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Dust Explosions: An Overview 133

1.5.3
SPECIAL ASPECTS FOR SOME SPECIFIC GROUPS OF POWDERS
AND DUSTS: A BRIEF LITERATURE SURVEY

1.5.3.1
Grain and Feed Dusts and Flour

The literature on preventing and mitigating dust explosions in the grain, feed, and flour
industry is substantial.This is easy to understand in view of the large losses of life and
property caused by dust explosions in this branch of industry. One of the earliest con-
tributions, by Weber (1878), is still relevant in many respects. In particular, he empha-
sized the marked influence of the moisture content of the dust or flow on the explosion
hazard.Almost a century later, Theimer (1972) gave his well-known summary of causes
and means of prevention of dust explosions in grain storage facilities and flour mills.
A useful summary of existing knowledge and experience at that time was collected
during an international symposium arranged by National Materials Advisory Board of
the United States (1978). Aldis and Lai (1979) reviewed literature related to the engi-
neering aspects of grain dust explosions.The National MaterialsAdvisory Board (1982)
produced a set of well-structuredrecommendationsfor the selection of adequate means
to prevent and mitigate dust explosions in grain storage facilities and flour mills. The
reason why soybean oil is used to reduce dust formation in grain storage facilities (see
Section 1.4.10) was not mentioned but is simple. The potential of this very promising
method of dust control was just not known at that time. This illustrates that knowledge
and technology change continuously,necessitatingregular updating of sources of infor-
mation.
A most informative document was issued by the Committee on Agriculture (l982), of
the U.S. House of Representatives.A number of witnesses, including both people from
industry and scientists, were asked to express their views on how to reduce the proba-
bility of dust explosionsin the US. grain industry. Severalwitnesses emphasizedthe need
for improved dust control.
Solymos (1985) discussed various “dry” methods of dust control as a means of pre-
venting dust explosions in grain storage facilities. Erling (1984) outlined the very com-
prehensive system for preventing and mitigating fires and dust explosions in the rebuilt
oland flour mill in the Federal Republic of Germany. The mill suffered a catastrophic
explosion and fire in 1979.
Radandt (1987) reviewed the prevention and control of dust explosions in the grain,
feed, and flour industry in the Federal Republic of Germany in general; Zhang Fenfen
and Zhang Chunxiao (1987)consideredgrain dust explosionsand their prevention in grain
storage facilities in the Peoples Republic of China.
Tesler and Semyonov (1988, 1989) discussed new concepts for reducing the dust
explosion hazard in grain storage facilities, with particular reference to the situation in
the USSR. The latter paper included schemes of explosion protection systems for inte-
grated grain storage facilities and quantitative methods for design of equipment, struc-
tures, and buildings.
The venting of large silos in the grain, feed, and flour industry has been a topic for dis-
cussioinfor a long time. Experimentalfull-scale work conducted in Norway and discussed