The following words and terms, when used in this division (relating to Batch Processes), shall have the following meanings, unless the context clearly indicates otherwise. Additional definitions for terms used in this division are found in §§3.2, 101.1, and 115.10 of this title (relating to Definitions).
  (1) Aggregated--The summation of all process vents containing volatile organic compounds (VOC) within a process.
  (2) Annual mass emissions total--The sum of all VOC emissions (pounds per year), evaluated before control but after the last recovery device, from a process vent. Annual mass emissions shall be calculated from an individual process vent or groups of process vents by using emission estimation equations contained in Chapter 3 of EPA's Control of Volatile Organic Compound Emissions from Batch Processes-Alternative Control Techniques Information Document (EPA-453/R-94-020, February 1994) and then multiplying by the historical duration and frequency of the emission or groups of emissions over the course of a year. For process vents that are included in a new source review air permit, standard permit, or permit by rule registered by Form PI-8, the annual mass emissions total shall be based on the maximum allowable emission rate (MAER) levels in the permit or Form PI-8 (adjusted to represent the level before control, but after the last recovery device), whether they correspond to the maximum design production potential or to the actual annual production estimate.
  (3) Average flow rate--The flow rate in standard cubic feet per minute (scfm) averaged over the amount of time that VOCs are emitted during an emission event. For the evaluation of average flow rate from an aggregate of sources, the average flow rate is the weighted average of the average flow rates of the emission events and their annual venting time, or:
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  (4) Batch--A noncontinuous process involving the bulk movement of material through sequential manufacturing steps. Mass, temperature, concentration, and other properties of a system vary with time. Batch processes are not characterized by steady-state conditions. Reactants are not added and products are not removed simultaneously.
  (5) Batch cycle--A manufacturing event of an intermediate or product from start to finish in a batch process.
  (6) Batch process (for the purpose of determining reasonably available control technology (RACT) applicability)--The batch equipment assembled and connected by pipes, or otherwise operated in a sequence of steps, to manufacture a product in a batch fashion.
  (7) Batch process train--An equipment train that is used to produce a product or intermediates in batch fashion. A typical equipment train consists of equipment used for the synthesis, mixing, and purification of a material.
  (8) Emissions before control--The emissions total before the application of a control device but after the last recovery device, or the emissions total if no control device is used. The emissions total may not be reduced to account for discharge of VOC into wastewater if the wastewater is further handled or processed with the potential for VOC emissions to the atmosphere.
  (9) Primary fuel--The fuel that provides the principal heat input to a device. To be considered a primary fuel, the fuel must be able to sustain operation without the addition of other fuels.
  (10) Process vent--A vent gas stream that is discharged from a batch process. Process vents include gas streams that are discharged directly to the atmosphere or are discharged to the atmosphere after diversion through a recovery device. Process vents exclude relief valve discharges, leaks from equipment, vents from storage tanks, vents from transfer/loading operations, and vents from wastewater. Process gaseous streams that are used as primary fuels are also excluded. The lines that transfer such fuels to a plant fuel gas system are not considered to be vents.
  (11) RACT--Reasonably available control technology.
  (12) Recovery device--An individual unit of equipment capable of and used for recovering chemicals for use, reuse, or sale. Recovery devices include, but are not limited to, absorbers, carbon adsorbers, and condensers.
  (13) Unit operations--Those discrete processing steps that occur within distinct equipment that are used to prepare reactants, facilitate reactions, separate and purify products, and recycle materials.
  (14) Volatility--As follows.
    (A) Low volatility VOCs are those which have a vapor pressure less than or equal to 75 millimeters of mercury (mm Hg) at 20 degrees Celsius.
    (B) Moderate volatility VOCs are those which have a vapor pressure greater than 75 and less than or equal to 150 mm Hg at 20 degrees Celsius.
    (C) High volatility VOCs are those which have a vapor pressure greater than 150 mm Hg at 20 degrees Celsius.
    (D) To evaluate VOC volatility for single unit operations that service numerous VOCs or for processes handling multiple VOCs, the weighted average volatility can be calculated from the total amount of each VOC emitted in a year and the individual component vapor pressure, as follows.
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Source Note: The provisions of this §115.160 adopted to be effective November 18, 1999, 24 TexReg 10095; amended to be effective January 17, 2003, 28 TexReg 113