40 CFR § 1066.630 - PDP, SSV, and CFV flow rate calculations.
This section describes the equations for calculating flow rates from various flow meters. After you calibrate a flow meter according to § 1066.625, use the calculations described in this section to calculate flow during an emission test. Calculate flow according to 40 CFR 1065.642 instead if you calculate emissions based on molar flow rates.
(1) Based on the speed at which you operate the PDP for a test interval, select the corresponding slope, a1, and intercept, a0, as determined in § 1066.625(a), to calculate PDP flow rate, v , as follows:
(2) Calculate Vrev using the following equation:
pout = static absolute pressure at the PDP outlet.
(b)SSV. Calculate SSV flow rate, v , as follows:
(c)CFV. If you use multiple venturis and you calibrated each venturi independently to determine a separate calibration coefficient, Kv, for each venturi, calculate the individual volume flow rates through each venturi and sum all their flow rates to determine CFV flow rate, V . If you use multiple venturis and you calibrated venturis in combination, calculate V using the Kv that was determined for that combination of venturis.
(1) To calculate V through one venturi or a combination of venturis, use the mean Kv you determined in § 1066.625(c) and calculate V as follows: