The owner or operator of each batch process operation in the Beaumont-Port Arthur, Bexar County, and Houston-Galveston-Brazoria areas shall determine the mass emissions and flow rates as follows.(1) Determination of Uncontrolled Annual Emission Total. The owner or operator shall determine the annual mass emissions total by using engineering estimates of the uncontrolled emissions from a process vent or group of process vents within a batch process train and multiplying by the potential or permitted number of batch cycles per year. Engineering estimates must follow the guidance contained in EPA's Control of Volatile Organic Compound Emissions from Batch Processes - Alternative Control Techniques Information Document (EPA-453/R-93-020, February 1994). Alternatively, if an emissions measurement is used to measure vent emissions, the measurement must conform with the requirements of measuring incoming mass flow rate of volatile organic compounds as specified in §115.165 of this title (relating to Approved Test Methods and Testing Requirements). (2) Determination of Average Flow Rate. To obtain a value for average flow rate, the owner or operator may choose to measure the flow rates or to estimate the flow rates using the estimation methods contained in EPA's Control of Volatile Organic Compound Emissions from Batch Processes - Alternative Control Techniques Information Document (EPA-453/R-93-020, February 1994). For existing manifolds, the average flow rate may be the flow rate that was assumed in the design.