Considerations regarding the increase of temperature during the tests in explosive mixtures for an enclosure with type of protection “d”

Equipment with type of protection “d” provides explosion protection by its enclosure that withstands the pressure of an internal explosion and prevents the transmission of explosion to the explosive atmosphere that surrounds the enclosure. In this case the explosion protection is maintained even in case of an internal explosion. The maximum surface temperature of a flameproof equipment considers the temperature of external surfaces (for the inclusion of equipment in a temperature class). There is also an increase of temperature during the internal explosion. The purpose of this paper is to monitor the temperature increase in case of an internal explosion considering an equipped flameproof enclosure (using an internal equivalent model instead of internal apparatus). The tests are performed with different gases, including hydrogen, considering the gas concentrations used to perform the tests in explosive mixtures for flameproof equipment.