With the rapid development of petroleum, chemical and Other industries, lighting fixtures are used more and more widely in production, warehousing and rescue. How to prevent accidental explosion of lighting fixtures has become a very important issue in explosive gas hazardous locations. As the lighting fixtures inevitably generate sparks or form hot surfaces when they work, once they meet the explosive gas mixture at the production or rescue site, it will lead to an explosion accident that will directly endanger the lives of national property and citizens. Therefore, as the most widely used lighting fixture, its explosion-proof technology has long attracted people's attention and great attention.
Scope of application
1, Zone 1, Zone 2 hazardous locations
2, IIA, IIB, IIC explosive gas environment
3, flammable dust environment 20 area, 21 area, 22 area
4, temperature group T1 ~ T6
Applicable range meaning
1.1 Division of Explosive Gas Environment Hazardous Areas
Different countries and regions divide explosion hazardous areas according to their respective standards. According to the frequency and duration of the occurrence of explosive gas mixtures in China, the explosive gas environment is divided into Zone O, Zone 1 and Zone 2. (consistent with IEC International Electrotechnical Commission)
Zone 0: Continuous or prolonged exposure to explosive gas mixtures.
Zone 1: The environment in which explosive gas mixtures may occur during normal operation.
Zone 2: The environment in which explosive gas mixtures cannot occur during normal operation, or even the presence of explosive gas mixtures that are present for a short period of time.
Zone 0 generally exists only in sealed containers, internal gas spaces such as tanks, and is rarely present in the actual design process. Most of the cases are in Zone 2.
1.2 explosion-proof electrical equipment is divided into two categories:
Class I coal mine underground electrical equipment
Class II electrical equipment used in areas other than mines
1.3 Class II electrical equipment is divided into three categories, IIA, IIB and IIC, according to the maximum test safety clearance or minimum ignition current ratio applicable to explosive gas mixtures; it is divided into six groups of T1-T6 according to the maximum surface temperature.
1.4 Explosive gas mixtures are grouped by ignition temperature, see Table 1.
1.5 Explosive gas mixtures are classified according to their maximum test safety clearance (MESG) or minimum ignition current ratio (MICR), see Table 2.
Table 1
Group - ignition temperature t (°C)
T1-----450
T2-----300
T3-----200
T4-----135
T5-----100
T6-----85
Table 2
Category---Maximum Test Safety Gap (MESG)(mm)—Minimum Ignition Current Ratio
IIA-----≥0.9----->0.8
IIB-----0.5
IIC-----≤0.5-----<0.45
Properties: The ratio of the minimum ignition current of gas and vapor explosive mixtures to the minimum ignition current of methane explosive mixtures under the specified test conditions. China stipulates that the gas and vapor hazardous materials have a minimum ignition current of scores IIA, IIB, and IIC. The minimum ignition current ratio ≤1.0,>0.8 is IIA; ≤0.8,>0.45 is IIB; ≤0.45 is IIC. For example, ethane, ethylene, and acetylene are classified as IIA, IIB, and IIC dangerous substances, respectively.
Ningbo Kyson Cool Electronic Technology Co., Ltd. , https://www.kysoncool.com