Page 168 - Dust Explosions in the Process Industries

Dust Explosions:An Overview 14 1

Dust explosions can also result from mining sulfide ores containing substances like
pyrite, pyrrhotite, arsenopyrite,sphalerite,and galena. The hazards of sulfidedust explo-
sions also include the toxic effects of the combustion products. Various aspects of sul-
phide ore dust explosionswere discussedby Polikarpov (1984),Enright (1984a, 1984b),
and Amaratunga (1988).
Finally, a quite special dust explosion hazard arises when burned-out fuel rods in
nuclear power plants are cut in reprocessing plants and fine zircaloy dust is generated.
Zircaloy is essentially zirconium with small percentages of antimony, iron, and nickel.
t is used as claddingfor nuclear fuel rods. Because of the hazardous radioactivityof the
zircaloy dust, very specialprecautionsmust be taken when assessingthe ignitability and
explosibilityproperties of the dust. Andriessen et al. (1987),Hensel(1988), and Hattwig
et al. (1988) discussed the methods used and results obtained and suggested possible
means of preventing and mitigating zircaloy dust explosions in reprocessing plants.

1.5.4
STANDARDS, RECOMMENDATIONS, AND GU IDELlNE§

Most industrialized countries have their own officialcodes of practice for preventing and
mitigating dust explosions in industry.Examples include Germany, the United Kingdom,
France, Holland, Sweden, Norway, the United States, and Russia. Normally, the official
national factory inspectorate or health and safety inspectorate is the responsible author-
ity issuing the codes and controlling whether they are practiced.
In addition, independentbodies in many countries issue their own regulations, some of
which.are in reality consideredauthoritative.Examples of such bodies are the National Fire
Protection Association (NFPA) in the United States and the Verein deutscher Ingenieure
(VDI) in Germany. Sometimes,various industrialbranches in a country,such as the grain,
feed, and flour industry or the ferro alloy industry, issue their own set of specific guide-
lines. It is important that these comply with the general authoritativecodes of the country.
Codes and standards are also issued on an international level, through cooperation
among many countries.Examples of internationalorganizations set up for such work are
the International Standards Organization (ISO), the International Electrotechnical
Commission (IEC), and European Community bodies (CEN, CENELEC).
All the various codes, standards, regulations, and guidelines are, or should be, peri-
odically revised to keep pace with the development of knowledge and technology. One
should therefore always make sure that the document at hand is the latest, valid version.
Some recent standards and guidelines are mentioned in Chapters 8 and 9.

REFERENCES

Abbot, J. A. (1988) “Survey of Dust Fires andExplosions in UK 1979-1984: Dust Explosion Prevention
and Protection-Latest Development.” In Proceeding of the International Meeting Organized by
ZBCIBMHB. Ascot, Berkshire, UK British Material Handling Board.
Aellig, A, and R. Gramlich. (1984) “Einflussvon Ausblasrohren auf die Explosionsdruckentlastung.”
VDI-Berichte [VDI-Verlag GmbH, Dusseldorfl494, pp. 175-183.