m (tier 3); vent pipe outlets 15 m; LNG unloading points 15 m.

Table 4.3.3, Class A and B production plants and warehouses and Class A and B liquid storage tanks: LNG tanks 35 m (tier 1), 30 m (tier 2), 25 m (tier 3); vent pipe outlets 25 m; LNG unloading points 25 m.

Table 4.3.3, Class C, D and E production plants and warehouses, Class C liquid storage tanks, and buried Class A and B liquid storage tanks with a volume not greater than 50 cubic metres: LNG tanks 25 m (tier 1), 22 m (tier 2), 20 m (tier 3); vent pipe outlets 20 m; LNG unloading points 20 m.

Table 4.3.3, outdoor substations: LNG tanks 40 m (tier 1), 35 m (tier 2), 30 m (tier 3); vent pipe outlets 25 m; LNG unloading points 25 m.

Table 4.3.3, railways: LNG tanks 80 m (tier 1), 60 m (tier 2), 50 m (tier 3); vent pipe outlets 50 m; LNG unloading points 50 m.

Table 4.3.3, cable trenches, heating pipe trenches and sewers: LNG tanks 12 m (tier 1), 10 m (tier 2), 10 m (tier 3); vent pipe outlets 10 m; LNG unloading points 10 m.

Table 4.3.3, expressways and main arterial roads, expressway and Class I and II highways: LNG tanks 12 m (tier 1), 10 m (tier 2), 8 m (tier 3); vent pipe outlets 8 m; LNG unloading points 8 m.

Table 4.3.3, secondary arterial roads and branch roads, Class III and IV highways: LNG tanks 10 m (tier 1), 8 m (tier 2), 8 m (tier 3); vent pipe outlets 6 m; LNG unloading points 6 m.

Table 4.3.3, overhead power lines: without insulation layer, 1.5 times the pole height for tanks of all tiers, vent pipe outlets and LNG unloading points; with insulation layer, 1.5 times the pole height for tier 1 tanks and 1 time the pole height for tier 2 and tier 3 tanks, vent pipe outlets and LNG unloading points.

Table 4.3.3, overhead communication lines: national Class I and II lines, 1.5 times the pole height for tier 1 tanks and 1 time the pole height for tier 2 and tier 3 tanks, vent pipe outlets and unloading points; general lines, 1 time the pole height for tier 1 tanks and 0.75 times the pole height for tier 2 and tier 3 tanks, vent pipe outlets and unloading points.

Notes 1 to 3 to Table 4.3.3: the classification of protected civil buildings shall follow GB 50156; the distances between skid-mounted equipment of LNG fueling stations and buildings and structures outside the station shall be determined according to the distances for the corresponding equipment in this table; the distances for buried and underground LNG tanks may be reduced by 30% and 20% respectively.

Notes 4 to 6 to Table 4.3.3: distances from LNG tanks, vent pipe outlets and LNG unloading points to independent civil buildings (without open flames) with a floor area not exceeding 200 square metres may be reduced by 20% from the class 3 protected object values; where the wall of a civil building facing the station is a solid wall of fire resistance rating I or II without door or window openings, distances from tanks, dispensers and vent pipes may be reduced by 20%; railways and highways subject to special national provisions shall follow those provisions.

5 General layout within the station

5.1.1 Where the distance between process facilities in the station and buildings or structures outside the station is less than or equal to 25 m, a non-combustible solid boundary wall not lower than 2.2 m shall be provided on the adjacent side.

5.1.2 Where the distance between process facilities in the station and buildings or structures outside the station is greater than 25 m and meets 1.5 times the fire separation distance of Table 4.3.3, the adjacent side may have a non-solid boundary wall.

5.1.3 The side facing the entrance and exit roads of the fueling station should have a non-solid boundary wall or be left open.

5.2.1 Vehicle entrances and exits shall be provided separately.

5.2.2 The width of a single lane for LNG tank trucks shall not be less than 4.5 m, the width of other single lanes shall not be less than 4 m, and the width of double lanes shall not be less than 7 m.

5.2.3 The turning radius of roads shall be determined according to the vehicle types and should not be less than 9 m; parking spaces in the station shall be level, road gradients shall not exceed 6%, and roads should slope towards the outside of the station.

5.2.4 Roads within the station shall not have asphalt pavement.

5.3.1 Dikes shall be provided around LNG tanks and shall comply with the following: 1 they shall be made of non-combustible solid materials; 2 the effective capacity within the dike shall not be less than the capacity of the largest single LNG tank; 3 the ground inside the dike should be lower than the ground outside by not less than 0.1 m, and the top of the dike should be not less than 0.8 m above the ground inside the dike and shall be higher than the ground outside the dike, preferably by not less than 0.4 m.

5.3.2 The clear distance between LNG tanks within a dike shall not be less than half the diameter of the larger adjacent tank and not less than 2 m. The clear distance between the inner wall of the dike and the outer wall of an LNG tank shall not be less than 2 m for vertical tanks and 1.5 m for horizontal tanks.

5.3.3 No other flammable liquid storage tanks, CNG high-pressure cylinder banks or gas storage wells shall be installed within the dike.

5.3.4 Drainage facilities should be provided within the dike, but they shall not discharge directly into the municipal drainage pipelines.

5.4.1 Fueling islands shall be 0.15 m to 0.20 m higher than the pavement of the fueling area, and their width shall not be less than 1.2 m.

5.4.2 The design of canopies shall comply with the following: 1 fueling islands should have canopies of non-combustible materials with a clear height not less than 5 m, and the horizontal distance between the canopy edge and the dispenser should not be less than 2.0 m; 2 canopy columns shall be not less than 0.6 m from the ends of the fueling island; 3 lighting shall be provided in the fueling area with an illuminance not less than 100 lx.

5.4.3 Anti-collision posts (barriers) shall be installed near dispensers, with a height not less than 0.5 m.

5.5.1 Tanks and process equipment of fueling stations should be arranged in the open air, and the fueling area shall have an open layout.

5.5.2 Fire separation distances between facilities within the fueling station shall not be less than those specified in Table 5.5.2.

5.5.3 Explosion hazardous areas classified according to Appendix B of this code shall not extend beyond the boundary wall and the usable land boundary line.

Table 5.5.2, buried gasoline and diesel tanks: to LNG tanks 15 m (tier 1), 12 m (tier 2), 10 m (tier 3); to LNG system vent outlets 6 m; to LNG unloading points 6 m; to LNG dispensers 4 m; to LNG submerged pump sumps 6 m; to LNG plunger pumps 6 m; to high-pressure vaporizers 5 m; other distances as specified in GB 50156.

Table 5.5.2, oil tank vent pipe outlets: to LNG tanks 12 m (tier 1), 10 m (tier 2), 8 m (tier 3); to LNG system vent outlets 6 m; to LNG unloading points 8 m; to LNG dispensers 8 m; to LNG submerged pump sumps 8 m; to LNG plunger pumps 8 m; to high-pressure vaporizers 5 m.

Table 5.5.2, LNG tanks of tier 1 stations: between tanks 2 m; CNG cylinders (wells) 6 m; CNG system vent outlets 5 m; sealed oil unloading points 12 m; LNG unloading points 6 m; oil dispensers 8 m; CNG dispensers 8 m; LNG dispensers 6 m; LNG plunger pumps 2 m; high-pressure vaporizers 6 m; station house 10 m; fire pump house and fire water intake 20 m; gas (oil) fired boiler room and generator room 15 m; substation room 12 m; boundary wall 6 m.

Table 5.5.2, LNG tanks of tier 2 stations: between tanks 2 m; CNG cylinders (wells) 4 m; CNG system vent outlets 4 m; sealed oil unloading points 10 m; LNG unloading points 3 m; oil dispensers 6 m; CNG dispensers 6 m; LNG dispensers 4 m; LNG plunger pumps 2 m; high-pressure vaporizers 4 m; station house 8 m; fire pump house and fire water intake 15 m; boiler and generator room 12 m; substation room 10 m; boundary wall 5 m.

Table 5.5.2, LNG tanks of tier 3 stations: between tanks 2 m; CNG cylinders (wells) 4 m; CNG system vent outlets 4 m; sealed oil unloading points 8 m; LNG unloading points 2 m; oil dispensers 6 m; CNG dispensers 4 m; LNG dispensers 2 m; LNG plunger pumps 2 m; high-pressure vaporizers 3 m; station house 6 m; fire pump house and fire water intake 15 m; boiler and generator room 12 m; substation room 8 m; boundary wall 4 m.

Table 5.5.2, CNG cylinders (wells): to LNG system vent outlets 3 m; to LNG unloading points 6 m; to LNG dispensers 6 m; to LNG submerged pump sumps 6 m; to LNG plunger pumps 6 m; to high-pressure vaporizers 3 m; other distances as specified in GB 50156.

Table 5.5.2, CNG system vent outlets: to LNG unloading points 6 m; to LNG dispensers 6 m; to LNG submerged pump sumps 4 m; to LNG plunger pumps 6 m; no distance requirement to LNG system vent outlets and high-pressure vaporizers.

Table 5.5.2, LNG system vent outlets: to sealed oil unloading points 6 m; to oil dispensers 6 m; to CNG dispensers 8 m; to station house 8 m; to fire pump house and fire water intake 12 m; to boiler and generator room 12 m; to substation room 10 m; to boundary wall 3 m.

Table 5.5.2, sealed oil unloading points: to LNG unloading points 6 m; to LNG dispensers 6 m; to LNG submerged pump sumps 6 m; to LNG plunger pumps 6 m; to high-pressure vaporizers 5 m.

Table 5.5.2, LNG unloading points: to oil dispensers 6 m; to CNG dispensers 6 m; to LNG plunger pumps 2 m; to high-pressure vaporizers 4 m; to station house 6 m; to fire pump house and fire water intake 15 m; to boiler and generator room 12 m; to substation room 8 m; to boundary wall 2 m.

Table 5.5.2, oil dispensers: to LNG dispensers 2 m; to LNG submerged pump sumps 6 m; to LNG plunger pumps 6 m; to high-pressure vaporizers 6 m.

Table 5.5.2, CNG dispensers: to LNG dispensers 2 m; to LNG submerged pump sumps 6 m; to LNG plunger pumps 6 m; to high-pressure vaporizers 5 m.

Table 5.5.2, LNG dispensers: to high-pressure vaporizers 5 m; to station house 6 m; to fire pump house and fire water intake 15 m; to boiler and generator room 8 m; to substation room 8 m.

Table 5.5.2, LNG submerged pump sumps: to high-pressure vaporizers 5 m; to station house 6 m; to fire pump house and fire water intake 15 m; to boiler and generator room 8 m; to substation room 8 m; to boundary wall 2 m.

Table 5.5.2, LNG plunger pumps: to high-pressure vaporizers 2 m; to station house 6 m; to fire pump house and fire water intake 15 m; to boiler and generator room 8 m; to substation room 8 m; to boundary wall 2 m.

Table 5.5.2, high-pressure vaporizers: to station house 6 m; to fire pump house and fire water intake 15 m; to gas (oil) fired boiler room and generator room 8 m; to substation room 8 m; to boundary wall 2 m.

Notes 1 to 3 to Table 5.5.2: values marked with an asterisk are those of GB 50156; distances between buried and underground LNG tanks and buildings and structures within the station may be reduced by 30% and 20% respectively; distances between skid-mounted equipment of LNG fueling stations and buildings and structures within the station shall be determined according to the corresponding facilities in this table.

Notes 4 to 6 to Table 5.5.2: distances between non-high-pressure vaporizers and LNG tanks, LNG plunger pumps and CNG cylinders may be determined according to process requirements; distances to the station house and substation room shall be measured from their doors and windows; a dash in the table means no fire separation distance requirement.

6 Process facilities

6.1.1 The design and manufacture of LNG tanks shall comply with the relevant provisions of the current national standards GB 150 Steel pressure vessels, GB 18442 Cryogenic insulated pressure vessels and TSG R0004 Safety technical supervision regulation for stationary pressure vessels.

6.1.2 The ancillary equipment of LNG tanks shall comply with the following: 1) liquid level gauges and pressure gauges with local indication shall be provided; 2) tanks shall have high and low liquid level alarms and a high pressure alarm, with remote monitoring; 3) emergency shut-off valves shall be installed on the liquid phase connecting pipes of tanks; 4) tanks shall have full-lift closed safety valves, not fewer than 2 (1 duty and 1 standby), arranged in accordance with TSG R0004; 5) a shut-off valve shall be installed between the safety valve and the tank, sealed in the open position during normal operation; 6) manual vent valves shall be installed on pipes connected to the vapour space of the tank.

6.2.1 Shut-off valves and check valves shall be installed on the liquid phase pipes connecting to tank trucks, and shut-off valves should be installed on the vapour phase pipes.

6.2.2 LNG unloading should use austenitic stainless steel metal hoses, whose nominal pressure shall not be less than 2 times the working pressure of the loading and unloading system and whose minimum burst pressure shall be greater than 4 times the nominal pressure.

6.3.1 The piping system and ancillary equipment of LNG submerged pumps shall comply with the following: 1) the height difference between the bottom (outer wall) of the LNG tank and the top (outer wall) of the submerged pump sump shall meet the performance requirements of the pump; 2) the vapour return pipe of the pump sump should be connected to the vapour phase pipe of the LNG tank, or to the vapour phase pipe of the tank truck when the submerged pump is used for unloading; 3) pressure, temperature or liquid level detection devices shall be provided with remote monitoring; 4) full-lift closed safety valves and shut-off valves shall be installed on the pump outlet pipe.

6.3.2 Plunger pumps shall comply with the following: 1) LNG plunger pumps shall be arranged to meet the pump suction head requirements; 2) flexible and anti-vibration devices shall be provided on the inlet and outlet pipes; 3) check valves and full-lift closed safety valves shall be installed on the outlet pipe; 4) temperature and pressure detection devices shall be provided at the pump outlet, with interlocked pump shutdown on overpressure.

6.3.3 Effective noise control measures shall be taken for plunger pumps, and the impact of their operating noise on the surrounding environment shall comply with the relevant regional environmental provisions.

6.4.1 The technical requirements of LNG dispensers shall comply with the following: 1) the filling pressure of the fueling system shall not be greater than the maximum working pressure of the on-board vehicle cylinder; 2) the metering error of the dispenser should not exceed 1.5%; 3) the dispenser shall have a safety device with self-closing function under a certain external force or a breakaway valve, whose separation force should be in the range 400 N to 600 N; 4) dispenser hoses shall comply with clause 6.2.2.

6.4.2 LNG fueling islands should be provided with nitrogen or compressed air purge connections.

6.5.1 Several LNG tanks may share one pressure-building vaporizer.

6.5.2 The selection of ambient air vaporizers shall meet the operating requirements under the lowest local air temperature conditions.

6.5.3 The design pressure of vaporizers shall not be less than 1.2 times the maximum working pressure.

6.5.4 The outlet temperature of high-pressure vaporizers shall meet the requirements of gas storage and fueling devices, and temperature detection and interlock devices shall be provided.

6.6.1 The design of LNG pipes and cryogenic vapour phase pipes of fueling stations shall comply with the following: 1) the piping system shall be designed in accordance with GB 50316; 2) pipes and fittings shall comply with GB 150, GB 50316 and TSG R0004; 3) stainless steel seamless pipes shall comply with GB/T 14976 and fittings with GB/T 12459 Steel butt-welding seamless pipe fittings; 4) flanges, gaskets and fasteners shall match the standard system and specifications of the connected equipment and valves; 5) the flow velocity of LNG in pipes should be less than 1 m/s upstream of the pump and less than 3 m/s downstream of the pump.

6.6.2 The root valves of LNG tanks shall be connected to the tank by welding.

6.6.3 The insulation measures adopted for cryogenic pipes shall comply with the relevant provisions of GB 50264 Code for design of insulation engineering of industrial equipment and pipes.

6.6.4 Corrosion protection of pipes shall comply with the relevant provisions of Chapter 4 of SY 0007-1999 Code for design of corrosion control of steel pipelines and storage tanks.

6.6.5 A safety valve or other pressure relief device shall be installed between two shut-off valves on LNG pipes.

6.6.6 Natural gas venting shall comply with the following: 1) the outlet of a centralized vent pipe shall be at least 2.0 m above the LNG tanks and buildings within 12.0 m, and not less than 5.0 m above ground; the outlet shall not have rain caps or other devices obstructing upward gas flow, and drainage measures should be taken at its base; 2) cryogenic natural gas shall be heated by a heater before venting, and the vent temperature should not be more than 50 degrees Celsius below ambient temperature; 3) vent pipes shall have flashback prevention devices.

6.7.1 Fueling stations and oil and gas fueling stations shall have an emergency shut-off system able to rapidly close important LNG pipeline valves and cut off power to LNG pumps in an accident.

6.7.2 Emergency shut-off valves should be pneumatically operated valves.

6.7.3 Emergency shut-off valves and LNG pumps shall have interlock devices with both manual and automatic shut-off functions.

6.7.4 The emergency shut-off system shall have a manual reset function.

6.7.5 The emergency shut-off system should be able to be activated from the following locations: 1) within 5 m of the unloading point; 2) at a location near the dispensers easily accessible to staff; 3) in the control room or duty room.

6.8.1 Combustible gas leak detection devices shall be installed in operating areas and other hazardous locations, with audible and visual alarms both locally and in the control room.

6.8.2 The natural gas concentration alarm set point shall not exceed 20% of the lower explosive limit concentration (V%).

6.8.3 The design of the leak detection and alarm system shall comply with the relevant provisions of GB 50493 Code for design of combustible gas and toxic gas detection and alarm for petrochemical industry.

6.9.1 The tank volume of an LNG mobile fueling unit shall not exceed 20 cubic metres.

6.9.2 The fire separation distances between an LNG mobile fueling unit in fueling operation and buildings and structures inside and outside the station shall comply with the provisions of this code for tier 3 stations.

6.9.3 The process equipment of LNG mobile fueling units shall comply with the relevant provisions of Chapter 6 of this code.

6.9.4 LNG mobile fueling units may be installed without dikes.

6.9.5 Electrical facilities within explosive gas atmosphere hazardous areas shall comply with the relevant provisions of clause 8.1.4.

6.9.6 During LNG fueling operations the vehicle body shall be fixed in position.

6.9.7 LNG mobile fueling units shall be equipped with not fewer than 4 dry powder fire extinguishers of 4 kg.

7 Fire protection facilities, water supply and drainage

7.1.1 Each dispenser and each tank shall be provided with not fewer than 2 dry powder fire extinguishers of 4 kg.

7.1.2 LNG fueling stations shall be equipped with 2 wheeled dry powder fire extinguishers of 35 kg; where the distance between tanks of two different media exceeds 15 m, they shall be provided separately for each.

7.1.3 Fire extinguishing equipment for buildings shall comply with the current national standard GB 50140 Code for design of extinguisher distribution in buildings.

7.2.1 Tier 1 and tier 2 LNG fueling stations with aboveground LNG tanks and tier 1 oil and gas fueling stations shall be provided with a fire water supply system.

7.2.2 Tier 1 and tier 2 LNG fueling stations and tier 1 oil and gas fueling stations with aboveground LNG tanks located outside urban built-up areas in areas of severe water shortage may omit the fire water supply system when all of the following are met: 1) the distances from LNG tanks, vent pipes and unloading points to buildings and structures outside the station are increased to at least twice the required values; 2) the clear distance between LNG tanks is not less than 4 m; 3) the fire extinguishing equipment of the LNG station area is doubled.