In the new version of the GB/T 3836-2021 explosion-proof standard, explosion-proof protection levels have been added for flameproof electrical equipment, which are divided into:

"da" Protection Level (EPL "Ma" or "Ga");

"db" Protection Level (EPL "Mb" or "Gb");

"dc" Protection Level (EPL "Gc").

This standard update has added the flameproof "da" explosion-proof protection level, which is only applicable to catalytic sensor products of portable combustible gas detectors, and shall meet the following requirements:

1. The maximum internal net volume shall not exceed 5 cubic centimeters;

2. When introducing conductors into the sensor, a sealing joint surface complying with Chapter 6 shall be used directly in the enclosure wall;

3. The breathing device of the sensor shall comply with Chapter 10, and shall be bonded to the enclosure wall without gaps (such as bonding or sintered joint in accordance with 6.1), or shall be press-fitted on the enclosure wall by means of supplementary mechanical fixing (such as swaging);

4. Powered by circuits of "ia" protection level, the maximum dissipated power shall be limited to 3.3W (for Class I) and 1.3W (for Class II);

Note: Catalytic elements generally operate at high temperatures. If the dissipated power increases beyond the normal operating level, the element failure will cause an open circuit. Therefore, the required power limit provides a restriction on the external surface temperature.

5. Modify the flameproof test in 15.3 or 15.4.4 (if applicable) to increase the number of flameproof tests, as shown in Table 1.

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