[Code of Federal Regulations]
[Title 40, Volume 30]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1051.240]

[Page 618]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 1051_CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES
--Table of Contents
 
                  Subpart C_Certifying Engine Families
 
Sec. 1051.240  How do I demonstrate that my engine family complies with 
exhaust emission standards?

    (a) For certification, your engine family is considered to be in 
compliance with the numerical exhaust emission standards in subpart B of 
this part if all emission-data vehicles representing that family have 
test results showing emission levels at or below the standards.
    (b) Your engine family does not comply if any emission-data vehicle 
representing that family has test results showing emission levels above 
the standards for any pollutant.
    (c) To compare emission levels from the emission-data vehicle with 
the emission standards, apply deterioration factors (to three 
significant figures) to the measured emission levels. The deterioration 
factor is a number that shows the relationship between exhaust emissions 
at the end of useful life and at the low-hour test point. Section 
1051.520 specifies how to test your vehicle to develop deterioration 
factors that estimate the change in emissions over your vehicle's full 
useful life. Small-volume manufacturers may use assigned deterioration 
factors that we establish. Apply the deterioration factors as follows:
    (1) For vehicles that use aftertreatment technology, such as 
catalytic converters, the exhaust deterioration factor is the ratio of 
exhaust emissions at the end of useful life to exhaust emissions at the 
low-hour test point. Adjust the official emission results for each 
tested vehicle at the selected test point by multiplying the measured 
emissions by the deterioration factor. If the factor is less than one, 
use one.
    (2) For vehicles that do not use aftertreatment technology, the 
exhaust deterioration factor is the difference between exhaust emissions 
at the end of useful life and exhaust emissions at the low-hour test 
point. Adjust the official emission results for each tested vehicle at 
the selected test point by adding the factor to the measured emissions. 
If the factor is less than zero, use zero.
    (d) After adjusting 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 vehicle.