N.J. Admin. Code § 7:27-3.1
The following words and terms, when used in this subchapter, shall have the following meanings unless the context clearly indicates otherwise.
"Department" means the Department of Environmental Protection.
"Direct heat exchanger" means equipment in which heat from the combustion of fuel is transferred to a substance being heated so that the latter is contacted by the products of combustion and may contribute to the total effluent.
"Fuel" means solid, liquid or gaseous materials used to produce useful heat by burning.
"Indirect heat exchanger" means equipment in which heat from the combustion of fuel is transferred by conduction through a heat-conducting material to a substance being heated, so that the latter is not contacted by, and adds nothing to, the products of combustion. "Internal cross-sectional dimension" means any maximum linear perpendicular distance from an inside wall of a stack or chimney to the inside of an opposite wall, such as the diameter of a circular cross-section or the length or width of a rectangular cross-section.
"Manufacturing process" means any action, operation or treatment embracing chemical, industrial, manufacturing, or processing factors, methods or forms including, but not limited to, furnaces, kettles, ovens, converters, cupolas, kilns, crucibles, stills, dryers, roasters, crushers, grinders, mixers, reactors, regenerators, separators, filters, reboilers, columns, classifiers, screens, quenchers, cookers, digesters, towers, washers, scrubbers, mills, condensers or absorbers.
"Marine installation" means equipment for propulsion, power or heating on all types of marine craft and floating equipment.
"Mobile source" means equipment designed or constructed to be portable or movable from one location to another including but not limited to aircraft, locomotives operating on rails, tractors, earth moving equipment, hoists and mobile power generators.
"Motor vehicle" means any vehicle propelled otherwise than by muscular power, excepting such vehicles as run only upon rails or tracks.
"Opacity" means the property of a substance which renders it partially or wholly obstructive to the transmission of visible light expressed as the percentage to which the light is obstructed.
"Ringelmann smoke chart" means the Ringelmann's scale for grading the density of smoke as published by the United States Bureau of Mines or any chart, recorder, indicator or device which is approved by the Department as the equivalent of said Ringelmann's scale for the measurement of smoke density.
"Smoke" means small gasborne and airborne particles, exclusive of visible condensed water vapor, arising from a process of combustion in sufficient number to be observable.
"Stack or chimney" means a flue, conduit or opening designed, constructed, and/or utilized for the purpose of emitting air contaminants into the outdoor air.
"Visible smoke" means smoke which obscures light to a degree readily discernible by visual observation.
N.J. Admin. Code § 7:27-3.1