Classification of explosion hazard zones for valves with flange connections

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This post was last edited by hnan on 2015-10-19 at 19:11. When designing oil depots, in accordance with the \"Code for Design of Oil Depots\" GB50074-2014, leaks from outdoor valves and flanges are classified as Zone 2, with a radius of 3 meters. In the new \"Code for Design of Electrical Installations in Explosive Hazardous Environments\" GB50058-2014, Article 22 of Appendix B deals with the classification of areas at risk due to valves: 1. The areas surrounding isolation valves and check valves that are located in well-ventilated and unenclosed areas do not need to be classified. 2. The area surrounding the process control valve located in a well-ventilated and unenclosed area, as well as the 0.5-m radius area around the valve stem seal or similar seals, can be classified as Zone 2. Meanwhile, according to Article 1 of Appendix B, in main production areas where flammable substances are heavier than air, where ventilation is good, and which are classified as secondary release sources, the explosion hazard zone is defined as an area with a total radius of 30 meters... Question 1: The difference mentioned above is quite large; how should this be implemented? When following GB50058-2014, 2: For the discharge at the high and low points of pipe bends or compensation sections, flanged valves are used. How should the explosion hazard zone in these areas be defined? Use a plug + seal weld when the requirements are not met? 3. In GB50058-2014, does “not classified” mean it does not belong to a explosive hazard area? “How are the “shut-off valve” and the “process program control valve” distinguished from each other? If anyone has promotional materials for GB50058-2014, could you send me a copy? Thank you! @QQ Love @MintLife @Yimi @ylb913 @FishInTheDesert