Page 386 - Chemical engineering design

CHAPTER 9

Safety and Loss Prevention

9.1. INTRODUCTION

Any organisation has a legal and moral obligation to safeguard the health and welfare of
its employees and the general public. Safety is also good business; the good management
practices needed to ensure safe operation will also ensure efficient operation.
The term “loss prevention” is an insurance term, the loss being the financial loss caused
by an accident. This loss will not only be the cost of replacing damaged plant and third
party claims, but also the loss of earnings from lost production and lost sales opportunity.
All manufacturing processes are to some extent hazardous, but in chemical processes
there are additional, special, hazards associated with the chemicals used and the process
conditions. The designer must be aware of these hazards, and ensure, through the appli-
cation of sound engineering practice, that the risks are reduced to acceptable levels.
In this book only the particular hazards associated with chemical and allied processes
will be considered. The more general, normal, hazards present in all manufacturing process
such as, the dangers from rotating machinery, falls, falling objects, use of machine tools,
and of electrocution will not be considered. General industrial safety and hygiene are
covered in several books, King and Hirst (1998), Ashafi (2003) and Ridley (2003).
Safety and loss prevention in process design can be considered under the following
broad headings:
1. Identification and assessment of the hazards.
2. Control of the hazards: for example, by containment of flammable and toxic
materials.
3. Control of the process. Prevention of hazardous deviations in process variables
(pressure, temperature, flow), by provision of automatic control systems, interlocks,
alarms, trips; together with good operating practices and management.
4. Limitation of the loss. The damage and injury caused if an incident occurs: pressure
relief, plant layout, provision of fire-fighting equipment.

In this chapter the discussion of safety in process design will of necessity be limited. A
more complete treatment of the subject can be found in the books by Wells (1980) (1997),
Lees (1996), Fawcett and Wood (1984), Green (1982) and Carson and Mumford (1988)
(2002); and in the general literature, particularly the publications by the American Institute
of Chemical Engineers and the Institution of Chemical Engineers. The proceedings of the
symposia on safety and loss prevention organised by these bodies, and the European
Federation of Chemical Engineering, also contain many articles of interest on general
safety philosophy, techniques and organisation, and the hazards associated with specific

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