United States Air and Radiation EPA420-F-00-007
Environmental Protection March 2000
Agency
Office of Transportation and Air Quality
Regulatory
Announcement
Final Phase 2 Standards for Small
Spark-Ignition Handheld Engines
The U.S. Environmental Protection Agency (EPA) is adopting a second
phase of more stringent emission standards for nonroad small spark
ignition (SI) handheld engines (such as trimmers, brush cutters, and
chainsaws). In addition, EPA is revising the compliance program
provisions to be similar to those already adopted for nonhandheld
engines and reflect closer harmonization with those required by the
State of California. Small SI engines produce approximately one tenth of
U.S. mobile source hydrocarbon (HC) emissions and are the largest
single contributor to nonroad HC inventories. Thus, these standards will
help the States in their progress towards compliance with the National
Ambient Air Quality Standard (NAAQS) for ozone.
This final rule will reduce hydrocarbons plus oxides of nitrogen
(HC+NOx) by an additional 70 percent beyond the current Phase 1
standards. The final rulemaking includes provisions that give industry
flexibility and ease the transition to the more stringent Phase 2 program,
especially for small volume engine and equipment manufacturers. The
new standards will be phased in beginning with the 2002 model year.
EPA is also adopting standards for two additional classes of
nonhandheld engines that will apply to engines below 100 cubic
centimeters displacement used in nonhandheld equipment applications.
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of
In July 1995, EPA finalized the first federal regulations affecting small
nonroad SI engines at or below 19 kilowatts (kW), or 25 horsepower.
The regulations, commonly known as "Phase 1," took effect for most
new handheld and nonhandheld engines beginning in model year 1997
and are expected to result in a 32 percent reduction in HC emissions
from these engines. Table 1 lists the different small SI engine categories,
including the newly proposed Class I-A and I-B designations. For the
nonhandheld categories, Class I engines are used primarily in walk-
behind lawnmowers and Class II engines are used primarily in lawn and
garden tractors. For the handheld categories, Class III and IV engines are
used primarily in residential equipment such as string trimmers, leaf
blowers and chainsaws. Class V engines are used primarily in commer-
cial equipment such as chainsaws.
Table 1 : Small SI Engine Classes
Nonhandheld
Class I-A
<66cc
Class I-B
66 to <100cc
Class I
100 to <225 cc
Class II
>225 cc
Handheld
Class III
< 20 cc
Class IV
20cc to <50cc
Class V
>50 cc
In September 1993, EPA initiated a regulatory negotiation (or "reg-neg")
to develop a framework for a "Phase 2" rule that would further reduce
emissions from these engines. The reg-neg ended in February 1996
without a consensus among all the participants on a Phase 2 program.
However, the Agency continued to work with several former reg-neg
members.
In March 1997, EPA published an Advance Notice of Proposed Rule-
making (ANPRM) announcing the Agency's intent to issue a Notice of
Proposed Rulemaking (NPRM) which would cover both handheld and
nonhandheld engines. The ANPRM also published the text of two
Statements of Principles (SOPs) which were developed between the
Agency and interested parties in 1996. In January of 1998, the Agency
published the proposed rule for the Phase 2 regulations for small SI
engines, both handheld and nonhandheld engines, based on the SOPs.
Since the publication of the January 1998 NPRM, there have been rapid
and dramatic advances in emission reduction technologies for handheld
engines used in applications such as trimmers, brush cutters, and chainsaws.
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EPA had not been able to fully evaluate these technologies or discuss
their possible availability at the time of the January 1998 NPRM. Having
reviewed the available information regarding these new technologies,
EPA believes this new information supported Phase 2 standards for
handheld engines that are significantly more stringent than those pro-
posed in the January 1998 proposal. In light of this information, and in
the interest of providing an opportunity for public comment on the
stringent levels being considered for the Phase 2 handheld engine emis-
sion standards and the technologies available for meeting these stan-
dards, EPA reproposed Phase 2 regulations for handheld engines in a
July 1999 Supplemental Notice of Proposed Rulemaking (SNPRM).
This final rule adopts the final Phase 2 requirements for handheld en-
gines. EPA already finalized Phase 2 regulations for nonhandheld en-
gines in March 1999.
of the Final 2 for
III, IV and V
This final rule adopts emission standards and other regulatory require-
ments for Class III, IV and V engines as used in handheld equipment
applications. The Phase 2 program for handheld engines is expected to
result in a shift to dramatically cleaner engine technology. In addition,
the Phase 2 rule includes new programmatic requirements to ensure that
engines meet the tighter standards throughout the useful life of the
equipment. Highlights of the Phase 2 final rule include:
• Tighter emission standards for HC+NOx (in grams per kilowatt-
hour (g/kW-hr)) to be phased-in over a number of years, allowing
the manufacturers an orderly and efficient transition of engine
designs and technologies from those complying with the existing
Phase 1 standards to those necessary to meet the Phase 2 require-
ments. Table 2 contains the Phase 2 emission standards for
handheld engines.
Table 2: Phase 2 HC+NOx Emission Standards for Handheld Engines
(in g/kW-hr) by Model Year
Engine Class
Class III
Class IV
Class V
2002
238
196
—
2003
175
148
—
2004
113
99
143
2005
50
50
119
2006
50
50
96
2007 and later
50
50
72
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Three useful life categories for handheld engines to account for
widely varying product lives as noted in Table 3.
Table 3 : Useful Life Categories for Handheld Engines (hours of use)
Ail Handheld Classes
50
125
300
A compliance program to ensure engines continue meeting the
standards for the useful life of the engine, including certification,
production line testing, and voluntary in-use testing.
An Averaging, Banking, and Trading (ABT) program to provide
engine manufacturers with additional flexibility in meeting the
Phase 2 handheld standards.
The Phase 2 handheld engine standards will result in a 70 percent reduc-
tion in HC+NOx emissions from these engines beyond the 32 percent
reduction expected from the Phase 1 standards. This is equivalent to an
annual reduction of 500,000 tons of exhaust HC+NOx emissions by the
year 2027. This reduction in HC+NOx emissions will be accompanied
by an overall reduction in fuel consumption.
Small SI engines currently produce approximately one tenth of U.S.
mobile source HC emissions and are the largest single contributor to
nonroad HC inventories. Thus, the Phase 2 standards will help the States
in their progress towards compliance with the NAAQS for ozone.
Both HC and NOx contribute to the formation of tropospheric ozone
through a complex series of reactions. In a recent report, researchers
emphasize that both HC and NOx controls are needed in most areas of
the United States. EPA's primary reason for controlling emissions from
small SI handheld engines is the role of their HC emissions in forming
ozone. Of the major air pollutants for which National Ambient Air
Quality Standards have been designated under the Clean Air Act, the
most widespread problem continues to be ozone, which is the most
important component of smog.
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The Phase 2 standards will generate significant reductions in emissions
from these engines with small increases in cost. Table 4 presents the
estimated average price increase for handheld equipment due to the
Phase 2 standards.
Table 4: Estimated Handheld Equipment Price Increase Due to
Phase 2 Standards
Class III
$23
Class IV
$20
Class V
$56
In addition, the technological changes necessary to bring these engines
into compliance with the new emission standards would cause a decrease
in fuel consumption of approximately 30 percent for handheld engines,
resulting in lower operating costs to the consumer. Table 5 presents the
cost effectiveness of the Phase 2 program for handheld engines.
Table 5: Cost Effectiveness of Phase 2 Handheld Engine
Final Rulemaking
Without Fuel Savings
With Fuel Savings
per ton HC+NOx
$560 per ton HC+NOx
on
The final rule requires engine manufacturers to:
• build significantly cleaner, more durable engines
• certify that those engines will meet standards for their full regula-
tory useful lives
Some of the technologies currently in development to achieve these
standards with the use of a catalyst (e.g., John Deere's "LE technology"
and Komatsu Zenoah's "Stratified Scavenged" design) are anticipated to
be a primary choice for manufacturers of Class III and IV engines to
meet their Phase 2 emission levels. Class V engines are expected to use
the same technologies without catalysts to meet their Phase 2 emission
levels.
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The rule includes provisions to ease the transition from the Phase 1
program to the Phase 2 program to ensure that the Phase 2 standards are
cost-effective and achievable, and to minimize the compliance burden
while maintaining the environmental benefits of the rule. These provi-
sions include a declining set of average standards, a certification ABT
program, and special provisions to ease and/or delay the impact of the
rule on small volume engine families and equipment models.
For
You can access additional documents on small nonroad SI engine
rulemakings electronically on the Office of Transportation and Air
Quality Web site at:
http://www.epa.gov/otaq/equip-ld.htm
You can also contact the NVFEL Library for document information at:
U.S. Environmental Protection Agency
Office of Transportation and Air Quality
NVFEL Library
2000 Traverwood Road
Ann Arbor, Michigan 48105
(734)214-4311
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