(a) Electric arc furnace (EAF) means a furnace that produces molten steel and heats the charge materials with electric arcs from carbon electrodes. Furnaces that continuously feed direct-reduced iron ore pellets as the primary source of iron are not affected facilities within the scope of this definition.

(b) Dust-handling equipment means any equipment used to handle particulate matter collected by the control device and located at or near the control device for an EAF subject to this subpart.

(c) Control device means the air pollution control equipment used to remove particulate matter generated by an EAF(s) from the effluent gas stream.

(d) Capture system means the equipment (including ducts, hoods, fans, dampers, etc.) used to capture or transport particulate matter generated by an EAF to the air pollution control device.

(e) Charge means the addition of iron and steel scrap or other materials into the top of an electric arc furnace.

(f) Charging period means the time period commencing at the moment an EAF starts to open and ending either three minutes after the EAF roof is returned to its closed position or six minutes after commencement of opening of the roof, whichever is longer.

(g) Tap means the pouring of molten steel from an EAF.

(h) Tapping period means the time period commencing at the moment an EAF begins to pour molten steel and ending either three minutes after steel ceases to flow from an EAF, or six minutes after steel begins to flow, whichever is longer.

(i) Meltdown and refining means that phase of the steel production cycle when charge material is melted and undesirable elements are removed from the metal.

(j) Meltdown and refining period means the time period commencing at the termination of the initial charging period and ending at the initiation of the tapping period, excluding any intermediate charging periods and times when power to the EAF is off.

(k) Shop opacity means the arithmetic average of 24 or more opacity observations of emissions from the shop taken in accordance with Method 9 of appendix A of this part for the applicable time periods.

(l) Heat time means the period commencing when scrap is charged to an empty EAF and terminating when the EAF tap is completed.

(m) Shop means the building which houses one or more EAF's.

(n) Direct shell evacuation system means any system that maintains a negative pressure within the EAF above the slag or metal and ducts these emissions to the control device.

(o) Bag leak detection system means a system that is capable of continuously monitoring relative particulate matter (dust) loadings in the exhaust of a baghouse to detect bag leaks and other conditions that result in increases in particulate loadings. A bag leak detection system includes, but is not limited to, an instrument that operates on triboelectric, electrodynamic, light scattering, light transmittance, or other effect to continuously monitor relative particulate matter loadings.