UL 60079-18-2019 pdf free download

UL 60079-18-2019 pdf free download.Explosive Atmospheres-Part 18 : Equipment Protection by Encapsulation ” m”.
8.2.2 Maximum temperature
8.2.2DV DR Modification of Clause 8.2.2 to replace with the following:
A sample of “m” equipment shall be subjected to a type test to ensure that:
a) the temperature limits specified In 6.1 are not exceeded in normal operation;
b) for level of protection “ma” and “mb” the maximum surface temperature Is not exceeded under fault conditions as defined In 7.2.1.
For “rn” equipment without an external load, the test shall be carried out in accordance with the temperature measurements of lEG !Jj 60079-0 taking into account the supply conditions given in 4.4.
For “rn” equipment with an external load, the test shall be carried out for level of protection “ma” and “mb” by adjusting the current to the highest value, which does not cause the protective device to operate, and for level of protection “mc” at the specified load parameters in normal operation and in the case of regular expected occurrences.
For level of protection “ma” equipment, designed for EPL “Da” the maximum surface temperature shall be determined with the equipment mounted in accordance with the manufacturer’s instructions, and surrounded on all available surfaces by dust with a layer thickness of at least 200 mm. The final temperature shall be considered to have been reached when the rate of rise of temperature does not exceed 1 K124 h.
For EPL “Db”. the maximum surface temoerature shall be determined with the eauioment mounted in accordance with the manufacturer’s Instructions with the additional reuuirement that the aooaratus shall be covered with the maximum amount of dust that It can retain.
The measurement for the maximum surface temoerature shall be determined uslna a test dust havina a thermal conductivIty of no more than 0.10 W!(m.K) measured at (100 – 5) °C. or grain dust consisting of wheat or corn dust. or both. that has Dassed through a USA Standard 150 Micron (100 mesh) wire cloth oer ASTM-E11.
NOTE 1 TestIng, simulation and analysis is sometimes used In order to achieve the required temperature limitations under malfunction conditions for equipment with characteristics such as non-linear external loads. Input power control, or difficult to define failure modes.
NOTE 2 The IEC 60079 series only permits use of a test dust having a thermal conductlvty of no more than 0.10 W/im.K) measured at Clog 5 C.UL 60079-18-2019 pdf free download.