Scholarly record
EXPERIMENTAL EVALUATION OF DUST THERMAL CONDUCTIVITY IMPACT ON MAXIMUM SURFACE TEMPERATURE AND IGNITION RISK OF EX EQUIPMENT
Abstract
This study investigates experimentally the influence of dust thermal conductivity on the maximum surface temperature of Ex equipment operating under dust layer conditions at a fixed dissipated power of 3 W. Experiments were conducted using a purpose-built resistive test sample, designed and manufactured at INCD INSEMEX, tested with two dust materials representing boundary conditions of thermal behaviour: vermiculite, selected as a worst-case insulating material, and Portland cement dust, selected for its industrial relevance in classified explosive dust environments. The proposed methodology combines infrared thermographic pre-mapping with equivalent thermal resistance analysis, enabling improved hot spot identification and physically grounded interpretation of heat accumulation phenomena. At 3 W, a temperature difference of 24.22 degree Celsius was measured between vermiculite (152.52 degree Celsius) and Portland cement dust (128.30 degree Celsius), with the dust layer contributing up to 20% of total system thermal resistance. The findings demonstrate that current certification procedures based solely on dust layer thickness may significantly underestimate ignition risk, and support the inclusion of dust thermal conductivity as a mandatory parameter for thermal safety classification under IEC 60079-31. Keywords: Explosive atmospheres, dust layer, thermal conductivity, maximum surface temperature, ignition risk, Ex equipment, vermiculite, Portland cement dust.
Publication details
References6
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