The new version of the GB/T3836 series standard has been officially implemented on May 1, 2022. The difference between new and old standards is a concern for many corporate customers, and explosion-proof signs serve as the "ID card" of products,It can enable users and installation personnel to quickly understand the safety of this explosion-proof productExplosion proof typeCorresponding gas/dust and temperature groups. So as to avoid installing gas explosion-proof products in dust areas, and installing "n" type products in explosion-proof areas in Zone 1. Ensure that explosion-proof products match hazardous areas in terms of selection.

Based on the introduction of the new GB/T 3836-2021 standard, Zhongnuo Testing summarizes the content and meaning of the explosion-proof signs for Ex equipment used in combustible dust environments.

The explosion-proof signs for Ex equipment used in combustible dust environments should include:
1、 The symbol Ex indicates that the Ex equipment complies with one or more explosion-proof types listed in Chapter 1 of GB/T 3836.1-2021's special standards.
2、 Explosion proof protection type,The explosion-proof protection measures, explosion-proof protection types, and corresponding code relationships adopted by the equipment are shown in the table below.

Note: In addition to the four explosion-proof protection types listed above, there are also light radiation explosion-proof types and explosion-proof special types for Ex equipment used in combustible dust. Due to the scarcity of such products, we will not elaborate on them here.

3、 Combustible dust category
III. AIIIB andIIIClass C: Other combustible dust except for coal mine gas environment, as shown in the table below.

Note: Under the same conditions, IIIC>IIIB>IIIA

4、 Temperature group refers to the temperature limit at which the ignition temperature of a combustible dust mixture can be ignited.

5、 Applicable Equipment Protection Level (EPL)
The relationship between different equipment protection levels and explosion-proof areas is shown in the table below.

Remarks:
1. Da/DB/DC is the protection level of Ex equipment for combustible dust environments other than coal mine gas environments
2. Under equal conditions,DA>DB>DC
3. The Ex signs should be marked in the order given in the above columns, with small intervals between them.

Example of explosion-proof signs:
Ex tb IIIC T130 ° C Db
Ex: Electrical equipment marking for combustible dust environments
Tb: The protection type is an anti dust ignition housing type
IIICConductive dust environment

T130 ° C: The maximum surface temperature of the equipment does not exceed 130 ° C
Db: Equipment protection level, can be used in zones 21 and 22

Ex ia IIIB T₂₀₀80 ° C Da
Ex:Electrical equipment marking for combustible dust environments
Ia: The protection type is intrinsically safe
IIIB:Non conductive combustible dust environment
T ₂₀₀80 ° C:The maximum surface temperature of the equipment under the condition of dust cloud 200mm shall not exceed 80 ° C
Da: Equipment protection level, can be used in zones 20, 21, and 22


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