CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 86—CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES > SUBPART D—Emission Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures (§86.301-79 to §86.348-79) > 86.321-79—NDIR water rejection ratio check.

86.321-79—NDIR water rejection ratio check.

(a) Zero and span the analyzer on the lowest range that will be used.
(b) Introduce a saturated mixture of water and zero gas at room temperature directly to the analyzer.
(c) Determine and record the analyzer operating pressure (GP) in absolute units in pascals. Gauges G3 and G4 may be used if the values are converted to the correct units.
(d) Determine and record the temperature of the zero-gas mixture.
(e) Record the analyzers' response (AR) in ppm to the saturated zero-gas mixture.
(f) For the temperature recorded in step (d), determine the saturation vapor presssure (P WB) from § 86.344(d).
(g) Calculate the water concentration (Z) in the mixture from:

Code of Federal Regulations

Z = (P WB /GP)(106)
(h) Calculate the water rejection ratio (WRR) from:

Code of Federal Regulations

WRR = (Z/AR)