United States Air and Radiation EPA420-P-02-014
Environmental Protection December 2002
Agency NR-005b
&EPA Median Life, Annual
Activity, and Load Factor
Values for Nonroad Engine
Emissions Modeling
> Printed on Recycled Paper
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EPA420-P-02-014
December 2002
Median Life, Annual Activity, and Load Factor
Values for Nonroad Engine Emissions Modeling
NR-005b
Assessment and Standards Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
NOTICE
This technical report does not necessarily represent final EPA decisions or positions.
It is intended to present technical analysis of issues using data that are currently available.
The purpose in the release of such reports is to facilitate the exchange of
technical information and to inform the public of technical developments which
may form the basis for a final EPA decision, position, or regulatory action.
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Median Life, Annual Activity, and Load Factor Values
for Nonroad Engine Emissions Modeling
Report No. NR-005b
Revised December 6, 2002
Assessment and Standards Division
EPA, Office of Transportation and Air Quality
Purpose
EPA's NONROAD model computes emission inventories for nonroad engines. This
report documents the default input values of median life, annual activity, and load factor for
various types of nonroad engines. The model uses annual activity and load factor values to
calculate yearly emissions for each engine type. In addition, the model uses activity and load
factor, in combination with median life, to calculate the fleet age distributions for each engine
type, as it projects future (or past) engine populations.
Introduction
This report documents the default annual activity, load factor, and median life values.
The model uses the following equation to calculate exhaust emissions from nonroad engines.
The derivation of default values for equipment population, average rated power, and emission
factors are discussed in reports NR-006b, NR-009b, and NR-OlOc.
Emissions = (Pop) (Power) (LF) (A) (EF)
where Pop = Engine Population
Power = Average Power (hp)
LF = Load Factor (fraction of available power)
A = Activity (hrs/yr)
EF = Emission Factor (g/hp-hr)
This report also documents the default values for the median life of engines. In the
population input files (*.pop) this parameter is expressed in "hours of life at full load." In
developing the age distribution for a given equipment type, the model begins by converting the
hours-at-full-load to years at average load, on the basis of average activity and load factor, as
defined above and as shown in the equation below.
1
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Median Lifetime (years) =
Median Life (hrs)
Activity (hrs/yr) * Load Factor
The use of median life in calculating the scrappage and resulting age distribution of each
equipment type is explained in report NR-007a, "Calculation of Age Distributions in the
Nonroad Model: Growth and Scrappage."
Values Used in NONROAD for Median Life, Annual Activity, and Load Factor
This report describes the default estimates for median life, activity, and load factor used
as default data in the input files provided withNONROAD.
Median Life
Engine life varies with engine type and power level. In general, larger engines last longer
than smaller ones, and diesel engines last longer than gasoline engines.
The NONROAD model uses median (expected) life estimates based primarily on those used in
the OFFROAD model, developed by the California Air Resources Board (ARB)(3). These
estimates are listed by horsepower class and engine type in Table 1, with horsepower classes
defined in Table 2. In certain cases the ARE horsepower ranges were adjusted to match the
ranges used in the NONROAD model. The 120 hp dividing point used by ARB was the 100 hp
point in NONROAD; the 250 hp point was used as the 300 hp point in NONROAD; and ARB's
500 hp point was used as the 600 hp dividing point in NONROAD. Additional modifications
that EPA made to the ARB median life values for diesel engines, small gasoline engines, and
recreational equipment are described below.
Table 1. Expected Engine Life in Hours at Full Load (3, 4)
Engine
Type
Diesel
2-stroke
Gasoline
HP1
2500
150
HP 2
2500
200
HP 3
2500
750
HP 4
4667
—
HP 5
4667
—
HP 6
4667
—
HP 7
7000
—
HP 8
7000
—
HP 9
7000
—
HP 10
—
—
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4-stroke
Gasoline
CNG/
LPG
200
200
400
400
750
750
1500
1500
3000
3000
3000
3000
3000
3000
3000
3000
3000
3000
3000
3000
Table 2. Horsepower Classes for Median Life (3, 4)
HP Class
HP 1
HP2
HP3
HP4
HP5
HP6
HP7
HP8
HP9
HP 10
Diesel
<16
17-25
26-50
51-100
101-175
176-300
301-600
601-750
751+
—
2-stroke
<3
3-16
16-25
26-50
51-100
101-175
176-250
301-600
601-750
751+
4-stroke
<6
6-16
16-25
26-50
51-100
101-175
176-300
301-600
601-750
751+
In prior draft versions of NONROAD the median life estimates of most equipment (CI
and SI) were based on the values in the 1997 documentation for the ARB OFFROAD model,
prepared by Energy and Environmental Analysis (EEA)(3). These are presented in EPA's
technical report NR-005a (revised 6/15/1998) and in Table 3 below. For CI these numbers were
either 1,250, 2,500, 4,000, or 6,000 hours at full load, depending on rated horsepower.
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Table 3. CI Median Life Comparison
Hp Range
0- 16
16-25
25-50
50-300
300+
Previous NONROAD
Median Life
1,250
2,500
2,500
4,000
6,000
New NONROAD
Median Life
2,500
2,500
2,500
4,667
7,000
Regulatory
Useful Life*
3,000
3,000
5,000
8,000
8,000
* The Regulatory Useful Life is considered to represent in-use loads, rather than full load.
NONROAD model diesel load factors range from 0.21 to 0.59.
In researching the issues related to estimation of equipment sales, population, diesel fuel
consumption, load factors, and median life, EPA asked EEA for more complete documentation
of the values that had been provided to ARB. At EPA's request, EEA supplemented the
documentation of their previous work. The resulting report is attached as Appendix B (4).
After reviewing the new EEA report, EPA determined that modifications to the median
life estimates were appropriate. Information that EEA gathered from highway diesel engine
manufacturers suggested an expected life for heavy-duty diesel highway engines of 7,000 hours
at full load. In preparing initial estimates for use in OFFROAD, EEA had reduced this estimate
by 15% to compensate for the "rough-duty" use of off-road engines relative to highway engines.
This yielded the 6,000 hour estimate mentioned above for engines over 300 hp. In reviewing this
work, EPA determined that it did not make sense to reduce the 7000 hour estimate for off-road
applications, since when engines are used in off-road applications they are typically derated to
compensate for the rougher operating conditions. Thus the horsepower rating of the offroad
engine may be lower than its highway counterpart, but its expected life would not be lower.
EEA estimated medium duty diesel engine life to be two-thirds that of the heavy-duty
engines and applied that to diesel engines in the range of 50 - 300 hp.
EPA applied this same factor to the 7000 hour value yielding a median life estimate of 4667
hours at full load for 50 - 300 hp engines. For engines in the 16 - 50 hp range EEA based its
estimate of 2500 hours at full load on information from light-duty highway diesels. No
adjustments were made by EEA or EPA for off-road use, since these engines are typically not
used in rough duty applications. For engines under 16 hp EEA had somewhat arbitrarily cut the
life estimate of the 16 - 50 hp engines in half, yielding the 1250 hour estimate mentioned above.
Since this low estimate was not supported by any data, and since after accounting for load factors
it can yield expected life values less than the regulatory useful life set by EPA for these engines,
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EPA decided to use the 2500 hour estimate in NONROAD for all diesel engines from 0-50 hp,
rather than have a separate lower life category under 16 hp.
Liquid petroleum gas (LPG) and compressed natural gas (CNG) engines are primarily
four-stroke spark-ignition engines and hence have many similarities with four-stroke gasoline
engines. Because LPG and CNG engines are similar in design to gasoline engines, their median
life is likely to be similar to the median life of gasoline engines. For this reason and the lack of
relevant data to the contrary, LPG and CNG engines are assumed to have the same median life as
gasoline engines in the NONROAD model.
The values described represent the most comprehensive review available of the engine
life associated with engine type and power level. They represent median values of engine life,
not distinguishing the engine by make or model. Individual engine models may have longer or
shorter median lives. Surveys of engine life by application or engine type are encouraged to
improve the estimates shown here.
Small Spark-Ignition Engines (rated at <25 hp)
The median life (the point where 50% of engines have been scrapped) for several
applications of nonroad engines have been estimated previously in terms of years of use(5,8).
For use in the NONROAD model, these estimates were converted from units of years to units of
hours using the equation previously shown. Median life in years from Table 4 was multiplied by
hours per year and load factor (described later in the report and given in Table 5) to create the
Median Life (Hours at Full Load) entry in Table 4, which is used as input to the NONROAD
model.
The final values for the median life used in NONROAD for these selected applications
are shown in Table 4. Lower or higher power level engines use the default values from ARB per
Tables 1 and 2 above.
Table 4. Median Life for the Bulk of Several Small Spark-Ignition Engine Applications
Application
Lawn Mowers
Trimmer/Edger/Cutter
Chainsaws
Use
Residential
Commercial
Residential
Commercial
Residential
Commercial
Power
(min.)
1
1
0
0
0
0
Power
(max.)
6
6
o
J
o
J
6
6
Median Life
(Hours at Full Load)
47.9
268
35.3
286.8
39.2
191
Median Life
(Years) (5, 6)
5.8
2
4.3
2.3
4.3
0.9
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Leaf Blower/Vacuum
Tillers
Snowblowers
Commercial Turf
Rear Engine Rider
Lawn and Garden
Tractor
Residential
Commercial
Residential
Commercial
Residential
Commercial
Commercial
Residential
Commercial
Residential
Commercial
0
0
0
0
0
0
3
3
6
3
6
6
6
11
11
6
6
25
16
16
25
25
40.4
609.7
39.4
830.7
12.3
209.4
988.9
79.3
627
114.8
920
4.3
2.3
5.8
4.4
4.4
4.4
2.9
5.8
2.9
5.8
2.9
Recreational Marine Stern-Drive/Inboard Engines (SD/I)
For purposes of median life the previous publicly available version of NONROAD
treated gasoline-powered stern-drive and inboard engines the same as spark-ignition engines over
50 hp. Per Table 1 this meant they were assigned a median life of 3,000 hours at full load. Upon
review, it became apparent that when annualized, this result was implausible; this median life,
divided by the product of activity and load factor, gave an annualized estimate of 300 years
(3,000 hours/(48 hr/yearxQ.21) = 300 years). To address this issue, NONROAD2002 assumes a
median life of 20 years (197 hrs at full load) for all gasoline SD/I engines.
Recreational Equipment
The median life values used for snowmobiles, all-terrain vehicles (ATVs), and offroad
motorcycles are given in Table 5. These estimates were developed for the proposed rulemaking
for large spark-ignition and recreational engines (19). Since the final rule was just completed in
September 2002, changes that have occurred subsequent to the proposal have not been
incorporated in this version of the model. The regulatory support document for the final rule
provides a detailed description of the most recent median life estimates (21).
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Table 5. Median Life for Snowmobiles, All-Terrain Vehicles, and Offroad Motorcycles
Application
Snowmobiles
All-Terrain Vehicles
Offroad Motorcycles
Median Life
(Hours at Full Load or Miles)
174 hours
20,4 10 miles
21,600 miles
Median Life
(Years)
9
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9
Equipment Activity
Activity represents annual equipment usage expressed in hours of operation (hours/year).
Except as noted below, we use equipment activity estimates from a 1998 database developed by
Power Systems Research, Inc. (PSR), an independent research firm, as default input values in
draft NONROAD2002. The PSR data represents the most comprehensive review of application-
specific activity available to EPA. PSR conducts several yearly surveys of equipment owners
and determines a mean usage rate for engines by application and fuel type(7). The PSR
methodology is described and evaluated in a report produced by E.H. Pechan & Associates (8).
We are unaware of activity estimates specific to LPG and CNG engines. These engines
are similar to gasoline engines in that they employ spark-ignition. Because LPG and CNG
engines are presumably used in applications where gasoline engines are used, we assume that
their usage rates are similar to those for gasoline engines.
The activities in the draft NONROAD2002 model for each equipment type are provided
in Appendix A.
Load Factor
Rated power is the maximum power level that an engine is designed to produce at its
rated speed. Engines typically operate at a variety of speeds and loads, and operation at rated
power for extended periods is rare. To take into account the effect of operation at idle and partial
load conditions, as well as transient operation, a load factor is developed to indicate the average
proportion of rated power used. For example, at a 0.3 (or 30 percent) load factor, an engine rated
at 100 hp would be producing an average of 30 hp over the course of normal operation. Load
factor can vary widely for nonroad engines, depending on their usage patterns.
PSR also estimates the load factor from surveys of equipment users. PSR calculates the
fraction of load from the estimate of hours of usage per year, the fuel consumption per year, and
the fuel consumption rate at rated power for each engine in the field. A median fraction of
available power is determined for specific applications. The load factor is determined from
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actual and maximum fuel consumption rates for various pieces of equipment. For reference, the
PSR methodology is explained in detail in the Pechan report(8).
For the draft NONROAD2002 model, PSR load factors were used with the exceptions
described below. As was the case for activity levels, LPG and CNG engines are assigned the
load factors for gasoline engines. The load factors in the draft NONROAD2002 model for each
equipment type are also provided in Appendix A.
Small (<25 hp) Spark-Ignition Engines
The activity for small spark-ignition engines, mainly lawn and garden equipment, were
derived from data supplied to EPA during the comment period for the regulation of these
applications. The supporting documentation for those regulations include estimates of activity for
a few important applications(5). These alternate values are shown in Table 6 and represent a
departure from the PSR values. For applications not shown in Table 6, PSR values were used
because the PSR survey includes such categories as construction, agricultural, commercial, and
many other engines applications that were not included in the data submitted for the rulemaking.
The load factors for lawn mowers, tillers, snowblowers, rear engine riders, and lawn and
garden tractors in Table 6 were also derived from the same data supplied to EPA during the
comment period for the regulation of small SI engines.
Table 6. Usage and Load Factors for Several Small Spark-Ignition Engine Applications
Application
Lawn Mowers
Trimmer/Edger/Cutter
Chainsaws
Leaf Blower\ Vacuum
Tillers
Use
Residential
Commercial
Residential
Commercial
Residential
Commercial
Residential
Commercial
Residential
Commercial
Annual Hours
25
406
9
137
13
303
10
282
17
472
Load Factor
(fraction of power)
0.33
0.33
0.91
0.91
0.70
0.70
0.94
0.94
0.40
0.40
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Snowblowers
Commercial Turf
Rear Engine Rider
Lawn and Garden Tractor
Residential
Commercial
Commercial
Residential
Commercial
Residential
Commercial
8
136
682
36
569
45
721
0.35
0.35
0.60
0.38
0.38
0.44
0.44
For the three most populous handheld applications (i.e., chainsaws,
trimmers/edgers/brush cutters, and blowers/vacuums), the previous version of NONROAD
assumed a load factor of 0.50. The estimate of 0.50 was supplied by manufacturers to the
California Air Resource Board in 1990 and is based on manufacturers' belief that it accurately
reflects the typical usage pattern of most portable two-stroke power equipment. In support of a
more recent effort to analyze the test cycle currently used for certification of Phase 1 handheld
engines, manufacturers monitored the in-use operation of a number of chainsaws,
trimmers/edgers/brush cutters, and blowers/vacuums to determine the appropriate weighting of
wide open throttle (WOT) and idle operation for certification testing purposes. Based on this
information, the load factors for chainsaws, trimmers/edgers/brush cutters, and blowers/vacuums
are now 0.70, 0.91, and 0.94, respectively (6).
For commercial turf equipment, the previous load factor of 0.50 was revised to 0.60,
based on 1998 PSR data.
Many of the small spark-ignited engines are used in lawn and garden equipment
applications, and lawn and garden equipment is used both by commercial and residential users.
The commercial users are grounds keepers for nonresidential, large apartment complexes, and
some single-family homes. Commercial equipment therefore has significantly different usage in
terms of hours per year and weekday and weekend day than residential equipment. To account
for these differences in equipment usage, separate SCC's are used to distinguish commercial
from residential lawn and garden equipment.
Recreational Marine Engines
As described in the technical report on nonroad engine populations (2) , recreational
marine engines are divided into three applications; inboard, outboard, and personal watercraft.
Due to the similarity of engines, the inboard category includes the inboard/outboard sterndrive
engines formerly considered as a separate SCC category. The inboard engines are associated
with the PSR category "powerboats."
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The June 1998 draft of the NONROAD model used fuel consumption data to estimate
activity for outboard engines (9). The April 1999 draft version and subsequent drafts of the
model have used activity data collected during the recreational marine rulemaking process,
provided by the National Marine Manufacturers Association and individual marine vessel
manufacturers (10). Draft NONROAD2002 continues to use these estimates, which are shown in
Table 7.
Table 7. Recreational Marine Activity and Load Factors
Recreational Marine
Engine/Equipment Type
Four-stroke Inboards
Two-stroke Outboards
Personal Watercraft
Activity
(hours/year)
47.6
34.8
77.3
Load Factor
(fraction of
power)
0.21
0.21
0.21
Based on other comments, we revised the load factor to reflect the average load for the
marine engine certification test cycle (20.7%). In-use data for load factor arenot available., and
the PSR estimates of load factor (32% for outboard, 38% for inboard, and 42% for personal
water craft) are not currently documented.
Recreational Equipment
In the course of the rulemaking process for recreational equipment and large spark-
ignition engines, the activity and load factor estimates for recreational equipment (i.e.,
snowmobiles, all-terrain vehicles, and off-road motorcycles) have been updated in Draft
NONROAD2002 (11,12). In estimating operating hoursfor recreational vehicles, a number of
sources are available for each vehicle type.
For snowmobiles activity information is available from (a) studies on the economic
impact of snowmobile operation in seven states (12-18), (b) consumer-satisfaction survey results
from the snowmobile industry, and (c) snowmobile enthusiasts' self-reported usage estimates
compiled and provided by the Bluewater Network (an environmental organization). These
sources presented usage information in terms of average or typical miles ridden per year. To
convert the mileage estimates to operating hours, we estimated the average speed for typical
snowmobile operation.
The information available on average speed was collected on instrumented machines
during development of an emissions test cycle for snowmobiles, performed by Southwest
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Research Institute under sponsorship of the International Snowmobile Manufacturers Association
(11). The cycle development work encompassed operation over varied conditions, including
moderate and aggressive trail riding, lake riding, off-trail freestyle riding, and operation with
single and double riders. Sled speeds ranged from 14 to 32 mph, although the bulk of the data
falls between 20 and 30 mph. Because of the large variation in speed estimates, it is difficult to
determine what average speed is the most representative. We know that the correct speed is
somewhere within this range and that the mode of the estimates fell at the midpoint of the range.
Therefore, we are using an average speed of 23 mph for snowmobile operation. We believe that
this value is reasonable and it is supported by the snowmobile manufacturers per a recent
discussion .
Having estimated average speed, it is possible to convert the estimated average yearly
mileage into yearly operating hours. The range of average yearly mileage estimates available to
us is 540 to 1,800 miles. Manufacturers have indicated that for winters with average or above
average snowfall, the average yearly mileage is approximately 1,500 miles and that for poorer
winters, with less than average snowfall, the average yearly mileage is approximately 1,200
miles. These estimates fall well within the range of estimates given above . In fact, several of
the state economic studies indicated that their estimates for mileage were low due to poor
snowfall during the winter in which they performed their studies. Therefore, we estimate the
average yearly travel distance for snowmobiles at 1,300 miles. Given an average speed of 23 mph
and an average mileage of 1,300 miles, we estimate the average yearly activity at 57 hours per
year.
For snowmobiles, the load factor of 0.34 is derived from data collected during the cycle
development project described above (11).
Based on data that has become available since the publication of the Proposed Rule for
control of emissions from recreational engines, we have revised the activity estimate for all-
terrain vehicles (ATVs). For reference, the prior estimate, which is superseded by the estimate
described in this report and referenced Rule documents, is presented and described in the docket
memorandum Emission Modeling for Recreational Vehicles (EPA420-F-00-051, Docket A-98-
Ol).1
Data sources used to derive the revised estimate include: (a) A phone survey sponsored
by Honda in which owners of TRX model utility ATVs were requested to report odometer and
hour-meter readings, (b) a database of warranty claim information provided by another
manufacturer, which included odometer and hour-meter readings, (c) a national survey of ATV
population and usage sponsored by the Consumer Product Safety Commission (20), and (d) a
"market panel" survey of ATV usage sponsored by major manufacturers. The manufacturers'
This memorandum supplements the Advance Notice of Proposed Rulemaking: Control of Emissions from
Nonroad Large Spark Ignition Engines, Recreational Engines (Marine and Land-based), and Highway Motorcycles
(November 20, 2000). See http://www.otaq.gov/otaq/recveh.htm.
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survey was performed during the same time period as the CPSC study, employed similar
interview methods and obtained very similar results.
Based on these sources, ATV activity has been re-estimated at 1,570 miles/year. This
value is intended to represent a national annual average, and may be further revised following
additional analyses in support of the rulemaking. For a more detailed description of the
derivation of this estimate and any minor updates to it, see the Final Regulatory Support
Document: Control of Emissions from Unregulated Nonroad Engines (21).
For off-road motorcycles, there are two sources of information on activity or usage rates.
The first source is information provided by the Motorcycle Industry Council (MIC). MIC
periodically conducts surveys on motorcycle usage. . MIC uses two methods to estimate off-
road motorcycle usage from the survey results. Method one is based on the results of a single
question that asks the respondent how many miles they rode in the last year. Method two is
based on the multiplication of the responses from three questions: (a) during how many months
of the year did the respondent ride?, (b) how many days during a typical month did the
respondent ride?, and (c) how many hours did the respondent ride in a typical day? The estimate
from method one is 222 miles per year and that from method two is 1,260 miles per year. MIC
has suggested that method one is the more appropriate estimate because method two may
compound any error that exists in the results of each of the three questions. We have concerns
with the results of the MIC survey because the values for method one and two are dramatically
different. Activity expressed in miles/year is consistent with corresponding emission factors for
off-road motorcycles, which are expressed in grams/mile.
The second source of information is a study done in 1994 by the Oak Ridge National
Laboratory (ORNL) titled, "Fuel Used for Off-Road Recreation" (22). This study estimated total
average fuel usage for off-road motorcycles at 59 gallons/year, which ORNL considers to be a
"medium" estimate. Recent data from California (), combined with older data collected at
Southwest Research Institute (SwRI), suggest that the average fuel economy for off-road
motorcycles is approximately 50 miles per gallon (mpg), as tested over the Federal Test
Procedure (FTP). This estimate may be too high for actual operation off-road, so we assume an
estimate of 40 mpg. By multiplying the annual average fuel usage by the average fuel economy,
we arrive at an estimate of approximately 2,400 miles per year.
Due to uncertainty related to interview methods in the MIC survey, we have estimated
motorcycle activity based on fuel use as estimated by ORNL, and fuel economy estimated in-use
and on the FTP, as described above. Thus, we estimate annual activity at 2,400 miles per year for
two and four-stroke off-road motorcycles. As of this writing, this estimate is under review and
may be revised to incorporate analyses supporting the final rule covering recreational vehicles.
For ATVs and off-road motorcycles, load factors are no longer necessary, since the
emission factors are expressed as grams per mile. As a result, for these equipment types, load
factors and average rated horsepowers are simply set to 1.0 in the input file. This modification
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effectively converts the emissions calculation from a power-output basis to a distance-traveled
basis, similar to that used for cars and trucks. The operating hours, mileage, and load factors used
for recreational vehicles are listed in Table 8.
Table 8. Activity and Load Factors for Recreational Vehicles
Application
ATVs
Off-Road
Motorcycles
Snowmobiles
Type
2 & 4-stroke
2 & 4-stroke
2-stroke
Load Factor
1.0*
1.0*
0.34
Hours per Year
—
—
57
Mileage per Year
1,570
2,400
—
* Average rated horsepower is also set at 1.0, effectively removing power output (rated power * load factor) from
the equation; emissions are thus calculated on the basis of EF*Act*Population, where units equal
g/mile*miles/year = g/year, which the model converts to tons/year.
Compression-Ignition (CD Equipment
For CI equipment, we are using activity estimates from the 1998 PSR database.
The PSR CI load factors used in previous versions of NONROAD, which are based on
information obtained from surveys of equipment owners, have been replaced by load factors
obtained from actual engine testing over several transient cycles. The transient cycle
development and engine tests were conducted by Southwest Research Institute under contract to
EPA (with some of the cycle development work also co-sponsored by the Engine Manufacturers
Association) (23, 24, 25). Seven transient cycles were developed: agricultural tractor, backhoe
loader, crawler dozer, rubber-tire loader, skid-steer loader, arc welder, and excavator. For the
rubber-tire loader, skid-steer loader, and arc welder cycles, both "typical transient" and "high
transient" versions of the cycles were developed; for this work, the typical versions were used.
The load factors for the seven transient cycles are given in Table 9. The seven load
factors were further binned into three categories, "High," "Low," and "steady-state " (represented
by an average of the seven cycles). . We consider this approach simpler and more defensible,
given the limited number of cycles designed to represent in-use operation for specific equipment
types and uncertainty in extrapolating the test data to broader equipment populations. This
approach is also consistent with that used to develop the new transient adjustment factors in the
model . The high load factor bin includes the following cycles: agricultural tractor (LF=0.78),
crawler dozer (LF=0.58), rubber-tire loader (LF=0.48), and excavator (LF=0.53). The low load
factor bin includes the remaining cycles: backhoe/loader (LF=0.21), skid-steer loader (LF=0.23),
and arc welder (LF=0.19). The "high" load factor cycles were averaged to obtain a composite
High LF (0.59). Similarly, the "low" load factor cycles were averaged to obtain a composite
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Low LF (0.21). The load factors for all seven cycles were averaged to obtain a composite 7-cycle
average "steady-state" LF (0.43). See Table 9.
Table 9. Compression-Ignition Load Factors
Cycle
Agricultural
Tractor
Crawler Dozer
Rubber-tired
Loader
Excavator
Cycle Load Factors
0.78
0.58
0.48
0.53
Assignment
High
Average
0.59
Backhoe
Loader
Skid-steer
Loader
Arc Welder
0.21
0.23
0.19
Low
0.21
7-cycle average
—
Steady- state
0.43
Each diesel nonroad equipment type was assigned one of these three composite load
factors (Hi LF, Lo LF, or 7-cycle average). To apply these load factors, we matched nonroad
applications with the test cycle that most closely represents the nonroad activity for the
application. Table 10 lists the diesel nonroad applications used in the NONROAD model and the
load factor assignment considered representative of that application. If steady-state operation is
typical of an application, the 7-cycle average load factor was assigned.
The resulting load factors for each equipment type are provided in Appendix A.
14
-------
Table 10. CI Load Factor Assignments by Equipment Type
sec
2270001000
2270001020
2270001030
2270001040
2270001050
2270001060
2270002003
2270002006
2270002009
2270002015
2270002018
2270002021
2270002024
2270002027
2270002030
2270002033
2270002036
2270002039
2270002042
2270002045
2270002048
2270002051
2270002054
2270002057
2270002060
2270002063
2270002066
2270002069
2270002072
2270002075
2270002078
2270002081
2270003010
2270003020
2270003030
2270003040
2270003050
2270003060
2270003070
2270004000
2270004010
227000401 1
2270004015
2270004016
2270004020
2270004021
Equipment Type
Recreational Vehicles All
Recreational Vehicles Snowmobiles
Recreational Vehicles All Terrain Vehicles
Recreational Vehicles Minibikes
Recreational Vehicles Golf Carts
Recreational Vehicles Speciality Vehicle Carts
Construction Equipment Pavers
Construction Equipment Tampers/Rammers
Construction Equipment Plate Compactors
Construction Equipment Rollers
Construction Equipment Scrapers
Construction Equipment Paving Equipment
Construction Equipment Surfacing Equipment
Construction Equipment Signal Boards
Construction Equipment Trenchers
Construction Equipment Bore/Drill Rigs
Construction Equipment Excavators
Construction Equipment Concrete/Industrial Saws
Construction Equipment Cement & Mortar Mixers
Construction Equipment Cranes
Construction Equipment Graders
Construction Equipment Off-highway Trucks
Construction Equipment Crushing/Proc. Equipment
Construction Equipment Rough Terrain Forklifts
Construction Equipment Rubber Tire Loaders
Construction Equipment Rubber Tire Dozers
Construction Equipment Tractors/Loaders/Backhoes
Construction Equipment Crawler Dozer
Construction Equipment Skid Steer Loaders
Construction Equipment Off-Highway Tractors
Construction Equipment Dumpers/Tenders
Construction Equipment Other Construction Equipment
Industrial Equipment Aerial Lifts
Industrial Equipment Forklifts
Industrial Equipment Sweepers/Scrubbers
Industrial Equipment Other General Industrial Equipment
Industrial Equipment Other Material Handling Equipment
Industrial Equipment AC\Refrigeration
Terminal Tractors
Lawn & Garden Equipment ALL
Lawn & Garden Equipment Lawn mowers (Residential)
Lawn & Garden Equipment Lawn mowers (Commercial)
Lawn & Garden Equipment Rotary Tillers < 6 HP
Lawn & Garden Equipment Rotary Tillers < 6 HP
Lawn & Garden Equipment Chain Saws < 6 HP
Lawn & Garden Equipment Chain Saws < 6 HP
Representative
Cycle
Backhoe
None
None
None
None
Backhoe
Crawler
None
None
Crawler
Crawler
Crawler
Crawler
None
Crawler
None
Excavator
Crawler
None
None
Crawler
Crawler
None
RTLoader
RTLoader
Crawler
Backhoe
Crawler
SSLoader
Crawler
Backhoe
Crawler
Backhoe
RTLoader
None
None
Backhoe
None
Crawler
None
None
None
None
None
None
None
Load Factor
Assignment
LoLF
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
LoLF
HiLF
Avg 7-cycle
Avg 7-cycle
HiLF
HiLF
HiLF
HiLF
Avg 7-cycle
HiLF
Avg 7-cycle
HiLF
HiLF
Avg 7-cycle
Avg 7-cycle
HiLF
HiLF
Avg 7-cycle
HiLF
HiLF
HiLF
LoLF
HiLF
LoLF
HiLF
LoLF
HiLF
LoLF
HiLF
Avg 7-cycle
Avg 7-cycle
LoLF
Avg 7-cycle
HiLF
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
15
-------
Table 10. CI Load Factor Assignments by Equipment Type
sec
2270004025
2270004026
2270004030
2270004031
2270004035
2270004036
2270004040
2270004041
2270004045
2270004046
2270004050
2270004051
2270004055
2270004056
2270004060
2270004061
2270004065
2270004066
2270004071
2270004075
2270004076
2270005010
2270005015
2270005020
2270005025
2270005030
2270005035
2270005040
2270005045
2270005050
2270005055
2270005060
2270006000
2270006005
2270006010
2270006015
2270006020
2270006025
2270006030
2270007005
2270007010
2270007015
2270008005
2270009010
2270010010
2282020005
Equipment Type
Lawn & Garden Equipment Trimmers/Edgers/Brush
Lawn & Garden Equipment Trimmers/Edgers/Brush
Lawn & Garden Equipment Leafblowers/Vacuums
Lawn & Garden Equipment Leafblowers/Vacuums
Lawn & Garden Equipment Snowblowers
Lawn & Garden Equipment Snowblowers (Commercial)
Lawn & Garden Equipment Rear Engine Riding Mowers
Lawn & Garden Equipment Rear Engine Riding Mowers
Lawn & Garden Equipment Front Mowers
Lawn & Garden Equipment Front Mowers (Commercial)
Lawn & Garden Equipment Shredders < 6 HP
Lawn & Garden Equipment Shredders < 6 HP
Lawn & Garden Equipment Lawn & Garden Tractors
Lawn & Garden Equipment Lawn & Garden Tractors
Lawn & Garden Equipment Wood Splitters
Lawn & Garden Equipment Wood Splitters (Commercial)
Lawn & Garden Equipment Chippers/Stump Grinders
Lawn & Garden Equipment Chippers/Stump Grinders
Lawn & Garden Equipment Commercial Turf Equipment
Lawn & Garden Equipment Other Lawn & Garden
Lawn & Garden Equipment Other Lawn & Garden
Farm Equipment 2-Wheel Tractors
Farm Equipment Agricultural Tractors
Farm Equipment Combines
Farm Equipment Balers
Farm Equipment Agricultural Mowers
Farm Equipment Sprayers
Farm Equipment Tillers > 6 HP
Farm Equipment Swathers
Farm Equipment Hydro Power Units
Farm Equipment Other Agricultural Equipment
Farm Equipment Irrigation Sets
Light Commercial ALL
Light Commercial Generator Sets
Light Commercial Pumps
Light Commercial Air Compressors
Light Commercial Gas Compressors
Light Commercial Welders
Light Commercial Pressure Washers
Logging Equipment Chain Saws > 6 HP
Logging Equipment Shredders > 6 HP
Logging Equipment Forest Equipment
Airport Service Equipment Airport Support Equipment
Other Underground Mining Equipment
Other Oil Field Equipment
Recreational Pleasure Craft, Inboards
Representative
Cycle
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
None
AgTractor
AgTractor
AgTractor
AgTractor
AgTractor
AgTractor
AgTractor
AgTractor
None
AgTractor
None
None
None
None
None
None
ArcWelder
None
RTLoader
RTLoader
RTLoader
RTLoader
Backhoe
None
None
Load Factor
Assignment
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
HiLF
HiLF
HiLF
HiLF
HiLF
HiLF
HiLF
HiLF
Avg 7-cycle
HiLF
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
LoLF
Avg 7-cycle
HiLF
HiLF
HiLF
HiLF
LoLF
Avg 7-cycle
Avg 7-cycle
16
-------
Table 10. CI Load Factor Assignments by Equipment Type
sec
2282020010
2282020015
2282020025
2285002015
Equipment Type
Recreational Pleasure Craft, Outboards
Recreational Pleasure Craft, Personal Water Craft
Recreational Pleasure Craft, Sailboat Aux. Outboard
Railway Maintenance
Representative
Cycle
None
None
None
Backhoe
Load Factor
Assignment
Avg 7-cycle
Avg 7-cycle
Avg 7-cycle
LoLF
References
(1) U. S. EPA. "Growth and Scrappage Methodology Report for NONROAD," Office of
Transportation and Air Quality, Assessment & Standards Division. NONROAD
Technical Report NR-007a, May 2002.
(2) U. S. EPA. "Nonroad Engine Population Estimates," Office of Transportation and Air
Quality, Assessment & Standards Division. NONROAD Technical Report NR-006b,
May 2002.
(3) California Air Resources Board. (CARB). "Documentation of Input Factors for the New
Off-Road Mobile Source Emissions Inventory Model," Energy and Environmental
Analysis, Inc., February, 1997. Table 3-1, page ??.
(4) Energy and Environmental Analysis, Inc. "Documentation of Diesel Engine Life Values
Used in the ARE Off-Highway Model." Unpublished Report, prepared for U. S.
Environmental Protection Agency, Office of Transportation and Air Quality, September
2001.
(5) U. S. Environmental Protection Agency. "Phase 2 Emission Standards for New
Nonhandheld Engines at or below 19 Kilowatts (kW)." Office of Mobile Sources,
Regulatory Impact Analysis, EPA420-R-99-003, March 1999.
(6) U. S. EPA. "Phase 2 Final Rule: Emission Standards for New Nonroad Handheld
Spark-Ignition Engines At or Below 19 Kilowatts." Office of Transportation and Air
Quality. Final Regulatory Impact Analysis, EPA420-R-00-004. March 2000.
(7) Power Systems Research, Inc. "Reference Guide, U.S. PartsLink" Edition 6.2 St. Paul,
MN.
(8) E.H. Pechan & Associates. "Evaluation of Power Systems Research (PSR) Nonroad
Population Data Base," prepared for U.S. Environmental Protection Agency, Office of
17
-------
Mobile Sources. EPA Contract No. 68-D3-0035, Work Assignment No. HJ-107, Pechan
Report No. 97.09.003/1807. September, 1997.
(9) United States Environmental Protection Agency. "Median Life, Annual Activity, and
Load Factor Values for Nonroad Engine Emissions Modeling," Office of Mobile Sources,
Assessment & Modeling Division. NONROAD Technical Report NR-005A. June 15,
1998.
(10) United States Environmental Protection Agency. "Regulatory Impact Analysis: Control of
Air Pollution Emission Standards for New Nonroad Spark-Ignition Marine Engines."
Office of Air and Radiation. ANR-443. June 1996.
(11) United States Environmental Protection Agency. "Emission Modeling for Recreational
Vehicles," Memorandum to Public Docket A-98-01. EPA420-F-00-051, November 13,
2000.2
(12) Me Elvany, Norman D. 1995. Snowmobiling in Vermont: An Economic Study and
Snowmobile User Survey. Johnson State College, Johnson, VT. Prepared for Vermont
Association of Snow Travelers (VAST).
(13) Robertson, Robert A. Assessment of Snowmobiling in New Hampshire "1996:" Summary
and Recommendations. Tourism Planning and Development Program, Department of
Resource Economics and Development, University of New Hampshire, Durham.
Prepared for the New Hampshire Snowmobile Association. August, 1996.
(14) Sylvester, James T. Snowmobile Gasoline Usage in Montana. Bureau of Business and
Economic Research, University of Montana, Missoula. Prepared for Montana
Department of Fish, Wildlife and Parks, and Montana Snowmobile Association.
September 28, 1996.
(15) Reiling, Stephen; Kotchen, Matthew; Kezis, Alan. An Economic Evaluation of
Snowmobiling in Maine. Department of Resource Economics and Policy, University of
Maine, Orono. Maine Agricultural and Forest Experiment Station No. 2069. Prepared for
the Maine Snowmobile Association. January, 1997.
(16) Nelson, Charles M., Lynch, Joel A., Stynes, Daniel J. An Assessment of Snowmobiling
in Michigan by Snowmobilers with Michigan Trail Permits. Department of Park,
Recreation and Tourism Resources, Michigan State University, East Lansing. Prepared
This memorandum supplements the Advance Notice of Proposed Rulemaking: Control of Emissions from
Nonroad Large Spark Ignition Engines, Recreational Engines (Marine and Land-based), and Highway Motorcycles
(November 20, 2000). See http://www.otaq.gov/otaq/recveh.htm.
18
-------
for Michigan Department of Natural Resources, Forest Management Division. February
10, 1998.
(17) Merwin Rural Services Institute. Snowmobiling in New York: An Analysis of Economic
Impact and Overview of the Industry in the Empire State. State University of New York,
Potsdam. Prepared for New York State Snowmobile Association, Inc. April, 1998.
(18) Loomis, David K; Lundrigan, Heather. 1999 Assessment of Snowmobiling in
Massachusetts. Human Dimensions Research Unit, Department of Natural Resources
Conservation University of Massachusetts, Amherst. Prepared for Snowmobiling
Association of Massachusetts. March 30, 2000.
(19) United States Environmental Protection Agency. "Draft Regulatory Support Document:
Control of Emissions from Nonroad Large Spark Ignition Engines, Recreational Engines
(Marine and Land-based), and Highway Motorcycles." Office of Transportation & Air
Quality, Assessment & Standards Division. EPA420-D-01-004, September 2001.
(20) United States Consumer Product Safety Commission. "Report on 1997 ATV Exposure
Survey." Directorate for Economic Analysis, Bethesda, Maryland. April 1998.
(21) United States Environmental Protection Agency. "Final Regulatory Support Document:
Control of Emissions from Unregulated Nonroad Engines." EPA420-R-02-022,
September 2002.
(22) Oak Ridge National Laboratory. "Fuel Used for Off-Highway Recreation" Center for
Transportation Analysis, Statistics and Data Analysis Group. ORNL-6794. July, 1994.
(23) Fritz, S.G. and M.E. Starr, "Emission Factors for Compression Ignition Nonroad Engines
Operated on Number 2 Highway and Nonroad Diesel Fuel," Southwest Research
Institute. SwRI 08-7601-822, March 1998.
(24) Starr, Michael E., "Nonroad Engine Emissions Testing," Southwest Research Institute.
SwRI???-??? September 1999.
(25) Starr, Michael E., "Excavator Cycle Development," Southwest Research Institute. SwRI
2206-801, September 1999.
19
-------
20
-------
Appendix A
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2260001010
2260001020
2260001030
2260001050
2260001060
2260002003
2260002006
2260002009
2260002012
2260002015
2260002018
2260002021
2260002024
2260002027
2260002030
2260002033
2260002036
2260002039
2260002042
2260002045
2260002048
2260002051
2260002054
2260002057
2260002060
2260002063
2260002066
2260002069
2260002072
2260002075
2260002078
2260002081
2260003010
2260003020
2260003030
2260003040
2260003050
2260003060
2260003070
2260004010
2260004011
2260004015
2260004016
2260004020
2260004021
2260004025
2260004026
2260004030
2260004031
Equipment Description
2 -Stroke Motorcycles: Off -Road
2 -Stroke Snowmobiles
2 -Stroke All Terrain Vehicles
2 -Stroke Golf Carts
2 -Stroke Specialty Vehicle Carts
2 -Stroke Asphalt Pavers
2 -Stroke Tampers /Rammers
2 -Stroke Plate Compactors
2 -Stroke Concrete Pavers
2 -Stroke Rollers
2 -Stroke Scrapers
2 -Stroke Paving Equipment
2 -Stroke Surfacing Equipment
2 -Stroke Signal Boards
2 -Stroke Trenchers
2 -Stroke Bore/Drill Rigs
2 -Stroke Excavators
2 -Stroke Concrete/Industrial Saws
2 -Stroke Cement & Mortar Mixers
2 -Stroke Cranes
2 -Stroke Graders
2 -Stroke Off -highway Trucks
2 -Stroke Crushing/Proc . Equipment
2-Stroke Rough Terrain Forklifts
2 -Stroke Rubber Tire Loaders
2 -Stroke Rubber Tire Dozers
2 -Stroke Tractors/Loaders/Backhoes
2 -Stroke Crawler Dozer
2 -Stroke Skid Steer Loaders
2 -Stroke Off -Highway Tractors
2 -Stroke Dumpers /Tenders
2 -Stroke Other Construction Equipment
2 -Stroke Aerial Lifts
2-Stroke Forklifts
2 -Stroke Sweepers /Scrubbers
2-Stroke Other General Industrial Equipment
2-Stroke Other Material Handling Equipment
2-Stroke Refrigeration
2-Stroke Terminal Tractors
2-Stroke Lawn mowers (Residential)
2-Stroke Lawn mowers (Commercial)
2-Stroke Rotary Tillers < 6 HP (Residential)
2-Stroke Rotary Tillers < 6 HP (Commercial)
2-Stroke Chain Saws < 6 HP (Residential)
2-Stroke Chain Saws < 6 HP (Commercial)
2-Stroke Trimmers/Edgers/Brush Cutters
2-Stroke Trimmers/Edgers/Brush Cutters
2-Stroke Leaf blowers/Vacuums (Residential)
2-Stroke Leaf blowers/Vacuums (Commercial)
Load Factor
(fraction of powerl
1 .00
0 .34
1 .00
0 .46
0.58
0.66
0 .55
0 .55
0.55
0.62
0 .70
0 .59
0 .49
0.72
0.66
0.79
0.53
0 .78
0 .59
0 .47
0 .64
0.80
0.85
0.63
0.71
0 .75
0 .48
0 .80
0 .58
0.70
0.41
0.48
0.46
0 .30
0 .71
0 .54
0 .53
0.46
0.78
0.33
0.33
0 .40
0 .40
0 .70
0 .70
0.91
0.91
0.94
0.94
Activity
(hours /vearl
2400*
57
7000*
1080
65
392
160
166
0
621
540
175
488
318
402
107
378
610
84
415
504
450
241
413
512
900
870
700
310
155
127
371
361
1800
516
713
386
605
827
25
406
17
472
13
303
9
137
10
282
21
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2260004035
2260004036
2260004040
2260004041
2260004045
2260004046
2260004050
2260004051
2260004055
2260004056
2260004060
2260004061
2260004065
2260004066
2260004070
2260004071
2260004075
2260004076
2260005010
2260005015
2260005020
2260005025
2260005030
2260005035
2260005040
2260005045
2260005050
2260005055
2260005060
2260006005
2260006010
2260006015
2260006020
2260006025
2260006030
2260007005
2260007010
2260007015
2260007020
2260008005
2260009010
2260010010
2265001010
2265001020
2265001030
2265001050
2265001060
2265002003
2265002006
2265002009
2265002012
2265002015
Equipment Description
2 -Stroke Snowblowers (Residential)
2 -Stroke Snowblowers (Commercial)
2-Stroke Rear Engine Riding Mowers (Res.)
2-Stroke Rear Engine Riding Mowers (Comm. )
2 -Stroke Front Mowers (Residential)
2-Stroke Front Mowers (Commercial)
2-Stroke Shredders < 6 HP (Residential)
2-Stroke Shredders < 6 HP (Commercial)
2-Stroke Lawn & Garden Tractors (Residential)
2-Stroke Lawn & Garden Tractors (Commercial)
2-Stroke Wood Splitters (Residential)
2-Stroke Wood Splitters (Commercial)
2-Stroke Chippers /Stump Grinders (Res.)
2-Stroke Chippers /Stump Grinders (Comm.)
2-Stroke Commercial Turf Equipment (Res.)
2-Stroke Commercial Turf Equipment (Comm)
2-Stroke Other Lawn & Garden Equipment
2-Stroke Other Lawn & Garden Equipment
2-Stroke 2-Wheel Tractors
2-Stroke Agricultural Tractors
2-Stroke Combines
2-Stroke Balers
2-Stroke Agricultural Mowers
2-Stroke Sprayers
2-Stroke Tillers > 6 HP
2-Stroke Swathers
2-Stroke Hydro Power Units
2-Stroke Other Agricultural Equipment
2-Stroke Irrigation Sets
2-Stroke Light Commercial Generator Set
2-Stroke Light Commercial Pumps
2-Stroke Light Commercial Air Compressors
2-Stroke Light Commercial Gas Compressors
2-Stroke Light Commercial Welders
2-Stroke Light Commercial Pressure Wash
2-Stroke Logging Equipment Chain Saws > 6 HP
2-Stroke Logging Equipment Shredders > 6 HP
2-Stroke Logging Equipment Skidders
2-Stroke Logging Equipment Fellers/Bunchers
2-Stroke Airport Support Equipment
2-Stroke Other Underground Mining Equipment
2-Stroke Other Oil Field Equipment
4 -Stroke Motorcycles: Off -Road
4 -Stroke Snowmobiles
4 -Stroke All Terrain Vehicles
4 -Stroke Golf Carts
4 -Stroke Specialty Vehicle Carts
4 -Stroke Asphalt Pavers
4 -Stroke Tampers /Rammers
4 -Stroke Plate Compactors
4 -Stroke Concrete Pavers
4 -Stroke Rollers
Load Factor
(fraction of powert
0 .35
0 .35
0 .38
0 .38
0.65
0.65
0 .80
0 .80
0 .44
0 .44
0.69
0.69
0.78
0.78
0 .60
0 .60
0 .58
0 .58
0.62
0.62
0.74
0.62
0 .48
0 .65
0 .71
0 .52
0.56
0.55
0.60
0.68
0 .69
0 .56
0 .85
0 .68
0.85
0.70
0.80
0.70
0 .70
0 .56
0 .80
0 .90
1.00
0.34
1.00
0.46
0 .58
0 .66
0 .55
0 .55
0.55
0.62
Activity
(hours /vearl
8
136
36
569
86
86
50
50
45
721
76
76
488
488
682
682
61
61
286
550
125
68
175
80
43
95
450
124
716
115
221
484
6000
408
115
303
50
350
0
681
260
1104
2400
57
7000
1080
65
392
160
166
0
621
22
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2265002018
2265002021
2265002024
2265002027
2265002030
2265002033
2265002036
2265002039
2265002042
2265002045
2265002048
2265002051
2265002054
2265002057
2265002060
2265002063
2265002066
2265002069
2265002072
2265002075
2265002078
2265002081
2265003010
2265003020
2265003030
2265003040
2265003050
2265003060
2265003070
2265004010
2265004011
2265004015
2265004016
2265004020
2265004021
2265004025
2265004026
2265004030
2265004031
2265004035
2265004036
2265004040
2265004041
2265004045
2265004046
2265004050
2265004051
2265004055
2265004056
2265004060
2265004061
2265004065
Equipment Description
4 -Stroke Scrapers
4 -Stroke Paving Equipment
4 -Stroke Surfacing Equipment
4 -Stroke Signal Boards
4 -Stroke Trenchers
4 -Stroke Bore/Drill Rigs
4 -Stroke Excavators
4 -Stroke Concrete/Industrial Saws
4 -Stroke Cement & Mortar Mixers
4 -Stroke Cranes
4 -Stroke Graders
4 -Stroke Off -highway Trucks
4 -Stroke Crushing/Proc . Equipment
4-Stroke Rough Terrain Forklifts
4 -Stroke Rubber Tire Loaders
4 -Stroke Rubber Tire Dozers
4 -Stroke Tractors/Loaders/Backhoes
4 -Stroke Crawler Tractors
4 -Stroke Skid Steer Loaders
4 -Stroke Off -Highway Tractors
4 -Stroke Dumpers /Tenders
4 -Stroke Other Construction Equipment
4 -Stroke Aerial Lifts
4-Stroke Forklifts
4 -Stroke Sweepers /Scrubbers
4-Stroke Other General Industrial Equipment
4-Stroke Other Material Handling Equipment
4-Stroke Industial AC\Ref rigeration
4-Stroke Terminal Tractors
4-Stroke Lawn mowers (Residential)
4-Stroke Lawn mowers (Commercial)
4-Stroke Rotary Tillers < 6 HP (Residential)
4-Stroke Rotary Tillers < 6 HP (Commercial)
4-Stroke Chain Saws < 6 HP (Residential)
4-Stroke Chain Saws < 6 HP (Commercial)
4-Stroke Trimmers/Edgers/Brush Cutters
4-Stroke Trimmers/Edgers/Brush Cutters
4-Stroke Leaf blowers/Vacuums (Residential)
4-Stroke Leaf blowers/Vacuums (Commercial)
4-Stroke Snowblowers (Residential)
4-Stroke Snowblowers (Commercial)
4-Stroke Rear Engine Riding Mowers (Res.)
4-Stroke Rear Engine Riding Mowers (Comm)
4-Stroke Front Mowers (Residential)
4-Stroke Front Mowers (Commercial)
4-Stroke Shredders < 6 HP (Residential)
4-Stroke Shredders < 6 HP (Commercial)
4-Stroke Lawn & Garden Tractors (Residential)
4-Stroke Lawn & Garden Tractors (Commercial)
4-Stroke Wood Splitters (Residential)
4-Stroke Wood Splitters (Commercial)
4-Stroke Chippers /Stump Grinders (Res.)
Load Factor
(fraction of powert
0 .70
0 .59
0 .49
0 .72
0.66
0.79
0 .53
0 .78
0 .59
0 .47
0.64
0.80
0.85
0.63
0 .71
0 .75
0 .48
0 .80
0.58
0.70
0.41
0.48
0 .46
0 .30
0 .71
0 .54
0.53
0.46
0.78
0.33
0 .33
0 .40
0 .40
0 .70
0.70
0.91
0.91
0.94
0 .94
0 .35
0 .35
0 .38
0.38
0.65
0.65
0.80
0 .80
0 .44
0 .44
0 .69
0.69
0.78
Activity
(hours /vearl
540
175
488
318
402
107
378
610
84
415
504
450
241
413
512
900
870
700
310
155
127
371
361
1800
516
713
386
605
827
25
406
17
472
13
303
9
137
10
282
8
136
36
569
86
86
50
50
45
721
76
76
488
23
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2265004066
2265004070
2265004071
2265004075
2265004076
2265005010
2265005015
2265005020
2265005025
2265005030
2265005035
2265005040
2265005045
2265005050
2265005055
2265005060
2265006005
2265006010
2265006015
2265006020
2265006025
2265006030
2265007005
2265007010
2265007015
2265007020
2265008005
2265009010
2265010010
2270001020
2270001030
2270001050
2270001060
2270002003
2270002006
2270002009
2270002012
2270002015
2270002018
2270002021
2270002024
2270002027
2270002030
2270002033
2270002036
2270002039
2270002042
2270002045
2270002048
2270002051
2270002054
2270002057
Equipment Description
4-Stroke Chippers /Stump Grinders (Comm. )
4-Stroke Commercial Turf Equipment (Res.)
4 -Stroke Commercial Turf Equipment (Comm)
4-Stroke Other Lawn & Garden Equipment
4-Stroke Other Lawn & Garden Equipment
4-Stroke 2-Wheel Tractors
4-Stroke Agricultural Tractors
4-Stroke Combines
4-Stroke Balers
4-Stroke Agricultural Mowers
4-Stroke Sprayers
4-Stroke Tillers > 5 HP
4-Stroke Swathers
4-Stroke Hydro Power Units
4-Stroke Other Agricultural Equipment
4-Stroke Irrigation Sets
4-Stroke Light Commercial Generator Sets
4-Stroke Light Commercial Pumps
4-Stroke Light Commercial Air Compressors
4-Stroke Light Commercial Gas Compressors
4-Stroke Light Commercial Welders
4-Stroke Light Commercial Pressure Washers
4-Stroke Logging Equipment Chain Saws > 6 HP
4-Stroke Logging Equipment Shredders > 6 HP
4-Stroke Logging Equipment Skidders
4-Stroke Logging Equipment Fellers/Bunchers
4-Stroke Airport Support Equipment
4-Stroke Other Underground Mining Equipment
4-Stroke Other Oil Field Equipment
Diesel Snowmobiles (unused)
Diesel All Terrain Vehicles/MC (unused)
Diesel Golf Carts (unused)
Diesel Specialty Vehicle Carts
Diesel Pavers
Diesel Tampers /Rammers (unused)
Diesel Plate Compactors
Diesel Concrete Pavers (unused)
Diesel Rollers
Diesel Scrapers
Diesel Paving Equipment
Diesel Surfacing Equipment
Diesel Signal Boards
Diesel Trenchers
Diesel Bore/Drill Rigs
Diesel Excavators
Diesel Concrete/Industrial Saws
Diesel Cement & Mortar Mixers
Diesel Cranes
Diesel Graders
Diesel Off-highway Trucks
Diesel Crushing/Proc . Equipment
Diesel Rough Terrain Forklifts
Load Factor
(fraction of powert
0 .78
0 .60
0 .60
0 .58
0.58
0.62
0 .62
0 .74
0 .62
0 .48
0.65
0.71
0.52
0.56
0 .55
0 .60
0 .68
0 .69
0.56
0.85
0.68
0.85
0 .70
0 .80
0 .70
0 .70
0.56
0.80
0.90
0.34
0 .42
0 .49
0 .21
0 .59
0.43
0.43
0.59
0.59
0 .59
0 .59
0 .59
0 .43
0.59
0.43
0.59
0.59
0 .43
0 .43
0 .59
0 .59
0.43
0.59
Activity
(hours /vearl
488
682
682
61
61
286
550
125
68
175
80
43
95
450
124
716
115
221
484
6000
408
115
303
50
350
0
681
260
1104
40
0
1150
435
821
460
484
0
760
914
622
561
535
593
466
1092
580
275
990
962
1641
955
662
24
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2270002060
2270002063
2270002066
2270002069
2270002072
2270002075
2270002078
2270002081
2270003010
2270003020
2270003030
2270003040
2270003050
2270003060
2270003070
2270004010
2270004011
2270004015
2270004016
2270004020
2270004021
2270004025
2270004026
2270004030
2270004031
2270004035
2270004036
2270004040
2270004041
2270004045
2270004046
2270004050
2270004051
2270004055
2270004056
2270004060
2270004061
2270004065
2270004066
2270004070
2270004071
2270004075
2270004076
2270005010
2270005015
2270005020
2270005025
2270005030
2270005035
2270005040
2270005045
2270005050
Equipment Description
Diesel Rubber Tire Loaders
Diesel Rubber Tire Dozers
Diesel Tractors/Loaders/Backhoes
Diesel Crawler Tractors
Diesel Skid Steer Loaders
Diesel Off-Highway Tractors
Diesel Dumpers /Tenders
Diesel Other Construction Equipment
Diesel Aerial Lifts
Diesel Forklifts
Diesel Sweepers /Scrubbers
Diesel Other General Industrial Equipment
Diesel Other Material Handling Equipment
Diesel AC\Ref rigeration
Diesel Terminal Tractors
Diesel Lawn mowers (Residential)
Diesel Lawn mowers (Commerical)
Diesel Rotary Tillers < 6 HP (Residential)
Diesel Rotary Tillers < 6 HP (Commercial)
Diesel Chain Saws < 6 HP (Residential)
Diesel Chain Saws < 6 HP (Commercial)
Diesel Trimmers/Edgers/Brush Cutters (Res.)
Diesel Trimmers/Edgers/Brush Cutters (Comm. )
Diesel Leaf blowers/Vacuums (Residential)
Diesel Leaf blowers/Vacuums (Commercial)
Diesel Snowblowers (Residential)
Diesel Snowblowers (Commercial)
Diesel Rear Engine Riding Mowers (Res . )
Diesel Rear Engine Riding Mowers (Comm. )
Diesel Front Mowers (Residential)
Diesel Front Mowers (Commercial)
Diesel Shredders < 6 HP (Residential)
Diesel Shredders < 6 HP (Commercial)
Diesel Lawn & Garden Tractors (Residential)
Diesel Lawn & Garden Tractors (Commercial)
Diesel Wood Splitters (Residential)
Diesel Wood Splitters (Commercial)
Diesel Chippers /Stump Grinders (Residential)
Diesel Chippers /Stump Grinders (Commercial)
Diesel Commercial Turf Equipment (Res . )
Diesel Commercial Turf Equipment (Comm. )
Diesel Other Lawn & Garden Equipment (Res . )
Diesel Other Lawn & Garden Equipment (Comm. )
Diesel 2-Wheel Tractors
Diesel Agricultural Tractors
Diesel Combines
Diesel Balers
Diesel Agricultural Mowers
Diesel Sprayers
Diesel Tillers > 6 HP
Diesel Swathers
Diesel Hydro Power Units
Load Factor
(fraction of powert
0 .59
0 .59
0 .21
0 .59
0.21
0.59
0 .21
0 .59
0 .21
0 .59
0.43
0.43
0.21
0.43
0 .59
0 .43
0 .43
0 .43
0.43
0.43
0.43
0.43
0 .43
0 .43
0 .43
0 .43
0.43
0.43
0.43
0.43
0 .43
0 .43
0 .43
0 .43
0.43
0.43
0.43
0.43
0 .43
0 .43
0 .43
0 .43
0.43
0.59
0.59
0.59
0 .59
0 .59
0 .59
0 .59
0.59
0.43
Activity
(hours /vearl
761
899
1135
936
818
855
566
606
384
1700
1220
878
421
1341
1257
320
320
172
172
70
70
60
60
120
120
400
400
480
480
480
480
120
120
544
544
265
265
465
465
1068
1068
433
433
544
475
150
95
363
90
172
110
790
25
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2270005055
2270005060
2270006005
2270006010
2270006015
2270006020
2270006025
2270006030
2270007005
2270007010
2270007015
2270007020
2270008005
2270009010
2270010010
2267001020
2267001030
2267001050
2267001060
2267002003
2267002006
2267002009
2267002012
2267002015
2267002018
2267002021
2267002024
2267002027
2267002030
2267002033
2267002036
2267002039
2267002042
2267002045
2267002048
2267002051
2267002054
2267002057
2267002060
2267002063
2267002066
2267002069
2267002072
2267002075
2267002078
2267002081
2267003010
2267003020
2267003030
2267003040
2267003050
2267003060
Equipment Description
Diesel Other Agricultural Equipment
Diesel Irrigation Sets
Diesel Light Commercial Generator Sets
Diesel Light Commercial Pumps
Diesel Light Commercial Air Compressors
Diesel Light Commercial Gas Compressors
Diesel Light Commercial Welders
Diesel Light Commercial Pressure Washer
Diesel Logging Equipment Chain Saws > 6 HP
Diesel Logging Equipment Shredders > 6 HP
Diesel Logging Equip Fell/Bunch/Skidders
Diesel Logging Equip Fell /Bunch (unused)
Diesel Airport Support Equipment
Diesel Other Underground Mining Equipment
Diesel Other Oil Field Equipment
LPG Snowmobiles
LPG All Terrain Vehicles/MC
LPG Golf Carts
LPG Specialty Vehicle Carts
LPG Asphalt Pavers
L PG Tampe r s / Ramme r s
LPG Plate Compactors
LPG Concrete Pavers
LPG Rollers
LPG Scrapers
LPG Paving Equipment
LPG Surfacing Equipment
LPG Signal Boards
LPG Trenchers
LPG Bore/Drill Rigs
LPG Excavators
LPG Concrete/Industrial Saws
LPG Cement & Mortar Mixers
LPG Cranes
LPG Graders
LPG Off-highway Trucks
LPG Crushing/Proc . Equipment
LPG Rough Terrain Forklifts
LPG Rubber Tire Loaders
LPG Rubber Tire Dozers
LPG Tractors/Loaders/Backhoes
LPG Crawler Tractors
LPG Skid Steer Loaders
LPG Off -Highway Tractors
LPG Dumpers /Tenders
LPG Other Construction Equipment
LPG Aerial Lifts
LPG Forklifts
LPG Sweepers/Scrubbers
LPG Other General Industrial Equipment
LPG Other Material Handling Equipment
LPG AC\Refrigeration
Load Factor
(fraction of powert
0 .59
0 .43
0 .43
0 .43
0.43
0.43
0 .21
0 .43
0 .59
0 .59
0.59
0.59
0.59
0.21
0 .43
0 .34
0 .42
0 .46
0.58
0.66
0.55
0.55
0 .55
0 .62
0 .70
0 .59
0.49
0.72
0.66
0.79
0 .59
0 .78
0 .59
0 .47
0.64
0.80
0.85
0.63
0 .71
0 .75
0 .48
0 .80
0.58
0.70
0.41
0.48
0 .46
0 .30
0 .71
0 .54
0.53
0.46
Activity
(hours /vearl
381
749
338
403
815
8500
643
145
70
120
1276
0
732
1533
1231
40
63
1080
65
392
160
166
0
621
540
175
488
318
402
107
378
610
84
415
504
450
241
413
512
900
870
700
310
155
127
371
361
1800
516
713
386
605
26
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2267003070
2267004010
2267004011
2267004015
2267004016
2267004020
2267004021
2267004025
2267004026
2267004030
2267004031
2267004035
2267004036
2267004040
2267004041
2267004045
2267004046
2267004050
2267004051
2267004055
2267004056
2267004060
2267004061
2267004065
2267004066
2267004070
2267004071
2267004075
2267004076
2267005010
2267005015
2267005020
2267005025
2267005030
2267005035
2267005040
2267005045
2267005050
2267005055
2267005060
2267006005
2267006010
2267006015
2267006020
2267006025
2267006030
2267007005
2267007010
2267007015
2267007020
2267008005
2267009010
Equipment Description
LPG Terminal Tractors
LPG Lawn mowers (Residential)
LPG Lawn mowers (Commercial)
LPG Rotary Tillers < 6 HP (Residential)
LPG Rotary Tillers < 6 HP (Commercial)
LPG Chain Saws < 6 HP (Residential)
LPG Chain Saws < 6 HP (Commercial)
LPG Trimmers/Edgers/Brush Cutters (Res.)
LPG Trimmers/Edgers/Brush Cutters (Comm.)
LPG Leaf blowers /Vacuums (Residential)
LPG Leaf blowers /Vacuums (Commercial)
LPG Snowblowers (Residential)
LPG Snowblowers (Commercial)
LPG Rear Engine Riding Mowers (Residential)
LPG Rear Engine Riding Mowers (Commercial)
LPG Front Mowers (Residential)
LPG Front Mowers (Commercial)
LPG Shredders < 6 HP (Residential)
LPG Shredders < 6 HP (Commercial)
LPG Lawn & Garden Tractors (Residential)
LPG Lawn & Garden Tractors (Commercial)
LPG Wood Splitters (Residential)
LPG Wood Splitters (Commercial)
LPG Chippers/Stump Grinders (Residential)
LPG Chippers/Stump Grinders (Commercial)
LPG Commercial Turf Equipment (Residential)
LPG Commercial Turf Equipment (Commercial)
LPG Other Lawn & Garden Equipment (Res.)
LPG Other Lawn & Garden Equipment (Comm.)
LPG 2 -Wheel Tractors
LPG Agricultural Tractors
LPG Combines
LPG Balers
LPG Agricultural Mowers
LPG Sprayers
LPG Tillers > 6 HP
LPG Swathers
LPG Hydro Power Units
LPG Other Agricultural Equipment
LPG Irrigation Sets
LPG Light Commercial Generator Sets
LPG Light Commercial Pumps
LPG Light Commercial Air Compressors
LPG Light Commercial Gas Compressors
LPG Light Commercial Welders
LPG Light Commercial Pressure Washers
LPG Logging Equipment Chain Saws > 6 HP
LPG Logging Equipment Shredders > 6 HP
LPG Logging Equipment Skidders
LPG Logging Equipment Fellers/Bunchers
LPG Airport Support Equipment
LPG Other Underground Mining Equipment
Load Factor
(fraction of powert
0 .78
0 .33
0 .33
0 .40
0.40
0.70
0 .70
0 .91
0 .91
0 .94
0.94
0.35
0.35
0.38
0 .38
0 .65
0 .65
0 .80
0.80
0.44
0.44
0.69
0 .69
0 .78
0 .78
0 .60
0.60
0.58
0.58
0.62
0 .62
0 .74
0 .62
0 .48
0.65
0.71
0.52
0.56
0 .55
0 .60
0 .68
0 .69
0.56
0.85
0.68
0.85
0 .70
0 .80
0 .70
0 .70
0.56
0.80
Activity
(hours /vearl
827
25
406
17
472
13
303
9
137
10
282
8
136
36
569
86
86
50
50
45
721
76
76
488
488
682
682
61
61
286
550
125
68
175
80
43
95
450
124
716
115
221
484
6000
408
115
303
50
350
0
681
260
27
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2267010010
2268001020
2268001030
2268001050
2268001060
2268002003
2268002006
2268002009
2268002012
2268002015
2268002018
2268002021
2268002024
2268002027
2268002030
2268002033
2268002036
2268002039
2268002042
2268002045
2268002048
2268002051
2268002054
2268002057
2268002060
2268002063
2268002066
2268002069
2268002072
2268002075
2268002078
2268002081
2268003010
2268003020
2268003030
2268003040
2268003050
2268003060
2268003070
2268004010
2268004011
2268004015
2268004016
2268004020
2268004021
2268004025
2268004026
2268004030
2268004031
2268004035
2268004036
2268004040
Equipment Description
LPG Other Oil Field Equipment
CNG Snowmobiles
CNG All Terrain Vehicles/MC
CNG Golf Carts
CNG Specialty Vehicle Carts
CNG Asphalt Pavers
CNG Tampe r s / Ramme r s
CNG Plate Compactors
CNG Concrete Pavers
CNG Rollers
CNG Scrapers
CNG Paving Equipment
CNG Surfacing Equipment
CNG Signal Boards
CNG Trenchers
CNG Bore/Drill Rigs
CNG Excavators
CNG Concrete/Industrial Saws
CNG Cement & Mortar Mixers
CNG Cranes
CNG Graders
CNG Off-highway Trucks
CNG Crushing/Proc . Equipment
CNG Rough Terrain Forklifts
CNG Rubber Tire Loaders
CNG Rubber Tire Dozers
CNG Tractors/Loaders/Backhoes
CNG Crawler Tractors
CNG Skid Steer Loaders
CNG Off -Highway Tractors
CNG Dumpers /Tenders
CNG Other Construction Equipment
CNG Aerial Lifts
CNG Forklifts
CNG Sweepers/Scrubbers
CNG Other General Industrial Equipment
CNG Other Material Handling Equipment
CNG AC\Refrigeration
CNG Terminal Tractors
CNG Lawn mowers (Residential)
CNG Lawn mowers (Commercial)
CNG Rotary Tillers < 6 HP (Residential)
CNG Rotary Tillers < 6 HP (Commercial)
CNG Chain Saws < 6 HP (Residential)
CNG Chain Saws < 6 HP (Commercial)
CNG Trimmers/Edgers/Brush Cutters (Res.)
CNG Trimmers/Edgers/Brush Cutters (Comm.)
CNG Leaf blowers /Vacuums (Residential)
CNG Leaf blowers /Vacuums (Commercial)
CNG Snowblowers (Residential)
CNG Snowblowers (Commercial)
CNG Rear Engine Riding Mowers (Residential)
Load Factor
(fraction of powert
0 .90
0 .34
0 .42
0 .46
0.58
0.66
0 .55
0 .55
0 .55
0 .62
0.70
0.59
0.49
0.72
0 .66
0 .79
0 .53
0 .78
0.59
0.47
0.64
0.80
0 .85
0 .63
0 .71
0 .75
0.48
0.80
0.58
0.70
0 .41
0 .48
0 .46
0 .30
0.71
0.54
0.53
0.46
0 .78
0 .33
0 .33
0 .40
0.40
0.70
0.70
0.91
0 .91
0 .94
0 .94
0 .35
0.35
0.38
Activity
(hours /vearl
1104
40
63
1080
65
392
160
166
0
621
540
175
488
318
402
107
378
610
84
415
504
450
241
413
512
900
870
700
310
155
127
371
361
1800
516
713
386
605
827
25
406
17
472
13
303
9
137
10
282
8
136
36
28
-------
Load Factor and Activity Estimates in Draft NONROAD2002
sec
2268004041
2268004045
2268004046
2268004050
2268004051
2268004055
2268004056
2268004060
2268004061
2268004065
2268004066
2268004070
2268004071
2268004075
2268004076
2268005010
2268005015
2268005020
2268005025
2268005030
2268005035
2268005040
2268005045
2268005050
2268005055
2268005060
2268006005
2268006010
2268006015
2268006020
2268006025
2268006030
2268007005
2268007010
2268007015
2268007020
2268008005
2268009010
2268010010
2282005010
2282005015
2282010005
2282020005
2282020010
2282020025
2285002015
2285003015
2285004015
2285006015
2285008015
Equipment Description
CNG Rear Engine Riding Mowers (Commercial)
CNG Front Mowers (Residential)
CNG Front Mowers (Commercial)
CNG Shredders < 6 HP (Residential)
CNG Shredders < 6 HP (Commercial)
CNG Lawn & Garden Tractors (Residential)
CNG Lawn & Garden Tractors (Commercial)
CNG Wood Splitters (Residential)
CNG Wood Splitters (Commercial)
CNG Chippers/Stump Grinders (Residential)
CNG Chippers/Stump Grinders (Commercial)
CNG Commercial Turf Equipment (Residential)
CNG Commercial Turf Equipment (Commercial)
CNG Other Lawn & Garden Equipment (Res.)
CNG Other Lawn & Garden Equipment (Comm.)
CNG 2 -Wheel Tractors
CNG Agricultural Tractors
CNG Combines
CNG Balers
CNG Agricultural Mowers
CNG Sprayers
CNG Tillers > 6 HP
CNG Swathers
CNG Hydro Power Units
CNG Other Agricultural Equipment
CNG Irrigation Sets
CNG Light Commercial Generator Sets
CNG Light Commercial Pumps
CNG Light Commercial Air Compressors
CNG Light Commercial Gas Compressors
CNG Light Commercial Welders
CNG Light Commercial Pressure Washers
CNG Logging Equipment Chain Saws > 6 HP
CNG Logging Equipment Shredders > 6 HP
CNG Logging Equipment Skidders
CNG Logging Equipment Fellers/Bunchers
CNG Airport Support Equipment
CNG Other Underground Mining Equipment
CNG Other Oil Field Equipment
2 -Stroke Outboards
2 -Stroke Personal Watercraft
4 -Stroke Inboards
Diesel Inboards
Diesel Outboards
Diesel Sailboat Aux. Outboard (unused)
Diesel Railway Maintenance
2 -Stroke Gasoline Railway Maintenance
4 -Stroke Gasoline Railway Maintenance
LPG Railway Maintenance
CNG Railway Maintenance
Load Factor
(fraction of powert
0 .38
0 .65
0 .65
0 .80
0.80
0.44
0 .44
0 .69
0 .69
0 .78
0.78
0.60
0.60
0.58
0 .58
0 .62
0 .62
0 .74
0.62
0.48
0.65
0.71
0 .52
0 .56
0 .55
0 .60
0.68
0.69
0.56
0.85
0 .68
0 .85
0 .70
0 .80
0.70
0.70
0.56
0.80
0 .90
0 .21
0 .21
0 .21
0.43
0.43
0.43
0.21
0 .62
0 .62
0 .62
0 .62
Activity
(hours /vearl
569
86
86
50
50
45
721
76
76
488
488
682
682
61
61
286
550
125
68
175
80
43
95
450
124
716
115
221
484
6000
408
115
303
50
350
0
681
260
1104
34 .8
77 .3
47 .6
200
150
68
943
184
184
184
184
* Activities for off-road motorcycles and all terrain vehicles are in units of miles per year.
29
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Appendix B
Documentation of the Median Life Values in the California OFFROAD
Model
30
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DOCUMENTATION OF DIESEL ENGINE LIFE
VALUES USED IN THE ARE
OFF-HIGHWAY MODEL
Prepared for:
OFFICE OF MOBILE SOURCES
ENVIRONMENTAL PROTECTION AGENCY
Ann Arbor, MI
EPA Purchase Order: 1A-0462-NASX
Prepared by:
ENERGY AND ENVIRONMENTAL ANALYSIS, INC.
1655 North Fort Myer Drive
Suite 600
Arlington, VA 22209
September 2001
31
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32
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TABLE OF CONTENTS
Page
1. BACKGROUND 1
2. PSR DATA DESCRIPTION 2
3. EEA ANALYSIS OF THE PSR DATA 3
4. USEFUL LIFE VALUES IN THE MODEL 8
5. SUMMARY 13
APPENDIX A: LIST OF CONTACTS 14
LIST OF TABLES
Page
Table 1 PSR Data on Engine Life at Rated Load 6
Table 2 1991 Engine Models by Horsepower Category 9
LIST OF FIGURES
Page
Figure 1 51-750 HP Diesel Engine Life Spans 7
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1. BACKGROUND
In the 1992-1993 time frame, EEA developed a model for the California Air Resources Board
(ARB). The model estimates emission inventory from off-highway mobile sources of all types.
The model's emissions calculations require tracking of the population of each equipment
type/engine combination by vintage. The vintage distribution of any particular type of off-
highway equipment and engine type is determined from a scrappage model that requires engine
useful life as an input. The same engine type can be utilized across a number of equipment types
that place different loads on the engine. The scrappage model is constructed in a manner that
allows useful life for a given equipment type to vary based on the simple formulation that engine
life in application "i" is given by:
.„ . T .. . (Engine Life)fuiiioad
(Engine Life); =
(Load Factor)!
Hence, engine life in a particular application is inversely proportional to the average load factor,
and engine life at full load is specified within the model.
Engines were categorized by fuel type, horsepower range and engine cycle (two- versus four-
stroke). At this subcategory level, the population of engines was assumed to be homogeneous,
based on the fact that engines competing in the marketplace for the same market segment offer
competitive durability. The development of specific engine life estimates for each engine
subcategory is described in this memorandum.
It should be noted that the ARB Off-Highway Model is the first of its kind, and was developed in
a period when virtually all information had to be obtained from original sources and very few
were available publicly. Given the wide range of engines and equipment available in the off-
highway market, a number of simplifying assumptions had to be made. Some of the data and
inputs in the model are potentially outdated, based on new research and testing conducted in the
last decade years following its development.
Second, it should be noted that the single most important source of data for equipment type,
population and useful life was Power Systems Research (PSR), that has a proprietary database on
off-highway equipment sales, population and scrappage. While the Power Systems Research
data was the single largest and most unified source of data, EEA conducted a detailed assessment
of PSR populations and sales data provided by comparing these data with data from other
sources. In many instances, we found PSR data could not be justified, and EEA changed the data
based on inputs from industry associations and engine manufacturers. In particular, the PSR
engine life data appeared to be most incorrect for smaller engines.
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This memo first describes the PSR data and specifically identifies areas where our comparison
indicated that PSR was likely in potential error. Second, EEA describes the methodology by
which we derived other data that were judged more appropriate for the model.
2. PSR DATA DESCRIPTION
Data purchased from PSR included detailed breakouts of California off-highway populations by
engine type, fuel type and horsepower range. PSR also provide a separate data file on the mean
engine life by engine model in hours at rated load.
The PSR methodology for estimating population is based on sales and scrappage. PSR obtains
sales data from a number of proprietary sources including manufacturers and dealers.
Nationwide sales are allocated to regions based on survey data and dealer based information.
Scrappage is estimated as a function of vintage and engine mean life. Central to the estimates is
a non-dimensional survival curve that provides survival rates in percent on the Y-axis against
fraction of engine life used. The curve is S-shape, and starts at one at zero engine life used. At
engine life equal to one, the survival rate is fifty percent, and at engine life equal to two, survival
rate is zero. Hence, the engine life value is the point where half of all engine are scrapped.
Engine life in a particular application is engine life at rated load divided by the load factor on a
typical duty cycle for the application. PSR has developed load factors for each application
although we have no explicit understanding of how the load factors were developed. Engine life
at rated load is determined by a proprietary formula that related life to bore/stroke, design type
and specific output. The formula itself is proprietary and undocumented. Nevertheless, we
obtained a detailed database on life by engine model to allow us to assess the formula.
Population is derived from sales with the formula:
Population = £ Sales, x Survival Rate;
summed over i = 0 to twice the engine life in the application. Engine life in years for an
application is given by:
Engine Life at Rated HP (hours)
Load Factor x Use (hours/year)
Population = Average Sales x engine life (years)
For equipment types that have no time trend in sales, we can estimate population using:
35
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We utilized the above formula in several instances to estimate populations from available sales
data. In many cases, sales of off-highway equipment have shown no growth trend over a long
period, so that the above formula can provide a reasonable estimate of population.
3. EEA ANALYSIS OF THE PSR DATA
A very detailed comparison of PSR population estimates by equipment category was undertaken.
Briefing charts presented to the ARE documenting all the comparisons have been provided to
EPA, and only the key data and major conclusions are presented here.
In lawn and garden equipment. PSR population data from most non-commercial equipment such
as chain saws and lawn mowers were a factor often higher than estimates from the industry or
estimates based on (sales x useful life). For commercial equipment, PSR's estimates were more
reasonable and comparable to other estimates. However, most lawn and garden equipment are
powered by gasoline engines. For recreational equipment such as motorcycles, snowmobiles and
ATVs, PSR estimates were very low relative to other estimates. This category also has no diesel
powered equipment.
For industrial equipment. PSR totals across all fuel types and horsepower categories were
comparable to estimates from industry associations. However, the gasoline (and LPG)-to-diesel
split was very different. Diesel engine equipment populations were significantly over-estimated
by PSR (by a factor of three to four), while gasoline engine equipment populations were
underestimated significantly. Similar trends were also found for transport refrigeration units, and
diesel airport ground support equipment. These equipment typically are powered by diesel
engines in the 25 to 100 HP range.
No validation of PSR data could be done for light commercial equipment such as generator sets,
pumps and compressors. One study by Booz-Allen Hamilton suggested PSR estimates for
diesels were incorrect by more than an order of magnitude, although the Booz-Allen numbers for
diesels are not well documented. Equipment in this category utilize diesel engines under 50 HP.
PSR population data for agricultural tractors (typically in the 50 to 150 HP range) were also
significantly higher than estimates from the Agricultural Census and sales based estimates. The
differences were in the range of 50 to 150 percent.
Finally PSR estimates of populations for construction equipment were much closer to those
derived from sales or industry data on populations. These equipment typically use diesel engines
over 200 HP. PSR estimates were higher than those from industry, but the margin of difference
was not large, ranging from 10 to 30 percent.
As a result of this comparison, we concluded that PSR's diesel engine life estimates appeared to
be optimistic, and the level of optimism increased with decreasing HP. It appeared that for small
diesel engines (less than 50 HP), the PSR life estimates were potentially in serious error. As a
36
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result of the population analysis, we requested and obtained the detailed PSR life data by engine
model. Due to its proprietary nature, only aggregate statistics are provided in this report.
Table 1 provides the PSR useful life data after filtering the data for zeroes and blanks. (There
were only a very small number of such cases, including one obvious typographical error). As
shown in Table 1, the average engine life by HP range declines with increasing horsepower,
although the decline is not large relative the distribution of values within engine HP range. For
example, all engines in the 25 to 750 HP range have an average life of 10,700±1300 hours.
Based on our knowledge of engines and their applications, the declining trend as well as the
absolute values appeared incorrect, especially for the smaller engines.
Since the variation of useful life with HP ranges were larger than the changes to the averages
across HP ranges, we use investigated the data more thoroughly. The detailed data showed that
engine life appeared to be a stronger function of its aspiration (turbocharged or naturally
aspirated) than its displacement or power output. Within naturally aspirated engines, there was a
trend to increasing average useful life with size and horsepower, ranging from 12,000 hours for
small engines to 18,000 hours for the largest engines. (A few engines had even higher useful life
numbers, but it was not clear why). However, a given engine model's useful life was found to be
inversely proportional to its horsepower output. For example, most of the larger engines are
offered in naturally aspirated, turbocharged and aftercooled models at a variety of HP ratings.
The PSR model simply scales the life in exact inverse proportion to the HP rating.
Figure 1 shows the distribution of useful life ratings from engines in the 50 to 750 HP range.
Most naturally aspirated engine are in the upper end of the life range, turbocharged engines in the
middle of the range and turbocharged/aftercooled engines in the lower end of the useful life
range, in concert with their increasing specific output. Two stroke engine, with specific output
almost twice the specific output of four-stroke engines, had the lowest useful life values. The
decline in average useful life with increasing HP in Table 1 is due to the fact that a larger
proportion of high HP engines are turbocharged, or turbocharged and aftercooled, but is not
related to the larger engine size.
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TABLE 1
PSR DATA ON ENGINE LIFE AT RATED LOAD
(hours)
HP Range
2.1-15
15.1-25
25.1-50
50.1-120
120.1-175
175.1-250
250.1-500
500.1-750
750+
Sample Size
104
88
118
241
106
17
189
36
27
Average*
13,704
12,364
11,315
10,331
11,994
11,038
10,076
9,490
8,264
Maximum
29,713
16,062
23,625
22,627
31,171
20,847
19,452
18,968
18,654
Minimum
5,579
4,178
5,406
4,469
3,910
3,029
4,464
3,927
5,070
Standard
Deviation
1,705
2,404
3,463
3,463
4,135
3,907
2,695
2,986
2,818
* Average across all engine models without sales weighting.
38
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Figure 1
51-750 HP Diesel Engine Life Spans
o
4000
8000 12000
Life (hours)
16000
20000
39
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EEA's knowledge of engines suggested that the PSR approach was incorrect. For example,
Detroit Diesel's two-stroke engines do not have the reputation for wearing out twice as fast as
other competitive four-stroke engines in truck applications. In addition, we are generally
unaware of any major decrease in life for turbocharged and aftercooled engines in the on-
highway segment relative to turbocharged or naturally aspirated engines. Hence, EEA
decided to specify the useful life data independently of PSR data.
4. USEFUL LIFE VALUES IN THE MODEL
EEA took a three-step approach to determining the correct useful life, as follows. First, we
identified popular (high sales) engines within each horsepower category. Second, we
contacted a subset of the engine manufacturers of these popular engines to obtain their views
on engine life. Third, we developed engine life based on a combination of manufacturer
comments and available data from on-highway engines.
The identification of popular engine models by horsepower range was based on data
developed under earlier studies for ARE by EEA. Table 2 shows the data for diesel engines
above 50 FTP. (The horsepower ranges in the table do not exactly correspond to those in the
model, since ARE requested some changes in the ranges towards the end of the project).
In general, the four major on-highway diesel engine manufacturers (Cummins, Caterpillar,
Detroit Diesel and IH, now Navistar) offer versions of their on-highway products for the off-
highway market. In addition, John Deere is the only the other major domestic engine
manufacturer that sells engines directed almost completely to the off-highway market.
Kubota, Deutz and Perkins are the major import engine brands in the market for engines over
50 HP.
In the 50-120 HP market, sales are dominated by four-cylinder versions of six-cylinder on-
highway medium heavy-duty engines such as the Cummins B and C series, the Caterpillar
l.lL/cylinder series and the 3200 series, and Detroit Diesel's 53 Series engines. In the next
higher range of 120 to 175 HP, on-highway medium-heavy duty engines and some naturally
aspirated versions of heavy-heavy duty engines dominate sales. Above 175 HP, a majority of
engines are derivatives of heavy-heavy duty on-highway engines, except at the highest
horsepower end, over 500 HP. At these high HP levels, some specialized engines such as
Caterpillar's 3500 series, DDC's 149 series and Cummins KT series are available and are not
generally sold in the on-highway market. Sales of engines in the very high HP categories are
quite small.
In the lower horsepower ranges below 50 HP, two types of engines dominate sales. In
industrial tractors and small airport ground support equipment, derated versions of passenger
car diesel engines (from manufacturers like Perkins, VW, Isuzu and Toyota) are utilized.
Such engines are typically rated from 30 to 50 HP.
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TABLE 2
1991 ENGINE MODELS BY HORSEPOWER CATEGORY
Manufacturer
Caterpillar
Cummins
Detroit Diesel
Deere
ffl
Komatsu
Deutz
Perkins
50 to!20 HP
3114T
3204NA
3304NA
4A2.3
6A3.4
4B3.9
3-53N/T
4-53N
8.2LN
3-179N/T
4-23 9N/T
4-276N/T
D-239N/T
D-360N
4D-94N/T
4D-95N/T
4D-105N
FL912N/T
FL913N/T
3-153N/T
4-23 6N/T
120 to 250 HP
3116T
3208NA
3306NA
6B5.9T/TA
6C8.3T/TA
3-53T
4-53T
6-7 IN
6-359T/TA
6-414T/TA
6-466T/TA
D-360T
D-466N/T/TA
4D-130N/T
6D-95N/T
6D-105N/T
FL913T/TA
FL413N/T
6-354N/T
8-540N/T
250 to 500 HP
3306T/TA
3406T/TA
3408T/TA
L-10T/TA
NTC-855T/TA
6-71T/TA
8-71T/TA
6-92N/T/TA
6-619T/TA
8-955T/TA
6D-125T/TA
6D-140N/T
6D-155N/T
FL413T/TA
FL513T/TA
6-734T/TA
8-1062T/TA
Over 500 HP
3412T/TA
3408TA
All 3500 series
KT-19
VT-28
KV-38
8-92T/TA
12-92T/TA
All 149 series
6D-170T/TA
8V-170T/TA
12V170T/TA
N is for naturally aspirated, T for turbocharged and A for aftercooled.
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Small two- or three-cylinder engines from manufacturers such as Kubota, Yanmar, Onan, and
Teledyne-Wisconsin are utilized in the 15-40 HP range and are a mix of air cooled and
water-cooled engines. Engines under 15 HP are also offered by these same manufacturers
and are mostly single-cylinder air-cooled diesels. Most of these engines find application is
light commercial equipment.
Useful life estimates for engines over 50 HP were based on information from heavy-duty
diesel engine manufacturers. EEA spoke with representatives from Caterpillar, Cummins,
Navistar and Detroit-Diesel.3 All were questions about the:
correctness of the PSR algorithm of scaling life by load factor, and by specific output;
typical useful life in on-highway applications;
comparability to useful life in off-highway applications.
Information obtained was subjective and experienced based, but no hard data was provided
by manufacturers.
On PSR's useful life algorithms, manufacturers agreed that load factor was inversely related
to engine life but cautioned that this relationship could not hold over the entire range of load
factors from zero to one. They believed it would overestimate life at very light load factors
and underestimate life as load factor approached one. They did not agree, however, with
PSR's method of derating life at full load inversely with specific output across all aspiration
types. While suggesting that there is variation in life with increasing output, manufacturers
also stated that many components are upgraded in turbocharged engines relative to their
naturally aspirated counterparts, and that warranty protection is the same for all engine types.
They also pointed to the evidence that inspite of increasing specific output in the late-1980s
and early 1990s, they had not observed any significant change in useful life.
For heavy-heavy duty on-road engines, most manufacturers agreed that engine life (defined as
the point when the engine is removed from the truck for a rebuild) for an over-the-road
application, i.e., mostly highway miles, was in the 700,000 to 750,000 miles range. Note that
this referred to engines from the last decade, as we understand that current engines last up to
a million miles. Manufacturers suggested that miles could be converted to hours by assuming
that most mileage was accumulated at highway speeds of, say, 60 mph as an average.
Manufacturers also generally agreed that EPA's original durability finding that medium-
heavy duty engines have two-thirds the life of heavy-heavy duty engines was a reasonable
estimate.
In order to develop useful life at rated HP, a load factor corresponding to 60 MPH operation
is required. Simulation models such as "TCAPE" show that an 80,000 Ib. GVW truck
cruising on a level road at 60 mph requires 210 to 220 HP. A typical engine rated HP for the
application is 350 HP to 375 HP, suggesting a load factor of 0.6. It is also known that trucks
3* contact names are listed in Appendix A.
42
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are geared to operate at close to the best bsfc point at cruising speed. The best bsfc point
usually occurs at 70 percent of peak torque and close to the peak torque RPM which is about
70 percent of rated RPM. Peak torque is usually about 20 percent higher than trque at rated
RPM. Since:
Rated HP = (Torque)R x (RPM)R
where subscript R is for rated values, we can calculate
Peak Torque @ 1.2 x (Torque)R
RPM @ Peak Torque = 0.7 x (RPM)R
Cruise Point 0 0.7 x Peak Torque x RPM @ Peak Torque
0.7 x 1.2 x (Torque)R x 0.7 x (RPM)R
@ 0.6 x (Torque)R x (RPM)R
Hence, the cruise point calculation also implies a load factor of about 0.6.
From this, we can derive a life at rated power in hours:
Life = 700,000 miles y Load Factor
60 mph
= 7000 hours
Manufacturers had only subjective opinions for the life in off-road use, and suggested some
adjustment factor for "rough-duty" conditions. These suggestions were to reduce the on-
highway life by 10 to 20 percent, and we selected 15 percent as an approximate average.
Adjusting the on-highway life of 7000 hours by 15 percent provided a useful life rating for
off-highway engines of 6000 hours. Using the fact that medium duty engines offered two-
thirds the life of heavy-heavy duty engines, we estimated their life at 4000 hours.
Useful life for smaller engines (under 50 HP) was based on less information. EEA contacted
representatives from Kubota, Yanmar, Perkins and VW to obtain information on diesel
engine useful life but they had no specific information on hours. One manufacturer
suggested using information on forklift truck scrappage, but we found that the Industrial
Truck Association only has an average life for all fork-lifts (gasoline and diesel), and the data
was not directly useful. Several members commented that the engines were physically
similar in design to light-duty automotive diesels, which was the basis for our estimate of
life. Because of the very low load factor (around 0.1) in typical automotive use, a mileage
based estimate leads to very long useful life (>10,000 hours). Rather, we utilized the fact that
small light duty (passenger car) diesel have durability comparable to gasoline engines of
similar displacement. Data from auto-manufacturers show that a typical wide open throttle
durability requirement for gasoline four-cylinder engines is about 2500 hours. This value
was used for diesel engines in the 15 to 50 HP range. No adjustments were made for off-
highway use, since these engines are typically not used in rough duty applications.
43
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Diesels in the under 15 HP category are typically small single cylinder air-cooled engines.
Again, no specific life figures were obtained from manufacturers. However, they believed
that durability was lower than the value of the larger water cooled multi-cylinder units in the
15-50 HP category. EEA selected 1250 hours as a plausible value, but recognize that this is
not supported by any data. It also reflects the fact that it is about ten percent of PSR's
estimate. Given that PSR estimates of small diesel populations are over ten times the
estimates of other organizations, the value appears to be a reasonable estimate.
5. SUMMARY
Based on detailed comparison of populations, it appeared that PSR overestimates diesel
equipment populations, with the level of overestimate increasing from the 20 percent range
for the largest diesels to over 1000 percent for the smallest diesels.
A detailed examination of their data on engine useful life at rated load showed
counterintuitive estimates, with the smallest diesel engine having substantially higher useful
life relative to the largest diesels. These estimate were traced to assumptions about the
relationship of engine life to specific output (HP/liter) that EEA believes are incorrect.
EEA developed its own estimates by comparison with on-road engines useful life, where
engine types in each HP range were matched with on-road counterparts. Data for engines
under 50 HP, however, was unavailable and based largely on subjective comments from the
manufacturers. The ratio of EEA useful life estimates to PSR estimates for each HP category
is quite similar to the ratio of equipment population estimates from other sources to PSR's
equipment population estimates, suggesting that EEA useful life estimates are reasonable.
44
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APPENDIX A
LIST OF CONTACTS
Caterpillar
Cummins
Navistar (ffl)
Detroit Diesel
Kubota
Yanmar
Perkins
VW
Don Dowdall
Mike Brand
Ed Sienecke
John Fisher
Kevin Kokrda
Norman Weir and Kozuhiro Nomura
P. A. Harrison (England)
Wolfsans Groth
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