The UWB explosion-proof rating is an important indicator used to measure the safety performance of UWB devices in flammable and explosive environments. It covers multiple key elements, starting with the "Ex" symbol to demonstrate compliance with explosion-proof standards. The equipment categories are divided into Class I for coal mine gas environments, Class II for other explosive gas environments, and Class III for explosive dust environments. The gas groups are represented by different gases, including A, B, and C groups, with C group having a higher risk. The temperature range is from T1 to T6, and the lower the temperature, the wider the explosion-proof safety. There are also device protection levels such as Ga, Gb, Gc, corresponding to different levels of protection. Different explosion-proof level markings clearly demonstrate the safe use of UWB devices in hazardous environments, gas conditions, and corresponding temperature limits, helping users accurately select UWB devices suitable for specific hazardous locations, ensuring operational safety, and avoiding safety accidents such as explosions and fires caused by equipment.
The explosion-proof level of UWB devices usually consists of multiple parts, and the following is a detailed explanation:
Ex is the explosion-proof mark of China and the International Electrotechnical Commission, indicating that electrical equipment complies with one or more explosion-proof types listed in Chapter 1 of GB3836.1.
Equipment category symbol
Class I: Used for gas environment in coal mines.
Class II: Used in explosive gas environments other than coal mines, such as hydrogen, acetylene, methane, and other gas environments commonly found in petrochemical and refinery facilities.
Class III: Used in explosive dust environments other than coal mines, such as flour mills, cement plants, and other places with dust explosion hazards.
Gas group symbol
Group A: The representative gas is propane.
Group B: The representative gas is ethylene.
Group C: The representative gas is hydrogen. Among them, the explosion hazard of Group C gas is relatively higher, so equipment that meets the explosion-proof requirements of Group C gas has stricter explosion-proof performance and can be used in Group A and Group B gas environments, but not vice versa.
Temperature group symbol
T1: The maximum surface temperature of the equipment shall not exceed 450 ℃.
T2: The maximum surface temperature of the equipment shall not exceed 300 ℃.
T3: The maximum surface temperature of the equipment shall not exceed 200 ℃.
T4: The maximum surface temperature of the equipment shall not exceed 135 ℃.
T5: The maximum surface temperature of the equipment shall not exceed 100 ℃.
T6: The maximum surface temperature of the equipment shall not exceed 85 ℃. The lower the temperature group, the lower the surface temperature generated by the equipment during operation, and the higher its explosion-proof safety, making it suitable for a wider range of hazardous environments.
Equipment Protection Level (EPL) symbol
Ga level: equipment used in explosive gas environments, with a "very high" protection level, and is not an ignition source in normal operation, expected faults, or rare faults.
Gb level: equipment used in explosive gas environments, with a "high" protection level, and is not an ignition source under normal operation or expected fault conditions.
Gc level: equipment used in explosive gas environments, with a "general" protection level. It is not an ignition source during normal operation, and additional protective measures can be taken to ensure that effective ignition does not occur in situations where the ignition source is expected to frequently occur (such as lamp failure).
Example:
The UWB device with an explosion-proof rating of ExibIICT6 indicates that the device is an inherently safe explosion-proof device, suitable for Group C gases in explosive gas environments other than coal mines, and the maximum surface temperature of the device does not exceed 85 ℃. It has a high protection level and can prevent it from becoming an ignition source under normal operation or expected fault conditions.
The UWB device with an explosion-proof rating of ExibIICT4Gb is suitable for Group C gases in explosive gas environments other than coal mines. The maximum surface temperature of the device does not exceed 135 ℃, and the protection level is Gb level.
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