Section 1060.230 - How do I select emission families?(a) For purposes of certification, divide your product line into families of equipment (or components) that are expected to have similar emission characteristics throughout their useful life.(b) Group fuel lines into the same emission family if they are the same in all the following aspects:(1) Type of material including barrier layer.(3) Types of connectors and fittings (material, approximate wall thickness, etc.) for fuel line assemblies certified together.(c) Group fuel tanks (or fuel systems including fuel tanks) into the same emission family if they are the same in all the following aspects:(1) Type of material, including any pigments, plasticizers, UV inhibitors, or other additives that are expected to affect control of emissions.(3) Relevant characteristics of fuel cap design for fuel systems subject to diurnal emission requirements.(5) Emission control strategy.(6) Family emission limit, if applicable.(d) Group other fuel-system components and equipment into the same emission family if they are the same in all the following aspects: (1) Emission control strategy and design.(2) Type of material (such as type of charcoal used in a carbon canister). This paragraph (d)(2) does not apply for materials that are unrelated to emission control performance.(3) The fuel systems meet the running loss emission standard based on the same type of compliance demonstration specified in § 1060.104(b) , if applicable.(e) You may subdivide a group of equipment or components that are identical under paragraphs (b) through (d) of this section into different emission families if you show the expected emission characteristics are different during the useful life.(f) In unusual circumstances, you may group equipment or components that are not identical with respect to the things listed in paragraph (b) through (d) of this section into the same emission family if you show that their emission characteristics during the useful life will be similar. The provisions of this paragraph (f) do not exempt any engines or equipment from meeting all the applicable standards and requirements in subpart B of this part.(g) Emission families may include components used in multiple equipment categories. Such families are covered by a single certificate. For example, a single emission family may contain fuel tanks used in both Small SI equipment and Marine SI vessels. 73 FR 59298 , Oct. 8, 2008, as amended at 86 FR 34529 , June 29, 2021