18 August 2014

1

“Control of Air Pollution from Motor Vehicles: 

Tier 3 Motor Vehicle Emissions

And Fuel Standards”

§80.47 Performance-based Analytical Test Method Approach

79 Federal Register 23633 – 23640 (April 28, 2014)

API Identification of items in need of either 

technical correction or further clarification

Precision criteria: all fuel properties - §80.47(b)(1), §80.47(c)(1), §80.47(d)(1), §80.47(e)(1),

§80.47(f)(1), §80.47(g)(1), §80.47(h)(1), §80.47(i)(1), §80.47(j)(1)

“The 20 results must be a series of tests with a sequential record of analysis and no emissions

omissions.”

The reference to emissions (shown in red strikeout) is incorrect and should be corrected as 

illustrated by the red underlined text.

Precision criteria: sulfur in gasoline - §80.47(b)(1)

“Beginning January 1, 2016...the maximum allowable standard deviation computed from the 

results of a minimum of 20 tests made over 20 days (seven or fewer tests per week and two or 

fewer tests per day tests may be arranged into no fewer than five batches of four or fewer tests 

each, with only one such batch allowed per day over the minimum of 20 days) on samples...”

The instructions shown in red strikeout are inconsistent with discussion in the Preamble and 

the clause, “five batches or fewer tests each” is confusing to the reader. (Perhaps it is missing 

some text?) We suggest that it be corrected as illustrated.

Precision criteria: sulfur in butane - §80.47(c)(1)

“Beginning January 1, 2016...the maximum allowable standard deviation computed from the 

results of a minimum of 20 tests made over 20 days (tests may be arranged into no fewer than 

five batches of four or fewer tests each, with only one such batch allowed per day over the 

minimum of 20 days) on samples...”

The wording shown in red underline font should be added as illustrated to be consistent with 

§80.47(b)(1).
18 August 2014

2

Precision criteria: fuel properties specified in §80.47(d)(1), §80.47(e)(1), §80.47(f)(1), 

§80.47(g)(1), §80.47(h)(1), §80.47(i)(1), §80.47(j)(1)

“Beginning January 1, 2016...the maximum allowable standard deviation computed from the 

results of a minimum of 20 tests made over 20 days (tests may be arranged into no fewer than 

five batches of four or fewer tests each, with only one such batch allowed per day over the 

minimum of 20 days) on samples...”

The wording shown in red underline font should be added as illustrated to be consistent with 

the wording suggested above for the same text which appears in §80.47(c)(1).

Precision criteria: RVP - §80.47(g)(1) 

“(Example: A gasoline having a RVP of 6.8psi: Maximum allowable standard deviation of 20 

tests withdrawn from a 250 mL container ≤0.3*(0.40psi) = 0.12 psi”). 

The example references the reproducibility of 0.40psi for a 250 mL container and should be 

clarified as illustrated by the additional text in red underline font.

Precision criteria: gasoline distillation- §80.47(h)(1)

“(Example: A gasoline having an initial boiling point of 26 °C ....maximum allowable standard 

deviation of 20 tests for E90t E90 ≤0.3*(2.0+2.53*Sc) °C ... where Sc is the average slope (or rate 

of change) of the gasoline distillation curve as calculated in accordance with section 13.5 13.2

of ASTM D86-07.”

The reference to E90t (shown in red strikeout) is incorrect and should be corrected as 

illustrated. In addition, there is no section 13.5 in ASTM D86-12. In earlier revisions such as 

D86-07, section 13.5 covers information on bias. The slope calculation is given in section 13.2. 

Since the precision calculation is from an earlier revision of ASTM D86, it should be specifically 

referenced as shown. Alternatives include:

 as calculated in accordance with section A4.10.1 of D86-12 OR

 as calculated in accordance with D86

Precision criteria: aromatics in diesel - §80.47(j)(1) 

“Beginning January 1, 2016, for motor vehicle gasoline, gasoline blendstock, and gasoline fuel 

additives motor diesel fuel subject to the motor vehicle diesel standards at §80.520 the 

maximum allowable standard deviation computed from the results of a minimum of 20 tests 

made over 20 days (tests may be arranged into no fewer than five batches or fewer tests each, 

with only one such batch allowed per day over the minimum of 20 days) on samples using good 

laboratory practices taken from a single homogeneous commercially available gasoline diesel 

fuel..”
18 August 2014

3

The references to gasoline (shown above in red strikeout) are incorrect and should be corrected 

as illustrated.

“(Example: A diesel fuel containing 35 Vol% aromatics: maximum allowable standard deviation 

of 20 tests ≤0.3*(3.7 3.3 Vol%) = 1.11 0.99 Vol%).” 

Note: 3.7 (shown above in red strikeout) pertains to the reproducibility of oxygenated gasoline

samples. The value should be 3.3 Vol% for diesel fuel.

Criteria for designated test method reference installations - §80.47(k)(2) 

“The reference installation of the method-defined fuel parameter for the applicable designated 

test method must be shown to stay within the middle 50% of the distribution of an industry or 

commercially available monthly inter-laboratory crosscheck program for 3 out of 5 successive 

exchanges for at least a period of five months using good laboratory practices. Specifically, 

compute the difference between the instrument's average measurement of the fuel closest to 

the applicable fuel standard (or to the average value for the fuel parameter in the complex 

model) and the mean for that fuel obtained by all of the non-outlier labs in the monthly interlaboratory crosscheck program. Standardize this difference by expressing it in standard 

deviation units. These standardized inter-laboratory crosscheck differences should be placed in a 

moving average with a minimum span of five months. The instrument's moving average in 

standard deviation units cannot be outside the central 50% of the distribution of all laboratories 

that participated in the inter-laboratory crosscheck program.”

Please provide clarification and/or guidance on the process to be followed because the 

regulatory text in this section appears to be contradictory. For instance, should one use the 1

st

and 3rd quartiles to demonstrate that the reference installation stays “within the middle 50%”? 

If yes, this appears to be contradictory with the later requirement to: ”specifically, compute the 

difference between the instrument's average measurement... and the mean ...obtained in the

monthly inter-laboratory crosscheck program.” .

Qualification Criteria for Non-VCSB Method-Defined Parameter Test Methods - §80.47(m)(6) 

“The candidate method-defined non-VCSB test method precision qualification must be 

conducted in the form of “cross-method reproducibility” (Rcm) of the candidate method and 

applicable designated test method as required recommended1in ASTM D6708, where the Rcm

must be equal to or less than 70 percent of the published reproducibility of the applicable 

designated test method using good laboratory practices”. 

 

1

Note: Per the language stated in Section 6.6.3 of ASTM D6708-13, this practice is “recommended” not “required.”
18 August 2014

4

Cross-method reproducibility is a measure of accuracy as well as precision. This requirement 

would pose significant hurdles for a non-VCSB as Rcm represents an average of the designated 

and alternative test methods. Additional clarification and guidance is requested.

Accuracy SQC - - §80.47(o)(1)

“Every facility shall conduct tests of every instrument with a commercially available check 

standard as defined in the ASTM D6299 at least three times a year using good laboratory 

practices.”

Please clarify that participation in the ASTM RFG (reformulated gasoline) ILCP (Inter Laboratory 

Crosscheck Program) or ASTM MG (motor gasoline) ILCP a minimum of three times per year 

satisfies this Accuracy SQC requirement for method-defined parameters (i.e. vapor pressure, 

oxygenates, olefins, aromatics, boiling point and benzene) and plot accordingly.

Accuracy SQC - §80.47(o)(1), §80.47(p)(1)

“The Accepted Reference Value of the check standard must be determined by the respective 

designated test method for the fuel parameter following the guidelines of ASTM D6299.”

Please clarify the requirement to determine the ARV of the check standard by the respective 

designated test method.

The process of assessing accuracy based upon the designated EPA method result is 

unreasonable if an alternative VCSB method is used, particularly when matrix effects are

present and require a D6708 correlation bias correction to the designated method. Therefore, 

the accuracy SQC should use the alternative VCSB ILCP consensus or ARV (accepted reference 

value), without applying a bias correction. If the alternative VCSB ARV isn’t provided in the 

ASTM ILCP, accuracy should be assessed based upon the designated EPA method using 

appropriate production or equivalent samples.

An example (see figures below) of the issue presented by the presence of matrix effects for an 

alternative VCSB method is seen when correlating ASTM D1319 versus the EPA-designated 

ASTM D5769 test method for total aromatics. This example specifically addresses the 

justification of the use of the alternative VCSB ILCP result without applying a bias correction(s) 

instead of the designated ILCP ARV value to assess accuracy. The correlation bias varies 

between ASTM D1319 and ASTM D5769 depending on the 95% boiling point of the sample and 

cannot effectively be captured in a single correlation equation derived from ASTM D6708. The 

underlying mechanism of this deviation is believed by an ASTM committee to be due to an 

underestimation of the C10+ aromatics in the gasoline samples when ASTM method D5769 is 

used since not all C10+ standards are available for the proper calibration of D5769. The plot 

below illustrates the effect of the 95 % distillation temperature upon the average result 

difference of ASTM D5769 and D1319 (Figure 1). The sample matrix effects are even more 

pronounced if the alternative method ASTM D5580 is used instead of ASTM D5769 (Figure 2). 
18 August 2014

5

In summary, the use of an ILCP sample with known designated method ASTM D5769 ARV may 

not yield an acceptable value that agrees with the reported ARV. In contrast any ILCP ARV’s 

reported value for the alternative method D1319 would yield an acceptable value when tested 

by ASTM D1319 in the laboratory.

Figure 1: Effect of the average result difference of ASTM D5769 and ASTM D1319 aromatics content versus the 95 

% distillation temperature for ASTM ILCP data for RFG and MG from 2007 to current.

Figure 2: Effect of the average result difference of ASTM D5769 and ASTM D5580 aromatics content versus the 95 

% distillation temperature for ASTM ILCP data for RFG and MG from 2007 to current.

“Mean of multiple back-to-back tests“- §80.47(n)(1), §80.47(o)(1) and §80.47(p)(1) 

“In circumstances where the absolute difference between the mean of multiple back-to-back 

tests of the standard reference material and the accepted reference value of the standard 

reference material is greater than 0.75 times the published reproducibility of the test method 

must be investigated by the facility.”
18 August 2014

6

Is reference to the “mean” value correct? Or should the statement reference individual test 

results? Please clarify.

In addition, could EPA please clarify why this sentence is repeated in identical text in 

§80.47(p)(1) which focuses on non-VCSB method-defined parameters. It is our understanding 

that non-VCSB alternative methods will rarely have published reproducibilities.

“Precision SQC“-§80.47(n)(2)(i), § 80.47(o)(2)(i), §80.47(p)(3)(i)

“Every facility shall conduct tests on every instrument with a quality control material as defined 

in paragraph 3.2.3 3.2.8 in ASTM D6299 either once per week or once per every 20 productions 

tests, whichever is more frequent. The facility must construct and maintain an “I” chart as 

described in section 7 8 and section A1.5.1 and a “MR” chart as described in section A1.5.2 4.”

The references to the indicated sections in ASTM D6299-13 (shown in red strikeout) are 

incorrect and should be corrected as illustrated.

“Validation of New QC Material”- §80.47(n)(2)(ii), §80.47(o)(2)(ii), §80.47(p)(3)(ii)

“When a test facility is making a transition from one batch of QC material to the next batch of 

QC material, the facility will either construct an “I” chart as described in section 7 8.7 and 

section A1.5.1 of ASTM D6299, or follow the “Q-Procedure” in Annex 1.9 of ASTM D6299.”

The references to the indicated sections in ASTM D6299-13 (shown in red strikeout) are 

incorrect and should be corrected as illustrated.

“Expanded uncertainty of the accepted reference value”- §80.47(n)(2)(iv), §80.47(o)(2)(iv), 

§80.47(p)(3)(iv)

“The expanded uncertainty of the accepted reference value of consensus named fuels shall have 

the following accuracy qualification criterion: Accuracy qualification criterion = square root 

[(0.75R)^2+(0.75R)^2/L], where L = the number of single results obtained from different labs 

used to calculate the consensus ARV.”

This statement deals with accuracy, not precision. It should be moved to the relevant 

subsections in §80.47 that focus on Accuracy SQC.

Need to conduct a D6708 Assessment for Non-VCSB Alternative Test Methods for Absolute 

Fuel Parameters

An EPA memorandum dated April 30, 2013 and submitted to the Tier 3 Docket (Docket ID: EPAHQ-OAR-2011-0135-1784) summarizes a meeting with the API TMWG. Page 3 of the 

memorandum is a flowchart (reproduced below) that indicates that a D6708 assessment is 

required if an alternative test method for an absolute parameter is not a VCSB method. 
18 August 2014

7

This requirement is, however, not specified in the regulatory text of the final Tier 3 rulemaking.

It should be incorporated into §80.47 (l) as shown in the suggested text in red underline and 

strikeout font below:

“(l) Qualification criteria for Voluntary Consensus Standard Based (VCSB) Method-Defined 

Parameter Test Methods and Non-voluntary Consensus Standard Based (non-VCSB) Absolute

Fuel Parameter of Sulfur in Gasoline and Butane.

(1) Beginning January 1, 2016, include full test method documentation by the Voluntary 

Consensus Standard Based (VCSB) organization, including a description of the technology 

and/or instrumentation that makes the method functional.

(2) Include information reported in the test method that demonstrates the test method 

meets the applicable precision information for the method-defined fuel parameter as 

described in this section.

(i) For the absolute fuel parameter of sulfur in gasoline and butane, include information 

reported in the test method that demonstrates the applicable accuracy criteria as 

described in §80.47 (b)(2) for gasoline and §80.47 (c)(2) for butane.

(3) Include information reported in the test method that demonstrates the test method 

has been evaluated using ASTM D6708 and whether the comparison is a “null” result or 

whether a correlation equation needs to be applied that predicts designated test method 
18 August 2014

8

results from the applicable method-defined alternative test method.

(4) The test methods specified at §§80.2(w) and 80.46(a)(1), (a)(2), (b)(1), (c)(1), (d)(1), 

(e)(1), (f)(1), and (g)(1) and in use prior to October 28, 2013 are exempt from the 

requirements of paragraphs (l)(1) through (3) of this section.”
18 August 2014

9

“Control of Air Pollution from Motor Vehicles: 

Tier 3 Motor Vehicle Emissions

And Fuel Standards”

Preamble: Section VI.A.2. Performance Based Measurement Systems (PBMS)

79 Federal Register 23577 - 23589 (April 28, 2014)

Items that Require Editorial Correction

VI. Technical Amendments and Regulatory Streamlining, A. 2.c.ii, Table VI–4, Table VI-5, Table 

VI-6 

The reference to ASTM D6792 minimum TPI = (r/R’) (shown in yellow highlight) is incorrect and 

should be corrected to read R/R’.
18 August 2014

10

VI. Technical Amendments and Regulatory Streamlining, A. 2.c.ii, Table VI–9

The reference to ASTM D86-07, section 13.5 (shown in yellow highlight) is incorrect and should 

be corrected to read section 13.2. (Section 13.5 in ASTM D86-07 covers information on bias.)