CFR

91.120—Compliance with Family Emission Limits over useful life.

(a) If all test engines representing an engine family have emissions, as determined in paragraph (c)(3)(iii) of this section, less than or equal to the applicable Family Emission Limit (FEL) for each pollutant as determined according to § 91.104 (c), that family complies with the Family Emission Limit .

(b) If any test engine representing an engine family has emissions (as determined in paragraph (c)(3)(iii) of this section, greater than the applicable Family Emission Limit for any pollutant as determined according to § 91.104(c), that family will be deemed not in compliance with the Family Emission Limits.

(2) Since emission control efficiency generally decreases with the accumulation of service on the engine, deterioration factors must be used in combination with emission data engine test results as the basis for determining compliance with the standards.

(3) (i) Paragraph (c)(3)(ii) of this section describes the procedure for determining compliance of an engine with family emission limits, based on deterioration factors supplied by the manufacturer.

(ii) Separate exhaust emission deterioration factors, determined by the manufacturer, must be supplied for each engine family. The deterioration factors must be applied as follows:

(A) For marine spark-ignition engines not utilizing aftertreatment technology (for example, catalytic converters), the official exhaust emission results for each emission data engine at the selected test point are adjusted by adding the appropriate deterioration factor to the results. However, if the deterioration factor supplied by the manufacturer is less than zero, it is zero for the purposes of this paragraph.

(B) For marine spark-ignition engines utilizing aftertreatment technology (for example, catalytic converters), the official exhaust emission results for each emission data engine at the selected test point are adjusted by multiplying the results by the appropriate deterioration factor. However, if the deterioration factor supplied by the manufacturer is less than one, it is one for the purposes of this paragraph.

(iii) The emission values to compare with the Family Emission Limits (FELs) are the adjusted emission values of paragraph (c)(3)(ii) of this section, rounded to the same number of significant figures as contained in the applicable standard in accordance with ASTM E 29-93a, for each emission data engine. This procedure has been incorporated by reference. See § 91.6.

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