Regarding the issue of explosive hazard areas for fuel oil
Thread Content
The explosion-proof zones in the tank area and at the dock front are designated in accordance with GB50058 and GB50074; the classification of fuel oils is specified in Appendix C of GB50058. GB50058-92 introduces the concept of fire-hazardous areas, and electrical equipment in such areas must be explosion-proof. The 2014 version removes the classification of fire hazard areas; so how should the electrical equipment in such areas be classified? Should it be classified according to explosion hazard areas and explosion-proof electrical equipment be used, or should it be classified as non-explosion hazard areas without the need for explosion-proof electrical equipment? The main concern regarding this question lies in clause 3.1.1 of GB50058: 1 Under atmospheric conditions, combustible gases mix with air to form explosive gas mixtures ； 2 Vapors or mists of flammable liquids with a flash point equal to or below the ambient temperature, when mixed with air, form explosive gas mixtures ； 3 When the operating temperature of the material is above the flash point of the flammable liquid, and there is a risk of leakage of that liquid, its vapors or mist mix with air to form an explosive gas mixture. Firstly, the flash point of fuel oil is above 55°C, so no flammable gases are formed under atmospheric conditions. Moreover, operations at storage tanks and docks are limited to transfer only, and the operating temperatures do not exceed the flash point of the fuel oil. How should explosive hazard areas be classified?
Appendix B of 50074 clearly specifies the explosion-proof areas; it indicates which level of explosion-proof electrical equipment should be used in those areas. In the oil and chemical industry, even in areas that are not considered explosion-proof, it is best to use explosion-proof electrical equipment – safety comes first. Also, as the original poster said, “Firstly, the flash point of fuel oil is above 55°C, so no flammable gases are formed under normal atmospheric conditions.” But flammable gases have little to do with atmospheric conditions, don’t they?
Everything is carried out according to the latest version; it originally had nothing to do with the fire anyway
The classification of explosion-proof areas is carried out in accordance with the diagrams in the appendix; the main issue lies in the properties of fuel oil, whose ignition point is between 220–300°C and flash point is above 55°C, which conflicts with clause 3.1.1 of GB50058-2014 (based on my personal understanding). So, how are explosive hazard zones determined for fuel oil?