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Research and Development 6 7 7

in determining both ignition sensitivity and explosion violence need to be investigated
more closely. Cashdollar (1998) discussed various central aspects of dust explosion
research, prevention, and mitigation.

9.3.2
INHERENTLY SAFE PROCESS DESIGN

Kletz (1999) outlined his important message of adopting the concept of inherently safe
process design whenever possible. Traditionally, industry has tried to prevent acciden-
tal explosions mostly by adding preventive and mitigatory equipment and enforcing
safe procedures.But such equipmentis often expensive,and proceduresmay fail. Inherent
safety impliesthat the process design itself is such that no explosionhazard exists. Kletz
gives some examples of inherently safe process design in practice.
Amyotte and Khan (2002) proposed a framework for directing the concept of inher-
ently safe process design specificallytoward reducing the dust explosionhazard in indus-
try. One hopes this contribution will stimulate to further work in this important area.

9.3.3
PAPERS COVERING SEVERAL METHODS
AND SPECIFIC APPLICATIONS

An overview of preventive and mitigatory techniques in use is given in Section 1.4 in
Chapter 1.
In the late 1970s and early 1980s,a significant fire and explosion problem existed in
the U.S. grain handling and grain related industry. Because of investigationsinitiated by
the federal government and research undertaken by government and the industry, fed-
eral safety regulations were issued and an educationalprogram initiated by the industry
and affiliated labor unions, as reviewed by Kauffman et al. (1996).As a result, the fre-
quency and severity of these accidents decreased significantly.
Siwek (1992) described experiments where a combination of explosion venting and
automatic suppression was adopted for mitigating or controllingdust explosionsin var-
ious enclosures. Sliz, Lebecki, and Dyduch (1993) investigatedthe performanceof such
a combined system for mitigating grain dust explosions in an 8 m3experimentalvessel.
Different types of vent covers and suppressors were tested.
Zeeuwen (1996) discussed alternative strategies for protecting process installations
against dust explosions-full containment,explosion venting, automatic explosion sup-
pression, and explosion isolation-using a grinding installation as an example. Hoppe,
Jaeger, and Terry (1998,2000) discussed strategies and specific measures for preventing
and mitigating dust explosions, developed and implemented in a major international
chemical process company. Stevenson (1998) gave a broad overview of availablemeth-
ods for dust explosion prevention and mitigation. Jaeger (2001) used a practical exam-
ple to illustratea strategy for minimizing the dust explosionhazard in the process industries.
The two main elements form the strategy, relevant ignitability and explosibility charac-
teristics of the dusts in question and adequate methods for performing risk analyses.