Section 1060.240 - How do I demonstrate that my emission family complies with evaporative emission standards?(a) For purposes of certification, your emission family is considered in compliance with an evaporative emission standard in subpart B of this part if you do either of the following:(1) You have test results showing a certified emission level from the fuel tank or fuel line (as applicable) in the family are at or below the applicable standard.(2) You comply with design specifications as specified in paragraphs (d) through (f) of this section.(b) Your emission family is deemed not to comply if any fuel tank or fuel line representing that family has an official emission result above the standard.(c) Round each official emission result to the same number of decimal places as the emission standard.(d) You may demonstrate for certification that your emission family complies with the fuel tank permeation standards specified in § 1060.103 with any of the following control technologies:(1) A coextruded high-density polyethylene fuel tank with a continuous ethylene vinyl alcohol barrier layer (with not more than 40 molar percent ethylene) making up at least 2 percent of the fuel tank's overall wall thickness with any of the following gasket and fuel-cap characteristics:(i) No nonmetal gaskets or fuel caps.(ii) All nonmetal gaskets and fuel caps made from low-permeability materials.(iii) Nonmetal gaskets and fuel caps that are not made from low-permeability materials up to the following limits:(A) Gaskets with a total exposed surface area less than 0.25 percent of the total inside surface area of the fuel tank. For example, a fuel tank with an inside surface area of 0.40 square meters may use high-permeation gasket material representing a surface area of up to 1,000 mm2 (0.25% * 1/100 * 0.40 m2 * 1,000,000 mm2/m2). Determine surface area based on the amount of material exposed to liquid fuel.(B) Fuel caps directly mounted to the fuel tank with the surface area of the fuel cap less than 3.0 percent of the total inside surface area of the fuel tank. Use the smallest inside cross-sectional area of the opening on which the cap is mounted as the fuel cap's surface area.(2) A metal fuel tank with the gasket and fuel-cap characteristics meeting the specifications in paragraphs (d)(1)(i) through (iii) of this section.(e) You may demonstrate for certification that your emission family complies with the diurnal emission standards specified in § 1060.105 with any of the following control technologies:(1) A Marine SI fuel tank sealed up to a positive pressure of 7.0 kPa (1.0 psig); however, the fuel tank may contain air inlets that open when there is a vacuum pressure inside the tank.(2) A Marine SI fuel tank equipped with a passively purged carbon canister that meets the requirements of this paragraph (e)(2). The carbon must adsorb no more than 0.5 grams of water per gram of carbon at 90% relative humidity and a temperature of 25±5 °C. The carbon granules must have a minimum mean diameter of 3.1 mm based on the procedures in ASTM D2862 (incorporated by reference in § 1060.810 ). The carbon must also pass a dust attrition test based on ASTM D3802 (incorporated by reference in § 1060.810 ), except that hardness is defined as the ratio of mean particle diameter before and after the test and the procedure must involve twenty 1/2-inch steel balls and ten 3/4-inch steel balls. Use good engineering judgment in the structural design of the carbon canister. The canister must have a volume compensator or some other device to prevent the carbon pellets from moving within the canister as a result of vibration or changing temperature. The canister must have a minimum working capacity as follows:(i) You may use the measurement procedures specified by the California Air Resources Board in Attachment 1 to TP-902 to show that canister working capacity is least 3.6 grams of vapor storage capacity per gallon of nominal fuel tank capacity (or 1.4 grams of vapor storage capacity per gallon of nominal fuel tank capacity for fuel tanks used in nontrailerable boats).(ii) You may produce canisters with a minimum carbon volume of 0.040 liters per gallon of nominal fuel tank capacity (or 0.016 liters per gallon for fuel tanks used in nontrailerable boats). The carbon canister must have a minimum effective length-to-diameter ratio of 3.5 and the vapor flow must be directed with the intent of using the whole carbon bed. The carbon must have a minimum carbon working capacity of 90 grams per liter.(f) We may establish additional design certification options where we find that new test data demonstrate that the use of a different technology design will ensure compliance with the applicable emission standards.(g) You may not establish a family emission limit below the emission standard for components certified based on design specifications under this section even if actual emission rates are much lower. 73 FR 59298 , Oct. 8, 2008, as amended at 86 FR 34530 , June 29, 2021