Chemical Engineering November 2018 - 58

The more recent CDID data show
a steady continuation in the number
of recorded dust-related explosions
per year. The total increased by another
50% in the 10 years since the
CSB report was published. However,
the incident reports also suggest that
the overall number of injuries and fatalities
may be flattening or decreasing
compared to the number of incidents.
This tentatively suggests that
an emphasis on combustible dust
awareness, prevention and protection
practices over the last decade
may be reducing the average severity
of any given explosion. It is again important
to note that under-reporting
in previous data may influence this
conclusion. Furthermore, although
the severity may be decreasing, neither
dataset shows any single year
with zero fatalities due to dust explosions
in the U.S. since 1983.
Materials and industries
From the 2018 CDID incident reporting,
wood processing, food processing
and agricultural activities account
for almost 60% of the dust-related
fire and explosion incidents. Automotive
manufacturing, metal working,
power generation and mining
contributed an additional 17%. The
remaining 24% of incidents occurred
in other industries, including pulp
and paper, education, coatings, oil
and gas, textiles and recycling.
Very frequently, materials involved
in wood-product incidents were
Equipment
Dust collectors
Storage silos
Elevators/conveyors
Other storage
Other equipment
No details mentioned
TABLE 2. EQUIPMENT CITED IN COMBUSTIBLE DUST INCIDENTS
Fires
25
8
7
Explosions
3
12
21
16
specified as sawdust or wood dust,
and materials involved in food processing
or agriculture were specified
as grain dust. In cases were specific
materials were named, pine chips,
cellulose, corn, pecan, cocoa, flour,
cereal, barley and spices were implicated
in dust incidents. Although
not broken out in the data, coal dust
accounted for almost 7% of the total
incidents. In cases involving metal
dusts, aluminum, titanium, magnesium
and iron were cited most often.
Equipment and causes
Dust collectors tend to have the
highest number of total incidents of
all equipment involved
in powder
processing. However, the 2018 incident
data suggest that these were
more often fires than explosions. It is
often difficult to distinguish between
storage silos and elevators - these
two terms are often used synonymously
in much of the news reporting.
Overall, storage silos, elevators
and conveyors made up half of the
explosion incidents, while accounting
for a smaller proportion of the
overall fires (Table 2). Other equipment
includes mills, shakers, grind9
5
2
3
4
Total
28
17
12
14
24
20
ers,
saws, dryers and cyclones.
Often, very little information is
available that points to the initiating
cause of combustible dust fire and
explosion incidents. In specific cases
highlighted in the reports, hot work,
including welding and cutting metal,
are listed as the initiating cause.
Sometimes machine sparking and
static electricity are indicated in news
reports, although it is rare to have this
substantiated by a formal technical
review. Further development of the
CDID will focus on working with local
fire departments and government organizations
to better communicate
these causes when an official investigation
has been performed.
Loss overview
It is instructive to organize the combustible-dust
incident data in terms of
different types of loss. This comparison
provides some information about
how fires and explosions impact injury
totals, fatalities and facility damages
individually, and allows trends from
different materials involved in processing
operations to be explored.
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Chemical Engineering November 2018

Table of Contents for the Digital Edition of Chemical Engineering November 2018
