1 Scope
This standard presents the current state of knowledge and technology in the fields of static electricity, lightning, and stray currents applicable to the prevention of hydrocarbon ignition. The recommended preventive measures are based on the research and practical experience in the petroleum industry. Furthermore, the principles discussed in this standard are applicable to other operations where ignitable liquids and gases are handled. Their use will lead to improved safety practices and evaluations of existing installation methods and production procedures. When the narrow limits of static electricity ignition are properly understood, fire investigators should be encouraged to search more diligently for the true ignition sources in instances where static ignition is unlikely or impossible.
The following chapters will discuss some basic procedures taken to protect against the static ignition. These recommended practices and preventive measures proposed in this standard are not applicable under the following conditions:
a) Static discharges may occur, but flammable vapors are always excluded by gas freeing or inerting the atmosphere in the area of discharge.
b) Product handling occurs in a closed system, and oxygen in that system is always below the minimum concentration required to support combustion, such as in the handling of liquefied petroleum gas (LPG).
c) The flammable concentration is always above the upper flammable limit (UFL).
This document does not address electrostatic hazards relating to solids handling. (See [12] and [13] in the bibliography.)
