Definitions cont'd - hdbk10920265

DOE-HDBK-1092-98

Center pivot irrigation machine--A center pivot irrigation machine is a multi-motored irrigation

machine which revolves around a central pivot and employs alignment switches or similar devices

to control individual motors.

Certified--Equipment is "certified" if it (a) has been tested and found by a nationally recognized

testing laboratory to meet nationally recognized standards or to be safe for use in a specified manner,

or (b) is of a kind whose production is periodically inspected by a nationally recognized testing

laboratory, and (c) it bears a label, tag, or other record of certification.

Circuit breaker--

(600 volts nominal, or less). A device designed to open and close a circuit by nonautomatic

means and to open the circuit automatically on a predetermined overcurrent without injury to

itself when properly applied within its rating.

ii. (Over 600 volts, nominal). A switching device capable of making, carrying, and breaking

currents under normal circuit conditions, and also making, carrying for a specified time, and

breaking currents under specified abnormal circuit conditions, such as those of short circuit.

Class I locations--Class I locations are those in which flammable gases or vapors are or may be

present in the air in quantities sufficient to produce explosive or ignitable mixtures. Class I locations

include the following:

Class I, Division 1. A Class I, Division 1 location is a location:

a. in which hazardous concentrations of flammable gases or vapors may exist under normal

operating conditions; or

b. in which hazardous concentrations of such gases or vapors may exist frequently because of

repair or maintenance operations or because of leakage; or in which breakdown or faulty

operation of equipment or processes might release hazardous concentrations of flammable

gases or vapors, and might also cause simultaneous failure of electric equipment.

NOTE: This classification usually includes locations where volatile flammable liquids or liquefied

flammable gases are transferred from one container to another; interiors of spray booths and

areas in the vicinity of spraying and painting operations where volatile flammable solvents are

used; locations containing open tanks or vats of volatile flammable liquids; drying rooms or

compartments for the evaporation of flammable solvents; locations containing fat and oil

extraction equipment using volatile flammable solvents; portions of cleaning and dyeing plants

where flammable liquids are used; gas generator rooms and other portions of gas manufacturing

plants where flammable gas may escape; inadequately ventilated pump rooms for flammable gas

or for volatile flammable liquids; the interiors of refrigerators and freezers in which volatile

flammable materials are stored in open, lightly stoppered, or easily ruptured containers; and all

other locations where ignitable concentrations of flammable vapors or gases are likely to occur

in the course of normal operations.

ii. Class I, Division 2. A Class I, Division 2 location is a location:

a. in which volatile flammable liquids or flammable gases are handled, processed, or used, but

in which the hazardous liquids, vapors, or gases will normally be confined within closed

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