United States Air and Radiation EPA42Q-F-99-027
Environmental Protection June 1999
Agency
Office of Mobile Sources
2 for
The U.S Environmental Protection Agency (EPA) is reproposing Phase
2 emission standards and other regulatory requirements for nonroad
small spark ignition (SI) handheld engines (such as trimmers, brush
cutters, and chainsaws). Small SI engines currently produce
approximately one tenth of U.S. mobile source hydrocarbon (HC)
emissions and are the largest single contributor to nonroad HC
inventories. Thus, the proposed Phase 2 standards would help the
in their progress towards compliance with the National Ambient
Air Quality Standard (NAAQS) for ozone.
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.
> Printed on Recycled Paper
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Table I : Small SI Engine Classes
Noiihandheld
Class I-A
<66cc
Class I-B
66 to<100cc
Class I
1 00 to <225 cc
Class II
>225cc
Handheld
Class III
<20cc
Class IV
20cc to <50cc
Class V
>50cc
In September 1993, the Agency initiated a regulatory negotiation (or
"reg-neg") to develop a framework for a "Phase 2" rule. The reg-neg
ended in February 1996 without a consensus among all the participants
on a Phase 2 program. However, EPA continued to work with several
former reg-neg members.
In March of 1997, EPA published an Advance Notice of Proposed
Rulemaking (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 State-
ments of Principles (SOPs) which were developed between the Agency
and other interested parties in 1996. In January of 1998, the Agency
published the NPRM 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. EPA had not been able to fully evaluate these technologies or
discuss their possible availability at the time of the January 1.998 NPRM.
Having reviewed the available information regarding these new technolo-
gies, EPA now believes this new information supports proposed Phase 2
standards for handheld engines that are significantly more stringent than
those proposed in the January 1998 NPRM.
In light of this information, and in the interest of providing an opportu-
nity for public comment on the stringent levels being considered for the
Phase 2 handheld engine emission standards and the technologies avail-
able for meeting these standards, EPA is reproposing the Phase 2 regula-
tions for handheld engines in this Supplemental Notice of Proposed
Rulemaking (SNPRM). EPA finalized Phase 2 regulations for
nonhandheld engines in a Final Rulemaking (FRM) in March of 1999.
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The reproposed emission standards are considerably more stringent than
those originally proposed in the January 1998 NPRM for handheld
engines. In addition, the reproposed compliance program provisions are
similar to those recently adopted for nonhandheld engines and reflect
closer harmonization with those required by the State of California.
This proposal will reduce hydrocarbons plus oxides of nitrogen
(HC+NOx) by an additional 78 percent beyond the current Phase 1
standards. The reproposed rule 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 would be phased in beginning with the 2002 model year.
EPA is also proposing standards for two additional classes of
nonhandheld engines that would apply to engines below 100 cubic
centimeters displacement used in nonhandheld equipment applications.
for
III, IV V
This SNPRM proposes emission standards and other regulatory require-
ments for Class III, IV and V engines as used in handheld equipment
applications. The reproposed Phase 2 program for handheld engines is
expected to result in a shift to dramatically cleaner engine technology. In
addition, the proposed Phase 2 rules include new programmatic require-
ments to ensure that engines meet the tighter standards throughout the
useful life of the equipment. Highlights of the proposed 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 reproposed emission standards for
handheld engines.
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Engine
Class
Class !!!
Class IV
Class V
Table 2: Re-Proposed HC+NOx Emission Standards for Handheld Engines
(in g/kW-hr) by Model Year
2002
226
187
—
2003
200
168
—
2004
150
129
138
2005
100
89
129
2006
50
50
110
2007
50
50
91
2008
and later
50
50
72
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)
All 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
reproposed Phase 2 handheld standards.
and
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 (NAAQS) have been designated under the Clean Air
Act (CAA), the most widespread problem continues to be ozone, which
is the most prevalent photochemical oxidant and an important compo-
nent of smog.
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The reproposed Phase 2 handheld engine standards should result in a 78
percent reduction 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 258,000 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 proposed Phase 2 standards would
help the States in their progress towards compliance with the NA.AQS
for ozone.
The proposed standards will generate significant reductions in emissions
from these engines with small increases in cost. In addition, the techno-
logical changes necessary to bring these engines into compliance with
the proposed emission standards would cause a decrease in fuel con-
sumption of approximately 30 percent for handheld engines, resulting in
even lower costs to the consumer. Table 4 presents the cost effectiveness
of the reproposed Phase 2 program for handheld engines.
Table 4: Cost Effectiveness of Proposed Phase 2 Handheld Engine Rulemaking
Without Fuel Savings
With Fuel Savings
$2, 150/ton HC+NOx
$l,900/ton HC+NOx
on
The proposed rule would require 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 proposed rule includes provisions to ease the transition from Phase 1
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 provisions
include a declining set of average standards, a certification ABT pro-
gram, and special provisions to ease and/or delay the impact of the
proposed rule on small volume engines and equipment.
Public
We welcome public comments on this proposed rule from all interested
parties. For instructions on submitting written comments, please see the
Federal, Register notice. It is available from the EPA Air Docket by
calling 202-260-7548; please refer to Docket No. A-96-55. In addition,
the proposed rule and related documents are available electronically via
the EPA Internet server at:
http://www.epa.gov/oms/equip-ld.htm
For
Additional documents on small nonroad SI engines are available elec-
tronically at the Internet site given above, or by writing to:
U.S. Environmental Protection Agency
Office of Mobile Sources
2000 Traverwood Road
Ann Arbor, Michigan 48105
(734)214-4278
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