
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY
                             2000 TRAVERWOOD DRIVE
                           ANN ARBOR, MI  48105-2498


									     OFFICE OF
									AIR AND RADIATION
February 18, 2014

MEMORANDUM

SUBJECT:  	Revised PBMS Flow Charts from April 18, 2013 Meeting with American Petroleum Institute (API) Test Methodologies Workgroup

FROM:	Joe Sopata, Chemist
		USEPA/OAR/OTAQ/CD/FCC

TO:  		EPA Docket # EPA-HQ-OAR-2011-0135


This memo corrects the flow charts that were provided to the docket documenting a meeting held on April 18, 2013 between representatives of API Test Methodologies Workgroup and the United States Environmental Protection Agency (EPA) to discuss EPA's Performance Based Analytical Test Method Approach included in the proposed rule entitled, "Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards".  The meeting attendees from API Test Methodologies Workgroup included David Lax (API), Janice Raburn (BP), Kathryn Brtko (BP), Sonia Bain (Marathon), John Rizzo (Marathon), Richard Stanley, Alex Lao, Frank Disanzo (ExxonMobil), Barbara Schroeder (Shell), Al Verstuft (Chevron) and Kishore Nadkarni, , and from EPA included Joe Sopata, Robert Anderson, Winifred Okoye, and John Weihrauch.

The discussion topics during this meeting included background, proposed qualification criterion, statistical quality control requirements, implementation dates and Agency approval options which were presented in detail in the preamble and regulations of the Tier 3 proposal.  In addition, meeting attendees from the API Test Methodologies Workgroup requested EPA provide flow chart examples of qualification requirements for Absolute Fuel Parameters and Method Defined Fuel Parameters.  During the comment period for the proposed rulemaking, API and AFPM provided editorial comments for the Absolute Fuel Parameter flow chart and requested that these flow charts be corrected in the docket for the Tier 3 final rulemaking.  In addition, during the comment period for the proposed rulemaking, several comments were made on the criterion for the reference installation of the designated test method as well as the precision criterion for method defined fuel parameters in which EPA agreed.  Thus the flow chart example for method defined fuel parameter was corrected to reflect the changes applicable to method defined fuel parameters in the Tier 3 final rule.  The corrected flow charts for both the Absolute Fuel Parameter and Method Defined Fuel Parameter are attached to this memorandum but are not intended to cover all aspects of the Performance Based Analytical Test Method Approach requirements.  EPA encourages review of both the Tier 3 final rule's preamble and regulations for details not covered in these flow charts. 
Flow Chart Example: Absolute Fuel Parameter (Absolute) - Sulfur in Gasoline 
Note: Fuel parameters categorized as "Absolute" are sulfur in gasoline and sulfur in butane, besides sulfur in diesel fuel (VCSB  -  Voluntary Consensus Standards Body)
Precision - the maximum allowable standard deviation of 20 test results on a 10 ppm gasoline would be 0.95 ppm.
Accuracy  -  the average of 10 consecutive results on a 1-10 ppm gravimetric sulfur standard cannot differ by more than 0.71 ppm from the ARV of the standard and the average of 10 consecutive results on a 10-20 ppm gravimetric sulfur standard cannot differ by more than 1.00 ppm from the ARV of the standard.

Method Qualified

Is Alternative Test Method a Voluntary Consensus Standard Body (VCSB Method)?


				YES									YES
															
                                                                                                            
                                                                                                            


															
		NO
					          							           	         
Lab determines if ASTM D6708 reveals that sample-specific biases cannot be determined as random?


																	      NO			NO
															
Method Disqualified
							



		
 Method Disqualified.
	YES Flow Chart Example: Method-Defined Fuel Parameter (Method-Defined) Aromatics in Gasoline: Note: All other fuel parameters besides sulfur in diesel fuel, sulfur in gasoline, and sulfur in butane currently designated in our gasoline and diesel fuel programs are Method-Defined  (VCSB  -  Voluntary Consensus Standards Body)

Obtain use of a Reference Installation of Designated Test Method (DM):
1) DM near middle distribution of within the middle 50% of the distribution of measurements for 3 out of 5 exchanges of either the industry or commercially available monthly ILCC program for at least five months.
2) DM has been shown to be in statistical control for a period of 5 months. 

Is Alternative Test Method a Voluntary Consensus Standard Body (VCSB) Method?

	Precision - the maximum allowable standard deviation of 20 test results on a 32 volume percent aromatics gasoline would be 1.11 volume percent.
                                                
Same as ** but Lab also determines if the cross method reproducibility (Rcm) is <= 70% of published R of DM.

VCSB determines if use of ASTM D6708 yields a null result compared to designated test method (DM)?(**).
Method Disqualified.
VCSB uses ASTM D6708 to determine correlation equation to DM.
Use Alternative Test Method result w/o correlation.					
Lab determines if ASTM D6708 reveals that sample-specific biases cannot be determined as random?

																																																																																																							YES			NO																																																																																																																																								YES		NO				YES			NO																																			 





