Applicability. The Department may approve the use of a PAL for any existing major stationary source if the requirements in this regulation are met. Any physical change or change in the method of operation of a major stationary source that maintains its total source-wide emissions below the PAL level meets the requirements of this chapter and complies with the PAL permit if: It is not a major modification for the PAL pollutant; It does not have to be approved through Regulations .01—.03 of this chapter; and It is not subject to Regulation .02G of this chapter. Except as provided under §A(2) of this regulation, a major stationary source shall continue to comply with all applicable federal and State requirements, emission limitations, and work practice requirements that were established before the effective date of the PAL. Definitions. In Regulations .07—.09 of this chapter, the following terms have the meanings indicated: “Actual PAL” means, for a major stationary source, a PAL based on the baseline actual emissions of all emissions units at the source that emit or have the potential to emit the PAL pollutant. “Allowable emissions” has the meaning stated in Regulation .01B(2) of this chapter, except that this definition is modified as follows: The allowable emissions for any emissions unit shall be calculated considering any emission limitations that are enforceable as a practicable matter on an emissions unit's potential to emit; An emissions unit's potential to emit shall be determined using the definition in Regulation .01B(21) of this chapter, except that the words “or enforceable as a practicable matter” shall be added after “federally enforceable”. “Continuous emissions monitoring system (CEMs)” means all of the equipment that may be required to meet the data acquisition and availability requirements of this regulation, to sample, condition (if applicable), analyze, and provide a record of emissions on a continuous basis. “Continuous emissions rate monitoring system (CERMs)” means the total equipment required for determining and recording the pollutant mass emissions rate (in terms of mass per unit of time). “Continuous parameter monitoring system (CPMs)” means all of the equipment necessary to meet the data acquisition and availability requirements of this regulation to monitor process and control device operational parameters (for example, control device secondary voltages and electric currents) and other information (for example, gas flow rate, oxygen or carbon dioxide concentrations), and to record average operational parameter values on a continuous basis. “Major emissions unit” means an emissions unit that emits or has the potential to emit: 100 tons per year or more of the PAL pollutant in an attainment area; or The PAL pollutant in an amount that is equal to or greater than the major source threshold for the PAL pollutant. “PAL effective date” means the date of issuance of a PAL permit or a revised PAL permit, except that the PAL effective date for an increased PAL is the date an emissions unit which is part of the PAL major modification becomes operational and begins to emit the PAL pollutant. “PAL effective period” means the period beginning with the PAL effective date and ending 5 years later. “PAL major modification” means any physical change in or changes in the method of operation of the PAL source that causes it to emit the PAL pollutant at a level equal to or greater than the PAL. “PAL permit” means the permit issued by the Department that establishes a PAL for a major stationary source. “PAL pollutant” means the pollutant for which the PAL is established. “Plantwide applicability limit (PAL)” means an emissions limitation, expressed in tons per year, for a pollutant at a major stationary source, that is enforceable as a practicable matter and established source-wide according to Regulation .08B of this chapter. “Predictive emissions monitoring system (PEMS)” means all of the equipment necessary to monitor process and control device operational parameters (for example, control device secondary voltages and electric currents) and other information (for example, gas flow rate, oxygen or carbon dioxide concentrations), and calculate and record the mass emissions rate (for example, pounds per hour) on a continuous basis. “Significant emissions unit” means an emissions unit that emits or has the potential to emit a PAL pollutant in an amount that is equal to or greater than the significant level for the PAL pollutant, but less than the amount that would qualify the unit as a major emissions unit. “Small emissions unit” means an emissions unit that emits or has the potential to emit the PAL pollutant in an amount less than the significant level for that PAL pollutant, as defined in Regulation .01B(26) of this chapter or in the Clean Air Act, whichever is lower.