This Listserv is to clarify the calculation procedures for ∆Pmin/max for M201A, and to clarify the use of ∆Pmin/max in performing the method.  Below is a list of the calculation procedures for three possible scenarios:

1. If testing for PM10 alone:
  a. Use Equation 7 to calculate Qs.
  b. Use a value of 10 for D50T in Equation 7.

2. If testing for PM2.5 alone:
  a. Use Equation 4 to calculate the Cunningham Correction Factor. 
  b. Use a value of 2.5 for D50 in Equation 4.
  c. Use Equation 8 to calculate QIV.
  d. Use a value of 2.5 for D50 in Equation 8.
  e. Use Equation 10 to calculate the Reynolds Number.
  f. Based on the Reynolds Number, use Equation 8 or 9 to recalculate QIV.
  g. Do this iterative process a few times to get the best possible QIV.

3. If testing for PM10 and PM2.5 combined:
  a. Use Equation 4 to calculate the Cunningham Correction Factor. 
  b. Use a value of 2.25 for D50 in Equation 4.
  c. Use Equations 5 through 7 to calculate Qs.

In Scenario 1 (PM10 alone) and Scenario 3 (PM10 and PM2.5 combined), the calculated Qs will be used in Equations 15, 16 and 17 to calculate Vn, Rmin and Rmax.  In Scenario 2 (PM2.5 alone), the calculated QIV  is used in place of Qs in Equations 15, 16 and 17 to calculate Vn, Rmin and Rmax.  Based on the values of Rmin and Rmax, use the appropriate equations from 18 through 23 to calculate ∆Pmin and ∆Pmax.

Moving forward, NJDEP is no longer requiring that the ∆Pmin / ∆Pmax range be satisfied for each test run.  The point-by-point isokinetics, the overall run isokinetics and the cut size criteria are sufficient in proving the validity of a test run.  The ∆Pmin / ∆Pmax range will be used only as a QA/QC check for nozzle selection during the preliminary velocity profile traverse.  One can then choose (and BTS advises it be done) to use the ∆Pmin / ∆Pmax range calculated from Run 1 data to ensure the continued nozzle acceptability for Run 2, and then Run 2 calculated values for Run 3 continued nozzle acceptability.