World Grain - August 2018 - 70
sion. A more complex answer to the question uses a measure
called the Maximum Explosive Concentration (MEC). This
concentration varies by particle size, with smaller particles
more hazardous. The small particles of most grains mean
as wheat should always be considered combustible.
MITIGATING AND PREVENTING EXPLOSIONS
Many improvements in design, monitoring, maintenance,
and training employees have reduced the number of explosions that occur. One of the challenges of prevention is that
explosion events after occurrence. Of the 104 explosions
reported from 2005 through 2017, the ignition source and
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multiple sources of dust generation within the grain facility, poorly maintained handling or conveyance equipment, and a lack of a preventive maintenance approach in
grain and feed handling and processing facilities. A lack of
workers, supervisors and contractors is another challenge.
The responsibility for overseeing details or creating awareness on these items belongs to workers and supervisors.
Safety directors in grain and feed handling facilities
balance multiple hazards and, in some cases, prioritizing
housekeeping and equipment maintenance can be challenging. Further, having safety standards and implementing these standards consistently can be an obstacle. The
reluctance of personnel to accept the potential grain dust
hazards in grain and feed handling facilities is a major barrier. Narrow opinions such as "nothing has happened until
now" or "accidents occur no matter how much you train
the workers" must be overcome to successfully deliver the
safety message about grain dust explosion threats faced
by the grain handling and processing industry. Additionally, grains are handled and processed differently based on
industry type. As a result, safety requirements may vary,
leading to a discrepancy in the literature and confusion
about best practices for managing grain dust hazards.
Advanced engineering controls such as explosion suppression systems and dust collection systems have been successful
in lowering the number of grain
dust explosions. Yet, the
presence of advanced control
equipment can raise a false
sense of security in managers,
supervisors and workers. Grain
dust collection and mitigation
systems work well when installed
and used correctly and in align70
Five died in an explosion in July 2007 at this flour mill in Fossano, Italy.
Photo courtesy of ANTIM.
dust collectors are inadequately designed for the environment they operate within or process changes are made after
the installation without an adequate review, the system may
not protect the facility or its employees as expected. Also,
outside parties who inspect facilities may not always be
able to identify dust explosion hazards.
Awareness and use of these advanced controls are mostly
limited to larger organizations with many employees and
a dedicated safety staff. Smaller facilities often operate
without any advanced dust control or explosion mitigation
plan. Facilities with a smaller budget have options to minimize grain dust hazards in their facility, but they must take
the hazard seriously. In all mitigation methods, the focus
explosions from the mix. Effective dust collection at the
loading and unloading points is one option as is managing
dust once it has entered the facility.
turbulence of grain at transfer points to minimize dust separaAugust 2018 / World Grain / www.World-Grain.com