Section 7: Calculations

• 7.1 Equations
• 7.2 Nomenclature

To simplify recording during a test, field data may be entered in the units for which the sampling equipment is designed. These values must be converted, if necessary, to the metric units specified in the applicable equations.

The total sample volume measured by the dry gas meter is corrected to reference temperature and pressure conditions (25°C and 101.3 kPa) using Equation 1. For a temperature-compensated dry gas meter (T_m)_avg should be substituted by the temperature specified by the manufacturer.

The volume of water vapour in the sack gas sample expressed at reference conditions (25°C and 101.3 kPa) is calculated by using Equation 2.

The volumetric fraction of water vapour in the stack gas expressed at reference conditions (25°C and 101.3 kPa) is calculated using Equation 3.

For a saturated or suspersaturated stack, use a psychrometric chart to determine B_wo.

The absolute stack gas pressure is calculated using Equation 4.

The stack gas molecular weight on a wet basis is calculated using Equation 5.

The stack gas velocity measured at each traverse point is calculated using Equation 6.

The average stack gas velocity ((U_s)_avg) and stack gas temperature ((T_s)_avg) for the test run are determined by averaging the velocities and temperatures respectively measured at the traverse points.

The average volumetric stack gas flow rate expressed on a dry basis and at reference conditions (25°C and 101.3 kPa) is calculated using Equation 7.

The isokinetic variation for each traverse points is calculated using Equation 8.

A test shall be considered valid when no more than 10% of the isokinetic values fall outside the range 90% to 110% and the average for all the traverse points I_avg falls within the range 90% to 110%.

The pollutant concentrations expressed in this method must be corrected to a basis of 11% O₂. The correction factor to express concentrations at 11% O₂ is calculated using Equation 9.

The emission rate of polychlorinated biphenyls is calculated using Equation 10.

The concentration of 2,3,7,8-TCDD equivalent PCDDs and PCDFs corrected to 11% O₂ is calculated using Equation 11. The weight of 2,3,7,8-TCDD equivalent PCDDs and PCDFs is determined from Figure 5.