CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER U—AIR POLLUTION CONTROLS (Parts 1027–1074) > PART 1065—ENGINE-TESTING PROCEDURES > SUBPART G—Calculations and Data Requirements (§1065.601 to §1065.695) > 1065.660—THC and NMHC determination.

1065.660—THC and NMHC determination.

(a) THC determination and THC/CH 4 initial contamination corrections. (1) If we require you to determine THC emissions, calculate x THC[THC-FID]cor using the initial THC contamination concentration x THC[THC−FID]init from § 1065.520 as follows:
Example:
xTHCuncor = 150.3 µmol/mol
xTHCinit = 1.1 µmol/mol
xTHCcor = 150.3−1.1
xTHCcor = 149.2 µmol/mol
(2) For the NMHC determination described in paragraph (b) of this section, correct xTHC[THC-FID] for initial HC contamination using Eq. 1065.660-1. You may correct xTHC[NMC-FID] for initial contamination of the CH4 sample train using Eq. 1065.660-1, substituting in CH4 concentrations for THC.
(3) For the CH4 determination described in paragraph (c) of this section, you may correct xTHC[NMC-FID] for initial contamination of the CH4 sample train using Eq. 1065.660-1, substituting in CH4 concentrations for THC.
(b) NMHC determination. Use one of the following to determine NMHC concentration, xNMHC :
(1) If you do not measure CH4, you may determine NMHC concentrations as described in § 1065.650(c)(1)(vi).
(2) For nonmethane cutters, calculate x NMHC using the nonmethane cutter's penetration fractions (PF) of CH4 and C2 H6 from § 1065.365, and using the HC contamination and dry-to-wet corrected THC concentration x THC[THC-FID]cor as determined in paragraph (a) of this section.
(i) Use the following equation for penetration fractions determined using an NMC configuration as outlined in § 1065.365(d) :
Where:
xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.
xTHC[NMC-FID]cor = concentration of THC, HC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC.
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).
RFPFC2H6[NMC-FID] = nonmethane cutter combined ethane response factor and penetration fraction, according to § 1065.365(d).

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Example:

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x THC[THC-FID]cor = 150.3 µmol/mol

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x THC[NMC-FID]cor = 20.5 µmol/mol

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RFPF C2H6[NMC-FID] = 0.019

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RF CH4[THC-FID] = 1.05

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x NMHC = 131.4 µmol/mol
(ii) For penetration fractions determined using an NMC configuration as outlined in section § 1065.365(e), use the following equation:
Where:
xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.
PFCH4[NMC-FID] = nonmethane cutter CH4 penetration fraction, according to § 1065.365(e).
xTHC[NMC-FID]cor = concentration of THC, HC contamination (optional) and dry-to-wet corrected, as measured by the THC FID during sampling through the NMC.
PFC2H6[NMC-FID] = nonmethane cutter ethane penetration fraction, according to § 1065.365(e).

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Example:

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x THC[THC-FID]cor = 150.3 µmol/mol

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PF CH4[NMC-FID] = 0.990

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x THC[NMC-FID]cor = 20.5 µmol/mol

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PF C2H6[NMC-FID] = 0.020

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x NMHC = 132.3 µmol/mol
(iii) For penetration fractions determined using an NMC configuration as outlined in section § 1065.365(f), use the following equation:
Where:
xNMHC = concentration of NMHC.
xTHC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.
PFCH4[NMC-FID] = nonmethane cutter CH4 penetration fraction, according to § 1065.365(f).
xTHC[NMC-FID]cor = concentration of THC, HC contamination (optional) and dry-to-wet corrected, as measured by the THC FID during sampling through the NMC.
RFPFC2H6[NMC-FID] = nonmethane cutter CH4 combined ethane response factor and penetration fraction, according to § 1065.365(f).
RFCH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d).

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Example:

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x THC[THC-FID]cor = 150.3 µmol/mol

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PF CH4[NMC-FID] = 0.990

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x THC[NMC-FID]cor = 20.5 µmol/mol

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RFPF C2H6[NMC-FID] = 0.019

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RF CH4[THC-FID] = 0.980

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x NMHC = 132.5 µmol/mol
(3) For a gas chromatograph, calculate xNMHC using the THC analyzer's response factor (RF) for CH4, from § 1065.360, and the HC contamination and dry-to-wet corrected initial THC concentration xTHC[THC-FID]cor as determined in paragraph (a) of this section as follows:
Where:

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x NMHC = concentration of NMHC.

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x THC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC FID.

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x CH4 = concentration of CH4, HC contamination (optional) and dry-to-wet corrected, as measured by the gas chromatograph FID.

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RF CH4[THC-FID] = response factor of THC-FID to CH4.

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Example:

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x THC[THC-FID][cor = 145.6 µmol/mol

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RF CH4[THC-FID] = 0.970

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x CH4 = 18.9 µmol/mol

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x NMHC = 145.6−0.970 · 18.9

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x NMHC = 127.3 µmol/mol
(c) CH 4 determination. Use one of the following methods to determine CH4 concentration, x CH4 :
(1) For nonmethane cutters, calculate x CH4 using the nonmethane cutter's penetration fractions (PF) of CH4 and C2 H6 from § 1065.365, using the dry-to-wet corrected CH4 concentration x THC[NMC-FID]cor as determined in paragraph (a) of this section and optionally using the CH4 contamination correction under paragraph (a) of this section.
(i) Use the following equation for penetration fractions determined using an NMC configuration as outlined in § 1065.365(d) :
Where:

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x CH4 = concentration of CH4.

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x THC[NMC-FID]cor = concentration of THC, HC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC.

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x THC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC
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FID during sampling while bypassing the NMC.

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RFPF C2H6[NMC-FID] = the combined ethane response factor and penetration fraction of the nonmethane cutter, according to § 1065.365(d) .

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RF CH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d) .

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Example:

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x THC[NMC-FID]cor = 10.4 µmol/mol

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x THC[THC-FID]cor = 150.3 µmol/mol

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RFPF C2H6[NMC-FID] = 0.019

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RF CH4[THC-FID] = 1.05

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x CH4 = 7.69 µmol/mol
(ii) For penetration fractions determined using an NMC configuration as outlined in § 1065.365(e), use the following equation:
Where:

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x CH4 = concentration of CH4.

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x THC[NMC-FID]cor = concentration of THC, HC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC.

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x THC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

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PF C2H6[NMC-FID] = nonmethane cutter ethane penetration fraction, according to § 1065.365(e) .

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RF CH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d) .

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PF CH4[NMC-FID] = nonmethane cutter CH4 penetration fraction, according to § 1065.365(e) .

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Example:

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x THC[NMC-FID]cor = 10.4 µmol/mol

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x THC[THC-FID]cor = 150.3 µmol/mol

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PF C2H6[NMC-FID] = 0.020

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RF CH4[THC-FID] = 1.05

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PF CH4[NMC-FID] = 0.990

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x CH4 = 7.25 µmol/mol
(iii) For penetration fractions determined using an NMC configuration as outlined in § 1065.365(f), use the following equation:
Where:

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x CH4 = concentration of CH4.

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x THC[NMC-FID]cor = concentration of THC, HC contamination (optional) and dry-to-wet corrected, as measured by the NMC FID during sampling through the NMC.

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x THC[THC-FID]cor = concentration of THC, HC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

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RFPF C2H6[NMC-FID] = the combined ethane response factor and penetration fraction of the nonmethane cutter, according to § 1065.365(f) .

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PF CH4[NMC-FID] = nonmethane cutter CH4 penetration fraction, according to § 1065.365(f) .

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RF CH4[THC-FID] = response factor of THC FID to CH4, according to § 1065.360(d) .

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Example:

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x THC[NMC-FID]cor = 10.4 µmol/mol

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x THC[THC-FID]cor = 150.3 µmol/mol
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RFPF C2H6[NMC-FID] = 0.019

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PF CH4[NMC-FID] = 0.990

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RF CH4[THC-FID] = 1.05

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x CH4 = 7.78 µmol/mol
(2) For a gas chromatograph, xCH4 is the actual dry-to-wet corrected CH4 concentration as measured by the analyzer.

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[73 FR 37336, June 30, 2008, as amended at 73 FR 59339, Oct. 8, 2008; 74 FR 56516, Oct. 30, 2009; 75 FR 68464, Nov. 8, 2010]