United States Air and Radiation EPA420-F-99-008
Environmental Protection March 1999
Agency
Office of Mobile Sources
&EPA Regulatory
Announcement
New Phase 2 Standards for Small
Spark-Ignition Nonhandheld Engines
The U.S. Environmental Protection Agency (EPA) is setting stringent
new Phase 2 emission standards for nonroad small spark-ignition (SI)
nonhandheld engines that will reduce hydrocarbons plus oxides of
nitrogen (HC+NOx) by an additional 59 percent beyond the current
Phase 1 standards. The adopted 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 will be phased in between 2001 and
2007.
History of Rulemaking
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 hydrocarbon (HC)
emissions from these engines. (See Table 1 for examples of small
nonroad SI engines.)
> Printed on Recycled Paper
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Nonhandheld
Handheld
Class I
Class II
Class III
Class IV
Class V
<225 cc
>=225 cc
<20 cc
20 cc <=XX <50cc
>=50 cc
Examples: lawn
mowers, lawn
tractors, generator
sets, pumps, air
compressors,
commercial turf
equipment
Examples: augers, brush cutters, chain saws,
string trimmers, leaf blowers
Table 1. Small SI Engine Classes
In September 1993, the Agency initiated a regulatory negotiation to
develop a framework for a "Phase 2" rule. This process ended in Febru-
ary 1996 without a consensus among all the participants on a Phase 2
program. However, EPA continued to work with several former
regulatory negotiation members.
In March of 1997, EPA published an Advance Notice of Proposed
Rulemaking (ANPRM) announcing the Agency's intent to issue a
proposed rule which would cover both handheld and nonhandheld
engines. This ANPRM also published the text of two Statements of
Principles (SOPs) which were developed between EPA and other inter-
ested parties in 1996. In January of 1998, the Agency published a Notice
of Proposed Rulemaking (NPRM) for the Phase 2 regulations for small
SI engines.
Based on the public comments EPA received on the NPRM, this final
rule for nonhandheld engines adopts emission standards considerably
more stringent than those proposed for Class I nonhandheld engines, as
well as compliance program provisions reflecting closer harmonization
with those required by the State of California.
In addition, there have been rapid advances in emission reduction tech-
nologies for handheld engines since the publication of the NPRM. EPA
has very recently received information which could potentially support
handheld standards much more stringent than those originally proposed.
In light of this new information, which addresses a new technology that
EPA did not analyze at the NPRM stage, and in the interest of providing
an opportunity for public comment on more stringent levels for
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handheld engine emission standards, Phase 2 regulations for handheld
engines (such as trimmers, brush cutters, and chainsaws) will be ad-
dressed in a separate Supplemental Notice of Proposed Rulemaking
(SNPRM) in June of 1999, with a final rule in March of 2000.
of the Final
This final rule adopts emission standards and other regulatory require-
ments only for Class I and II engines as used in nonhandheld equipment
applications. The adopted Phase 2 program for nonhandheld engines is
expected to result in a shift to cleaner, more durable engine technology.
Notably, the Phase 2 program will lead to increased use of automotive-
style overhead valve (OHV) technology in nonhandheld engines. In
addition, these Phase 2 rules include new programmatic requirements to
ensure that engines meet the tighter standards throughout the useful life
of the equipment. Highlights of the 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 manu-
facturers 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 requirements.
Engine
Class
Class I
Class II
HC+NOx
(g/kW-hr)
16.1
12.1
Time Line
August 1, 2007; in addition, any Class I
engine family initially produced on or after
August 1, 2003 must meet the Phase 2 Class I
standards before they may be introduced into
commerce.
2001-2005
Table 2. Phase 2 HC+NOx Emission Standards for Nonhandheld
Engines
* Three useful life categories for nonhandheld engines to account for
widely varying product lives.
Class I
Class II
Category C
125
250
Category B
250
500
Category A
500
1000
Table 3. Useful Life Categories for Nonhandheld Engines (hours)
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A compliance program to ensure engines continue meeting the stan-
dards for the useful life of the engine, including certification, produc-
tion line testing, and in-use testing.
EPA's primary reason for controlling emissions from small SI
nonhandheld engines is the role of their HC emissions in forming ozone,
a significant component of smog. Of the major air pollutants for which
National Ambient Air Quality Standards (NAAQS) have been designated
under the Clean Air Act, the most widespread problem continues to be
ozone. The Phase 2 nonhandheld engine standards should result in a 59
percent reduction in HC + NOx emissions from these engines beyond
the 32 percent reduction expected from the Phase I standards. This is
equivalent to an annual reduction of 390,000 tons of HC+NOx emissions
by year 2027. In addition, this reduction in HC + NOx emissions will be
accompanied by an overall reduction in fuel consumption.
Small SI engines produce approximately one tenth of U.S. mobile source
HC emissions and are the largest single contributor to nonroad HC
inventories. Thus, the final Phase 2 standards would help the States in
their progress towards compliance with the National Ambient Air Qual-
ity Standards for ozone.
The final standards will generate significant reductions in emissions
from these engines at very low costs. When fuel savings are considered,
costs are lower and a net savings may actually result for some larger
nonhandheld engines.
Class
I
II
Cost Per Engine
$19.63
$12.64
Savings Per Engine
$14.22
$55.72
Resultant Cost Per Engine
$5.41
($43.08)
Table 4. Engine Yearly Fuel Savings Resultant Cost Per Engine
The technological changes necessary to bring these engines into compli-
ance with the emission standards will cause a decrease in fuel consump-
tion of approximately 15 percent for nonhandheld Class I and II side-
valve (SV) engines. For Class I and II engines, EPA assumes that there
will be fuel savings as SV engines are phased-out and replaced with
more fuel efficient overhead-valve (OHV) engines. The high savings per
equipment in Class II are influenced by the fact that the engines in this
class are utilized for longer hours compared to the equipment in Class I.
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Without Fuel Savings
With Fuel Savings
Cost Effectiveness (S cost/ton HC+NOx)
$852
($507)
Table 5. Cost Effectiveness of Phase 2 Noiihandheld Engine Final
Rule
on
The final rule will require engine manufacturers to:
• build cleaner, more durable engines; and
• certify that those engines will met standards for their full regulatory
useful lives.
One of the technology changes available to achieve these standards
(adopting an overhead-valve configuration) has already been done on
some Class I engines and is also anticipated to be a primary choice for
manufacturers of Class II engines to meet their Phase 2 emission levels.
The rule will not require the use of catalysts for any group of engines.
The final 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 phase-in schedules, a certification averaging, banking, and
trading program, special compliance provisions for very low emitting
engines, and special provisions to ease and/or delay the impact of the
rule on low volume engines and equipment.
For
Additional documents on this small nonroad SI engines are available
electronically from the EPA Internet server at:
http://www.epa.gov/oms/equip-ld.htm
Document information is also available by writing to:
U.S. Environmental Protection Agency
Office of Mobile Sources
2000 Traverwood Drive
Ann Arbor, MI 48105
(734) 214-4278
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