(a) For all affected sources complying with the batch process vent testing provisions in §63.490(c) and the operating limit provisions in §63.505(c), the terms used in this subpart and in subpart U of this part are defined in §63.482 and paragraph (g) of this section.

(b) For all affected sources complying with the closed-vent system and bypass line requirements in §63.148, the terms used in this subpart and in subpart G of this part are defined in §63.111 and paragraph (g) of this section.

(c) For all affected sources complying with the heat exchanger system requirements in §63.104, the terms used in this subpart and in subpart F of this part are defined in §63.101 and paragraph (g) of this section.

(d) For cellulose ether affected sources complying with the maintenance wastewater, process wastewater, and liquid stream in open system requirements of subparts F and G of this part, the terms used in this subpart and in subparts F and G of this part are defined in §§63.101 and 63.111 and paragraph (g) of this section.

(e) For cellulose ether affected sources complying with the equipment leak requirements of subpart H of this part, the terms used in this subpart and in subpart H of this part are defined in §63.161 and paragraph (g) of this section.

(f) For cellulose ether affected sources complying with the equipment leak requirements of subpart UU of this part, the terms used in this subpart and in subpart UU of this part are defined in §63.1020 and paragraph (g) of this section.

(g) All other terms used in this subpart have the meaning given them in §63.2 and this paragraph (g). If a term is defined in §63.2, §63.101, §63.111, §63.161, or §63.1020 and in this paragraph (g), the definition in this paragraph (g) applies for purposes of this subpart.

Bottoms receiver means a tank that collects distillation bottoms before the stream is sent for storage or for further downstream processing.

Carbon disulfide unloading and storage operation means a system at an affected source that includes unloading of carbon disulfide from a railcar using nitrogen or water displacement and storage of carbon disulfide in a storage vessel using nitrogen or water padding.

Cellophane means a thin, transparent cellulose material, which is manufactured using the viscose process and used in food packaging (e.g., candy, cheese, baked goods), adhesive tapes, and membranes for industrial uses, such as batteries.

Cellophane operation means the collection of the cellophane process unit and any other equipment, such as heat exchanger systems, wastewater and waste management units, or cooling towers, that are not associated with an individual cellophane process unit, but are located at a cellophane operation for the purpose of manufacturing cellophane and are under common control.

Cellophane process unit means all equipment associated with the viscose process or solvent coating process which collectively function to manufacture cellophane and any associated storage vessels, liquid streams in open systems (as defined in §63.149), and equipment (as defined in §63.161) that are used in the manufacturing of cellophane.

Cellulose ether means a compound, such as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, or hydroxypropyl methyl cellulose, which is manufactured using the cellulose ether process and used mainly as a thickener, viscosifier, or binder in a wide variety of consumer and other products.

Cellulose ether operation means the collection of the cellulose ether process unit and any other equipment, such as heat exchanger systems, wastewater and waste management units, or cooling towers, that are not associated with an individual cellulose ether process unit, but are located at a cellulose ether operation for the purpose of manufacturing a particular cellulose ether and are under common control.

Cellulose ether process means the following:

(1) A manufacturing process that includes the following process steps:

(i) Reaction of cellulose (e.g., wood pulp or cotton linters) with sodium hydroxide to produce alkali cellulose;

(ii) Reaction of the alkali cellulose with a chemical compound(s), such as ethylene oxide, propylene oxide, methyl chloride, or chloroacetic acid, to produce a particular cellulose ether;

(iii) Washing and purification of the cellulose ether; and

(iv) Drying of the cellulose ether.

(2) Solids handling steps downstream of the drying process are not considered part of the cellulose ether process.

Cellulose ether process change means a change to the cellulose ether process that occurred no earlier than January 1991 that allows the recovery of organic HAP, reduction in organic HAP usage, or reduction in organic HAP leaving the reactor. Includes extended cookout.

Cellulose ether process unit means all equipment associated with a cellulose ether process which collectively function to manufacture a particular cellulose ether and any associated storage vessels, liquid streams in open systems (as defined in §63.149), and equipment (as defined in §63.161 or §63.1020) that are used in the manufacturing of a particular cellulose ether.

Cellulose Ethers Production source category means the collection of cellulose ether operations that use the cellulose ether process to manufacture a particular cellulose ether.

Cellulose food casing means a cellulose casing, which is manufactured using the viscose process, used in forming meat products (e.g., hot dogs, sausages) and, in most cases, removed from the meat products before sale.

Cellulose food casing operation means the collection of the cellulose food casing process unit and any other equipment, such as heat exchanger systems, wastewater and waste management units, or cooling towers, that are not associated with an individual cellulose food casing process unit, but are located at a cellulose food casing operation for the purpose of manufacturing cellulose food casings and are under common control.

Cellulose food casing process unit means all equipment associated with the viscose process which collectively function to manufacture cellulose food casings and any associated storage vessels, liquid streams in open systems (as defined in §63.149), and equipment (as defined in §63.161) that are used in the manufacturing of cellulose food casings.

Cellulosic sponge means a porous cellulose product, which is manufactured using the viscose process and used mainly for consumer use (e.g., for cleaning).

Cellulosic sponge operation means the collection of the cellulosic sponge process unit and any other equipment, such as heat exchanger systems, wastewater and waste management units, or cooling towers, that are not associated with an individual cellulosic sponge process unit, but are located at a cellulosic sponge operation for the purpose of manufacturing cellulosic sponges and are under common control.

Cellulosic sponge process unit means all equipment associated with the viscose process which collectively function to manufacture cellulosic sponges and any associated storage vessels, liquid streams in open systems (as defined in §63.149), and equipment (as defined in §63.161) that are used in the manufacturing of cellulosic sponges.

Closed-loop system means a system wherein the emission stream is not normally vented to the atmosphere but is recycled back to the process.

Control technique means any equipment or process control used for capturing, recovering, treating, or preventing HAP emissions. The equipment includes recovery devices and non-recovery control devices, as defined in this paragraph. The process control includes cellulose ether process changes and viscose process changes, as defined in this paragraph.

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

(1) Fails to meet any requirement or obligation established by this subpart, including, but not limited to, any emission limit, operating limit, or work practice standard;

(2) Fails to meet any term or condition that is adopted to implement an applicable requirement in this subpart and that is included in the operating permit for any affected source required to obtain such a permit; or

(3) Fails to meet any emission limit, operating limit, or work practice standard in this subpart during startup, shutdown, or malfunction, regardless of whether or not such failure is permitted by this subpart.

Emission point means an individual process vent, storage vessel, waste management unit, or equipment leak.

Extended cookout (ECO) means a cellulose ether process change that reduces the amount of unreacted ethylene oxide, propylene oxide, methyl chloride, or chloroacetic acid leaving the reactor. This is accomplished by allowing the product to react for a longer time, thereby leaving less unreacted ethylene oxide, propylene oxide, methyl chloride, or chloroacetic acid and reducing emissions of ethylene oxide, propylene oxide, methyl chloride, or chloroacetic acid that might have occurred otherwise.

Miscellaneous Viscose Processes source category means the collection of cellulose food casing, rayon, cellulosic sponge, and cellophane operations that use the viscose process to manufacture a particular cellulose product. These cellulose products include cellulose food casings, rayon, cellulosic sponges, and cellophane.

Nitrogen storage system means a system of padding the carbon disulfide storage vessels with nitrogen to prevent contact with oxygen.

Nitrogen unloading and storage system means the combination of a nitrogen unloading system for unloading carbon disulfide and a nitrogen storage system for storing carbon disulfide.

Nitrogen unloading system means a system of unloading carbon disulfide from railcars to storage vessels using nitrogen displacement to prevent gaseous carbon disulfide emissions to the atmosphere and to preclude contact with oxygen.

Non-recovery control device means an individual unit of equipment capable of and normally used for the purpose of capturing or treating HAP emissions. Examples of equipment that may be non-recovery control devices include, but are not limited to, biofilters, caustic scrubbers, flares, thermal oxidizers, and water scrubbers.

Oil absorber means a packed-bed absorber that absorbs pollutant vapors using a type of oil (e.g., kerosene) as the absorption liquid.

Onsite means that records are stored at a location within a major source which encompasses the affected source. Onsite includes, but is not limited to, storage at the affected source or process unit to which the records pertain or storage in central files elsewhere at the major source.

Process vent means a point of discharge to the atmosphere (or the point of entry into a control device, if any) of a HAP-containing gas stream from the unit operation. Process vents do not include vents with a flow rate less than 0.005 standard cubic meter per minute or with a concentration less than 50 parts per million by volume (ppmv) of HAP or TOC, vents on storage tanks, vents on wastewater emission sources, or pieces of equipment regulated under equipment leak standards.

Rayon means cellulose fibers, which are manufactured using the viscose process and used in the production of either textiles (e.g., apparel, drapery, upholstery) or non-woven products (e.g., feminine hygiene products, wipes, computer disk liners, surgical swabs).

Rayon operation means the collection of the rayon process unit and any other equipment, such as heat exchanger systems, wastewater and waste management units, or cooling towers, that are not associated with an individual rayon process unit, but are located at a rayon operation for the purpose of manufacturing rayon and are under common control.

Rayon process unit means all equipment associated with the viscose process which collectively function to manufacture rayon and any associated storage vessels, liquid streams in open systems (as defined in §63.149), and equipment (as defined in §63.161) that are used in the manufacturing of rayon.

Recovery device means an individual unit of equipment capable of and normally used for the purpose of recovering HAP emissions for fuel value (i.e., net positive heating value), use, reuse, or for sale for fuel value, use, or reuse. Examples of equipment that may be recovery devices include, but are not limited to, absorbers, carbon adsorbers, condensers, oil-water separators or organic-water separators, or organic removal devices such as decanters, strippers, or thin-film evaporation units.

Responsible official means responsible official as defined in 40 CFR 70.2.

Safety device means a closure device such as a pressure relief valve, frangible disc, fusible plug, or any other type of device which functions exclusively to prevent physical damage or permanent deformation to a unit or its air emission control equipment by venting gases or vapors directly to the atmosphere during unsafe conditions resulting from an unplanned, accidental, or emergency event. For the purposes of this subpart, a safety device is not used for routine venting of gases or vapors from the vapor headspace underneath a cover such as during filling of the unit or to adjust the pressure in this vapor headspace in responses to normal daily diurnal ambient temperature fluctuations. A safety device is designed to remain in a closed position during normal operation and open only when the internal pressure, or another relevant parameter, exceeds the device threshold setting applicable to the air emission control equipment as determined by the owner or operator based on manufacturer recommendations, applicable regulations, fire protection and prevention codes, standard engineering codes and practices, or other requirements for the safe handling of flammable, combustible, explosive, reactive, or hazardous materials.

Solvent coating process means a manufacturing process in which cellophane film is coated (e.g., with Saran® or nitrocellulose) to impart moisture impermeability to the film and to make it printable. Both Saran and nitrocellulose use the same solvents—tetrahydrofuran and toluene.

Storage vessel means a tank or other vessel used to store liquids that contain one or more HAP. Storage vessels do not include the following:

(1) Vessels permanently attached to motor vehicles such as trucks, railcars, barges, or ships;

(2) Pressure vessels designed to operate in excess of 204.9 kilopascals (30 pounds per square inch) and without emissions to the atmosphere;

(3) Vessels with capacities smaller than 38 cubic meters (10,000 gallons);

(4) Vessels and equipment storing and/or handling material that contains no HAP or contains HAP as impurities only;

(5) Bottoms receiver tanks;

(6) Surge control vessels;

(7) Wastewater storage vessels; and

(8) Storage vessels assigned to another process unit regulated under another subpart of part 63.

Surge control vessel means feed drums, recycle drums, and intermediate vessels. Surge control vessels are used within a process unit when in-process storage, mixing, or management of flow rates or volumes is needed to assist in production of a product.

Total HAP means the sum of organic HAP emissions measured using EPA Method 18.

Total sulfide means the sum of emissions for carbon disulfide, hydrogen sulfide, and carbonyl sulfide reported as carbon disulfide. Total sulfide, as defined for the purposes of this subpart, does not include other sulfur compounds, such as sulfur dioxide.

Viscose process means the following:

(1) A manufacturing process that includes the following process steps:

(i) Reaction of cellulose (e.g., wood pulp) with sodium hydroxide to produce alkali cellulose;

(ii) Reaction of alkali cellulose with carbon disulfide to produce sodium cellulose xanthate;

(iii) Combination of sodium cellulose xanthate with additional sodium hydroxide to produce viscose solution;

(iv) Extrusion of the viscose into various shapes (e.g., hollow casings, thin fibers, thin sheets, molds);

(v) Regeneration of the cellulose product;

(vi) Washing of the cellulose product; and

(vii) Possibly acid or salt recovery.

(2) The cellulose products manufactured using the viscose process include cellulose food casings, rayon, cellulosic sponges, and cellophane.

Viscose process change means a change to the viscose process that occurred no earlier than January 1991 that allows either the recovery of carbon disulfide or a reduction in carbon disulfide usage in the process.

Wastewater means water that:

(1) Contains either:

(i) An annual average concentration of organic HAP (listed in Table 9 to subpart G of this part) of at least 5 parts per million by weight (ppmw) and has an annual average flow rate of 0.02 liter per minute or greater; or

(ii) An annual average concentration of organic HAP (listed in Table 9 to subpart G of this part) of at least 10,000 ppmw at any flow rate.

(2) Is discarded from a cellulose food casing, rayon, cellulosic sponge, cellophane, or cellulose ether process unit that is part of an affected source. Wastewater is process wastewater or maintenance wastewater.

Water storage system means a system of padding the carbon disulfide storage vessels with water to prevent contact with oxygen. The water, which is saturated with carbon disulfide, is later sent to wastewater treatment.

Water unloading and storage system means the combination of a water unloading system for unloading carbon disulfide and a water storage system for storing carbon disulfide.

Water unloading system means a system of unloading carbon disulfide from railcars to storage vessels using water displacement to prevent gaseous carbon disulfide emissions to the atmosphere and to preclude contact with oxygen.

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.

[67 FR 40055, June 11, 2002, as amended at 70 FR 36524, June 24, 2005; 70 FR 46693, Aug. 10, 2005]