The degree of danger in the atmosphere of a hazardous location needs to be determined prior to selecting an acceptable electrical equipment installation. If maximum safety is the predominant factor in determining the type of electrical installations, the cost of electrical equipment will be extremely high. If low cost of electrical installation is the predominant factor, safety to personnel and equipment may be unacceptably low. It is, therefore, necessary to find a point of balance at which the cost and safety requirements are both satisfied and acceptable.

The intent of this book is to provide an in-depth understanding of the factors that influence the classification of a hazardous location. One factor, in combination with one or more other factors, will have an impact on the level of danger and its hazardous boundaries. These factors and their influences are explained in detail, and once their impact is understood, the classification of a hazardous location becomes a straightforward procedure.

The intent of the classification of a hazardous location is to provide safety for personnel and equipment. The intent is also to achieve an economical electrical installation which will provide an acceptable level of safety for personnel and equipment at the lowest possible cost. To accomplish this, it is necessary to analyze in detail the environmental conditions of the location and the characteristics of the source of hazard. The engineer who is involved in preparing the area classification must understand all of the details which will have an impact on his decision to classify the area Division 1, Division 2, or Non-hazardous. Without the knowledge of the environmental conditions,and the characteristics of the source of hazard, he most certainly will give the location a safety level much too high, which is not economically justified, or a level too low, which is unsafe. This approach must be avoided.

In nine out of ten cases, a hazardous location is classified much too conservatively. The reason for this conservative approach is a lack of knowledge and a misunderstanding of the actual concept of safety and danger.

The application of the information in this book is mainly for flammable liquids, vapors, and gases that are processed, handled, stored, and/or transferred.

This book provides comprehensive coverage of electrical system installation within areas where flammable gases and liquids are handled and processed. The accurate hazard evaluation of flammability risks associated with chemical and petrochemical locations is critical in determining the point at which the costs of electrical equipment and installation is balanced with explosion safety requirements. The book offers the most current code requirements along with tables and illustrations as analytic tools.

Environmental characteristics are covered in Section 1 along with recommended electrical installation and safety recommendations. Section 2 treats a number of application illustrations in detail. Section 3 presents examples for the application of classifying NEC Class 1 locations.

Key Features:

- An in-depth treatment of factors that influence the classification of hazardous locations

- Recommendations for required electrical safety measures in controlling injuries and property damage in workplace and process areas

- Comprehensive coverage of factors in achieving economic electrical installation while providing recommended safety levels for personnel and equipment

- Contains 126 tables and illustrations guiding the reader about characterizing the explosion properties of flammable liquids, vapors, and gases that are processed, stored, handled and transported