Combustibility determination for cotton gin dust and almond huller dust

Authors: Hughs, Sidney; WAKELYN, P - Wakelyn Associates, Llc

Submitted to: Journal of Agricultural Safety and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/2016
Publication Date: 4/20/2017
Citation: Hughs, S.E., Wakelyn, P.J. 2017. Combustibility determination for cotton gin dust and almond huller dust. Journal of Agricultural Safety and Health. 23(2):125-132. https://doi.org/10.13031/jash.11824.
DOI: https://doi.org/10.13031/jash.11824

Interpretive Summary: Dusts produced during the processing of some agricultural materials will burn very rapidly under certain conditions causing dust explosions. Past dust explosions occurring in facilities handling either sugar or grain have caused significant physical damage to the facility and loss of human life in some cases. A relatively recent catastrophic dust explosion in a sugar processing plant caused OSHA and other regulators to question whether dust collecting in the interiors of cotton gins or almond huller plants during operation constituted an explosion risk. There exists a screening test to determine if dusts with an unknown explosion potential represent a safety risk from dust explosions. Representative dusts were collected from the interiors of both cotton gins and almond huller plants and subjected to the screening test. The screening test indicated that neither the cotton gin dust nor the almond huller dust should be considered combustible and therefore were not dust explosion risks for their respective industries.

Technical Abstract: It has been documented that some dusts generated while processing agricultural products, such as grain and sugar (OSHA, 2009), can constitute combustible dust hazards. After a catastrophic dust explosion in a sugar refinery in 2008, OSHA initiated action to develop a mandatory standard to comprehensively address the fire and explosion hazards of combustible dusts (OSHA, 2009). Cotton fiber and related materials from cotton ginning, in loose form, can support smoldering combustion if ignited by an outside source. However, dust fires and other more hazardous events, such as dust explosions, are unknown in the cotton ginning industry. Dust material that can accumulate during normal processing operations in the interiors of both cotton gins and almond huller plants was collected for testing to determine combustibility. Cotton gin dust is composed of greater than 50% inert, inorganic mineral dust (ash content), while almond huller dust is composed of 7% or higher inert inorganic material. Inorganic mineral dust is not a combustible dust. The cotton gin dust and almond huller dust material samples collected were sieved to a known particle size range for testing (UN, 2009) to determine combustibility potential. A combustible dust test was conducted on both the cotton gin dust and almond huller dust samples. This testing indicated that neither the cotton gin dust nor the almond huller dust should be considered combustible dusts [i.e., are not a Division 4.1 flammable hazard (49 CFR 173.124; NFPA, 2016)].