Section 1065.720 - Liquefied petroleum gas(a) Except as specified in paragraph (b) of this section, liquefied petroleum gas for testing must meet the specifications in the following table: Table 1 to Paragraph (a) of § 1065.720 -Test Fuel Specifications for Liquefied Petroleum Gas
| Property | Value | Reference procedurea |
| Propane, C3H8 | Minimum, 0.85 m3/m3 | ASTM D2163. |
| Vapor pressure at 38 °C | Maximum, 1400 kPa | ASTM D1267 or
ASTM D2598b. |
| Butanes | Maximum, 0.05 m3/m3 | ASTM D2163. |
| Butenes | Maximum, 0.02 m3/m3 | ASTM D2163. |
| Pentenes and heavier | Maximum, 0.005 m3/m3 | ASTM D2163. |
| Propene | Maximum, 0.1 m3/m3 | ASTM D2163. |
| Residual matter (residue on evaporation of 100 ml oil stain observation) | Maximum, 0.05 ml passc | ASTM D2158. |
| Corrosion, copper strip | Maximum, No. 1 | ASTM D1838. |
| Sulfur | Maximum, 80 mg/kg | ASTM D6667. |
| Moisture content | pass | ASTM D2713. |
a Incorporated by reference; see § 1065.1010 . See § 1065.701(d) for other allowed procedures.
b If these two test methods yield different results, use the results from ASTM D1267.
c The test fuel must not yield a persistent oil ring when you add 0.3 ml of solvent residue mixture to a filter paper in 0.1 ml increments and examine it in daylight after two minutes.
(b) In certain cases you may use test fuel not meeting the specifications in paragraph (a) of this section, as follows:(1) You may use fuel that your in-use engines normally use, such as commercial-quality liquefied petroleum gas.(2) You may use fuel meeting alternate specifications if the standard-setting part allows it.(3) You may ask for approval to use fuel that does not meet the specifications in paragraph (a) of this section, but only if using the fuel would not adversely affect your ability to demonstrate compliance with the applicable standards in this chapter.(c) When we conduct testing using liquefied petroleum gas, we will use fuel that meets the specifications in paragraph (a) of this section.(d) At ambient conditions, liquefied petroleum gas must have a distinctive odor detectable down to a concentration in air not more than one-fifth the lower flammable limit. 73 FR 37342 , June 30, 2008, as amended at 79 FR 23811 , Apr. 28, 2014; 86 FR 34573 , June 29, 2021; 88 FR 4687 , Jan. 24, 2023 86 FR 34573 , 7/29/2021; 88 FR 4687 , 3/27/2023