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In order to adapt to the general rules of international technical regulations and technical standards, the Ministry of Housing and Urban-Rural Development has successively issued documents such as Opinions on Deepening the Reform of Standardization of Engineering Construction since 2016, which put forward the long-term goal of the government to develop mandatory standards and social organizations to develop voluntary standards and define the reform task of gradually replacing the mandatory provisions scattered in current standards with full-text mandatory engineering construction codes, gradually forming a "technical regulations" system composed of technical provisions in laws, administrative regulations and departmental rules and full-text mandatory engineering construction codes.
About the types of codes. The mandatory engineering construction code system covers all kinds of construction projects in the field of engineering construction, and is divided into two types, namely engineering project codes (hereinafter referred to as project codes) and general technical codes (hereinafter referred to as general codes). The project codes take the whole engineering construction project as the object, with five major factors, such as project scale, layout, function, performance and key technical measures, as the main content. The general codes take the general technology of each discipline to meet the functional performance requirements of engineering construction projects as the object, with the general technical requirements, such as survey, design, construction, repair and maintenance, as the main content. In the full-text mandatory engineering construction code system, the project codes are the backbone, and the general codes are the common and general professional key technical measures for all kinds of projects.
About the five major factor indicators. The factors in the mandatory engineering construction codes are the basic provisions to ensure the systematization and efficiency improvement of urban and rural infrastructure construction, and the basic requirements to support the high-quality development of urban and rural construction. The scale requirements of the project mainly stipulate that the construction project shall have complete production or service capacity and shall adapt to the level of economic and social development. The layout requirements of the project mainly stipulate the industrial layout, site selection of construction projects, overall design, general layout and integrated technical requirements coordinated with the scale. Reasonable distribution of supply capacity shall be considered to improve the overall level of related facilities construction. The functional requirements of the project mainly stipulate the composition and purpose of the project and clarify the basic components of the project, which are the guarantee for the project to play its expected role. The performance requirements of the project mainly stipulate the construction level or technical level of the construction project, reflect the applicability of the construction project, and define the basic level that the project quality, safety, energy conservation, environmental protection, livable environment and sustainable development shall achieve. Key technical measures are the basic technical regulations for realizing the functional and performance requirements of construction projects, and the basic guarantee for implementing the development goals of urban and rural construction such as safety, green, resilience, wisdom, livability, fairness and efficiency.
About the implementation of codes. Mandatory engineering construction codes have mandatory binding force, which are the bottom line for ensuring people's life and property safety, personal health, engineering safety, ecological environment safety, public rights and interests as well as promoting energy and resource conservation and meeting economic and social management, must be strictly implemented in the whole process of construction activities such as survey, design, construction, acceptance, repair, maintenance and demolition of engineering construction projects. For existing building renovation projects (meaning that existing use functions are not changed), when the conditions are not available and it is really difficult to implement the current code, the stringency of the code implemented shall not be inferior to that implemented in construction. The voluntary engineering construction standards matching with the mandatory engineering construction codes is a mature technical measure that has been tested by practice and guarantees to meet the requirements of the mandatory codes, and shall also be implemented under normal circumstances. On the premise of meeting the project functional and performance requirements and key technical measures stipulated in mandatory engineering construction codes, relevant group standards and enterprise standards may be reasonably selected to optimize the project function and performance or make them reach a higher level. Voluntary engineering construction standards, group standards and enterprise standards shall be coordinated and match with mandatory engineering construction codes, and all technical requirements shall not be lower than the relevant technical level of mandatory engineering construction codes.
After the implementation of the mandatory engineering construction codes, the mandatory provisions in the current national standards and professional standards related to engineering construction shall be abolished at the same time. The mandatory provisions in the current provincial standards for engineering construction shall be revised in time, and shall not be less stringent than the provisions of the mandatory engineering construction codes. If the relevant provisions in current engineering construction standards, including mandatory and voluntary standards, are inconsistent with those of the mandatory engineering construction codes, the provisions of the mandatory engineering construction codes shall prevail.
Project code for gas engineering
1 General provisions
1.0.1 The code is formulated to promote the high-quality development of urban and rural gas engineering, prevent and reduce gas safety accidents, ensure the continuous and stable gas supply, and safeguard the personal, property and public safety.
1.0.2 The code must be implemented for the gas engineering projects in cities, towns and villages. The code is not applicable to the following engineering projects:
1 Long-distance gas transmission pipeline engineering project before town gas gate station;
2 Gas engineering projects for internal production in industrial enterprises;
3 Production and utilization engineering project of biogas and straw gas;
4 Gas application projects on marine and inland ships, railway vehicles, automobiles and other means of transportation.
1.0.3 Gas engineering shall realize continuous and stable gas supply and safe operation, and shall follow the following principles:
1 Comply with national policies on energy, ecological environment, land utilization, disaster prevention and mitigation, emergency management, etc.;
2 Guarantee personal, property and public safety;
3 Encourage engineering technology innovation;
4 Actively adopt modern information technology;
5 Improve the quality of engineering construction and the level of operation and maintenance.
1.0.4 Whether the technical methods and measures adopted in the project construction meet the requirements of the code shall be judged by the relevant responsibility subjects. Innovative technical methods and measures shall be demonstrated and meet the performance requirements in the code.
2 Basic requirements
2.1 Scale and layout
2.1.1 The scale of gas used in gas engineering shall be determined according to the conditions of urban and rural development, population scale, user demand and gas supply resources, through market investigation and scientific prediction, and in combination with comprehensive analysis of gas consumption index and gas consumption law.
2.1.2 The selection of gas source shall be based on the national energy policy, follow the principles of energy conservation, environmental protection, stability and reliability, consider the alternative resource conditions, and be determined through technical and economic demonstration.
2.1.3 The gas supply system shall have the gas supply capacity reserve to meet the requirements of peak regulation supply and emergency supply. The gas supply capacity reserve shall be determined according to the requirements of gas supply conditions, supply and demand balance, system dispatching and emergency.
2.1.4 The gas supply system facilities shall be so arranged that it is coordinated with the urban and rural functional structure, and shall meet the needs of urban and rural construction and development, gas industry development and urban and rural safety.
2.2 Construction requirements
2.2.1 The gas supply system shall be provided with stations, pipelines and necessary facilities for operation and maintenance to ensure safe and stable gas supply. The operating process parameters such as pressure and flow shall ensure the safety of the supply system and the normal use of users, and shall meet the following requirements:
1 The supply system shall have the function of timely cutting off under accident conditions, and shall be provided with the measures to prevent overpressure in the pipe network;
2 Gas equipment and pipelines shall have the strength and tightness to withstand the design pressure and temperature;
3 The gas supply pressure shall be stable, and the pressure change before the gas appliance and gas-consuming equipment shall be within the allowable range.
2.2.2 The gas supply system shall be equipped with an information management system, and shall have data collection and monitoring functions. Gas automation control system, basic network facilities and information management system shall meet the requirements for national information security.
2.2.3 Materials and equipment used in gas facilities shall meet the requirements for energy conservation and environmental protection, system medium characteristics, function demands, external environment and design conditions. The pressure of equipment, pipelines and accessories shall not be less than the system design pressure.
2.2.4 Within the design working life, it shall be ensured that the gas facilities operate reliably under normal use and maintenance conditions. When the gas facilities need to be used continuously after the design working life is reached or the gas facilities are damaged by geological disasters, operation accidents or external forces, the gas facilities shall be evaluated for suitability for use.
2.2.5 Measures such as fire prevention, explosion prevention and earthquake resistance shall be taken for gas facilities to effectively prevent accidents.
2.2.6 The pipelines as well as the connection mode of pipelines and equipment shall conform to the medium characteristics and process conditions, and the connection must be tight and reliable.
2.2.7 Conditions of gas accumulation after gas leakage shall not be available at places where gas equipment, pipelines and gas appliances are installed. Gas pipelines, pressure regulating devices and gas appliances with gas relative density greater than or equal to 0.75 shall not be installed in basements, semi-basements, underground boxes, underground utility tunnel and other underground spaces.
2.2.8 The performance parameters of gas appliances and gas-consuming equipment shall be compatible with the characteristics and supply pressure of the gas used, and the use places of gas appliances and gas-consuming equipment shall meet the safe use conditions.
2.3 Operation and maintenance
2.3.1 Gas facilities can only be put into use after the completion acceptance and commissioning are passed. The following conditions must be met before the gas facilities are put into use:
1 Safety facilities to prevent safety accidents shall be put into use at the same time as the main project;
2 Facilities to prevent or reduce pollution shall be put into use at the same time as the main project.
2.3.2 The construction and operation units of gas facilities shall establish and improve the safety management system, formulate the operation and maintenance regulations and accident emergency plan, and arrange full-time safety management personnel.
2.3.3 The construction, operation, maintenance, emergency repair and other places of gas facilities and important gas facilities shall be provided with standardized and obvious safety warning signs.
2.3.4 The operation unit of gas facilities shall be equipped with emergency rescue teams with professional skills without duty interruption, necessary spare parts, repair machines and emergency equipment, and shall set up and announce the 24-h repair service telephone number and other contact information to the public.
2.3.5 A special person shall be assigned for supervision in the operation process where gas facilities may leak gas, and it is not allowed to operate alone. Effective safety measures shall be taken before the cause of gas leakage is found out or the leakage is fixed.
2.3.6 The on-site operation of gas facilities shall meet the following requirements:
1 Operators shall master the knowledge and skills of gas characteristics, related processes and emergency treatment;
2 The operation area shall be marked for the operation or emergency repair operation, and guardrails and warning signs shall be set at the boundary of the area;
3 Operators or emergency repair personnel shall wear anti-static workwear and other protective appliances, and shall not wear or take off protective appliances in the operation area;
4 No kindling such as mobile phones, matches or lighters shall be carried in the operation or emergency repair area, and no clothes that are easy to generate sparks shall be worn.
2.3.7 Process wastes that fail to meet the emission standards during the normal operation of gas facilities shall not be directly discharged.
3 Gas quality
3.0.1 The quality of gas supplied by the gas engineering shall meet the following requirements:
1 It shall comply with the gas classification and quality standards specified by the nation;
2 It shall meet the gas demand and use conditions of all kinds of users;
3 The calorific capacity (calorific value) shall be stable;
4 The component changes shall ensure the normal operation of the gas appliance.
3.0.2 The reference calorific capacity (calorific value) of gas supplied by the system shall be determined, and the change of calorific capacity (calorific value) shall be within ±5% of the reference calorific capacity (calorific value). Gas composition and impurity content, dew point temperature, gas connecting point pressure and other gas quality parameters shall be determined according to gas source conditions and gas demand.
3.0.3 The quality of natural gas and such shale gas, coalbed methane, coal-based natural gas and biomass gas as are delivered according to the quality of natural gas shall meet the following requirements:
1 The quality of natural gas shall meet those specified in Table 3.0.3.
Table 3.0.3 Quality indicator of natural gas
Gross calorific value (MJ/m3) ≥31.4
Total sulfur (counted by sulfur) (mg/m3) ≤100
Hydrogen sulfide (mg/m3) ≤20
Carbon dioxide (y, %) ≤4.0
Note: The standard reference condition of gas volume in the table is 101.325kPa and 20℃.
2 Under the conditions with the pressure and temperature at the natural gas junction, the hydrocarbon dew point of natural gas shall be 5℃ lower than the lowest ambient temperature; there shall be no solid, liquid or colloidal substances in the natural gas.
3.0.4 The quality of liquefied petroleum gas (LPG) shall meet those specified in Table 3.0.4.
Table 3.0.4 Quality indicators of LPG
Item Quality indicator
Commercial propane Commercial butane-propane mixture Commercial butane
Density (15℃)(kg/m3) Reported
Vapour pressure (37.8℃)(kPa) ≤1,430 ≤1,380 ≤485
Component
Component of C3 hydrocarbons (volume fraction) (%) ≥95 — —
Component of C4 and above hydrocarbons (volume fraction) (%) ≤2.5 — —
Component of (C3+C4) hydrocarbons (volume fraction) (%) — ≥95 ≥95
Component of C5 and above hydrocarbons (volume fraction) (%) — ≤3.0 ≤2.0
Residue
Evaporation residue (mL/100mL) ≤0.05
Oil stain observation Passed
Copper corrosion (40℃, 1h) (Rating) ≤1
Total sulfur content (mg/m3) ≤343
Hydrogen sulfide (one of the following requirements shall be met):
Lead acetate method None
Chromatography (mg/m3) ≤10
Free water None
Notes:
1 Non-hydrocarbon compounds other than odorants are not allowed to be added artificially in liquefied petroleum gas;
2 “Passed” means that when droping 0.3mL of solvent-residue mixture liquor on the filter paper with an increments of 0.1mL each time, and observing it in sunlight after 2min, there is no permanent oil ring;
3 "-” means that it is not detectable.
3.0.5 The quality of manufactured gas shall meet the requirements of Table 3.0.5.
Table 3.0.5 Quality indicators of manufactured gas
Item Quality indicator
Lower calorific value1 (MJ/m3)
Gas of Category I 2
Gas of Category II 2
>14
>10
Impurities
Tar and dust (mg/m3)
Hydrogen sulfide (mg/m3)
Ammonia (mg/m3)
Naphthalene3 (mg/m3)
<10
<20
<50
<50×102/P (winter)
<100×102/P (summer)
Oxygen content 4 (volume fraction)
Gas of Category I
Gas of Category II
<2%
<1%
Carbon monoxide content 5(volume fraction) <10%
Notes:
1 The gas volume (m3) in the table refers to the volume at 101.325kPa and 15℃;
2 Gas of Category I refers to dry distillation gas, and gas of Category II refers to gas from coal gasification and oil gasification (including LPG and those from natural gas reforming).
3 Naphthalene refers to naphthalene and its homologues α -methylnaphthalene and β-methylnaphthalene. On the premise of ensuring no naphthalene precipitation in gas, each region may set its own naphthalene content index according to the soil temperature at the place where the gas pipeline is buried. If the absolute pressure (P) of the pipeline gas transmission point is less than 202.65 kPa, the pressure (P) may not be included in the calculation;
4 Oxygen content refers to the indicator required in the production process of a gas plant.
5 For gas of Category II or gas of Category I mixed with Category II, the carbon monoxide content shall be less than 20% (volume fraction).
3.0.6 If the quality of gas source fails to meet the quality requirements specified in 3.0.2~3.0.5 of the code, the gas shall be processed.
3.0.7 Gas shall have an undesirable odor that can be perceived by people with normal sense of smell so that, in case of any leakage, people can be warned before any danger occurs.
3.0.8 The supplied gas shall be odorized if it fails to meet the provisions of 3.0.7 of the code. The minimum amount of odorizer shall meet the following requirements:
1 In case of non-toxic gas, the gas leaks into the air shall be detectable when it reaches 20% of the lower explosive limit;
2 In case of toxic gas, the gas leaks into the air shall be detectable when it reaches the permissible harmful concentration for human body.;
3 For gas containing toxic carbon monoxide, it shall be detectable when the volume fraction of carbon monoxide in the air reaches 0.02%.
3.0.9 The odorant added to the gas shall meet the following requirements:
1 The odor of odorant shall be distinct from other odors in daily environment. The odorant, after mixing with the gas, shall maintain a distinct odor, which shall disappear slowly after the gas leakage.
2 The odorant and their combustion products shall not be toxic to human body, and shall not corrode or damage the materials and equipment in contact with them.
3 The odorant shall be soluble in water to the extent that its mass fraction is not greater than 2.5%.
3.0.10 When the gas in the gas supply system needs to be mixed with air, the volume fraction of the gas in the mixed gas shall be greater than 2 times its upper explosion limit, and the dew point temperature of the mixed gas shall be lower than the lowest temperature that may be reached on the outer wall of the transmission pipeline by more than 5℃. The hydrogen sulfide content in the mixture shall not exceed 20 mg/m3.
Foreword iv
1 General provisions
2 Basic requirements
2.1 Scale and layout
2.2 Construction requirements
2.3 Operation and maintenance
3 Gas quality
4 Gas stations
4.1 Station area
4.2 Process
4.3 Storage tanks and gas cylinders
5 Pipelines and pressure regulating facilities
5.1 Transmission and distribution pipelines
5.2 Pressure regulating facilities
5.3 User pipeline
6 Gas appliances and gas-consuming equipment
6.1 Household gas appliances and accessories
6.2 Commercial gas appliances, gas-consuming equipment and accessories
6.3 Flue gas removal
