GB 50058-1992 Code for design of electrical installations for explosive and fire hazardous environments
Some standard content:
Engineering Construction Standard Full Text Information System
National Standard of the People's Republic of China
50058-92
Design Code for Electrical Installations in Explosive Atmospheres and Fire Hazards
Electrical Installations Design Code for Explosive Atmospheres and Fire Hazards Construction Standard
1992-06-—09 Issued
State Bureau of Technical Supervision
Ministry of Construction of the People's Republic of China
Engineering Construction Standard Full Text Information System
1992-12-01 Implementation
Jointly Issued
Engineering Construction Standard Full Text Information System
National Standard of the People's Republic of China
Design Code for Electrical Installations in Explosive Atmospheres and Fire Hazards
GB50058-92
: Ministry of Chemical Industry of the People's Republic of China
Editor Department:
Approving Department: Ministry of Construction of the People's Republic of China Effective Date: December 1, 1992
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Notice on the Issuance of the National Standard "Design Specifications for Power Installations in Explosive and Fire Hazardous Environments" Jianbiao [1992] No. 354
According to the requirements of the State Planning Commission's Document No. Jizong [1986] 250, the "Design Specifications for Power Installations in Explosive and Fire Hazardous Environments" revised by the Ministry of Chemical Industry and relevant departments has been reviewed by relevant departments. The "Design Specifications for Power Installations in Explosive and Fire Hazardous Environments" GB50058-92 is now approved as a mandatory national standard and will be implemented from December 1, 1992. The original "Design Specifications for Power Installations in Explosive and Fire Hazardous Locations" GBJ58-83 will be abolished at the same time.
This specification is managed by the Ministry of Chemical Industry, and its specific interpretation and other work are the responsibility of China Global Chemical Engineering Corporation. The publication and distribution is organized by the Standard and Quota Research Institute of the Ministry of Construction. Ministry of Construction of the People's Republic of China
June 9, 1992
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Revision Notes
This specification is edited by the Ministry of Chemical Industry in accordance with the requirements of the State Planning Commission's Document No. 250 [1986], and is specifically revised by China Huanqiu Chemical Engineering Company and relevant units to jointly revise the "Design Specification for Electrical Installations in Explosion and Fire Hazardous Locations GBJ58-83". During the revision process, the specification group conducted extensive investigations and studies, carefully summarized the experience since the implementation of the specification, absorbed some scientific research results, and widely solicited opinions from relevant units across the country. Finally, our ministry and relevant departments reviewed and finalized the draft. The main contents of this revision include: the division of hazardous areas for explosive gas environments, explosive dust environments, and fire hazardous environments, the scope of hazardous areas, and the selection of electrical equipment.
During the implementation of this specification, if any amendment or supplement is found, please send your comments and relevant information to China Huanqiu Chemical Engineering Corporation (Beijing Heping Street North Exit, Postal Code 100029), and copy to the Ministry of Chemical Industry of the People's Republic of China for reference in future revisions.
Ministry of Chemical Industry
September 1991
Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Chapter 1 General
Chapter 2
Section 1
Section 2
Section 3
Section 4
Section 5
Chapter 3
Section 1
Section 2
Section 3
Section 4| |tt||Chapter 4
Section 1
Section 2
Section 3
Appendix 1
Appendix 2
Appendix 3
Appendix 4
Appendix 5
Explosive gas environment
General provisions·
Division of hazardous areas in explosive gas environment
Scope of hazardous areas in explosive gas environmentClassification and grouping of explosive gas mixturesElectrical devices in explosive gas environment·
Explosive dust environment
Division of hazardous areas in explosive dust environment.
Scope of hazardous areas in explosive dust environmentElectrical devices in explosive dust environment.
Fire hazard environment
General provisions……
Fire hazard Area division
Electrical installations in fire hazardous environments.
Explanation of terms
Example diagram of explosion hazardous area division and table of explosion hazardous area division conditions:
Examples of classification and grouping of explosive mixtures of gas or vapor Characteristics of explosive dust
Explanation of terms used in this specification
Additional instructions
Engineering construction standard full text information system
(19)
(30)
(38)
(38)
(39)
Engineering construction standard full text information system
Chapter 1 General provisions
Article 1.0.1 In order to make the design of electrical installations in explosion and fire hazardous environments in line with the principle of prevention first and to ensure the safety of people and property, measures shall be taken according to local conditions. This specification is formulated in order to take preventive measures to ensure that the technology is advanced, economically reasonable, safe and applicable. Article 1.0.2 This specification applies to the power design of new, expanded and rebuilt projects where explosion and fire hazards occur or may occur during production, processing, handling, transportation or storage.
This specification does not apply to the following environments:
1. Underground mines;
2. Environments where gunpowder, explosives and detonators are manufactured, used or stored;
3. Areas where electrical devices such as electrolysis and electroplating are used for production and are directly related to the production process;
4. Battery rooms;
5. Environments where strong oxidants are used and substances that can ignite on their own without external ignition sources;
6. Water, land and air transportation vehicles and offshore oil well platforms. Article 1.0.3 In addition to complying with the provisions of this specification, the power design of explosion and fire hazardous environments shall also comply with the provisions of the current relevant national standards and specifications. Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
Chapter 2 Explosive Gas Environment
Section 1 General Provisions
Article 2.1.1 When one of the following explosive gas mixture environments appears or may appear during the production, processing, handling, transportation or storage, the electrical design of the explosive gas environment shall be carried out:
1. Under atmospheric conditions, flammable substances such as flammable gases and flammable liquids' vapor or mist mix with air to form an explosive gas mixture; 2. The vapor or mist of flammable liquids with a flash point lower than or equal to the ambient temperature mix with air to form an explosive gas mixture; 3. When the material operating temperature is higher than the flash point of the flammable liquid and there is a possibility that the flammable liquid will leak, its vapor mixes with air to form an explosive gas mixture. Article 2.1.2 The following conditions must exist simultaneously for an explosion to occur in an explosive gas environment:
1. The presence of flammable gas, vapor or mist of flammable liquid, whose concentration is within the explosion limit;
2. The presence of sparks, arcs or high temperatures sufficient to ignite the explosive gas mixture. Article 2.1.3 The following measures should be taken to prevent explosions in an explosive gas environment:
1. First, the possibility of the simultaneous occurrence of conditions that produce an explosion should be minimized.
2. Measures to eliminate or reduce the generation and accumulation of flammable substances should be taken in process design:
1. Lower pressure and temperature should be adopted in the process flow to confine flammable substances in closed containers;
2. The process layout should limit and reduce the scope of the explosion hazard area, and explosion hazard areas of different levels, or explosion hazard areas and non-explosion hazard areas should be separated in their own engineering construction standard full-text information system
engineering construction standard full-text information system
factory buildings or boundaries;
3. Measures such as covering with nitrogen or other inert gases can be adopted in the equipment; 4. Measures such as safety interlocks or the addition of chemicals such as polymerization inhibitors in the event of an accident should be adopted.
3. To prevent the formation of explosive gas mixtures or shorten the residence time of explosive gas mixtures, the following measures should be taken: 1. The process equipment should be arranged in an open-air or dispersed manner; 2. Mechanical ventilation equipment should be installed;
3. Positive pressure chambers should be installed in explosion-hazardous environments; 4.Automatic measuring instruments shall be installed at locations in the area where explosive gas mixtures are likely to form and accumulate. When the gas or vapor concentration approaches 50% of the lower explosion limit, it shall be able to reliably send out signals or cut off the power supply. 4. Measures shall be taken to eliminate or control sparks, arcs or high temperatures generated by electrical equipment circuits in the area.
Section 2 Division of Hazardous Areas for Explosive Gas Environments Article 2.2.1 Explosive gas environments shall be divided into zones according to the frequency and duration of the occurrence of explosive gas mixtures in accordance with the following provisions: 1. Zone 0: An environment where explosive gas mixtures appear continuously or for a long time; 2. Zone 1: An environment where explosive gas mixtures may appear during normal operation 3. Zone 2: An environment where explosive gas mixtures are unlikely to appear during normal operation, or even if they appear, they only exist for a short time. Note: Normal operation refers to normal start-up, operation, parking, loading and unloading of flammable products, opening and closing of sealed container covers, and the state in which safety valves, discharge valves and all factory equipment are working within their design parameters.
Article 2.2.2 If any of the following conditions are met, it can be classified as a non-explosion hazardous area:
1. An area without a release source and where flammable substances may not invade: 2. The highest concentration of flammable substances that may appear does not exceed 10% of the lower explosion limit;
3. Near equipment that uses open flames during the production process, or near equipment where the surface temperature of hot parts exceeds the ignition temperature of flammable substances in the area; 4. Outside the production unit area, the area of overhead pipelines for transporting flammable substances in the open air or scattered, but the valves are determined according to specific circumstances. Article 2.2.3 The release source should be classified according to the frequency and duration of the release of flammable substances, and should comply with the following provisions. , Continuous release source: a release source that is expected to release for a long time or frequently in a short time. The following situations can be classified as continuous release sources: 1. The surface of flammable liquids in fixed-top storage tanks that are not covered with inert gas,
2. The surface of flammable liquids in direct contact with the space, such as oil and water separators; 3. Free exhaust holes and other openings that frequently or long-term release flammable gases or flammable liquid vapors into the space.
2. First-level release sources: Release sources that are expected to release periodically or occasionally during normal operation. The following situations can be classified as first-level release sources: 1. The seals of pumps, compressors and valves that will release flammable substances during normal operation,
2. Drainage systems installed on containers storing flammable liquids that will release flammable substances into the space during normal operation;
3. Sampling points that will release flammable substances into the space during normal operation. 3. Second-level release sources: Release sources that are expected not to release under normal operation, and even if they do, they will only release occasionally for a short time. The following situations can be classified as the second-level release source:
1. The seals of pumps, compressors and valves that cannot release flammable substances during normal operation;
2. Flanges, connectors and pipe joints that cannot release flammable substances during normal operation,
3. Safety valves, exhaust holes and other openings that cannot release flammable substances into the space during normal operation
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
4. Sampling points that cannot release flammable substances into the space during normal operation. 4. Multi-level release source: a release source composed of two or three levels of release sources mentioned above.
Article 2.2.4 Ventilation in explosion-hazardous areas can be considered as good ventilation when the air flow rate can quickly dilute flammable substances to less than 25% of the lower explosion limit. When mechanical ventilation is used in one of the following situations, the impact of mechanical ventilation failure can be ignored:
1. A backup independent ventilation system should be set up for closed or semi-closed buildings;
2. When the ventilation equipment fails, set up automatic alarms or stop the process flow to ensure that prevent the release of flammable substances, or preventive measures such as powering off electrical equipment.
Article 2.2.5 The division of explosion-hazardous areas shall be determined according to the level of release sources and ventilation conditions, and shall comply with the following provisions.
1. First, the areas shall be divided according to the level of the following release sources: 1. The area with continuous release sources can be divided into Zone 0; 2. The area with the first-level release source can be divided into Zone 1, 3. The area with the second-level release source can be divided into Zone 2. 2. Secondly, the area division should be adjusted according to the ventilation conditions: 1. When the ventilation is good, the explosion-hazardous area level should be lowered, and when the ventilation is poor, the explosion-hazardous area level should be increased.
2. When local mechanical ventilation is more effective than natural ventilation and general mechanical ventilation in reducing the concentration of explosive gas mixtures, local mechanical ventilation can be used to reduce the level of explosion hazard areas.
3. At obstacles, pits and dead ends, the level of explosion hazard areas should be locally increased.
4. By using obstacles such as embankments or walls to limit the diffusion of explosive gas mixtures heavier than air, the scope of explosion hazard areas can be reduced. Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Section 3 Scope of Hazardous Areas in Explosive Gas Environments Article 2.3.1 The scope of hazardous areas in explosive gas environments shall be determined in accordance with the following requirements:
1 The scope of explosion hazard areas shall be determined comprehensively based on the level and location of the release source, the nature of the flammable substances, ventilation conditions, obstacles and production conditions, and operating experience, and after technical and economic comparison.
2. Inside the building, the scope of the explosion hazard area should be delineated on a factory building basis. However, according to the specific production situation, when the space in the factory is large and the mass of flammable substances released by the release source is small, the explosion hazard area can be delineated according to part of the space in the factory, and the following provisions should be met:
1. When there are flammable substances heavier than air in the factory, the ventilation frequency in the factory should not be less than 2 times/h, and the ventilation is not hindered. The concentration of the explosive gas mixture formed by the air with a volume of 1m above the floor of the factory and the flammable substances released into the factory should be less than the lower explosion limit.
2. When there are flammable substances lighter than air in the factory, the concentration of the explosive gas mixture formed by the air with a volume of 1m below the flat roof plane of the factory, or 2m below the highest point of the dome or sloping roof and the flammable substances released into the factory should be less than the lower explosion limit. bzxZ.net
Note: ① The maximum amount of flammable substances released into the factory should be calculated as 3 times the amount released in 1h, but does not include the amount released when ruptured due to catastrophic accidents. ② Explosive gases with a relative density less than or equal to 0.75 are defined as gases lighter than air; explosive gases with a relative density greater than 0.75 are defined as gases heavier than air. 3. When flammable substances may be released in large quantities and spread beyond 15m, the scope of the explosion hazard zone shall be divided into two additional zones.
4. When the material operating temperature is higher than the flash point of the flammable liquid, and the flammable liquid may leak, the scope of its explosion hazard zone may be appropriately reduced. Article 2.32 The level and scope of the explosion hazard zone shall comply with the provisions of the typical examples in Articles 2.3.3 to 2.3.17, and shall be determined based on the conditions such as the release amount, release rate, boiling point, temperature, flash point, relative density, lower explosion limit, obstacles, etc. of the flammable substances, combined with practical experience. However, the determination of the scope of the explosion hazard zone of oil and gas fields, their pipeline projects, and oil depots is an exception. Article 2.3.3 For the main production equipment area where flammable substances are heavier than air, well ventilated and the second-level release source, the scope of the explosion hazard area should comply with the following provisions (Figure 2.3.3-1 and Figure 2.3.3-2): 1. In the explosion hazard area, the pits and ditches under the floor are divided into Zone 1; 2. With the release source as the center, the radius is 15m, the height above the floor is 7.5m and the radius is 7.5m, and the distance between the top and the release source is 7.5m is divided into Zone 2; Second-level release source | |tt||Ditches and pits under the floor
Figure 2.3.3-1
Attached zone e
When the release source is close to the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
First-level release
Ditches and pits under the floor
Added zone 2
2When the release source is above the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
Engineering Construction Standard Full Text Information System1. Explosive gas environments should be divided into zones according to the frequency and duration of the occurrence of explosive gas mixtures as follows: 1. Zone 0: An environment where explosive gas mixtures appear continuously or for a long time; 2. Zone 1: An environment where explosive gas mixtures may appear during normal operation; 3. Zone 2: An environment where explosive gas mixtures are unlikely to appear during normal operation, or even if they appear, they only exist for a short time. Note: Normal operation refers to normal start-up, operation, parking, loading and unloading of flammable products, opening and closing of sealed container covers, and the state in which safety valves, discharge valves and all factory equipment are working within their design parameters.
Article 2.2.2 If any of the following conditions are met, it can be classified as a non-explosion hazardous area:
1. An area without a release source and where flammable substances may not invade: 2. The highest concentration of flammable substances that may appear does not exceed 10% of the lower explosion limit;
3. Near equipment that uses open flames during the production process, or near equipment where the surface temperature of hot parts exceeds the ignition temperature of flammable substances in the area; 4. Outside the production unit area, the area of overhead pipelines for transporting flammable substances in the open air or scattered, but the valves are determined according to specific circumstances. Article 2.2.3 The release source should be classified according to the frequency and duration of the release of flammable substances, and should comply with the following provisions. , Continuous release source: a release source that is expected to release for a long time or frequently in a short time. The following situations can be classified as continuous release sources: 1. The surface of flammable liquids in fixed-top storage tanks that are not covered with inert gas,
2. The surface of flammable liquids in direct contact with the space, such as oil and water separators; 3. Free exhaust holes and other openings that frequently or long-term release flammable gases or flammable liquid vapors into the space.
2. First-level release sources: Release sources that are expected to release periodically or occasionally during normal operation. The following situations can be classified as first-level release sources: 1. The seals of pumps, compressors and valves that will release flammable substances during normal operation,
2. Drainage systems installed on containers storing flammable liquids that will release flammable substances into the space during normal operation;
3. Sampling points that will release flammable substances into the space during normal operation. 3. Second-level release sources: Release sources that are expected not to release under normal operation, and even if they do, they will only release occasionally for a short time. The following situations can be classified as the second-level release source:
1. The seals of pumps, compressors and valves that cannot release flammable substances during normal operation;
2. Flanges, connectors and pipe joints that cannot release flammable substances during normal operation,
3. Safety valves, exhaust holes and other openings that cannot release flammable substances into the space during normal operation
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
4. Sampling points that cannot release flammable substances into the space during normal operation. 4. Multi-level release source: a release source composed of two or three levels of release sources mentioned above.
Article 2.2.4 Ventilation in explosion-hazardous areas can be considered as good ventilation when the air flow rate can quickly dilute flammable substances to less than 25% of the lower explosion limit. When mechanical ventilation is used in one of the following situations, the impact of mechanical ventilation failure can be ignored:
1. A backup independent ventilation system should be set up for closed or semi-closed buildings;
2. When the ventilation equipment fails, set up automatic alarms or stop the process flow to ensure that prevent the release of flammable substances, or preventive measures such as powering off electrical equipment.
Article 2.2.5 The division of explosion-hazardous areas shall be determined according to the level of release sources and ventilation conditions, and shall comply with the following provisions.
1. First, the areas shall be divided according to the level of the following release sources: 1. The area with continuous release sources can be divided into Zone 0; 2. The area with the first-level release source can be divided into Zone 1, 3. The area with the second-level release source can be divided into Zone 2. 2. Secondly, the area division should be adjusted according to the ventilation conditions: 1. When the ventilation is good, the explosion-hazardous area level should be lowered, and when the ventilation is poor, the explosion-hazardous area level should be increased.
2. When local mechanical ventilation is more effective than natural ventilation and general mechanical ventilation in reducing the concentration of explosive gas mixtures, local mechanical ventilation can be used to reduce the level of explosion hazard areas.
3. At obstacles, pits and dead ends, the level of explosion hazard areas should be locally increased.
4. By using obstacles such as embankments or walls to limit the diffusion of explosive gas mixtures heavier than air, the scope of explosion hazard areas can be reduced. Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Section 3 Scope of Hazardous Areas in Explosive Gas Environments Article 2.3.1 The scope of hazardous areas in explosive gas environments shall be determined in accordance with the following requirements:
1 The scope of explosion hazard areas shall be determined comprehensively based on the level and location of the release source, the nature of the flammable substances, ventilation conditions, obstacles and production conditions, and operating experience, and after technical and economic comparison.
2. Inside the building, the scope of the explosion hazard area should be delineated on a factory building basis. However, according to the specific production situation, when the space in the factory is large and the mass of flammable substances released by the release source is small, the explosion hazard area can be delineated according to part of the space in the factory, and the following provisions should be met:
1. When there are flammable substances heavier than air in the factory, the ventilation frequency in the factory should not be less than 2 times/h, and the ventilation is not hindered. The concentration of the explosive gas mixture formed by the air with a volume of 1m above the floor of the factory and the flammable substances released into the factory should be less than the lower explosion limit.
2. When there are flammable substances lighter than air in the factory, the concentration of the explosive gas mixture formed by the air with a volume of 1m below the flat roof plane of the factory, or 2m below the highest point of the dome or sloping roof and the flammable substances released into the factory should be less than the lower explosion limit.
Note: ① The maximum amount of flammable substances released into the factory should be calculated as 3 times the amount released in 1h, but does not include the amount released when ruptured due to catastrophic accidents. ② Explosive gases with a relative density less than or equal to 0.75 are defined as gases lighter than air; explosive gases with a relative density greater than 0.75 are defined as gases heavier than air. 3. When flammable substances may be released in large quantities and spread beyond 15m, the scope of the explosion hazard zone shall be divided into two additional zones.
4. When the material operating temperature is higher than the flash point of the flammable liquid, and the flammable liquid may leak, the scope of its explosion hazard zone may be appropriately reduced. Article 2.32 The level and scope of the explosion hazard zone shall comply with the provisions of the typical examples in Articles 2.3.3 to 2.3.17, and shall be determined based on the conditions such as the release amount, release rate, boiling point, temperature, flash point, relative density, lower explosion limit, obstacles, etc. of the flammable substances, combined with practical experience. However, the determination of the scope of the explosion hazard zone of oil and gas fields, their pipeline projects, and oil depots is an exception. Article 2.3.3 For the main production equipment area where flammable substances are heavier than air, well ventilated and the second-level release source, the scope of the explosion hazard area should comply with the following provisions (Figure 2.3.3-1 and Figure 2.3.3-2): 1. In the explosion hazard area, the pits and ditches under the floor are divided into Zone 1; 2. With the release source as the center, the radius is 15m, the height above the floor is 7.5m and the radius is 7.5m, and the distance between the top and the release source is 7.5m is divided into Zone 2; Second-level release source | |tt||Ditches and pits under the floor
Figure 2.3.3-1
Attached zone e
When the release source is close to the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
First-level release
Ditches and pits under the floor
Added zone 2
2When the release source is above the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
Engineering Construction Standard Full Text Information System1. Explosive gas environments should be divided into zones according to the frequency and duration of the occurrence of explosive gas mixtures as follows: 1. Zone 0: An environment where explosive gas mixtures appear continuously or for a long time; 2. Zone 1: An environment where explosive gas mixtures may appear during normal operation; 3. Zone 2: An environment where explosive gas mixtures are unlikely to appear during normal operation, or even if they appear, they only exist for a short time. Note: Normal operation refers to normal start-up, operation, parking, loading and unloading of flammable products, opening and closing of sealed container covers, and the state in which safety valves, discharge valves and all factory equipment are working within their design parameters.
Article 2.2.2 If any of the following conditions are met, it can be classified as a non-explosion hazardous area:
1. An area without a release source and where flammable substances may not invade: 2. The highest concentration of flammable substances that may appear does not exceed 10% of the lower explosion limit;
3. Near equipment that uses open flames during the production process, or near equipment where the surface temperature of hot parts exceeds the ignition temperature of flammable substances in the area; 4. Outside the production unit area, the area of overhead pipelines for transporting flammable substances in the open air or scattered, but the valves are determined according to specific circumstances. Article 2.2.3 The release source should be classified according to the frequency and duration of the release of flammable substances, and should comply with the following provisions. , Continuous release source: a release source that is expected to release for a long time or frequently in a short time. The following situations can be classified as continuous release sources: 1. The surface of flammable liquids in fixed-top storage tanks that are not covered with inert gas,
2. The surface of flammable liquids in direct contact with the space, such as oil and water separators; 3. Free exhaust holes and other openings that frequently or long-term release flammable gases or flammable liquid vapors into the space.
2. First-level release sources: Release sources that are expected to release periodically or occasionally during normal operation. The following situations can be classified as first-level release sources: 1. The seals of pumps, compressors and valves that will release flammable substances during normal operation,
2. Drainage systems installed on containers storing flammable liquids that will release flammable substances into the space during normal operation;
3. Sampling points that will release flammable substances into the space during normal operation. 3. Second-level release sources: Release sources that are expected not to release under normal operation, and even if they do, they will only release occasionally for a short time. The following situations can be classified as the second-level release source:
1. The seals of pumps, compressors and valves that cannot release flammable substances during normal operation;
2. Flanges, connectors and pipe joints that cannot release flammable substances during normal operation,
3. Safety valves, exhaust holes and other openings that cannot release flammable substances into the space during normal operation
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
4. Sampling points that cannot release flammable substances into the space during normal operation. 4. Multi-level release source: a release source composed of two or three levels of release sources mentioned above.
Article 2.2.4 Ventilation in explosion-hazardous areas can be considered as good ventilation when the air flow rate can quickly dilute flammable substances to less than 25% of the lower explosion limit. When mechanical ventilation is used in one of the following situations, the impact of mechanical ventilation failure can be ignored:
1. A backup independent ventilation system should be set up for closed or semi-closed buildings;
2. When the ventilation equipment fails, set up automatic alarms or stop the process flow to ensure that prevent the release of flammable substances, or preventive measures such as powering off electrical equipment.
Article 2.2.5 The division of explosion-hazardous areas shall be determined according to the level of release sources and ventilation conditions, and shall comply with the following provisions.
1. First, the areas shall be divided according to the level of the following release sources: 1. The area with continuous release sources can be divided into Zone 0; 2. The area with the first-level release source can be divided into Zone 1, 3. The area with the second-level release source can be divided into Zone 2. 2. Secondly, the area division should be adjusted according to the ventilation conditions: 1. When the ventilation is good, the explosion-hazardous area level should be lowered, and when the ventilation is poor, the explosion-hazardous area level should be increased.
2. When local mechanical ventilation is more effective than natural ventilation and general mechanical ventilation in reducing the concentration of explosive gas mixtures, local mechanical ventilation can be used to reduce the level of explosion hazard areas.
3. At obstacles, pits and dead ends, the level of explosion hazard areas should be locally increased.
4. By using obstacles such as embankments or walls to limit the diffusion of explosive gas mixtures heavier than air, the scope of explosion hazard areas can be reduced. Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Section 3 Scope of Hazardous Areas in Explosive Gas Environments Article 2.3.1 The scope of hazardous areas in explosive gas environments shall be determined in accordance with the following requirements:
1 The scope of explosion hazard areas shall be determined comprehensively based on the level and location of the release source, the nature of the flammable substances, ventilation conditions, obstacles and production conditions, and operating experience, and after technical and economic comparison.
2. Inside the building, the scope of the explosion hazard area should be delineated on a factory building basis. However, according to the specific production situation, when the space in the factory is large and the mass of flammable substances released by the release source is small, the explosion hazard area can be delineated according to part of the space in the factory, and the following provisions should be met:
1. When there are flammable substances heavier than air in the factory, the ventilation frequency in the factory should not be less than 2 times/h, and the ventilation is not hindered. The concentration of the explosive gas mixture formed by the air with a volume of 1m above the floor of the factory and the flammable substances released into the factory should be less than the lower explosion limit.
2. When there are flammable substances lighter than air in the factory, the concentration of the explosive gas mixture formed by the air with a volume of 1m below the flat roof plane of the factory, or 2m below the highest point of the dome or sloping roof and the flammable substances released into the factory should be less than the lower explosion limit.
Note: ① The maximum amount of flammable substances released into the factory should be calculated as 3 times the amount released in 1h, but does not include the amount released when ruptured due to catastrophic accidents. ② Explosive gases with a relative density less than or equal to 0.75 are defined as gases lighter than air; explosive gases with a relative density greater than 0.75 are defined as gases heavier than air. 3. When flammable substances may be released in large quantities and spread beyond 15m, the scope of the explosion hazard zone shall be divided into two additional zones.
4. When the material operating temperature is higher than the flash point of the flammable liquid, and the flammable liquid may leak, the scope of its explosion hazard zone may be appropriately reduced. Article 2.32 The level and scope of the explosion hazard zone shall comply with the provisions of the typical examples in Articles 2.3.3 to 2.3.17, and shall be determined based on the conditions such as the release amount, release rate, boiling point, temperature, flash point, relative density, lower explosion limit, obstacles, etc. of the flammable substances, combined with practical experience. However, the determination of the scope of the explosion hazard zone of oil and gas fields, their pipeline projects, and oil depots is an exception. Article 2.3.3 For the main production equipment area where flammable substances are heavier than air, well ventilated and the second-level release source, the scope of the explosion hazard area should comply with the following provisions (Figure 2.3.3-1 and Figure 2.3.3-2): 1. In the explosion hazard area, the pits and ditches under the floor are divided into Zone 1; 2. With the release source as the center, the radius is 15m, the height above the floor is 7.5m and the radius is 7.5m, and the distance between the top and the release source is 7.5m is divided into Zone 2; Second-level release source | |tt||Ditches and pits under the floor
Figure 2.3.3-1
Attached zone e
When the release source is close to the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
First-level release
Ditches and pits under the floor
Added zone 2
2When the release source is above the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
Engineering Construction Standard Full Text Information SystemArticle 2 If any of the following conditions are met, it can be classified as a non-explosion hazardous area:
1. An area without a release source and where flammable substances may not invade;
2. The highest concentration of flammable substances that may appear does not exceed 10% of the lower explosion limit;
3. Near equipment that uses open flames during the production process, or near equipment where the surface temperature of hot parts exceeds the ignition temperature of flammable substances in the area;
4. Outside the production unit area, the area of overhead pipelines for transporting flammable substances in the open air or scattered, but the valves are determined according to specific circumstances. Article 2.2.3 The release source should be classified according to the frequency and duration of the release of flammable substances, and should comply with the following provisions. Continuous release source: a release source that is expected to release for a long time or frequently in a short time. The following situations can be classified as continuous release sources: 1. The surface of flammable liquids in fixed-top storage tanks that are not covered with inert gas,
2. The surface of flammable liquids in direct contact with the space, such as oil and water separators; 3. Free exhaust holes and other openings that frequently or long-term release flammable gases or flammable liquid vapors into the space.
2. First-level release sources: Release sources that are expected to release periodically or occasionally during normal operation. The following situations can be classified as first-level release sources: 1. The seals of pumps, compressors and valves that will release flammable substances during normal operation,
2. Drainage systems installed on containers storing flammable liquids that will release flammable substances into the space during normal operation;
3. Sampling points that will release flammable substances into the space during normal operation. 3. Second-level release sources: Release sources that are expected not to release under normal operation, and even if they do, they will only release occasionally for a short time. The following situations can be classified as the second-level release source:
1. The seals of pumps, compressors and valves that cannot release flammable substances during normal operation;
2. Flanges, connectors and pipe joints that cannot release flammable substances during normal operation,
3. Safety valves, exhaust holes and other openings that cannot release flammable substances into the space during normal operation
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
4. Sampling points that cannot release flammable substances into the space during normal operation. 4. Multi-level release source: a release source composed of two or three levels of release sources mentioned above.
Article 2.2.4 Ventilation in explosion-hazardous areas can be considered as good ventilation when the air flow rate can quickly dilute flammable substances to less than 25% of the lower explosion limit. When mechanical ventilation is used in one of the following situations, the impact of mechanical ventilation failure can be ignored:
1. A backup independent ventilation system should be set up for closed or semi-closed buildings;
2. When the ventilation equipment fails, set up automatic alarms or stop the process flow to ensure that prevent the release of flammable substances, or preventive measures such as powering off electrical equipment.
Article 2.2.5 The division of explosion-hazardous areas shall be determined according to the level of release sources and ventilation conditions, and shall comply with the following provisions.
1. First, the areas shall be divided according to the level of the following release sources: 1. The area with continuous release sources can be divided into Zone 0; 2. The area with the first-level release source can be divided into Zone 1, 3. The area with the second-level release source can be divided into Zone 2. 2. Secondly, the area division should be adjusted according to the ventilation conditions: 1. When the ventilation is good, the explosion-hazardous area level should be lowered, and when the ventilation is poor, the explosion-hazardous area level should be increased.
2. When local mechanical ventilation is more effective than natural ventilation and general mechanical ventilation in reducing the concentration of explosive gas mixtures, local mechanical ventilation can be used to reduce the level of explosion hazard areas.
3. At obstacles, pits and dead ends, the level of explosion hazard areas should be locally increased.
4. By using obstacles such as embankments or walls to limit the diffusion of explosive gas mixtures heavier than air, the scope of explosion hazard areas can be reduced. Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Section 3 Scope of Hazardous Areas in Explosive Gas Environments Article 2.3.1 The scope of hazardous areas in explosive gas environments shall be determined in accordance with the following requirements:
1 The scope of explosion hazard areas shall be determined comprehensively based on the level and location of the release source, the nature of the flammable substances, ventilation conditions, obstacles and production conditions, and operating experience, and after technical and economic comparison.
2. Inside the building, the scope of the explosion hazard area should be delineated on a factory building basis. However, according to the specific production situation, when the space in the factory is large and the mass of flammable substances released by the release source is small, the explosion hazard area can be delineated according to part of the space in the factory, and the following provisions should be met:
1. When there are flammable substances heavier than air in the factory, the ventilation frequency in the factory should not be less than 2 times/h, and the ventilation is not hindered. The concentration of the explosive gas mixture formed by the air with a volume of 1m above the floor of the factory and the flammable substances released into the factory should be less than the lower explosion limit.
2. When there are flammable substances lighter than air in the factory, the concentration of the explosive gas mixture formed by the air with a volume of 1m below the flat roof plane of the factory, or 2m below the highest point of the dome or sloping roof and the flammable substances released into the factory should be less than the lower explosion limit.
Note: ① The maximum amount of flammable substances released into the factory should be calculated as 3 times the amount released in 1h, but does not include the amount released when ruptured due to catastrophic accidents. ② Explosive gases with a relative density less than or equal to 0.75 are defined as gases lighter than air; explosive gases with a relative density greater than 0.75 are defined as gases heavier than air. 3. When flammable substances may be released in large quantities and spread beyond 15m, the scope of the explosion hazard zone shall be divided into two additional zones.
4. When the material operating temperature is higher than the flash point of the flammable liquid, and the flammable liquid may leak, the scope of its explosion hazard zone may be appropriately reduced. Article 2.32 The level and scope of the explosion hazard zone shall comply with the provisions of the typical examples in Articles 2.3.3 to 2.3.17, and shall be determined based on the conditions such as the release amount, release rate, boiling point, temperature, flash point, relative density, lower explosion limit, obstacles, etc. of the flammable substances, combined with practical experience. However, the determination of the scope of the explosion hazard zone of oil and gas fields, their pipeline projects, and oil depots is an exception. Article 2.3.3 For the main production equipment area where flammable substances are heavier than air, well ventilated and the second-level release source, the scope of the explosion hazard area should comply with the following provisions (Figure 2.3.3-1 and Figure 2.3.3-2): 1. In the explosion hazard area, the pits and ditches under the floor are divided into Zone 1; 2. With the release source as the center, the radius is 15m, the height above the floor is 7.5m and the radius is 7.5m, and the distance between the top and the release source is 7.5m is divided into Zone 2; Second-level release source | |tt||Ditches and pits under the floor
Figure 2.3.3-1
Attached zone e
When the release source is close to the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
First-level release
Ditches and pits under the floor
Added zone 2
2When the release source is above the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
Engineering Construction Standard Full Text Information SystemArticle 2 If any of the following conditions are met, it can be classified as a non-explosion hazardous area:
1. An area without a release source and where flammable substances may not invade;
2. The highest concentration of flammable substances that may appear does not exceed 10% of the lower explosion limit;
3. Near equipment that uses open flames during the production process, or near equipment where the surface temperature of hot parts exceeds the ignition temperature of flammable substances in the area;
4. Outside the production unit area, the area of overhead pipelines for transporting flammable substances in the open air or scattered, but the valves are determined according to specific circumstances. Article 2.2.3 The release source should be classified according to the frequency and duration of the release of flammable substances, and should comply with the following provisions. Continuous release source: a release source that is expected to release for a long time or frequently in a short time. The following situations can be classified as continuous release sources: 1. The surface of flammable liquids in fixed-top storage tanks that are not covered with inert gas,
2. The surface of flammable liquids in direct contact with the space, such as oil and water separators; 3. Free exhaust holes and other openings that frequently or long-term release flammable gases or flammable liquid vapors into the space.
2. First-level release sources: Release sources that are expected to release periodically or occasionally during normal operation. The following situations can be classified as first-level release sources: 1. The seals of pumps, compressors and valves that will release flammable substances during normal operation,
2. Drainage systems installed on containers storing flammable liquids that will release flammable substances into the space during normal operation;
3. Sampling points that will release flammable substances into the space during normal operation. 3. Second-level release sources: Release sources that are expected not to release under normal operation, and even if they do, they will only release occasionally for a short time. The following situations can be classified as the second-level release source:
1. The seals of pumps, compressors and valves that cannot release flammable substances during normal operation;
2. Flanges, connectors and pipe joints that cannot release flammable substances during normal operation,
3. Safety valves, exhaust holes and other openings that cannot release flammable substances into the space during normal operation
Engineering Construction Standard Full Text Information System
Engineering Construction Standard Full Text Information System
4. Sampling points that cannot release flammable substances into the space during normal operation. 4. Multi-level release source: a release source composed of two or three levels of release sources mentioned above.
Article 2.2.4 Ventilation in explosion-hazardous areas can be considered as good ventilation when the air flow rate can quickly dilute flammable substances to less than 25% of the lower explosion limit. When mechanical ventilation is used in one of the following situations, the impact of mechanical ventilation failure can be ignored:
1. A backup independent ventilation system should be set up for closed or semi-closed buildings;
2. When the ventilation equipment fails, set up automatic alarms or stop the process flow to ensure that prevent the release of flammable substances, or preventive measures such as powering off electrical equipment.
Article 2.2.5 The division of explosion-hazardous areas shall be determined according to the level of release sources and ventilation conditions, and shall comply with the following provisions.
1. First, the areas shall be divided according to the level of the following release sources: 1. The area with continuous release sources can be divided into Zone 0; 2. The area with the first-level release source can be divided into Zone 1, 3. The area with the second-level release source can be divided into Zone 2. 2. Secondly, the area division should be adjusted according to the ventilation conditions: 1. When the ventilation is good, the explosion-hazardous area level should be lowered, and when the ventilation is poor, the explosion-hazardous area level should be increased.
2. When local mechanical ventilation is more effective than natural ventilation and general mechanical ventilation in reducing the concentration of explosive gas mixtures, local mechanical ventilation can be used to reduce the level of explosion hazard areas.
3. At obstacles, pits and dead ends, the level of explosion hazard areas should be locally increased.
4. By using obstacles such as embankments or walls to limit the diffusion of explosive gas mixtures heavier than air, the scope of explosion hazard areas can be reduced. Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Section 3 Scope of Hazardous Areas in Explosive Gas Environments Article 2.3.1 The scope of hazardous areas in explosive gas environments shall be determined in accordance with the following requirements:
1 The scope of explosion hazard areas shall be determined comprehensively based on the level and location of the release source, the nature of the flammable substances, ventilation conditions, obstacles and production conditions, and operating experience, and after technical and economic comparison.
2. Inside the building, the scope of the explosion hazard area should be delineated on a factory building basis. However, according to the specific production situation, when the space in the factory is large and the mass of flammable substances released by the release source is small, the explosion hazard area can be delineated according to part of the space in the factory, and the following provisions should be met:
1. When there are flammable substances heavier than air in the factory, the ventilation frequency in the factory should not be less than 2 times/h, and the ventilation is not hindered. The concentration of the explosive gas mixture formed by the air with a volume of 1m above the floor of the factory and the flammable substances released into the factory should be less than the lower explosion limit.
2. When there are flammable substances lighter than air in the factory, the concentration of the explosive gas mixture formed by the air with a volume of 1m below the flat roof plane of the factory, or 2m below the highest point of the dome or sloping roof and the flammable substances released into the factory should be less than the lower explosion limit.
Note: ① The maximum amount of flammable substances released into the factory should be calculated as 3 times the amount released in 1h, but does not include the amount released when ruptured due to catastrophic accidents. ② Explosive gases with a relative density less than or equal to 0.75 are defined as gases lighter than air; explosive gases with a relative density greater than 0.75 are defined as gases heavier than air. 3. When flammable substances may be released in large quantities and spread beyond 15m, the scope of the explosion hazard zone shall be divided into two additional zones.
4. When the material operating temperature is higher than the flash point of the flammable liquid, and the flammable liquid may leak, the scope of its explosion hazard zone may be appropriately reduced. Article 2.32 The level and scope of the explosion hazard zone shall comply with the provisions of the typical examples in Articles 2.3.3 to 2.3.17, and shall be determined based on the conditions such as the release amount, release rate, boiling point, temperature, flash point, relative density, lower explosion limit, obstacles, etc. of the flammable substances, combined with practical experience. However, the determination of the scope of the explosion hazard zone of oil and gas fields, their pipeline projects, and oil depots is an exception. Article 2.3.3 For the main production equipment area where flammable substances are heavier than air, well ventilated and the second-level release source, the scope of the explosion hazard area should comply with the following provisions (Figure 2.3.3-1 and Figure 2.3.3-2): 1. In the explosion hazard area, the pits and ditches under the floor are divided into Zone 1; 2. With the release source as the center, the radius is 15m, the height above the floor is 7.5m and the radius is 7.5m, and the distance between the top and the release source is 7.5m is divided into Zone 2; Second-level release source | |tt||Ditches and pits under the floor
Figure 2.3.3-1
Attached zone e
When the release source is close to the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
First-level release
Ditches and pits under the floor
Added zone 2
2When the release source is above the floor, the flammable substance is heavier than the air and the production equipment area with good ventilation
Engineering Construction Standard Full Text Information System1. The sealing parts of pumps, compressors and valves that cannot release flammable substances during normal operation; 2. Flanges, connectors and pipe joints that cannot release flammable substances during normal operation; 3. Safety valves, exhaust holes and other openings that cannot release flammable substances into the space during normal operation. 4. Sampling points that cannot release flammable substances into the space during normal operation. 4. Multi-level release source: a release source composed of two or three levels of release sources mentioned above. Article 2.2.4 Ventilation in explosion-hazardous areas can be considered as good ventilation when the air flow rate can quickly dilute flammable substances to less than 25% of the lower explosion limit. When mechanical ventilation is used in one of the following situations, the impact of mechanical ventilation failure can be ignored:
1. A backup independent ventilation system should be set up for closed or semi-closed buildings;
2. When the ventilation equipment fails, set up automatic alarms or stop the process flow to ensure that prevent the release of flammable substances, or preventive measures such as powering off electrical equipment.
Article 2.2.5 The division of explosion-hazardous areas shall be determined according to the level of release sources and ventilation conditions, and shall comply with the following provisions.
1. First, the areas shall be divided according to the level of the following release sources: 1. The area with continuous release sources can be divided into Zone 0; 2. The area with the first-level release source can be divided into Zone 1, 3. The area with the second-level release source can be divided into Zone 2. 2. Secondly, the area division should be adjusted according to the ventilation conditions: 1. When the ventilation is good, the explosion-hazardous area level should be lowered, and when the ventilation is poor, the explosion-hazardous area level should be increased.
2. When local mechanical ventilation is more effective than natural ventilation and general mechanical ventilation in reducing the concentration of explosive gas mixtures, local mechanical ventilation can be used to reduce the level of explosion hazard areas.
3. At obstacles, pits and dead ends, the level of explosion hazard areas should be locally increased.
4. By using obstacles such as embankments or walls to limit the diffusion of explosive gas mixtures heavier than air, the scope of explosion hazard areas can be reduced. Engineering Construction Standards Full Text Information System
Engineering Construction Standards Full Text Information System
Section 3 Scope of Hazardous Areas in Explosive Gas Environments Article 2.3.1 The scope of hazardous areas in explosive gas environments shall be determined in accordance with the following requirements:
1 The scope of explosion hazard areas shall be determined comprehensively based on the level and location of the release source, the nature of the flammable substances, ventilation conditions, obstacles and production conditions, and operating experience, and after technical and economic comparison.
2. Inside the building, the scope of the explosion hazard area should be delineated on a factory building basis. However, according to the specific production situation, when the space in the factory is large and the mass of flammable substances released by the release source is small, the explosion hazard area can be delineated according to part of the space in the factory, and the following provisions should be met:
1. When there are flammable substances heavier than air in the factory, the ventilation frequency in the factory should not be less than 2 times/h, and the ventilation is not hindered. The concentration of the explosive gas mixture formed by the air with a volume of 1m above the floor of the factory and the flammable substances released into the factory should be less than the lower explosion limit.
2. When there are flammable substances lighter than air in the factory, the concentration of the explosive gas mixture formed by the air with a volume of 1m below the flat roof plane of the factory, or 2m below the highest point of the dome or sloping roof and the flammable substances released into the factory should be less than the lower explosion limit.
Note: ① The maximum amount of flammable substances released into the factory should be calculated as 3 times the amount released in 1h, but does not include the amount released when ruptured due to catastrophic accidents. ② Explosive gases with a relative density less than or equal to 0.75 are defined as gases lighter than air; explosive gases with a relative density greater than 0.75 are defined as gases heavier than air. 3. When flammable substances may be released in large quantities and spread beyond 15m, the scope of the explosion hazard zone shall be divided into two additional zones.
4. When the material operating temperature is higher than the flash point of the flammable liquid, and the flammable liquid may leak, the scope of its explosion hazard zone may be appropriately reduced. Article 2.32 The level and scope of the explosion hazard zone shall comply with the provisions of the typical examples in Articles 2.3.3 to 2.3.17, and shall be determined based on the conditions such as the release amount, release rate, boiling point, temperature, flash point, relative density, lower explosion limit, obstacles, etc. of t
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