Self-Ignition Risks in Hop, Alfalfa, Straw, and Hay Bales

Hops, alfalfa, straw, and hay have a relatively low ignition temperature. Oxidation in the presence of moisture and air or bacterial fermentation release heat. If the heat is unable to escape (hops, alfalfa, hay, straw etc. are good thermal insulators) and the temperature rises above the ignition point this may cause a self-ignition: A fire develops without an external ignition source.

During processing, hops, alfalfa, straw, and hay are often tightly compressed into bales for transportation and storage. Moisture plays a crucial role in this process, particularly because the bales have a propensity to absorb and retain moisture, which, when combined with other factors like temperature, sun, and airflow, can lead to self-ignition.

If these bales contain areas with elevated moisture levels, internal heat can build up, creating a potentially hazardous environment. This heightened temperature significantly increases the risk of self-ignition. Consequently, it is vital to identify and address moisture variations within these kinds of bales promptly.



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