40 C.F.R. § 1065.660

Current through October 31, 2024

Section 1065.660 - THC, NMHC, NMNEHC, CH[4], and C[2]H[6] determination

(a)THC determination and initial THC/CH₄contamination 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:

^x_{THC[THC-FID]cor} = ^x_{THC[THC-FID]uncor} - ^x_{THC[THC-FID]init}

Eq. 1065.660-1

Example:

[XI]_THCuncor

[XI]_THCinit

[XI]_THCcor

(2) For the NMHC determination described in paragraph (b) of this section, correct [XI]_THC[THC-FID] for initial THC contamination using Eq. 1065.660-1. You may correct [XI]_THC[NMC-FID] for initial contamination of the CH₄ sample train using Eq. 1065.660-1, substituting in CH₄ concentrations for THC.

(3) For the NMNEHC determination described in paragraph (c) of this section, correct [XI]_THC[THC-FID] for initial THC contamination using Eq. 1065.660-1. You may correct [XI]_THC[NMC-FID] for initial contamination of the CH₄ sample train using Eq. 1065.660-1, substituting in CH₄ concentrations for THC.

(4) For the CH₄ determination described in paragraph (d) of this section, you may correct [XI]_THC[NMC-FID] for initial THC contamination of the CH₄ sample train using Eq. 1065.660-1, substituting in CH₄ concentrations for THC.

(5) You may calculate THC as the sum of NMHC and CH₄ if you determine CH₄ with an FTIR as described in paragraph (d)(2) of this section and NMHC with an FTIR using the additive method from paragraph (b)(4) of this section.

(6) You may calculate THC as the sum of NMNEHC, C₂H₆, and CH₄ if you determine CH₄ with an FTIR as described in paragraph (d)(2) of this section, C₂H₆ with an FTIR as described in paragraph (e) of this section, and NMNEHC with an FTIR using the additive method from paragraph (c)(3) of this section.

(b)NMHC determination. Use one of the following to determine NMHC concentration, [XI]_NMHC:

(1) If you do not measure CH₄, you may omit the calculation of NMHC concentrations and calculate the mass of NMHC as described in § 1065.650(c)(5) .

(2) For an NMC, calculate [XI]_NMHC using the NMC's penetration fractions, response factors, and/or combined penetration fractions and response factors as described in § 1065.365 , the THC FID's CH₄ response factor, RF_{CH4[THC-FID],} from § 1065.360 , the initial THC contamination and dry-to-wet corrected THC concentration, [XI]_{THC[THC-FID]cor,} as determined in paragraph (a) of this section, and the dry-to-wet corrected CH₄ concentration, [XI]_{THC[NMC-FID]cor,} optionally corrected for initial THC contamination as determined in paragraph (a) of this section.

(i) Use the following equation for an NMC configured as described in § 1065.365(d) :

View Image

Eq. 1065.660-2

Where:

[XI]_NMHC = concentration of NMHC.

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

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

RF_CH4[THC-FID] = response factor of THC FID to CH_4, according to § 1065.360(d) .

RFPF_{C2H6[NMC-FID]} = NMC combined C₂H₆ response factor and penetration fraction, according to § 1065.365(d) .

RFPF_CH4[NMC-FID] = NMC combined CH₄ response factor and penetration fraction, according to § 1065.365(d) .

Example:

[XI]_{THC[THC-FID]cor}

[XI]_{THC[NMC-FID]cor}

RFPF_{C2H6[NMC-FID]}

RFPF_CH4[NMC-FID]

RF_CH4[THC-FID]

View Image

(ii) Use the following equation for penetration fractions determined using an NMC configuration as outlined in § 1065.365(e) :

View Image

Eq. 1065.660-3

Where:

[XI]_NMHC = concentration of NMHC.

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

PF_CH4[NMC-FID] = NMC CH₄ penetration fraction, according to § 1065.365(e) .

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

PF_{C2H6[NMC-FID]} = NMC C₂H₆ penetration fraction, according to § 1065.365(e) .

Example:

[XI]_{THC[THC-FID]cor}

PF_CH4[NMC-FID]

[XI]_{THC[NMC-FID]cor}

PF_{C2H6[NMC-FID]}

View Image

(iii) Use the following equation for an NMC configured as described in § 1065.365(f) :

View Image

Eq. 1065.660-4

Where:

[XI]_NMHC = concentration of NMHC.

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

PF_CH4[NMC-FID] = NMC CH₄ penetration fraction, according to § 1065.365(f) .

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

RFPF_{C2H6[NMC-FID]} = NMC combined C₂H₆ response factor and penetration fraction, according to § 1065.365(f) .

RF_CH4[THC-FID] = response factor of THC FID to CH_4, according to § 1065.360(d) .

Example:

[XI]_{THC[THC-FID]cor}

PF_CH4[NMC-FID]

[XI]_{THC[NMC-FID]cor}

RFPF_{C2H6[NMC-FID]}

RF_CH4[THC-FID]

View Image

(3) For a GC-FID or FTIR, calculate [XI]_NMHC using the THC analyzer's CH₄ response factor, RF_{CH4[THC-FID],} from § 1065.360 , and the initial THC contamination and dry-to-wet corrected THC concentration, [XI]_{THC[THC-FID]cor,} as determined in paragraph (a) of this section as follows:

[XI]_NMHC = [XI]_{THC[THC-FID]cor} - RF_CH4[THC-FID]· [XI]_CH4

Eq. 1065.660-5

Where:

[XI]_NMHC = concentration of NMHC.

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID.

RF_CH4[THC-FID] = response factor of THC-FID to CH_4.

[XI]_CH4 = concentration of CH_4, dry-to-wet corrected, as measured by the GC-FID or FTIR.

Example:

[XI]_{THC[THC-FID]cor}

RF_CH4[THC-FID]

[XI]_CH4

[XI]_NMHC

(4) For an FTIR, calculate [XI]_NMHC by summing the hydrocarbon species listed in § 1065.266(c) as follows:

View Image

Eq. 1065.660-6

Where:

[XI]_NMHC = concentration of NMHC.

[XI]_HCi = the C₁-equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination.

[XI]_HCi-init = the C₁-equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR.

Example:

[XI]_C2H6

[XI]_C2H4

[XI]_C2H2

[XI]_C3H8

[XI]_C3H6

[XI]_C4H10

[XI]_CH2O

[XI]_C2H4O

[XI]_CH2O2

[XI]_CH4O

[XI]_NMHC

(c)NMNEHC determination. Use one of the following methods to determine NMNEHC concentration, [XI]_NMNEHC:

(1) Calculate [XI]_NMNEHC based on the test fuel's ethane content as follows:

(i) If the content of your test fuel contains less than 0.010 mol/mol of ethane, you may omit the calculation of NMNEHC concentration and calculate the mass of NMNEHC as described in § 1065.650(c)(6)(i) .

(ii) If the content of your fuel test contains at least 0.010 mol/mol of C₂H₆, you may omit the calculation of NMNEHC concentration and calculate the mass of NMNEHC as described in § 1065.650(c)(6)(ii) .

(2) For a GC-FID, NMC FID, or FTIR, calculate [XI]_NMNEHC using the THC analyzer's CH₄ response factor, RF_{CH4[THC-FID],} and C₂H₆ response factor, RF_{C2H6[THC-FID],} from § 1065.360 , the initial contamination and dry-to-wet corrected THC concentration, [XI]_{THC[THC-FID]cor,} as determined in paragraph (a) of this section, the dry-to-wet corrected CH₄ concentration, [XI]_CH4, as determined in paragraph (d) of this section, and the dry-to-wet corrected C₂H₆ concentration, [XI]_C2H6, as determined in paragraph (e) of this section as follows:

[XI]_NMNEHC

Eq. 1065.660-7

Where:

[XI]_NMNEHC = concentration of NMNEHC.

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID.

RF_CH4[THC-FID] = response factor of THC-FID to CH_4.

[XI]_CH4 = concentration of CH_4, dry-to-wet corrected, as measured by the GC-FID, NMC FID, or FTIR.

RF_{C2H6[THC-FID]} = response factor of THC-FID to C₂H_6.

[XI]_C2H6 = the C₁-equivalent concentration of C₂H_6, dry-to-wet corrected, as measured by the GC-FID or FTIR.

Example:

[XI]_{THC[THC-FID]cor}

RF_CH4[THC-FID]

[XI]_CH4

RF_{C2H6[THC-FID]}

[XI]_C2H6

[XI]_NMNEHC

= 116.5 [MICRO]mol/mol

(3) For an FTIR, calculate x_NMNEHC by summing the hydrocarbon species listed in § 1065.266(c) as follows:

View Image

Eq. 1065.660-8

Where:

[XI]_NMNEHC = concentration of NMNEHC.

[XI]_HC_i = the C₁-equivalent concentration of hydrocarbon species i as measured by the FTIR, not corrected for initial contamination.

[XI]_HC_i_-init = the C₁-equivalent concentration of the initial system contamination (optional) of hydrocarbon species i, dry-to-wet corrected, as measured by the FTIR.

Example:

[XI]_C2H4

[XI]_C2H2

[XI]_C3H8

[XI]_C3H6

[XI]_C4H10

[XI]_CH2O

[XI]_C2H4O

[XI]_CH2O2

= 0.1 [MICRO]mol/mol

[XI]_NMNEHC

x_NMNEHC

(d)CH₄ determination. Use one of the following methods to determine methane (CH₄) concentration, [XI]_CH4:

(1) For an NMC, calculate x_CH4 using the NMC's penetration fractions, response factors, and/or combined penetration fractions and response factors as described in § 1065.365 , the THC FID's CH₄ response factor, RF_{CH4[THC-FID],} from § 1065.360 , the initial THC contamination and dry-to-wet corrected THC concentration, [XI]_{THC[THC-FID]cor,} as determined in paragraph (a) of this section, and the dry-to-wet corrected CH₄ concentration, [XI]_{THC[NMC-FID]cor,} optionally corrected for initial THC contamination as determined in paragraph (a) of this section.

(i) Use the following equation for an NMC configured as described in § 1065.365(d) :

View Image

Eq. 1065.660-9

Where:

[XI]_CH4 = concentration of CH₄.

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

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

RFPF_{C2H6[NMC-FID]} = NMC combined C₂H₆ response factor and penetration fraction, according to § 1065.365(d) .

RF_CH4[THC-FID] = response factor of THC FID to CH_4, according to § 1065.360(d) .

RFPF_CH4[NMC-FID] = NMC combined CH₄ response factor and penetration fraction, according to § 1065.365(d) .

Example:

[XI]_{THC[NMC-FID]cor}

[XI]_{THC[THC-FID]cor}

RFPF_{C2H6[NMC-FID]}

RFPF_CH4[NMC-FID]

= 1.05

View Image

(ii) Use the following equation for an NMC configured as described in § 1065.365(e) :

View Image

Eq. 1065.660-10

Where:

x_CH4 = concentration of CH_4.

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

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

PF_{C2H6[NMC-FID]} = NMC C₂H₆ penetration fraction, according to § 1065.365(e) .

RF_CH4[THC-FID] = response factor of THC FID to CH_4, according to § 1065.360(d) .

PF_CH4[NMC-FID] = NMC CH₄ penetration fraction, according to § 1065.365(e) .

Example:

[XI]_{THC[NMC-FID]cor}

[XI]_{THC[THC-FID]cor}

= 0.020

RF_CH4[THC-FID]

PF_CH4[NMC-FID]

View Image

(iii) Use the following equation for an NMC configured as described in § 1065.365(f) :

View Image

Eq. 1065.660-11

Where:

[XI]_CH4 = concentration of CH_4.

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

[XI]_{THC[THC-FID]cor} = concentration of THC, initial THC contamination and dry-to-wet corrected, as measured by the THC FID during sampling while bypassing the NMC.

RFPF_{C2H6[NMC-FID]} = the combined C₂H₆ response factor and penetration fraction of the NMC, according to § 1065.365(f) .

PF_CH4[NMC-FID] = NMC CH₄ penetration fraction, according to § 1065.365(f) .

RF_CH4[THC-FID] = response factor of THC FID to CH_4, according to § 1065.360(d) .

Example:

[XI]_{THC[NMC-FID]cor}

[XI]_{THC[THC-FID]cor}

RFPF_{C2H6[NMC-FID]}

PF_CH4[NMC-FID]

= 1.05

View Image

(2) For a GC-FID or FTIR, x_CH4 is the actual dry-to-wet corrected CH₄ concentration as measured by the analyzer.

(e)C₂ H₆ determination. For a GC-FID or FTIR, [XI]_C2H6 is the C₁-equivalent, dry-to-wet corrected C₂H₆ concentration as measured by the analyzer.

40 C.F.R. §1065.660

89 FR 29819 , Apr. 22, 2024

81 FR 74184, 12/27/2016; 86 FR 34566, 6/29/2021; 88 FR 4686, 3/27/2023; 89 FR 29819, 6/21/2024