Basic knowledge of explosion-proof certification

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I. Three elements of an explosion: https://pic1.zhimg.com/80/v2-b5be616398a3b2de2e24aed1bc18f8fc_720w.jpg II. Basic methods to prevent explosions: 1. Avoid creating explosive environments – Ideal methods include explosion-proof design of buildings and proper ventilation systems. 2. Eliminate or remove potential ignition sources – Practical methods include using explosion-proof electrical equipment. Definition of a place with explosion hazards: A location where, under normal atmospheric conditions, a mixture of combustible gases, vapors, mists, dusts, or fibers with air can cause combustion or explosion to spread throughout the entire unburned mixture once ignited. Definition of explosion-proof electrical equipment: Electrical equipment that is designed and manufactured under specified conditions so as not to cause an explosion in the surrounding explosive mixtures (explosion-hazardous areas). III. Classification of electrical equipment for explosive environments
Classification of electrical equipment for explosive environments:
Class I: Coal mine methane gas environments
Class II: Other explosive gas environments other than coal mine methane gas
Class III: Explosive dust environments other than those in coal mines

IV. Grading of electrical equipment for explosive environments
1. Grading based on the maximum test safety gap (MESG)
MESG = 1.14 (mm) for methane in coal mines; it falls under Class I without further grading, marked as I.
0.9 < MESG