&EPA
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
              EPA-420-B-16-023
                   March 2016
          Nonroad Large Spark-Ignition Engines: Exhaust and Evaporative Emission Standards

Federal b
Tier
1 
29
Year
2004-
2006
2007+
General Duty-Cycle
Standards
HC+NOxa
(g/kW-hr)
4.0 d
2.79
CO
(g/kW-hr)
50.0
4.49
Alternative Standards
for Severe-Duty
Engines
HC+NOxa
(g/kW-hr)
4.0 d
2.7
CO
(g/kW-hr)
130.0
130.0
Field Testing
Standards
HC+NOx a
(g/kW-hr)
-
3.89
CO
(g/kW-hr)
-
6.59
Useful Life
(years /
hours)
7 / 5,000 e
7 / 5,000 e
Evaporative Emission Standards (for engines fueled by a volatile liqued fuel)
Fuel line
permeation
Diurnal
emissions
Running
Loss
Nonmetallic fuel lines must meet the permeation
tions of SAE J2260 (November 1996)
specifica-
Evaporative HC emissions may not exceed 0.2 grams
per gallon of fuel tank capacity
Liquid fuel in the fuel tank may not reach boiling during
continuous engine operation in the final installation at an
ambient temperature of 30C
51-
Warranty
Period
3 / 2,500 f
3 / 2,500 f
Notes:
    The numerical emission standards for hydrocarbons (HC)
    must be met based on the following types of hydrocarbon
    emissions for engines powered by the following fuels: (1)
    non-methane hydrocarbons (NMHC) for natural gas; (2)
    total hydrocarbon equivalent (THCE) for alcohol; and (3)
    total hydrocarbons (THC) for other fuels.
    Voluntary Blue Sky standards for large spark-ignition (SI)
    engines are available.  Engines with displacement at or
    below 1,000 cubic centimeters (cc) and maximum power
    at or below 30 kilowatts (kW) may be certified under the
    program  for small SI engines.
    Emission standards are based on testing over a steady-
    state duty-cycle.
    The Tier  1 HC plus nitrogen oxides (NOx) emission stan-
    dard for in-use testing is 5.4 grams per kW-hour (g/kW-hr).
    Useful life is expressed  in years and hours, whichever
    comes first. These are the minimum useful life
    requirements. For severe-duty engines, the  minimum use-
    ful life is seven years or 1,500 hours of operation, which-
    ever comes first. A longer useful life in hours is required
    if: (a) the engine is designed to operate longer than the
    minimum useful life based on the recommended rebuild in-
    terval; or (b) the basic mechanical warranty  is longer than
    the minimum useful life.
                                           f   A longer warranty period of five years or 3,500 hours ap-
                                               plies for high-cost warranted parts (i.e., components with a
                                               replacement cost at time of certification exceeding $400 [in
                                               1998 dollars]).
                                           g   Optional engine certification is allowed according to the
                                               following formula: (HC+NOx)  x COO.784 < 8.57. The
                                               HC+NOx and carbon monoxide (CO)  emission levels se-
                                               lected to satisfy this formula, rounded to the nearest 0.1 g/
                                               kW-hr, become the emission standards that apply for those
                                               engines. One may not select an HC+NOx emission stan-
                                               dard higher than 2.7 g/kW-hr or a CO emission standard
                                               higher than 20.6 g/kW-hr.

                                           Code of Federal Regulations (CFR) Citations:
                                               40 CFR 1048.101 = Exhaust emission standards
                                               40 CFR 1048.105 = Evaporative emission standards
                                               40 CFR 1048.110 = Engine diagnostic requirements
                                               40 CFR 1048.120 = Warranty requirements

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