(4) If the average of your three Method 5 or 5I compliance test runs are below 75 percent of your PM emission limit, you must calculate an operating limit by establishing a relationship of PM CPMS signal to PM concentration using the PM CPMS instrument zero, the average PM CPMS values corresponding to the three compliance test runs, and the average PM concentration from the Method 5 or 5I compliance test with the procedures in (c)(4)(i)(A) through (D) of this section.(i) Determine your PM CPMS instrument zero output with one of the following procedures.(A) Zero point data for in-situ instruments should be obtained by removing the instrument from the stack and monitoring ambient air on a test bench.(B) Zero point data for extractive instruments should be obtained by removing the extractive probe from the stack and drawing in clean ambient air.(C) The zero point can also can be obtained by performing manual reference method measurements when the flue gas is free of PM emissions or contains very low PM concentrations (e.g., when your process is not operating, but the fans are operating or your source is combusting only natural gas) and plotting these with the compliance data to find the zero intercept.(D) If none of the steps in paragraphs (c)(4)(i)(A) through (C) of this section are possible, you must use a zero output value provided by the manufacturer.(ii) Determine your PM CPMS instrument average in milliamps or digital equivalent and the average of your corresponding three PM compliance test runs, using equation 1. View Image
Where:
X1 = The PM CPMS data points for the three runs constituting the performance test,
Y1 = The PM concentration value for the three runs constituting the performance test, and
n = The number of data points.
(iii) With your PM CPMS instrument zero expressed in milliamps or a digital value, your three run average PM CPMS milliamp or digital signal value, and your three run average PM concentration from your three PM performance test runs, determine a relationship of lb/ton-clinker per milliamp or digital signal with equation 2. View Image
Where:
R = The relative lb/ton clinker per milliamp or digital equivalent for your PM CPMS.
Y1 = The three run average PM lb/ton clinker.
X1 = The three run average milliamp or digital signal output from your PM CPMS.
z = The milliamp or digital equivalent of your instrument zero determined from (c)(4)(i) of this section.
(iv) Determine your source specific 30-day rolling average operating limit using the lb/ton-clinker per milliamp or digital signal value from Equation 2 above in Equation 3, below. This sets your operating limit at the PM CPMS output value corresponding to 75 percent of your emission limit. View Image
Where:
Ol = The operating limit for your PM CPMS on a 30-day rolling average, in milliamps or the digital equivalent.
L = Your source emission limit expressed in lb/ton clinker.
z = Your instrument zero in milliamps or a digital equivalent, determined from (1)(i).
R = The relative lb/ton-clinker per milliamp or digital equivalent, for your PM CPMS, from Equation 2.