[Code of Federal Regulations] [Title 40, Volume 30] [Revised as of July 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR1065.215] [Page 661] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 1065_TEST PROCEDURES AND EQUIPMENT--Table of Contents Subpart C_Test Fuels and Analytical Gases Sec. 1065.215 Test fuel specifications for natural gas. (a) Natural gas used as a test fuel must meet the specifications in the following table: Table 1 of Sec. 1065.215--Test-Fuel Specifications for Natural Gas ---------------------------------------------------------------------------------------------------------------- Item Procedure\1\ Value (mole percent) ---------------------------------------------------------------------------------------------------------------- 1. Methane.............................. ASTM D 1945-96 87.0 minimum. 2. Ethane............................... ASTM D 1945-96 5.5 maximum. 3. Propane.............................. ASTM D 1945-96 1.2 maximum. 4. Butane............................... ASTM D 1945-96 0.35 maximum. 5. Pentane.............................. ASTM D 1945-96 0.13 maximum. 6. C6 and higher........................ ASTM D 1945-96 0.1 maximum. 7. Oxygen............................... ASTM D 1945-96 1.0 maximum. 8. Inert gases (sum of CO2 and N2)...... ASTM D 1945-96 5.1 maximum. ---------------------------------------------------------------------------------------------------------------- \1\All ASTM standards are incorporated by reference in Sec. 1065.1010. (b) At ambient conditions, the fuel must have a distinctive odor detectable down to a concentration in air of not more than one-fifth of the lower flammability limit.