With regard to the explosion-proof form "tD", there are two different schemes in this section, both of which provide a level of energy efficiency protection.

　　Enclosure for type A and all other equipment

　　The temperature requirements are as follows:

　　- confirm the lowest touching temperature of dust layer according to the rule GB12476.8;

　　- the highest surface temperature shall be confirmed in the dust-free state according to the rule of 23.4.4.1 in 12476.1;

　　- the maximum allowable surface temperature for equipment with a dust layer thickness of no more than 5mm shall be calculated in accordance with the rule of 6.3.3.3.

　　Special case type B

　　- the temperature requirements are as follows:

　　- confirm the lowest touching temperature of dust layer according to the rule GB12476.8;

　　- the maximum surface temperature under dust cover is in accordance with iec61241-1:2004 8.2.2.2;

　　- the maximum surface temperature allowed for equipment with a dust layer thickness of no more than 12.5mm shall be calculated in accordance with the rules of 6.3.3.3.2.