Terms used in this subpart are defined in the CAA, in §63.2, and in this section.

Bag leak detection system means a system that is capable of continuously monitoring relative PM (i.e., dust) loadings in the exhaust of a fabric filter to detect bag leaks and other upset conditions. A bag leak detection system includes, but is not limited to, an instrument that operates on triboelectric, electrodynamic, light scattering, or other effect to monitor relative PM loadings continuously.

Capture system means the collection of components used to capture gases and fumes released from one or more emissions points and then convey the captured gas stream to a control device or to the atmosphere. A capture system may include, but is not limited to, the following components as applicable to a given capture system design: Duct intake devices, hoods, enclosures, ductwork, dampers, manifolds, plenums, and fans.

Charging means introducing materials to an EAF or other reaction vessel, which may consist of, but are not limited to, ores, slag, carbonaceous material, and/or limestone.

Control device means the air pollution control equipment used to remove PM from the effluent gas stream generated by an EAF furnace or other reaction vessel.

Electric arc furnace means any furnace wherein electrical energy is converted to heat energy by transmission of current between electrodes partially submerged in the furnace charge.

Electrometallurgical operations means the use of electric and electrolytic processes to purify metals or reduce metallic compounds to metals.

Fugitive emissions means any pollutant released to the atmosphere that is not discharged through a ventilation system that is specifically designed to capture pollutants at the source, convey them through ductwork, and exhausts them from a control device. Fugitive emissions include pollutants released to the atmosphere through windows, doors, vents, or other building openings. Fugitive emissions also include pollutants released to the atmosphere through other general building ventilation or exhaust systems not specifically designed to capture pollutants at the source.

Sealed EAF means a furnace equipped with the cover with seals around the electrodes and outer edges of the cover to eliminate air being drawn in under the cover.

Tapping means the removal of product from the EAF or other reaction vessel under normal operating conditions, such as removal of metal under normal pressure and movement by gravity down the spout into the ladle.