Page 21 - Electrical Installation in Hazardous Area

xviii Preface

occurring at particular situations and is thus not as easily specified as
equipment construction. It is, however, more specifiable than 1 above.

In writing this book I have tied to address all three facets of the tech-
nology and, rather than reproducing all the content of standards and codes, I
have been selective in discussing most of the principal requirements therein,
while at the same time trying to explain the reasoning which led to their
inclusion. Therefore, when applying the technology it will be necessary to
address the appropriate standards and codes in all cases but this book will,
by provision of the background reasoning, make those documents more
understandable. In addition, by developing practical examples of their use,
it will assist in their application.
This field is not one for inexperienced engineers and technologists and
thus must be approached with care. In addition there are many local condi-
tions which can vary the advice given here and those involved need to be
aware of this and have sufficient expertise to determine conditions under
which additional requirements are necessary and those, much less common,
where relaxations are possible. The onus is, of course, always on the occu-
pier of a location to be able to jus* what is done on safety grounds and
it is hoped that this book will assist in this activity.
The contents here relate to the situation in the UK but differences in
Europe and other counties are not great and its content should be useful
elsewhere.
Finally, unlike the situation historically existing, where this technology
was often applied in isolation, it is now important to recognize that it can
only be applied as a part of an overall safety strategy. That is not to say that
its requirements can be ignored if they adversely affect other safety features
but rather that, if such is the case, an alternative approach to achievement
of its requirements should be sought. It should always be remembered that
electrical installations in explosive atmospheres should only exist where
necessary (i.e., where they can be fully justified).
Alan McMillan