40 CFR § 1048.245 - How do I demonstrate that my engine family complies with evaporative emission standards?
(1) You have test results showing that evaporative emissions in the family are at or below the standards throughout the useful life.
(2) Where applicable, you comply with the design specifications in paragraph (e) of this section.
(d) If you adjust the emission levels for deterioration, round them to the same number of decimal places as the emission standard. Compare the rounded emission levels to the emission standard for each test fuel system.
(e) You may demonstrate that your engine family complies with the evaporative emission standards by demonstrating that you use the following control technologies:
(i) Use a tethered or self-closing gas cap on a fuel tank that stays sealed up to a positive pressure of 24.5 kPa (3.5 psig); however, they may contain air inlets that open when there is a vacuum pressure inside the tank. Nonmetal fuel tanks must also use one of the qualifying designs for controlling permeation emissions specified in 40 CFR 1060.240.
(2) For certification to the standards specified in § 1048.105(d), demonstrating that you use design features to prevent fuel boiling under all normal operation. If you install engines in equipment, you may do this using fuel temperature data measured during normal operation. Otherwise, you may do this by including appropriate information in your emission-related installation instructions.
(3) We may establish additional options for design-based certification where we find that new test data demonstrate that a technology will ensure compliance with the emission standards in this section.