Patterns of Wood Dust Fire Hazard Change in Contact with Lubricants

In this article, the authors present the results of a study aimed at identifying quantitative patterns of changes in the fire hazard of softwood and hardwood dust in contact with various types of lubricants. The studies were carried out using the thermogravimetric and differential thermal analysis (TG/DTA) method using the Thermoscan-2 derivatograph. Wood dust of birch and pine (100 μm ≤ fraction) in pure form was used as test samples, as well as with the addition of oils of different types in a ratio of 9:1. It was found that contact with lubricants leads to a decrease in the temperature of the onset of thermal decomposition by 10-40 °C (depending on the type of oil and wood species). This also leads to an increase in the number of exothermic peaks from 2 to 3-5 and a decrease in residual mass by 40-76%. Transmission and push-pull oils have the greatest significant impact due to the high content of volatile components. The mechanism of "chain transfer of combustion" was revealed: oil vapors ignite at 170-240 °C, creating conditions for the subsequent ignition of wood vapors. Based on the data obtained, practical recommendations have been developed, including the introduction of a correction factor k = 0.85-0.92 to the estimated spontaneous ignition temperature in the event of oil contamination, as well as an increase in the category of explosion and fire hazard of premises where wood dust and lubricants come into contact.