Additive means a minor addition of a chemical, mineral, or metallic substance that is added to a refractory mixture to facilitate processing or impart specific properties to the final refractory product.

Add-on air pollution control device (APCD) means equipment installed on a process vent that reduces the quantity of a pollutant that is emitted to the air.

Autoclave means a vessel that is used to impregnate fired and/or unfired refractory shapes with pitch to form pitch-impregnated refractory products. Autoclaves also can be used as defumers following the impregnation process.

Bag leak detection system means an instrument that is capable of monitoring particulate matter loadings in the exhaust of a fabric filter in order to detect bag failures. A bag leak detection system includes, but is not limited to, an instrument that operates on triboelectric, light-scattering, light-transmittance, or other effects to monitor relative PM loadings.

Basket means the metal container used to hold refractory shapes for pitch impregnation during the shape preheating, impregnation, defuming, and, if applicable, coking processes.

Batch process means a process in which a set of refractory shapes is acted upon as a single unit according to a predetermined schedule, during which none of the refractory shapes being processed are added or removed. A batch process does not operate continuously.

Binder means a substance added to a granular material to give it workability and green or dry strength.

Catalytic oxidizer means an add-on air pollution control device that is designed specifically to destroy organic compounds in a process exhaust gas stream by catalytic incineration. A catalytic oxidizer includes a bed of catalyst media through which the process exhaust stream passes to promote combustion and incineration at a lower temperature than would be possible without the catalyst.

Chromium refractory product means a refractory product that contains at least 1 percent chromium by weight.

Clay refractory product means a refractory product that contains at least 10 percent uncalcined clay by weight prior to firing in a kiln. In this definition, the term “clay” means any of the following six classifications of clay defined by the U.S. Geologic Survey: ball clay, bentonite, common clay and shale, fire clay, fuller's earth, and kaolin.

Coking oven means a thermal process unit that operates at a peak temperature typically between 540° and 870 °C (1000° and 1600 °F) and is used to drive off the volatile constituents of pitch-impregnated refractory shapes under a reducing or oxygen-deprived atmosphere.

Continuous parameter monitoring system (CPMS) means the total equipment that is used to measure and record temperature, pressure, liquid flow rate, gas flow rate, or pH on a continuous basis in one or more locations. “Total equipment” includes the sensor, mechanical components, electronic components, data acquisition system, data recording system, electrical wiring, and other components of a CPMS.

Continuous process means a process that operates continuously. In a continuous process unit, the materials or shapes that are processed are either continuously charged (fed) to and discharged from the process unit, or are charged and discharged at regular time intervals without the process unit being shut down. Continuous thermal process units, such as tunnel kilns, generally include temperature zones that are maintained at relatively constant temperature and through which the materials or shapes being processed are conveyed continuously or at regular time intervals.

Curing oven means a thermal process unit that operates at a peak temperature typically between 90° and 340 °C (200° and 650 °F) and is used to activate a thermosetting resin, pitch, or other binder in refractory shapes. Curing ovens also perform the same function as shape dryers in removing the free moisture from refractory shapes.

Defumer means a process unit that is used for holding pitch-impregnated refractory shapes as the shapes defume or cool immediately following the impregnation process. This definition includes autoclaves that are opened and exhausted to the atmosphere following an impregnation cycle and used for holding pitch-impregnated refractory shapes while the shapes defume or cool.

Deviation means any instance in which an affected source subject to this subpart, or an owner or operator of such a source:

Dry injection fabric filter (DIFF) means an add-on air pollution control device that includes continuous injection of hydrated lime or other sorbent into a duct or reaction chamber followed by a fabric filter.

Dry lime scrubber/fabric filter (DLS/FF) means an add-on air pollution control device that includes continuous injection of humidified hydrated lime or other sorbent into a reaction chamber followed by a fabric filter. These systems may include recirculation of some of the sorbent.

Dry limestone adsorber (DLA) means an air pollution control device that includes a limestone storage bin, a reaction chamber that is essentially a packed-tower filled with limestone, and may or may not include a peeling drum that mechanically scrapes reacted limestone to regenerate the stone for reuse.

Emission limitation means any restriction on the emissions a process unit may discharge.

Fabric filter means an add-on air pollution control device used to capture particulate matter by filtering a process exhaust stream through a filter or filter media; a fabric filter is also known as a baghouse.

Fired refractory shape means a refractory shape that has been fired in a kiln.

HAP means any hazardous air pollutant that appears in section 112(b) of the Clean Air Act.

Kiln means a thermal process unit that operates at a peak temperature greater than 820 °C (1500 °F) and is used for firing or sintering refractory, ceramic, or other shapes.

Kiln furniture means any refractory shape that is used to hold, support, or position ceramic or refractory products in a kiln during the firing process.

Maximum organic HAP processing rate means the combination of process and refractory product formulation that has the greatest potential to emit organic HAP. The maximum organic HAP processing rate is a function of the organic HAP processing rate, process operating temperature, and other process operating parameters that affect emissions of organic HAP. (See also the definition of organic HAP processing rate.)

Organic HAP processing rate means the rate at which the mass of organic HAP materials contained in refractory shapes are processed in an affected thermal process unit. The organic HAP processing rate is a function of the amount of organic HAP contained in the resins, binders, and additives used in a refractory mix; the amounts of those resins, binders, and additives in the refractory mix; and the rate at which the refractory shapes formed from the refractory mix are processed in an affected thermal process unit. For continuous process units, the organic HAP processing rate is expressed in units of mass of organic HAP per unit of time (e.g., pounds per hour). For batch process units, the organic HAP processing rate is expressed in units of mass of organic HAP per unit mass of refractory shapes processed during the batch process cycle (e.g., pounds per ton).

Particulate matter (PM) means, for the purposes of this subpart, emissions of particulate matter that serve as a measure of total particulate emissions as measured by EPA Method 5 of 40 CFR part 60, appendix A-3.

Peak emissions period means the period of consecutive hourly mass emissions of the applicable pollutant that is greater than any other period of consecutive hourly mass emissions for the same pollutant over the course of a specified batch process cycle, as defined in paragraphs (1) and (2) of this definition. The peak emissions period is a function of the rate at which the temperature of the refractory shapes is increased, the mass and loading configuration of the shapes in the process unit, the constituents of the refractory mix, and the type of pollutants emitted.

Period of natural gas curtailment or supply interruption means a period of time during which the supply of natural gas to an affected facility is halted for reasons beyond the control of the facility. An increase in the cost or unit price of natural gas does not constitute a period of natural gas curtailment or supply interruption.

Pitch means the residue from the distillation of petroleum or coal tar.

Pitch-bonded refractory product means a formed refractory product that is manufactured using pitch as a bonding agent. Pitch-bonded refractory products are manufactured by mixing pitch with magnesium oxide, graphite, alumina, silicon carbide, silica, or other refractory raw materials, and forming the mix into shapes. After forming, pitch-bonded refractory products are cured in a curing oven and may be subsequently fired in a kiln.

Pitch-impregnated refractory product means a refractory shape that has been fired in a kiln, then impregnated with heated coal tar or petroleum pitch under pressure. After impregnation, pitch-impregnated refractory shapes may undergo the coking process in a coking oven. The total carbon content of a pitch-impregnated refractory product is less than 50 percent.

Pitch working tank means a tank that is used for heating pitch to the impregnation temperature, typically between 150° and 260 °C (300° and 500 °F); temporarily storing heated pitch between impregnation cycles; and transferring pitch to and from the autoclave during the impregnation step in manufacturing pitch-impregnated refractory products.

Plant site means all contiguous or adjoining property that is under common control, including properties that are separated only by a road or other public right-of-way. Common control includes properties that are owned, leased, or operated by the same entity, parent entity, subsidiary, or any combination thereof.

Redundant sensor means a second sensor or a back-up sensor that is integrated into a CPMS and is used to check the parameter value (e.g., temperature, pressure) measured by the primary sensor of the CPMS.

Refractory product means nonmetallic materials containing less than 50 percent carbon by weight and having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 538 °C (1000 °F). This definition includes, but is not limited to: refractory bricks, kiln furniture, crucibles, refractory ceramic fiber, and other materials used as linings for boilers, kilns, and other processing units and equipment where extremes of temperature, corrosion, and abrasion would destroy other materials.

Refractory products that use organic HAP means resin-bonded refractory products, pitch-bonded refractory products, and other refractory products that are produced using a substance that is an organic HAP, that releases an organic HAP during production of the refractory product, or that contains an organic HAP, such as methanol or ethylene glycol.

Refractory shape means any refractory piece forming a stable mass with specific dimensions.

Research and development process unit means any process unit whose purpose is to conduct research and development for new processes and products and is not engaged in the manufacture of products for commercial sale, except in a de minimis manner.

Resin-bonded refractory product means a formed refractory product that is manufactured using a phenolic resin or other type of thermosetting resin as a bonding agent. Resin-bonded refractory products are manufactured by mixing resin with alumina, magnesium oxide, graphite, silica, zirconia, or other refractory raw materials, and forming the mix into shapes. After forming, resin-bonded refractory products are cured in a curing oven and may be subsequently fired in a kiln.

Responsible official means one of the following:

Shape dryer means a thermal process unit that operates at a peak temperature typically between 40° and 700 °C (100° and 1300 °F) and is used exclusively to reduce the free moisture content of a refractory shape. Shape dryers generally are the initial thermal process step following the forming step in refractory products manufacturing. (See also the definition of a curing oven.)

Shape preheater means a thermal process unit that operates at a peak temperature typically between 180° and 320 °C (350° and 600 °F) and is used to heat fired refractory shapes prior to the impregnation step in manufacturing pitch-impregnated refractory products.

Thermal oxidizer means an add-on air pollution control device that includes one or more combustion chambers and is designed specifically to destroy organic compounds in a process exhaust gas stream by incineration.

Uncalcined clay means clay that has not undergone thermal processing in a calciner.

Wet scrubber means an add-on air pollution control device that removes pollutants from a gas stream by bringing them into contact with a liquid, typically water.

Work practice standard means any design, equipment, work practice, or operational standard, or combination thereof, that is promulgated pursuant to section 112(h) of the Clean Air Act.