SAChE Explosion Hazards Practice Test 2025 – Complete Exam Prep

The correct answer is the Minimum Explosible Concentration (MEC). A dust explosion necessitates the presence of a specific concentration of combustible dust particles suspended in the air. The MEC is defined as the lowest concentration of combustible dust that can support a sustained explosion. This concentration is critical because if the dust concentration falls below this threshold, there won't be enough fuel to propagate the explosion.

In explosion dynamics, the MEC is a key parameter in evaluating the explosion potential of a dust cloud. It accounts for the volume of air that is mixed with the combustible particles, influencing the ignition and explosion characteristics. Therefore, understanding and identifying the MEC allows safety professionals to assess risks and implement control measures effectively, ensuring the concentration of dust remains below this hazardous level.

The other options relate to different thresholds in explosion dynamics. The Lower Explosive Limit (LEL) pertains to the minimum concentration of gas or vapor in air that can ignite, the Upper Explosive Limit (UEL) refers to the maximum concentration for an explosion to occur, while the Occupational Exposure Limit (OEL) is a guideline for acceptable exposure levels for workers but does not relate directly to explosion potential.