Terms in this subpart are defined in the Clean Air Act (Act), in subpart A of this part, or in this section as follows:

Bag leak detection system means a system that is capable of continuously monitoring particulate matter (dust) loadings in the exhaust of a baghouse in order 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, light scattering, light transmittance, or other effect to continuously monitor relative particulate matter loadings.

Capture system means the collection of components used to capture the 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, fans and roofline ventilation systems.

Casting means the period of time from when molten ferroalloy is removed from the tapping station until the pouring into casting molds or beds is completed. This includes the following operations: Pouring alloy from one ladle to another, slag separation, slag removal and ladle transfer by crane, truck, or other conveyance.

Crushing and screening equipment means the crushers, grinders, mills, screens and conveying systems used to crush, size and prepare for packing manganese-containing materials, including raw materials, intermediate products and final products.

Electric arc furnace means any furnace where electrical energy is converted to heat energy by transmission of current between electrodes partially submerged in the furnace charge. The furnace may be of an open, semi-sealed, or sealed design.

Furnace process cycle means the period in which the furnace is tapped to the time in which the furnace is tapped again and includes periods of charging, smelting, tapping, casting and ladle raking. For multiple furnaces operating within a single shop building, furnace process cycle means a period sufficient to capture a full cycle of charging, smelting, tapping, casting and ladle raking for each furnace within the shop building.

Ladle treatment means a post-tapping process including metal and alloy additions where chemistry adjustments are made in the ladle after furnace smelting to achieve a specified product.

Local ventilation means hoods, ductwork, and fans designed to capture process fugitive emissions close to the area where the emissions are generated (e.g., tap hoods).

Metal oxygen refining (MOR) process means the reduction of the carbon content of ferromanganese through the use of oxygen.

Outdoor fugitive dust source means a stationary source from which hazardous air pollutant-bearing particles are discharged to the atmosphere due to wind or mechanical inducement such as vehicle traffic. Fugitive dust sources include plant roadways, yard areas and outdoor material storage and transfer operation areas.

Plant roadway means any area at a ferromanganese and silicomanganese production facility that is subject to plant mobile equipment, such as forklifts, front end loaders, or trucks, carrying manganese-bearing materials. Excluded from this definition are employee and visitor parking areas, provided they are not subject to traffic by plant mobile equipment.

Process fugitive emissions source means a source of hazardous air pollutant emissions that is associated with a ferromanganese or silicomanganese production facility and is not a fugitive dust source or a stack emissions source. Process fugitive sources include emissions that escape capture from the electric arc furnace, tapping operations, casting operations, ladle treatment, MOR or crushing and screening equipment.

Roofline ventilation system means an exhaust system designed to evacuate process fugitive emissions that collect in the roofline area to a control device.

Shop building means the building which houses one or more electric arc furnaces or other processes that generate process fugitive emissions.

Shutdown means the cessation of operation of an affected source for any purpose.

Startup means the setting in operation of an affected source for any purpose.

Tapping emissions means the gases and emissions associated with removal of product from the electric arc furnace under normal operating conditions, such as removal of metal under normal pressure and movement by gravity down the spout into the ladle and filling the ladle.

Tapping period means the time from when a tap hole is opened until the time a tap hole is closed.

[80 FR 37390, June 30, 2015]