[Code of Federal Regulations]
[Title 40, Volume 18]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR91.120]

[Page 308-309]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 91--CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES--Table of 
Contents
 
       Subpart B--Emission Standards and Certification Provisions
 
Sec. 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 Sec. 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 Sec. 91.104(c), that family will be deemed not in 
compliance with the Family Emission Limits.
    (c)(1) The engine Family Emission Limits (FELs) apply to the 
emissions of engines for their useful lives.
    (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

[[Page 309]]

applicable standard in accordance with ASTM E 29-93a, for each emission 
data engine. This procedure has been incorporated by reference. See 
Sec. 91.6.