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Dust Explosions: An Overview 57

1.4
MEANS FOR PREVENTING AND MITIGATING
DUST EXPLOSIONS

1.4.1
THE MEANS AVAILABLE: AN OVERVIEW

The literature on the subject is substantial.Many authors have written short, general sur-
veys on the means of preventing and mitigating dust explosions in the process industry.
A few examples are Gibson (1978); Scholl, Fischer, and Donat (1979); Kuhnen and
Zehr (1980);Field (1982b, 1987);Woodcockand Reed (1983); Siwek (1986,1987); Swift
(1987’a, 1987b); and Bartknecht (1988). For more recent works, see Section 9.3.3. The
books mentioned in Sections 1.1.1.5 and 9.1.2 also contain valuable information.
Table 1.9 gives an overview of the various means presently known and in use. They
can be divided in two main groups, the means for preventing explosions and the means
for their mitigation. The preventive means can again be split in the two categories, pre-
vention of ignition sources and prevention of an explosible or combustible cloud. One
central issue is whether preventing only ignition sources can provide sufficient safety,
or is it also necessary, in general, to employ additional means of prevention or mitiga-
tion. In the following sections, the means listed in Table 1.9 are discussed separately.

Table l.9 Means of preventing and mitigating dust explosions: a schematic overview

I e. Heat from mechanical I n. Automatic suppression

impact (metal sparks and
0.Good housekeeping
(dust removal, cleaning)

1.4.2
PREVENTING IGNITION SOURCES

I .4.2.1
Introduction

The characteristics of various ignition sources are discussed in Section 1.1.4, and some
special aspects are elucidated more extensively in Chapter 5. The test methods used for
assessing the ignitability of dust clouds and layers, when exposed to various ignition
sources are discussed in Chapter 7.