Purpose
The purpose of the minimum ignition temperature of dust deposits test is to determine the minimum temperature required for self-ignition of a dust deposit as a function of the volume of the deposit.
This test is especially relevant for products that will be stored in bulk. A high initial storage temperature may make self-ignition more likely.
Self-heating is most commonly due to oxidation processes, which generate heat. Due to the insulation properties of the dust, the heat may not be easily transferred to the environment. When the rate of heat generation exceeds the rate of heat loss to the environment, the temperature of the dust keeps on increasing until it catches fire. A smouldering fire in products stored in bulk (e.g. in a silo) is very difficult to extinguish.
Method
Gexcon performs this test based on EN 15188: 2020: “Determination of the spontaneous ignition behaviour of dust accumulations”.
Dust samples are filled into mesh wire baskets of different volumes and put into an oven. The temperature of the sample and the oven are monitored. Tests are performed for a number of oven temperatures (which is held constant) and sample volumes to determine the highest oven temperature at which no ignition occurs, as well as the lowest oven temperature at which the dust sample showed an ignition.
Analysis of the test results allows for deducing the results to larger volumes, predicting the self-ignition temperature for your dust in the volume it will be stored, as well as the time it takes to catch fire.
Benefit
The test results allow for predicting whether self-ignition is possible in the volume the dust is stored as bulk material depending on its initial storage temperature, as well as the time it takes to cause self-ignition if stored at or close to conditions (temperature, volume) leading to self-ignition. The latter can be used to limit storage time.
Minimum ignition temperature of dust deposits test enquiries
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