Air and Radiation EPA420-D-04-004 

August 2004 

Test Procedures for 

Highway and Nonroad

Engines and Omnibus

Technical Amendments 

Draft Technical 

Support Document 
EPA420-D-04-004 

August 2004 

Test Procedures for Highway and Nonroad

Engines and Omnibus Technical Amendments 

Draft Technical Support Document 

Assessment and Standards Division 

Office of Transportation and Air Quality 

U.S. Environmental Protection Agency 
Table of Contents 

Chapter 1: Highway engines (40 CFR parts 85 and 86) ................................1

Chapter 2: Land-based nonroad diesel engines (40 CFR parts 89 and 1039) ................6

Chapter 3: Marine diesel engines (40 CFR part 94) ...................................8

Chapter 4: Locomotives (40 CFR part 92) .........................................21

Chapter 5: Small nonroad spark-ignition engines (40 CFR part 90) ......................22

Chapter 6: Large nonroad spark-ignition engines (40 CFR part 1048) ....................23

Chapter 7: Recreational vehicles (40 CFR part 1051) .................................29

Chapter 8: Test Procedures (40 CFR part 1065) .....................................40
Technical Amendments 

Chapter 1: Highway engines (40 CFR parts 85 and 86) 

I. Ramped-modal testing 

Manufacturers must meet emission standards using a Supplemental Emission Test (SET) 

starting in 2007. The SET measures emissions during 13 separate steady-state modes of engine 

operation. For the laboratory-based SET specified in §86.1360-2007, we propose that the 13-

mode test cycle be run using a Ramped-Modal Cycle (RMC), which is discussed below. 

An RMC operates at the same engine speeds and loads as in conventional discrete-mode 

testing, but the modes are connected by gradual ramps in engine speed and/or torque for a single, 

continuous emission-sampling period. For the RMC we are proposing for the SET, the steadystate modes would be connected with twenty-second linear speed transitions and linear torque 

transitions, which is consistent with the transition time currently allowed in §86.1360-2007. The 

difference is that these transitions would also be sampled as part of the SET. That is, emission 

sampling would start at the beginning of an RMC and would not stop until its last mode was 

completed. 

The RMC for the SET would involve a different sequence of modes than is currently 

specified in §86.1360-2007. For example, the first mode, which is engine idle, would be split so 

that half of the idle mode occurs at the beginning of the test and half occurs at the end of the test. 

This helps facilitate certain technical aspects of emission sampling. Instead of using weighting 

factors for each steady-state mode, an RMC specifies different time durations for each mode. 

Time durations of the modes and transitions are proportioned to the established modal weighting 

factors in §86.1360-2007. The information needed to run the SET as an RMC is given in the 

table below. 

There are several advantages to running the SET as an RMC. First, we anticipate that 

manufacturers will use aftertreatment systems with discrete regeneration events to meet the 

emission standards for 2007 and later model year heavy-duty diesel engines (January 18, 2001, 

66 FR 5002). Under the current procedure for conducting an SET in §86.1360-2007, 

manufacturers sample emissions for an unspecified time duration near the end of each of thirteen 

individual two-minute modes (except idle, which is four minutes). The result is thirteen separate 

measurements that must be combined mathematically to yield an overall emission result in g/hphr. Because discrete aftertreatment regeneration events typically cause short but large increases 

in emissions, the current procedure in §86.1360-2007 may not be repeatable—a regeneration 

event may or may not be sampled in a given mode. For sampling low concentrations of PM, this 

effect is exaggerated because sample times per mode may be as short as twenty seconds. 

Furthermore, without specific start and stop times for sampling each mode, an anticipated 

regeneration event may be intentionally or unintentionally included or excluded. With an RMC, 

this variability is removed by requiring emissions sampling for the entire forty-minute cycle. 

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Draft Technical Support Document 

The RMC involves one emission measurement rather than 13 separate measurements for each 

mode. The more frequent, separate measurements can cause inaccuracy, especially at low 

emission levels, since dead volumes in the sampling system and delayed sampling can cause the 

system to assign one mode’s emissions to a different mode. The RMC avoids this by collecting 

the total emissions into a single sample and dividing by the total work done over the test period. 

A single measurement also substantially reduces the resource burden to conduct testing. 

The RMC enables the use of batch sampling systems such as bag samplers. This is an 

advantage at low emissions, because these sampling systems are capable of quantifying lower 

levels than continuous sampling systems. 

The longer sampling period for RMC testing also increases the total collected mass of 

pollutants. This is especially significant because the heavy-duty highway diesel PM standard, 

effective in 2007, approaches current PM microbalance quantification limits. Sampling for 40 

minutes over the RMC increases the total collected PM by 500 percent compared with the 

conventional discrete-mode procedure. 

II. Maximum test speed 

Because maximum test speed in part 1065 differs from rated speed in part 86, we are 

considering a change to adjust how maximum test speed is applied to heavy-duty highway diesel 

engines. These speeds are used to transform normalized speeds into reference speeds for 

emission testing. For heavy-duty highway diesel engines, we require emission testing over the 

sequence speeds and torques in 40 CFR part 86, Appendix I, paragraph (f)(2), where rated speed 

is represented by 100 % speed (40 CFR 86.1333-90(g)). 

Rated speed and maximum test speed can differ. Rated speed may be declared by the 

manufacturer within or above the speed range between the lowest and highest speed at which an 

engine generates 98 % maximum power. As stated in 40 CFR 86.1333-90(g), “[Rated speed] is 

generally intended to represent the rpm at which maximum brake horsepower occurs.” In 

contrast, maximum test speed is the speed that lies farthest from the zero-speed, zero-power 

point on an engine power map that is normalized to 100 % power and 100 % speed at that power. 

Four such engine maps are illustrated below. For engines with low torque-rise, maximum test 

speed is at maximum power. So for these engines, there is little difference between maximum 

test speed and rated speed. Note that torque-rise means an increase in maximum torque from 

maximum power to maximum torque. We have observed, however, that all modern heavy-duty 

highway diesel engines have high torque-rise, which causes maximum test speed to be (15 to 35) 

% higher than rated speed. For these engines, a general shift toward higher test speeds is 

intentional in order to test these engines over their complete operating ranges. 

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Technical Amendments

3

The highest percent speed in the part 86 test sequence, however, is not 100 %, but 111.91 %

at the 392nd second of the 1200-second sequence. 

speeds greater than 100 %. ation using maximum test speed,

these normalized speeds in excess of 100 % might not represent in-use operation of high torquerise engines. e request comment on whether or not speeds above maximum test speed are

representative of in-use operation. e also request comment on ways to ensure representative

testing over the part 86 test sequence. e request comment on whether or not we should specify

that maximum test speed should be equal to 112 % speed for this particular sequence. 

would shift the prescribed speeds that are in excess of 100 % to be no greater than 99.92 % of

maximum test speed. ent would prevent excessive speeds, while ensuring our intent

to specify maximum test speed to test an engine over its complete operating range. 

0%

20%

40%

60%

80%

100%

120%

0% 20% 40% 60% 80% 100% 120% 140% 160%

% Speed at which maximum power occurs

% Maximum P

ower

maximum test speed = rated speed

(low torque-rise engines)

maximum test speed

of high-torque-rise

engines

There are also several other occurrences of

Coupled with a speed transform

W

W

W

This

This adjustm
Draft Technical Support Document 

Chapter 2: Land-based nonroad diesel engines (40 CFR 

parts 89 and 1039) 

As described in the preamble, we are proposing to clarify the standards applicable to 

Independent Commercial Importers under Part 89 Subpart G, which are also referenced in 

§1039.660. We are proposing to make clear that the applicable standards for nonroad diesel 

engines imported by ICIs are those that applied during the year of the original production of the 

engine. The current regulations were written when Part 89 was new and there was only one Tier 

of standards. At that time, there were only two categories of engines– those produced before the 

date of applicable standards and those produced after. Engines produced before any applicable 

standards are clearly unregulated under the Act and may be imported without any modification 

(although that does not mean they can be freely installed in any piece of equipment). For those 

that were produced after the effective date of applicable standards, there was no question as to 

which set of standards applied (what we now call Tier 1). Unfortunately, no amendments were 

made to the ICI provisions as first Tier 2, then Tier 3 and finally Tier 4 standards were 

promulgated. 

In the preamble, we explain that we are correcting text in the ICI provisions applicable to 

motor vehicles and motor vehicle engines to make clear that the applicable standards for those 

vehicles and engines are those of the original production year. There we set forth, from a 1996 

final rule, that “many older vehicles cannot be modified to meet current year standards without 

extraordinary cost, which makes the conversion financially unfeasible for many owners of such 

vehicles.” Particularly with the stringency of the Tier 4 standards, we believe that this statement 

also applies to past model year nonroad engines that might be imported by ICIs. Thus, we 

believe that the appropriate standards are those from the original year of production. However, 

as a precaution against the ICI program being used to circumvent new standards for large 

numbers of motor vehicles and motor vehicle engines, we are proposing to cap each ICI’s usage 

of the program at a total of 50 light-duty vehicles and trucks, 50 motorcycles, and 5 motor 

vehicle engines in cases where the year of production standards are less stringent than the 

standards that apply during the year of modification. 

We have issued only three certificates of conformity for nonroad engine ICIs in the history of 

our nonroad regulations, and each of those ICIs imported only a small number of engines. There 

are currently no ICIs with valid nonroad engine certificates. Additionally, the regulations 

generally require that, after certification, every third engine imported by an ICI be tested on an 

engine dynamometer under the federal test procedure (FTP). For these reasons, we do not 

believe that specifying original production year standards for these engines will lead to 

significant importation of older nonroad equipment or engines in the Tier 4 timeframe as a way 

to avoid incremental costs associated with Tier 4 engines. Still, as a precaution, we are 

proposing to cap the number of nonroad diesel engines that may be imported by an ICI in a given 

model year at 5 per year where the original production year standards are less stringent than 

those that apply during the year of modification. We believe this cap eliminates any concern that 

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the goals of the Tier 4 program might be jeopardized, without impacting the current activities of 

any ICI.. We request comment on the appropriateness and size of this cap. We believe it is 

appropriate to take this action to provide the opportunity for ICIs to participate in the U.S. 

market. They have historically been small businesses and their existence may help to increase 

equipment choices available in the U.S. We believe, for example, that ICIs could at some point 

provide a mechanism for the importation of unique and highly specialized machines where 

volumes are so small that the original engine manufacturer elects not to certify, so that the 

equipment might not be otherwise available in the U.S. We intend to monitor the usage of the 

ICI provisions when aftertreatment-based standards take effect for nonroad engines. If we 

believe that the ICI provisions are being misused, or adversely impacting air quality in a 

particular location, we will consider addressing the problem through future rulemaking. 

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Draft Technical Support Document 

Chapter 3: Marine diesel engines (40 CFR part 94) 

This chapter contains an explanation of several changes and clarifications we are proposing 

to apply to our marine diesel engine emission control program. We are adding a definition of 

amphibious vehicle and clarifying the meaning of auxiliary marine engine. We are also 

clarifying the application of certain certification flexibility provisions. These changes and 

clarifications are necessary to address issues that were raised by manufacturers and vessel 

owners as they implement this program. 

It should be noted that the proposed revisions described below do not affect the requirements 

contained in Annex VI, Air Pollution, to the International Convention on the Prevention of 

Pollution from Ships, 1978, as modified by the protocol of 1978 relating thereto. Engine 

manufacturers, boat builders, and vessel operators would still be subject to those requirements 

once the Annex goes into force.A 

3.1 Definition of Amphibious Vehicle (94.2) 

3.1.1 Background 

In our original nonroad diesel and marine engine emission control programs, we adopted a 

definition of marine vessel that is consistent with the General Provisions of 1 U.S.C. 3. (see 40 

CFR 89.2, 91.2, and 94.2). According to that definition, “the word ‘vessel’ includes every 

description of watercraft or other artificial contrivance used, or capable of being used, as a 

means of transportation on water.” 

In our recreational vehicle rule (67 FR 68242, November 8, 2002), we adopted a different 

definition of marine vessel for our standards for spark-ignition nonroad engines (40 CFR Parts 

90 and 1048). According to this definition, a marine vessel is “a vehicle that is capable of 

operation in water but is not capable of operation out of water.” This definition also specifies 

that “amphibious vehicles are not marine vessels.” (40 CFR 90.2 and 40 CFR 1048.801). This 

modification was intended to address certain kinds of all-terrain vehicles that can be used on 

both land and water. These include the Argo and the Max all-terrain vehicles, which are offroad 

AAnnex VI has been ratified by the required number of countries (15 countries 

representing at least 50 percent of the world’s merchant shipping tonnage) and will enter into 

force May 20, 2005. The countries that have ratified are: Bahamas, Bangladesh, Barbados, 

Denmark, Germany, Greece, Liberia, Marshall Islands, Norway, Panama, Samoa, Singapore, 

Spain, Sweden, and Vanuatu, representing about 55 percent of the world’s merchant shipping 

tonnage. More information about this Convention can be found on our website, 

www.epa.gov/otaq/marine.htm and on the International Maritime Organization website, 

www.imo.org. 

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Technical Amendments 

utility vehicles that can also be used in water. The body design of these nonroad vehicles allows 

them to float. They are propelled through the water by their tires, which can act as linear 

propellers, or by a jet or other type of propeller. These vehicles are designed to carry up to six 

passengers or two passengers plus a payload and are often used as utility or research vehicles in 

wetlands and swampy areas. Some are also marketed for recreational fishing in such areas. 

Because these vehicles are primary intended for use on land, however, we determined that it is 

appropriate that they be certified to the applicable ATV or offroad utility vehicle standards. 

We have since learned that there are similar amphibious vehicles that use compressionignition engines. These include small vehicles like the Supacat as well as larger vehicles like the 

DUKW, LARC, and ALVIS STALWART.B The existence of these land/sea vehicles leads us to 

reconsider the definition of marine vessel in our other nonroad programs with the goal of treating 

such vessels the same across our programs and to have a uniform definition. 

3.1.2 Definition of Amphibious Vehicle 

For the purpose of our mobile source emission control program, we are proposing to define 

amphibious vehicle as a vehicle with two or more wheels or with tracks and which is designed to 

be operated primarily on land but is also capable of operating in water. Amphibious vehicles 

would not be considered marine vessels and would be subject to the emission standards that 

apply to the land-based equivalent of the vehicle. We believe this approach is appropriate 

because it would subject all vehicles of a similar nature to the same set of emission standards. 

Otherwise, a manufacturer who makes available a marine-capable version of a land-based 

vehicle would have to certify the vehicle to two different standards. 

We propose to add this definition to our land-based compression-ignition nonroad engine 

regulations (40 CFR 89), our spark-ignition marine engine regulations (40 CFR 91), our 

compression-ignition marine engine regulations (40 CFR 94), our spark-ignition nonroad engine 

<19 kW regulations (40 CFR 90), our spark-ignition nonroad engine >19 kW regulations (40 

CFR 1048), and our recreational engine and vehicle regulations (40 CFR 1051). We also 

propose to make the necessary changes to the definition of marine vessel in those regulations. 

BAccording to the U.S. Coast Guard, the three main types of vehicles used in the 

amphibious industry today were originally designed as military transports and are known as 

DUKWs (D=1942; U=Utility; K=Front Wheel Drive; and W=Two rear driving axels), LARCs 

(Lighter, Amphibious, Resupply, Cargo), and ALVIS STALWARTs. DUKWs were originally 

manufactured in the early 1940s for the U.S. Army, while LARCs were manufactured for the 

Navy. STALWARTs were manufactured for the British Army in the late 1960s. See Navigation 

and Vessel Inspection Circular No. 1-01, Inspection of Amphibious Passenger Carrying 

Vehicles, COMDTPUB P16700.4 NVIC 1-01, 11 December 2000. 

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Draft Technical Support Document 

3.1.3 Applicable Emission Standards 

Amphibious vehicles can be street-legal, such as excursion vehicles for tourism purposes 

(e.g., TrolleyBoats) or designed only for off-highway use (e.g., Argo, Max, DUKW). To 

determine which engine standards apply, we would look to the land-based application. Under 

this approach, any vehicle that meets our definition of “motor vehicle” in 85.1703(a) would have 

to meet the highway emission standards that would otherwise be applicable to the vehicle if it 

were not capable of operating in water. So, for example, a street-legal TrolleyBoat would have 

to have an engine that meets our standards for heavy-duty highway diesel engines. 

If an amphibious vehicle is not street-legal, i.e., it is designed only for off-highway use, then 

it must meet the emission standards in effect for a similar nonroad vehicle. If it has a 

compression-ignition engine (e.g., a DUKW), it must be certified to meet our nonroad diesel 

engine standards. If it has a spark-ignition engine, it must be certified to meet the applicable 

nonroad standards: all-terrain vehicle standards, small SI (<19 kW) standards, or large (>19 kW) 

SI standards (see table X.1-1). 

Table X.1-1 

Cycle 

Application of Nonroad to Amphibious Vehicles 

Terrain Vehicle Characteristics Applicable Standards 

Spark-ignition Rough Saddle and handlebar ATV 

Rough No saddle, <25 mph Small SI 

Rough No saddle, >25 mph ATV 

Non-rough <19 kW Small SI 

Non-rough >19 kW Large SI 

CompressionIgnition Rough or non-rough Any Nonroad CI 

The proposed definition of amphibious vehicle and revision of our definition of marine 

vessel are intended solely for the purpose of our national emission control programs. These 

definitions do not affect in any way how these vehicles are treated by the United States Coast 

Guard or any other federal, state, or local agency that may have requirements for the safety, 

registration, or operation of such vehicles. It also does not affect the requirements for 

amphibious vessels under MARPOL Annex VI. Specifically, after the Annex comes into force, 

amphibious vessels with diesel engines above 130 kW will be required to have MARPOLcompliant engines as demonstrated by an Engine International Air Pollution Prevention (EIAPP) 

certificate and related documentation (Technical File and Record Book of Engine Parameters). 

In addition, vessels above 400 gross tons will be required to have an International Air Pollution 

Prevention (IAPP) certificate. These requirements are described in our rulemaking for marine 

8
Technical Amendments 

diesel engines at or above 30 liters per cylinder, which is available on our website, 

<www.epa.gov/otaq/marine.htm>. 

3.1.4 Hovercraft 

We have learned that there are small hydrofoils (hovercraft) that can also operate on land as 

well as water. One example is the Griffon Hovercraft, which weighs 825 to 2,200 lbs and can 

carry 5 to 80 passengers. 

A hovercraft would not be considered to be an amphibious vehicle under the above definition 

because it has neither wheels nor tracks. Instead, it would be considered a marine vessel and its 

engines would be subject to our marine engine emission control program. To meet these 

requirements, a hovercraft manufacturer could either purchase and install a certified marine 

engine or take advantage of our marine engine dresser provision. This provision allows an 

engine manufacturer, post-manufacturer marinizer, or boat builder to install a certified landbased or highway engine on a marine vessel as long as the engine has a valid certificate of 

conformity, it is properly labeled, and no changes are made to the engine that could reasonably 

be expected to increase its emissions. There are certain conditions associated with this 

flexibility: the original engine label must be clearly visible; a supplemental label must be affixed 

to the engine identifying it as a dressed engine, and certain information must be submitted to 

EPA with respect to the engine and the identity of the manufacturer. Section 3.4, below, has 

additional information about our engine dresser program. 

3.2 Auxiliary Engines (94.2) 

3.2.1 Background 

In our December 1999 marine diesel engine rulemaking, we adopted a definition of “marine 

engine” that is based on whether an engine is installed or intended to be installed on a marine 

vessel (40 CFR 94.2). Some manufacturers have requested further interpretation of the phrase 

“installed or intended to be installed” as used in the definition to determine whether their engines 

are subject to emission standards for land-based or marine engines. 

The definition adopted in 1999 states: 

Marine engine means an engine that is installed or intended to be installed on a marine vessel. This 

definition does not include portable auxiliary engines for which the fueling, cooling and exhaust systems 

are not integral parts of the vessel. (64 FR 73334) 

In our rule, we explained some background we considered in adopting this definition: 

In the final land-based nonroad engine rule, we determined that a portable auxiliary engine used onboard a 

marine vessel should not be considered a marine engine (October 23, 1998, 63 FR 56967). Instead, a portable 

auxiliary engine is considered to be a land-based engine subject to the requirements of 40 CFR Part 89. To 

distinguish a marine auxiliary engine installed on a marine vessel from a land-based portable auxiliary engine 

used on a marine vessel, we specified in that rulemaking that an auxiliary engine is installed on a marine vessel 

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if its fuel, cooling, or exhaust systems are an integral part of the vessel. These auxiliary engines are therefore 

not fundamentally different than land-based engines and we regulate them under 40 CFR Part 89. (64 FR 

73302, discussing EPA’s determination in “Summary and Analysis of Comments: Control of Emissions from 

Nonroad Diesel Engines,” August 1998, p. 92) 

The regulatory text and explanation in the final rule permit some narrow amount of 

portability for an engine to be considered “installed or to be installed on a marine vessel” and 

thus a marine engine. However, this portability is limited to engines that have systems that are 

integral to the vessel. If the engine does not have systems that are integral to the vessel, it would 

be considered a land-based nonroad engine. 

3.2.2 Clarification of “portable” 

Since we finalized the above definition, we learned that there continues to be confusion 

about what is meant by “portable” in our definition of marine engine. At least one engine 

manufacturer sought further clarification about whether, for example, an engine that is attached 

to a barge would be considered portable. 

EPA would not consider an engine “installed” if it can easily be removed from a vessel to 

provide power to another application without modifications. In this case, a pump engine that is 

bolted onto the main deck of a boat or barge would not be considered installed if it could be 

readily disconnected from the pump machinery and lifted off the vessel to power a pump (or 

other device) elsewhere. Such an engine operates more as a stand-alone auxiliary engine than a 

marine engine. In contrast, EPA would consider an engine installed if it is mounted in such a 

way that would require significant effort to remove the engine (i.e., there is more to the mounting 

than a few brackets or straps). 

The one exception to this “removability” interpretation of the regulation is for those engines 

that can easily be removed from a vessel, but whose fueling, cooling or exhaust systems are 

integral to the vessel. Such an engine, though conceptually portable because of its relationship 

to the vessel, cannot operate without a connection to the vessel. For example, if a portable 

engine could be designed with a quick-connect access to the onboard fuel supply or with other 

hardware that would allow the engine to tie into the vessel’s cooling or exhaust systems, EPA 

would consider such an engine installed. Even though it is portable, such an engine could not 

generally operate without the fueling or other systems available on the vessel. In other words, it 

could not be operated once it is removed from the vessel. 

3.2.3 Regulatory revision 

The clarification described in this section does not require further regulatory text in 40 CFR 

94. However, we are adding this definition to our other nonroad programs, including our landbased compression-ignition nonroad engine regulations (40 CFR 89), our spark-ignition marine 

engine regulations (40 CFR 91), our spark-ignition nonroad engine <19 kW regulations (40 CFR 

90), and our spark-ignition nonroad engine >19 kW regulations (40 CFR 1048). 

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3.3 Certification of Marine Auxiliary Engines (94.912) 

3.3.1 Background 

The general industry practice is to produce marine engines by modifying land-based engines 

so they are suitable for marine application. The most important changes usually relate to tuning 

the power characteristics for marine propulsion, adapting the engine for use with water-based 

cooling, and changing various parts for improved corrosion resistance or compliance with Coast 

Guard requirements. However, manufacturers have also informed us that they sometimes sell 

engines for marine auxiliary service that are identical to land-based engines. 

3.3.2 Streamlined certification for marine auxiliary engines 

To avoid the regulatory and compliance burdens associated with certifying identical auxiliary 

marine engines under two separate programs, land-based and marine, we are proposing to allow 

streamlined certification. Under this approach, manufacturers would be able to include auxiliary 

marine diesel engines in a land-based engine family certified under 40 CFR part 89 or 1039, with 

the following conditions: 

" The marine engine must be identical in all material respects to a land-based engine 

covered by a valid certificate of conformity; 

" The marine engine may not be used as a propulsion engine; 

" The engine must have the emission control information label required under the landbased program, including additional information to identify the engine as certified also 

for marine auxiliary purposes; 

" The number of marine engines in the engine family must be smaller than the number of 

land-based engines; and 

" The application for certification must identify the possibility of marine auxiliary 

installations, including projected sales of marine engines; if the projected marine sales 

are substantial, we may ask for the year-end report of production volumes to include 

actual marine auxiliary engine sales. 

The requirement that the marine engine be identical in all material respect to a land-based 

engine covered by a valid certificate of conformity means that there must be no changes to the 

engine for use in the marine application. There can be no changes to the fuel system, the 

turbocharger, the cooling system requirements or any other characteristic. The engine must be 

able to be used interchangeably in a marine or land-based application without modification. 

The proposed streamlined certification for auxiliary engines is intended solely for the 

purpose of our national emission control programs. This streamlined certification does not affect 

in any way how these engines are treated by the United States Coast Guard or any other federal, 

state, or local agency that may have requirements for the safety, registration, or other operation 

of such engines. It also does not affect the requirements for auxiliary engines under MARPOL 

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Annex VI.C Specifically, after the Annex comes into force, any diesel engine above 130 kW 

installed on a marine vessel constructed on or after January 1, 2000, and any engine above 130 

kW that undergoes a substantial conversion on or after January 1, 2000, will be required to be 

MARPOL-compliant as demonstrated by an Engine International Air Pollution Prevention 

(EIAPP) certificate and related documentation (Technical File and Record Book of Engine 

Parameters). Therefore, engine manufacturers who take advantage of the streamlined 

certification for auxiliary engines and who may sell those engines for use on vessels subject to 

MARPOL Annex VI should make sure they obtain the necessary MARPOL Annex VI 

certification when they apply for certification of their land-based family. The MARPOL Annex 

VI requirements are described in our rulemaking for marine diesel engines at or above 30 liters 

per cylinder, which is available on our website, <www.epa.gov/otaq/marine.htm>. 

3.4 Engine Dressing Provisions (94.907) 

3.4.1 Background 

Some companies produce marine engines by modifying new, land-based engines and 

modifying for installation on a marine vessel. This can be done in a way that does not affect 

emissions. For example, the modifications may consist of adding a generator or reduction gears 

for propulsion. It can also involve installing a new marine cooling system that meets original 

manufacturer specifications and duplicates the cooling characteristics of the land-based engine, 

but with a different cooling medium (i.e., water). This is similar to the process of buying 

certified land-based engines to make a generator or other equipment. This simplified approach 

of producing an engine can be described as dressing an engine for a particular marine 

application. Because the modified land-based engine is subsequently used on a marine vessel, 

however, it would be considered marine diesel engines pursuant to our definition of marine 

engine. 

We included a provision in our final commercial marine diesel engine rule that exempts 

engines from the marine certification requirements if the marinizing company meets the 

following conditions (64 CFR 73303, December 29, 1999; see 40 CFR 907): 

" The engine being dressed, (the “base” engine) must be a heavy-duty highway, land-based 

nonroad, or locomotive engine, certified pursuant to 40 CFR 86, 40 CFR 89, or 40 CFR 

92. The base engine must be certified to the standards that apply at the time the base 

engine manufacturer completes assembly of the engine. We don’t allow stockpiling of 

uncertified engines. 

CMARPOL Annex VI is Annex VI, Air Pollution, to the International Convention on the 

Prevention of Pollution from Ships, 1978, as modified by the protocol of 1978 relating thereto. 

More information about this Convention can be found on our website, 

www.epa.gov/otaq/marine.htm and on the International Maritime Organization website, 

www.imo.org. 

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Technical Amendments 

" The dressing process must not involve any changes that can reasonably be expected to 

increase engine emissions. This includes a requirement that engine cooling and 

aftercooling systems stay within the ranges specified by the original engine manufacturer. 

" The original emissions-related label must remain on the engine. 

" The dressing company must report annually to us the models that are exempt under this 

provision. 

" The engine model must not be primarily for marine application. 

It should be noted that the goal of our engine dressing provisions is to eliminate the burden 

of certification and other compliance requirements where we have confidence that an engine 

already certified to comparable standards for another program will meet marine engine emission 

standards. However, the certificate holder for the base engine continues to be liable, under the 

terms of the original certification, for the emissions performance of the dressed engine. 

3.4.2 Regulatory Changes 

The engine dresser provisions as they are currently written can be exercised by engine 

manufacturers, including post-manufacturer marinizers.D We are proposing to expand the list of 

companies who can use this flexibility to boat builders who produce a marine engine by 

installing a non-marine engine on a vessel without substantially modifying it. This provision is 

intended to cover circumstances, like the hovercraft example described in section 3.2, above, in 

which a vessel manufacturer uses a highway or nonroad engine on a vessel but does not modify 

it in any way that could affect its emissions. In the hovercraft example, the engine is used to run 

an air compressor that inflates the floating platform and generates air turbulence to propel the 

vessel forward. The engine does not require marine engine cooling systems, it is not adjusted to 

provide more power, and it requires no special fuel handling systems. A similar situation exists 

for airboats, where a highway or nonroad engine is used to run a large fan to propel the vessel 

forward. Because such engines are installed on a vessel they are considered to be marine 

engines. Under our existing programs, the boat builder manufacturer would have to certify the 

engines as marine engines even if they have a certificate of conformity under our highway or 

nonroad emission control programs because they do not qualify as engine manufacturers or postmanufacturer marinizers. Our proposed revision will make it clear that these vessel 

manufacturers would also qualify for the engine dressing exemption. 

In addition, we are clarifying the provision regarding the requirement to demonstrate that the 

engine model is not primarily used in marine applications. This demonstration requires that the 

engine manufacturer show that fewer than 50 percent of the engine model’s total sales for the 

model year are dressed engines. This includes engines dressed by others as well as the 

manufacturer of the base engine. This can be shown based on sales information. Engine 

DPost-manufacturer marinizers are companies that produce a marine engine by modifying 

a non-marine engine and vessel manufacturers that substantially modify marine engines. 

13 
Draft Technical Support Document 

dressers who are not also the manufacturer of the base engine must get the original manufacturer 

to confirm that the engine is not primarily a marine engine. 

We are also clarifying the requirements related to generating and using emission credits with 

these engines. Engines adapted for marine use through the engine dressing provisions may not 

generate or use emission credits under part 94. However, they may generate credits or use 

credits under the averaging, banking, and trading (ABT) provisions of the program under which 

they are originally regulated (highway, land-based nonroad, locomotive). 

3.4.3 Requirement to Submit Emission Data 

Under our existing program, base engine manufacturers utilizing the dressing exemption 

must submit marine-specific emission data on their dressed marine engines. In addition, we may 

request marine-specific data from the original engine manufacturer if another company is 

dressing their engines for marine application. We are not proposing to change this provision. 

We intend to use this data for program oversight, to determine the validity of the exemption. 

This is important because marine engines are not operated in the same way as highway or landbased nonroad engines. This is reflected in the different duty cycles used for certification 

testing. 

Specifically, we will use the test data to evaluate the extent to which the highway or landbased nonroad engines can be expected to achieve our marine engine emission limits when 

operated as marine engines. If we find that highway or land-based nonroad engines exceed the 

marine standards based on the marine duty cycle we will consider suspending this flexibility. 

The suspension of this flexibility would not affect marine engines already in the fleet, unless 

there is a substantial emission exceedence. 

Using the data obtained under the engine dresser flexibility program to evaluate the validity 

of the exemption suggests that engine manufacturers will need to design their highway or landbased nonroad engine certification test programs to include the marine duty cycle if the engine 

may be sold into a marine application. We do not believe this will be burdensome, especially 

considering that the alternative is to do a full certification application for the marine engine. 

As discussed above, land-based engines that are credit-users are eligible for the engine 

dressing exemption. Although they are properly certified, such dressed marine diesel engines 

may exceed the marine emission standards. We will take ABT credit use into account when we 

evaluate the validity of the program. 

3.4.4 Other engine dressing provisions remain unchanged 

The other components of our engine dressing provisions remain unchanged. These include 

the following: 

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Technical Amendments 

" Any certified heavy-duty highway, nonroad, or locomotive engine will be eligible for the 

dressing exemption. 

" The marine not-to-exceed (NTE) zone provisions do not apply to dressed engines, unless 

NTE provisions are in place for the certified base engine. 

" Engines that qualify as dressed engines are considered to have a certificate under 

regulatory programs for both land-based and marine engines. 

" If we find that a company with an engine dressing exemption does not, in fact, meet the 

criteria spelled out in the regulations, the engines are not exempt and we may pursue 

enforcement for selling uncertified marine engines and/or tampering with certified 

engines. 

" The engine dressing company must put a supplemental label on each exempted engine 

stating the name of the dressing company and the fact that the engine was marinized 

without affecting emission controls. This will make clear that the engine is acceptable 

for use in a marine vessel. In addition, dressing companies will need to give us minimal 

notification that they are modifying certified engines. This can be done once annually for 

a company’s whole range of dressed marine engines. 

In addition to the labeling requirement, we encourage engine manufacturers to inform 

companies dressing their engines of these requirements. This will not only aid us in educating 

affected companies, it may help protect engine manufacturers from exposure to liability if their 

engines are ever found in a marine vessel without proper documentation. 

The dressing provisions are intended solely for the purpose of our national emission control 

programs. This streamlined certification does not affect in any way how these engines are 

treated by the United States Coast Guard or any other federal, state, or local agency that may 

have requirements for the safety, registration, or other operation of such engines. It also does not 

affect the requirements for engines under MARPOL Annex VI.E Specifically, after the Annex 

comes into force, any diesel engine above 130 kW installed on a marine vessel constructed on or 

after January 1, 2000, and any engine above 130 kW that undergoes a substantial conversion on 

or after January 1, 2000, will be required to be MARPOL-compliant as demonstrated by an 

Engine International Air Pollution Prevention (EIAPP) certificate and related documentation 

(Technical File and Record Book of Engine Parameters). Therefore, engine manufacturers who 

take advantage of the engine dressing provisions and who may sell those engines for use on 

vessels subject to MARPOL Annex VI should make sure they obtain the necessary MARPOL 

Annex VI certification when they apply for certification of their land-based family. The 

MARPOL Annex VI requirements are described in our rulemaking for marine diesel engines at 

or above 30 liters per cylinder, which is available on our website, 

<www.epa.gov/otaq/marine.htm>. 

E

MARPOL Annex VI is Annex VI, Air Pollution, to the International Convention on the 

Prevention of Pollution from Ships, 1978, as modified by the protocol of 1978 relating thereto. 

More information about this Convention can be found on our website, 

www.epa.gov/otaq/marine.htm and on the International Maritime Organization website, 

www.imo.org. 

15 
Draft Technical Support Document 

3.5 Engine Repowers (94.1103(b)) 

We have received several requests for clarification about vessel repowers. Much of the 

existing confusion results from the fact that our marine engine program and the Annex VI 

program are slightly different and have different results depending on whether the engine used to 

repower the vessel is new or used. 

3.5.1 Repowering With a New Engine 

If a vessel owner is going to replace an existing engine on an existing vessel with a new

engine, then the new engine must comply with the requirements of MARPOL Annex VI and the 

EPA program. Under MARPOL Annex VI, the engine must meet the Regulation 13 NOx limits 

(it must have a Statement of Voluntary Compliance or an EIAPP). Under the EPA program, the 

engine must comply with the emission limits that are in effect when the repower occurs. Note 

that if the replacement engine is certified to our Tier 2 standards it should also have a Statement 

of Voluntary Compliance or EIAPP and therefore will meet both the MARPOL Annex VI NOx 

requirements and the EPA requirements. 

We provide an exemption in 40 CFR 941103(b)(3) which would allow a vessel owner to 

replace an existing engine with a new uncertified engine or a new engine certified to an earlier 

standard engine if it can be demonstrated that no new engine that is certified to the emission 

limits in effect at that time is produced by any manufacturer with the appropriate physical or 

performance characteristics needed to repower the vessel. In other words, if a new certified 

engine is not available that can be used, an engine manufacturer may produce a replacement 

engine that does not meet all of the requirements of our marine emission control program. For 

example, if an vessel has twin uncertified engines and it becomes necessary to replace one of 

them, the vessel owner can request approval for an engine manufacture to produce a new 

uncertified engine if it can be demonstrated that the vessel will not function properly if the 

engines are not identically matched. 

There are certain conditions for this exemption. The replacement engine must meet 

standards at least as stringent as those of the original engine. So, for example, if the original 

engine is a pre-Tier 1 engine, then the replacement engine would not have to meet emission 

limits. If it is a Tier 1 engine, it would not have to meet the Tier 2 limits if those are the limits in 

place when the replacement occurs. In addition, the engine manufacturer must take possession 

of the original engine or make sure it is destroyed. Also, the replacement engine must be clearly 

labeled to show that it does not comply with the standards and that sale or installation of the 

engine for any purpose other than as a replacement engine is a violation of federal law and 

subject to civil penalty. Our regulations contain the information that must be on the label; we are 

adding a provision to cover the case where the engine meets a previous tier of standards. 

Engines that qualify for this exemption are still subject to the Annex VI engine requirements. 

This means that if the vessel is subject to MARPOL Annex VI, the new replacement engine must 

be certified to the Annex VI NOx limits. 

16
Technical Amendments 

3.5.2 Repowering With a Used (Rebuilt) Engine 

If a vessel owner replaces an existing engine with a used (rebuilt) engine, then that 

replacement engine is not required to be certified to our marine standards. 

It should be noted, however, that if a vessel owner is going to replace an existing engine on 

an existing vessel constructed on or after January 1 2000 with a used (rebuilt) engine, the engine 

must comply with the requirements of MARPOL Annex VI. Under these requirements, the 

Annex VI NOx limits would apply if the used (rebuilt) engine undergoes a major conversion. 

This means it is substantially modified during the rebuilding process (e.g.,more was done than 

simply replacing used parts with identical new part) or it has a maximum continuous rating more 

than 10 percent higher than the old engine. If the original engine is being replaced by an 

identical used (rebuilt) engine, then there are no Annex VI emission requirements for the used 

(rebuilt) engine. 

The MARPOL Annex VI requirements apply to diesel marine engines above 130 kW. If the 

engine is not a diesel engine or is a diesel engine at or below 130 kW, then there are no 

requirements for the used (rebuilt) engine under Annex VI. 

3.5.3 Disposal of the Replaced Engine 

Our current regulations require the engine manufacturer to take possession of the engine that 

is replaced. We are revising this provision to allow the manufacturer to confirm that the engine 

has been destroyed instead. 

3.6 Other Revisions 

3.6.1 Excluded and Exempted Engines (94.904) 

We are proposing to add a new provision to Subpart J, Exclusion and Exemption Provisions, 

to allow an engine manufacturer to take an action with respect to an exempted or excluded 

engine that would otherwise be prohibited, such as selling it. Before the engine manufacturer 

can take such an action, the engine must either be certified or modified to make it identical to an 

engine that is already covered by a certificate. 

3.6.2 Requirements Applicable to Vessel Manufacturers, Owners, and Operators (94.1001) 

We are proposing to revise the applicability provisions in Section 94.1001 in Subpart K, 

Requirements Applicable to Vessel Manufacturers, Owners, and Operators, to specify that some 

of the requirements in that subpart apply to manufacturers, owners, and operators of marine 

vessels that contain engines with per-cylinder displacement of at least 2.5 liters. 

Currently, the provisions in this subpart apply only to manufacturers, owners, and operators 

of marine vessels that contain engines with per-cylinder displacement at or above 30 liters. 

17
Draft Technical Support Document 

This change is necessary because engines with per-cylinder displacement between 2.5 and 30 

liters were erroneously left out of this provision when we extended mandatory Tier 1 standards 

to these engines in our 2003 rule for marine diesel engines at or above 30 liters per cylinder. 

18
Technical Amendments 

Chapter 4: Locomotives (40 CFR part 92) 

As summarized in the preamble, we are proposing the following changes to 40 CFR part 92: 

§92.1 (a) & (d) Add paragraph (d) to clarify that subpart L applies to everyone. 

§92.2 Change "unique" to "specific" in definition of calibration. 

§92.2 Add "manufactured" to paragraph (5) of definition of new locomotive 

§92.2 Add "percent" to definition of repower 

§92.114(d)(2) Allow lower backpressures 

§92.123 (a)(2)(ii) Delete the word "not" 

Table B124-1 Clarify that 15 minute maximum refers to time after lowest idle setting is reached 

§92.132(d) Correct equation: 

KH= [C1+C2exp((- .0143)(10.714))]/ [C1+C2exp((-0.0143)(1000H))] 

§92.203(d) Correct reference from §92.208 to §92.204. 

§92.205(a)&(e), 

§92.210(d)(2)&(#), 

§92.215(b) 

Correct reference from "subpart" to "part" 

§92.208(a) Change "in which" to "for which". 

§92.210 Make reference plural in paragraph (b)(1), and add paragraph (b)(2) to clarify that 

manufacturers making engine modifications within an engine family must show that the 

modified engines still meet emission standards. 

§92.215(a)(2)(i)(A) Correct typo in "process" 

§92.216 Delete paragraph (a)(2) to allow the Office of Air and Radiation to represent itself at 

hearings. 

§92.212 Correct typo in (b)(2)(v)(G), replace "Locomotive" with "Engine" in (c)(2)(v)(A), and 

correct the applicable manufacture date in (c)(2)(v)(D)(2). 

§92.512(e) Delete "is made" 

§92.906(a) Delete "as defined in §92.2". 

§92.1106(a) Correct the penalty for tampering to be based on each engine in violation, as opposed to 

each engine and each day. 

Appendix IV to part 

92 

Correct "13-mode" to "10-mode" 

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Draft Technical Support Document 

Chapter 5: Small nonroad spark-ignition engines (40 CFR 

part 90) 

We have adopted a new approach to define maximum engine power in 40 CFR part 1039 for 

nonroad diesel engines for purposes of defining the applicability of standards. This definition 

includes a detailed procedure for determining this value. The current approach for Small SI 

engines is to rely on a definition of “gross power” that describes generally how to characterize an 

engine’s maximum power. We request comment on adopting the new definition of maximum 

engine power in 40 CFR part 90. This would have the advantage of harmonizing our treatment 

of this basic tool to characterize engines and would allow for consistent treatment across 

programs. 

The regulations for nonroad diesel engines include the following provisions to define 

maximum engine power in 40 CFR 1039.140: 

(a) An engine configuration’s maximum engine power is the maximum brake power point on the

nominal power curve for the engine configuration, as defined in this section. Round the power value

to the nearest whole kilowatt.

(b) The nominal power curve of an engine configuration is the relationship between maximum

available engine brake power and engine speed for an engine, using the mapping procedures of 40

CFR part 1065, based on the manufacturer’s design and production specifications for the engine. 

This information may also be expressed by a torque curve that relates maximum available engine

torque with engine speed.

(c) The nominal power curve must be within the range of the actual power curves of production

engines considering normal production variability. If after production begins it is determined that

your nominal power curve does not represent production engines, we may require you to amend your

application for certification under §1039.225.

20
Technical Amendments 

Chapter 6: Large nonroad spark-ignition engines (40 CFR 

part 1048) 

We adopted emission standards for Large SI engines in November 2002 (67 FR 68242). The 

regulations in 40 CFR part 1048 were our first attempt to draft emission-control regulations in 

plain-language format. In the recent final rule for nonroad diesel engines, we went through a 

similar process, including extensive interaction with a different set of manufacturers. This 

process led us to adopt regulatory provisions in 40 CFR part 1039 that differ from those in part 

1048. Since the process of meeting standards, applying for certificates, and complying with 

other emission-related requirements has a lot of commonality across programs, we have a strong 

interest in adopting consistent provisions and uniform terminology as much as possible. As a 

result, we are proposing extensive changes in part 1048 to align with the regulations in part 

1039. 

Many of the changes we are proposing for part 1048 involve relatively minor wording 

differences. Several other changes involve new or revised language to express a regulatory 

provision more clearly without changing the underlying policy. There are also some minor 

organizational changes to move certain provisions to a different location that better reflects their 

relationship to the overall process of certifying engines. We believe it is important to make these 

changes to avoid a situation where we unintentionally apply slightly different provisions to 

different categories of engines. These changes that are intended to involve no change in policy 

are not listed here.F 

The following tables highlight many of the specific changes we are proposing to part 1048. 

I. Subpart A—Overview and Applicability 

Reference Proposed Change 

1048.1 We now state that the part 1048 requirements apply to Large SI engines, rather than to the 

manufacturers of Large SI engines. 

1048.5 We no longer state that aircraft engines are excluded from emission standards under 40 CFR 

part 1048, since we have changed the definition of nonroad engine to clarify that aircraft are 

not considered nonroad engines. 

F

 See “Redline Version of 40 CFR Part 1048 Showing Proposed Changes,” EPA memo 

from Alan Stout to Docket OAR-2004-0017, July 5, 2004. 

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Draft Technical Support Document 

II. Subpart B—Emission Standards and Related Requirements 

Reference Proposed Change 

1048.101(a) In the November 2002 final rule, we excluded engines above 560 kW from transient emission 

standards on an interim basis, primarily to defer this decision to the rulemaking for nonroad 

diesel engines. Consistent with that rulemaking, we are affirming this decision as a long-term 

provision and are accordingly moving it from 1048.145 to 1048.101. These engines must still 

design for controlling transient emissions, but are not subject to the transient emission 

standards (see 1048.205). 

1048.101(g) The provision for a shorter useful life now includes provisions to clarify how a manufacturer 

can select and support some alternate useful life period. We also identify this as a shorter 

useful life in operating hours, not in years. Note that we are requesting comment on additional 

changes to this provision, as described in the preamble. 

1048.105 We are exempting marine auxiliary engines from the evaporative emission standards, since we 

are separately pursuing evaporative controls for marine systems, which will eventually extend 

to fuel systems for both propulsion and auxiliary engines. 

1048.115(a) Provisions related to controlling crankcase emissions more carefully explain how to account 

for crankcase emissions in those cases where manufacturers add crankcase emissions to 

measured exhaust emissions. 

1048.115(g) The prohibition regarding defeat devices originally specified that an emission-control strategy 

that is active during testing over the specific duty cycles would not be considered a defeat 

device. We have expanded that to include field-testing operation by excluding operation that 

occurs during all testing under the procedures of Part 1048, Subpart F. 

1048.120(a) The scope of the warranty now explicitly includes secondary purchasers to make clear that the 

emission-related warranty is fully transferrable throughout the specified warranty period. 

Also, the scope of the warranty includes the engine and all its emission-related components. 

1048.120(b) Warranty periods are clarified: (1) If mechanical warranties are offered without charge, the 

emission-related warranty for the corresponding components (or the whole engine, as 

applicable) may not be shorter than the mechanical warranty. (2) If manufacturers offer an 

extended warranty for an extra charge, the emission-related warranty may not be shorter than 

that, but only for those particular engines. (3) We clarify that the warranty period starts when 

the engine is first placed into service. 

1048.120(c) We clarify that the warranty includes components such as catalysts that are manufactured by 

another company, even if the component is shipped separately and the certifying manufacturer 

never takes possession of those components. 

1048.120(e) We add a requirement for manufacturers to describe the emission-related warranty provisions 

that apply to their engines in the owners manual. 

1048.125(c) The rule originally allowed for extra maintenance for special situations. We are clarifying this 

to point out that manufacturers must make clear to the operator that this additional maintenance 

is tied to some special situation. 

1048.125(g) This provision was originally adopted as §1048.120(d). We have modified this to more 

carefully track provisions in the Clean Air Act. In particular, this provision now clarifies that 

owners must generally pay for scheduled maintenance, with an exception for relatively 

expensive parts that have been added to meet emission standards and that are not needed for 

proper engine performance. 

1048.125(h) Consistent with §1048.125(g), we now require manufacturers to communicate the owner’s 

obligations to properly maintain their engines. 

22
Technical Amendments 

1048.130(d) We have added a provision allowing manufacturers to communicate installation instructions to 

engine installers other than sending a copy of the instructions along with each engine. 

Manufacturers would describe in their application for certification that they would, for 

example, post their installation instructions on a publicly available web site. 

1048.135(c) We have modified the requirements for the emission control information label: (1) We now 

allow manufacturers to apply the corporate name and trademark from another company, (2) 

The manufacturing date need not be on the label, as long as the manufacturer keeps records 

that allow us to find out the manufacturing date, (3) The maintenance specifications may be 

omitted from the label if there is not enough room on the label and the information is instead 

printed in the owners manual. (4) Useful life must be included only if it is different than the 

default value specified in §1048.101(g). 

1048.135(d) We are adding a provision to specifically allow manufacturers to include additional label 

information related to meeting other emission standards, or properly maintaining engines. 

1048.135(g) We are adding a requirement for engine manufacturers to supply duplicate labels to equipment 

manufacturers that need them and to keep basic records to document the transactions. We 

have already adopted corresponding limits on what equipment manufacturers must do to 

properly apply these duplicate labels and prevent abuse, such as proliferation of counterfeit 

labels. 

1048.139 We are adding a new section that describes more precisely how to determine maximum engine 

power. This applies to any provision in the regulations that relates to engine power, such as 

the applicability to engines above 19 kW. Maximum engine power values also serve to define 

a unique engine configuration (within normal production tolerances). If manufacturers want to 

include engines with different values for maximum engine power in an engine family, they 

would treat those as separate engine configurations. 

1048.140 We are adding a new set of voluntary emission standards that would allow a manufacturer to 

qualify for the Blue Sky designation. Some manufacturers have expressed an interest in using 

automotive engines in nonroad applications. The additional voluntary standards are intended 

to more closely reflect the emission-control potential of a modern automotive engine (lightduty or heavy-duty) when produced for nonroad applications. We are also interested in 

aligning our voluntary standards with those under consideration by the California Air 

Resources Board. 

1048.145(a) We are clarifying the provisions related to family banking. For example, we are adding a 

requirement that manufacturers start producing early engines by September 1, 2006 to reduce 

the compliance burden in 2007. This prevents manufacturers from reducing their burden by 

producing engines marginally earlier than is required under the Tier 2 standards. Once a 

manufacturer qualifies, all the engines produced before January 1, 2007 would count toward 

reducing the Tier 2 compliance burden. We also clarify that the “late” engines would need to 

continue to be certified to Tier 1 emission standards, with all the associated requirements. 

Finally, we require manufacturers opting into family banking to report at the end of each year 

how many “early” or “late” engines they produced in the preceding year. 

III. Subpart C—Certifying Engine Families 

Reference Proposed Change 

1048.201(g) We are including a clearer statement that we may require manufacturers to deliver test engines 

to a particular facility for our testing. 

1048.205(a) We are clarifying the direction to describe emission-control systems to require that 

manufacturers identify each unique configuration. 

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Draft Technical Support Document 

1048.205(b) We are adding a clarifying note to include part numbers for emission-related components. 

This information, which is already commonly included in applications, helps us to manage the 

information related to the certified configuration, especially as it relates to running changes in 

an engine family. 

1048.205(b)(11) The instructions for completing the certification application now include detailed items related 

to auxiliary emission-control devices. This clarifies the manufacturers’ existing responsibility 

to describe their emission-control systems. 

1048.205(r) Consistent with the Tier 4 final rule for nonroad diesel engines, we require manufacturers of 

engines above 560 kW to show how they control transient emissions. This gives us an 

opportunity in the certification process to ensure that engines are designed with control 

strategies that are similar to those for smaller engines and to ensure that engines have no defeat 

devices. 

1048.205(t) In addition to the existing requirement to describe adjustable parameters, we are including a 

requirement to describe how the adjustment limits are effective in preventing operators from 

making inappropriate adjustments. 

1048.250(b) We are adding a requirement to keep records related to production figures by separate 

assembly plants and lists of engine identification numbers in each engine family. 

IV. Subpart D— Production-line Testing 

1048.310(g) Clarify that the maximum testing rate of 1 percent for production-line testing applies only after 

testing the minimum number of engines specified. 

V. Subpart F—Test Procedures 

Reference Proposed Change 

1048.501(a) We are allowing testing with partial-flow dilute sampling. This approach is generally used for 

larger diesel engines, but some laboratories may also be set up to use partial-flow sampling for 

Large SI engines. 

1048.501(a) We no longer specify that testing must include measurement of CO2 emissions. However, if 

manufacturers use equipment and procedures that require measurement of CO2 emissions, then 

this information must be included in the application for certification (see §1048.205). 

1048.505 We adopted conventional duty cycles and procedures for steady-state testing in the November 

2002 final rule. We are supplementing these procedures with an option to test engines using a 

different kind of steady-state testing. Ramped modal cycles incorporate the same testing 

modes (in engine speed and load) into a single, continuous sampling period that involves 

gradual ramps to transition from one mode to the next. See the related supporting document 

for additional explanation of the development of ramped-modal testing.7 We are not requiring 

ramped-modal testing instead of conventional discrete-mode testing, since the emission-control 

systems on Large SI engines generally do not have technologies that are time-sensitive (such 

as aftertreatment devices that undergo regeneration events), nor are emission levels so low that 

it is difficult to get accurate measurements over relatively short sampling periods. 

7

 Final Regulatory Impact Analysis: Control of Emissions from Nonroad Diesel Engines, 

U.S. EPA, May 2004, EPA420-R-04-0xx (Docket OAR-2004-0017-00xx). 

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Technical Amendments 

VI. Subpart G—Compliance Provisions 

Reference Proposed Change 

1048.605 We have made changes to this section to clarify the responsibilities of the original 

manufacturer of the engine and that of the “engine dressing” company. We also clarify the 

ABT responsibilities relative to engines or vehicles that are certified under the motor-vehicle 

program and used in nonroad applications. 

1048.610 This section includes the same changes made in 1048.605 and adds a criterion such that adding 

500 pounds to the weight of the vehicle is considered to be a substantial change to the engine. 

This is consistent with the approach we have taken in guidance documents under current 

regulations. The requirement to avoid changing the emission-control system now includes the 

refueling controls, since the vehicle is being used in nonroad service in its certified 

configuration; no engine installation is required. 

1048.625 Provisions related to engines burning noncommercial fuels have been modified to clarify the 

engine manufacturer’s responsibilities under this section. We have also modified the definition 

of noncommercial fuel to include fuel that is, for example, captured from an oil well and sold 

without processing the fuel to conform to any standardized specifications for commercial fuels. 

1048.630 We are adding provisions describing a process by which manufacturers may produce engines 

that will be used solely for competition. These are consistent with provisions we have adopted 

for nonroad diesel engines. 

1048.635 We are adding provisions that will allow manufacturers to place another company’s brand 

name on the emission control information label. This is consistent with provisions we have 

adopted for nonroad diesel engines. 

VII. Subpart I—Definitions and Other Reference Information 

Reference Proposed Change 

1048.801 Brake power: We are revising the definition to focus on power required to fuel, lubricate, heat, 

and cool the engine, rather than on the components that do these things. This is necessary to 

address the ambiguity that would result from a single component such as a heat exchanger that 

cools the engine in addition to providing cooling for other purposes. 

1048.801 We are revising the definition for constant-speed engines to clarify the that there are two 

distinct types of constant-speed governing. We also differentiate between constant-speed 

engines (certified using constant-speed duty cycles) and constant-speed operation (any kind of 

engine operation that is governed to stay at a constant-speed). This distinction is necessary 

because some engines that are not restricted to constant-speed certification may be installed in 

constant-speed applications. 

1048.801 Noncommercial fuel: We have broadened this definition slightly to allow naturally emitted 

gases (such as from a landfill) to continue to be noncommercial fuels even if they are sold to an 

operator, as long as the product is not modified or processed in a way that would allow it to 

meet applicable standards for commercial fuels. 

1048.801 Round: We are changing our rounding specification from ASTM E29 to NIST Special 

Publication 811. Our understanding is that these two publications have equivalent 

specifications. 

1048.820 We are revising these provisions to clarify that we handle confidential information that we 

gather from manufacturers during inspections the same way that we handle what 

manufacturers send to us. 

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Draft Technical Support Document 

1048.825 We are adding details to better define the process for requesting hearings under part 1048. For 

example, manufacturers would need to send a written request within 30 days of an EPA 

judgment. Also, we would limit hearings to substantial factual issues. These are consistent 

with longstanding regulatory provisions from other programs. 

26
Technical Amendments 

Chapter 7: Recreational vehicles (40 CFR part 1051) 

We are considering several adjustments to the test procedures, definitions, and other 

provisions related to the emission-control program for recreational vehicles. 

1. Evaporative Emission Family Definition 

Manufacturers certify their fuel systems by grouping them into emission families that have 

similar emission characteristics. The emission family definition is fundamental to the 

certification process and to a large degree determines the amount of testing required for 

certification. In the preamble for recreational vehicle FRM (67 FR 68242, November 8, 2002), 

we stated that “the regulations include specific characteristics for grouping emission families for 

each category of tanks and hoses. For fuel tanks, key parameters include wall thickness, material 

used (including additives such as pigments, plasticizers, and UV inhibitors), and the emissioncontrol strategy applied. For hoses, key parameters include material, wall thickness, and 

emission-control strategy applied.” 

However, the regulatory text simply states “evaporative emission controls” as a subset of the 

engine family without detailing specific characteristics. We are proposing to modify 

§1051.230(b)(8) to include the key parameters discussed above. Types of evaporative emission 

controls include, but would not be limited to, permeation barriers, surface treatments, and barrier 

platelets (i.e. Selar®). 

In addition we are restructuring this section to distinguish between exhaust and evaporative 

emission families. Currently, the regulations state that “you may ask us to create separate 

families for exhaust emissions and evaporative emissions.” We are proposing that the primary 

approach be to have separate exhaust and evaporative emission families with the option for the 

manufacturer to combine these families into a single emission family. 

2. Sealing the Fuel Tank During Permeation Testing 

§1051.515 of the regulations specifies that the fuel tank must be sealed during the 

preconditioning fuel soak and permeation test. In §1051.515(a)(5), we expanded on how a tank 

may be sealed by stating: “Seal the fuel tank using nonpermeable fittings, such as metal or 

TeflonTM.” This statement, as it is written, has led to some confusion. One manufacturer was 

under the impression that they could seal all openings in the fuel tank with metal fittings 

including those openings that would be sealed in some other way in production vehicles. 

However, the intent of this statement was only to allow nonpermeable plugs in openings that 

would not normally be sealed such as hose connection fittings. In the case where a fuel cap 

directly mounted to the fuel tank, the production fuel cap (including gaskets) would have to be 

used during a permeation test. The inside surface area of the fuel cap would be included in the 

27
Draft Technical Support Document 

calculation of total tank surface area. However, if there is a vent hole in the fuel cap, the vent 

hole could be sealed using a nonpermeable plug. 

We are proposing to modify §1051.515(a)(5) to read: “Seal the fuel tank using fuel caps and 

other fittings that would be used to seal openings in a production fuel tank. In the case where 

openings are not normally sealed on the fuel tank (such as hose connection fittings and vents in 

fuel caps), these openings may be sealed using nonpermeable fittings such as metal or 

fluoropolymer plugs.” 

In addition, we are proposing to include a clarification in the definition of fuel system that 

states: “In the case where the fuel tank cap or other components (excluding fuel lines) are 

directly mounted on the fuel tank, they are considered to be a part of the fuel tank.” 

3. Definition of fuel lines 

The fuel system hose permeation regulations refer to “fuel lines” without providing a 

definition of what fuel lines are. The intent of the permeation standards is to prevent 

hydrocarbons from permeating through the walls of the fuel system. This permeation occurs at 

the same rate for materials exposed to saturated fuel vapor as it does for materials exposed to 

fuel.

8,9,10,11 Therefore the intent of the permeation standards was to include all hose and tubing in 

the fuel system that carries fuel or fuel vapor. To clarify this point we are proposing to add a 

definition of fuel lines that reads as follows: “fuel line means all hoses or tubing containing 

either liquid fuel or fuel vapor including fuel delivery hose to the engine, fuel lines on the 

engine, fill neck hose, hose connecting dual fuel tanks, and hose connecting a fuel tank to a 

carbon canister.” 

4. Timing of the permeation test run 

The fuel tank permeation test currently includes a soak period on gasoline blended with 10% 

ethanol (E10). The purpose of this soak is to stabilize the permeation rate of the fuel through the 

fuel tank. E10 is used because it generally represents the worst case for fuel that is commonly 

8

Tuckner, P., Baker, J., “Fuel Permeation Testing using Gravimetric Methods,” SAE 

Paper 2000-01-1096, 2000, Docket A-2000-01, Document IV-A-96. 

9

Nulman, M., Olejnik, A., Samus, M., Fead, E., Rossi, G., “Fuel Permeation Performance 

of Polymeric Materials,” SAE Paper 2001-01-1999, 2001, Docket A-2000-01, Document IV-A23. 

10Stevens, M., Demorest, R., “Fuel Permeation Analysis Method Correction,” SAE Paper 

1999-01-0376, 1999, Docket A-2000-02, Document IV-A-03. 

11Lockhart, M., Nulman, M., Rossi, G., “Estimating Real Time Diurnal Permeation from 

Constant Temperature Measurements,” SAE Paper 2001-01-0730, Docket A-2000-01, Document 

IV-A-21. 

28 
Technical Amendments 

used by in-use vehicles. After the soak, the fuel tank is drained and refilled with fresh fuel prior 

to the permeation weight loss test. The intent is to begin the test as soon as the fuel in the tank 

reaches the test temperature. However, the current regulations to not specify the allowable 

period between the fuel soak and the permeation test run. We are proposing to require the 

permeation test run to begin within eight hours of fueling the tank. This should provide ample 

time for the fuel to stabilize within the test temperature range. 

The length of the test run as described in the preamble is two weeks. This was determined to 

be ample time for the weight loss to be large enough for an accurate measurement to be made on 

a fuel tank meeting the permeation standards. In the regulations, we specify a range of 2 to 4 

weeks using good engineering judgement based on the permeation rate. The intent of this is to 

allow more time for tests on very low permeating fuel tanks to gain a large enough weight loss to 

make an accurate measurement. To provide clarification on the appropriate test length, we 

propose to update the regulations to more clearly define when a 4 week test may be used. 

The concern with the above timing issues is two-fold. First, if the fuel in the tank would sit 

long enough before the first measurement (or even during an overly long weight loss test), 

“weathering” of the fuel could reduce the measured permeation rate. Weathering refers to the 

evaporation of lighter hydrocarbons in the fuel resulting in a less volatile fuel. In this case, the 

fuel during the test could end up having a significantly lower Reid vapor pressure (RVP) than is 

specified in the regulations. 

The second concern with the timing of the permeation testing is related to the effects on 

ethanol on a fuel system. When the fuel tank is soaked using E10, the ethanol in the fuel can 

temporarily change the structure of the polymers used to construct the fuel tank. This change in 

structure increases the permeation rate through most materials. The fuel permeation test run 

itself can be performed using either gasoline or E10. We anticipated that either fuel would 

produce the same permeation results because, even if gasoline were used, the effects of the 

ethanol fuel soak would not be reversed in the short time needed to perform the weight loss test. 

Clearly, if the fuel tank were allowed to soak too long with gasoline during the permeation test, 

the effects of the ethanol soak would be reversed and the measured emissions could be 

underestimated. 

To provide further assurance that the effects of the ethanol soak are included in the 

permeation test, we are proposing another requirement for fuel tanks tested for permeation on 

gasoline. Weight measurements of the fuel tank would be made daily. In this case, daily means 

five days per week to allow for weekends. The daily weight loss would be plotted versus time to 

determine if a linear relationship was observed. We would expect that if the ethanol effects were 

to begin to reverse, that the slope of the weight loss line would flatten. If a linear relationship 

(minimum R-squared of 0.8) was not seen through the entire permeation test run, the test would 

be void. To avoid the issue of fuel effects on the permeation rate, EPA would likely perform any 

confirmatory tests using E10 fuel. 

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Draft Technical Support Document 

5. Phase-In for Youth ATV and Off-Highway Motorcycle Models 

It was our intention in the recreational vehicle regulations to include youth ATV and offhighway motorcycle models to be counted in the phase-in percentage requirements for ATVs and 

off-highway motorcycles. Therefore, we are proposing language to clarify that ATVs with a 

total displacement of 100 cc or less and off-highway motorcycles with a total displacement of 70 

cc or less will count in the phase-in (percentage) requirements of §1051.105. 

6. CO Maximum FEL for ATVs 

For standards that allow averaging, EPA has traditionally set a maximum allowable family 

emission limit (FEL) to ensure that manufacturers won’t establish FELs that unneccesarily 

exceed the standard. Table 1 of §1051.107, which lists the exhaust emission standards for 

ATVs, lists a maximum allowable family emission limit of 50 g/km for the CO standard. 

However, since there is not an option for CO averaging for ATVs, there is no need for a 

maximum allowable family emission limit. We are therefore proposing to remove the FEL cap 

of 50 g/km from Table 1. 

7. Emissions-Related Warranty Period 

The language in §1051.120(b) states “the emission-related warranty period must be valid for 

at least 50 percent of the vehicles minimum useful life in kilometers..” However, many 

recreational vehicles are equipped with hourmeters instead of odometers. Therefore it makes 

sense to add “hours of engine operation” to §1051.120(b). 

8. NER Equations 

The recreational vehicle rule requires manufacturers to label all of their certified vehicles 

with a removable hang-tag showing its emission characteristics relative to other models. In lieu 

of providing certification emission levels on the tag, manufacturers are required to calculate and 

provide a normalized emission rate (NER). §1051.135(g) requires manufacturers to round the 

NER to the nearest whole number. However, we believe that it would be more appropriate and 

equitable to round to one decimal place instead. We are therefore proposing to modify 

§1051.135(g) to allow rounding to one decimal place rather than to the nearest whole number. 

We are also proposing two additional equations for engines under 225 cc that are certified to 

g/kW-hr standards. The first equation is an interim provision for engines under 225 cc that are 

certified under §1051.145(b). The proposed equation is similar to the existing equation that will 

continue to apply to larger engines certified under §1051.145(b), but accounts for the higher 

standards that apply to engines under 225 cc. The second equations would apply to ATV 

engines under 100 cc that are certified under §1051.615. This equation was previously 

described in the 

30
Technical Amendments 

Regulatory Support Document for the recreational vehicle final rule.12 

9. Useful Life for Youth ATV and Off-Highway Motorcycle Models 

§1051.105(c) and §1051.107(c) state that “..ATVs and off-highway motorcycles must meet a 

minimum useful life of 10,000 kilometers, 1000 hours of operation, or five years, whichever 

comes first.” The Motorcycle Industry Council (MIC) provided us with survey data that 

indicates that for off-highway motorcycles with a displacement less than 70 cc and ATVs with a 

displacement less than 100 cc, the minimum useful life should be half of that for the larger 

displacement models. We are therefore proposing to change the minimum useful life for these 

youth models to 5,000 kilometers and 500 hours. 

10. Raw Gas Sampling Provisions 

In the preamble of the final rule adopting standards for recreational vehicles, we described 

our intent to allow all ATVs certifying to the J1088 cycle to use raw gas sampling. However, 

through oversight, this provision did not appear in the regulations. We are therefore proposing 

to adopt the intended provision allowing all ATVs certifying to J1088 to use the raw gas 

sampling provisions of Part 91 for engine testing through the 2008 model year. ATVs under 100 

cc and off-highway motorcycles under 70 cc certifying using J1088 may continue to use raw gas 

sampling through the 2010 model year after which time they must provide data and an analysis 

which demonstrates emissions equivalence between the raw gas and dilute sampling methods. 

11. Engine Test Speed 

The International Snowmobile Manufacturers Association (ISMA) and the Motorcycle 

Industry Council (MIC) have both stated that due to the nature of how snowmobiles and ATVs 

operate, §1065.515(d) which describes how to determine “maximum test speed,” is inappropriate 

and overly burdensome. They have suggested language that significantly reduces the number of 

steps involved in determining maximum test speed. ISMA has suggested the following 

language: “Maximum test speed for snowmobile testing is the maximum steady speed of the 

installed engine during normal in-use operation at wide-open throttle.” MIC suggested the 

following language: “For constant-speed engines, maximum test speed is the same as the 

engine’s maximum operating speed in use. For variable-speed engines, maximum test speed is 

the vehicle’s rated speed, where rated speed is the point at which the engine’s peak power 

occurs.” Rather than the specific wording recommended, we are proposing a more general 

approach that allows manufacturers to test engines from recreational vehicles based on an 

engine’s maximum power if that better represents in-use operation. We request comment on the 

appropriateness of this proposed provision. 

12 Final Regulatory Support Document: Control of Emissions from Unregulated Nonroad 

Engines, EPA420-R-02-022, September 2002. 

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Draft Technical Support Document 

12. Low-speed ATVs 

There are two types of vehicles that meet the definition of all-terrain vehicle. First, 

traditional ATV models have four wheels, a single seat straddled by the rider and handlebars. 

We also define other vehicles to be all-terrain vehicles if they are designed for operation over 

rough terrain. However, we exclude rough-terrain vehicles if they meet certain criteria as utility 

vehicles. Manufacturers have raised the concern that they produce low-speed models that would 

meet the second meaning of the definition for all-terrain vehicle. The engine technology and 

vehicle operation, however, are much more like that for Small SI engines covered under 40 CFR 

part 90. To address this, we are proposing to set a threshold to qualify as an all-terrain vehicle 

under this second meaning of the definition. Any such vehicles with maximum speed below 25 

miles per hour would not be considered an all-terrain vehicle and would therefore be subject to 

emission standards under 40 CFR part 90. We request comment on this approach to revising the 

definition for all-terrain vehicles. 

13. Ramped-modal Testing 

As described in Chapter 1, we have developed a testing method that simplifies steady-state 

emission measurements. Ramped-modal procedures combine the several discrete modes into a 

defined sequence of operation with a fixed amount of time in each mode to capture the 

appropriate weighting factor for individual modes. Emissions are measured continuously during 

engine operation, so there is a single measurement to quantify, rather than separately measuring 

emissions from each mode and mathematically determining the overall brake-specific emission 

level. We have proposed this testing method either as a required method or an alternative 

method for several other engine types. This approach may also be appropriate for the steadystate testing cycles specified for snowmobiles and youth-model ATVs and off-highway 

motorcycles. We are requesting comment on allowing manufacturers to choose between 

ramped-modal testing and the conventional approach with discrete-mode testing. 

The following tables show how we would convert the existing steady-state duty cycles in 

part 1051 to ramped-modal cycles. 

Ramped-modal Cycle for Testing Snowmobiles (§1051.505) 

RMC Mode Time in Mode Speed (percent) Torque (percent) 

1a Steady-state 

1b Transition 

2a Steady-state 

2b Transition 

3a Steady-state 

3b Transition 

4a Steady-state 

4b Transition 

5a Steady-state 

5b Transition 

6 Steady-state 

27 Warm Idle 0 

20 Linear Transition Linear Transition 

121 100 100 

20 Linear Transition Linear Transition 

347 65 19 

20 Linear Transition Linear Transition 

305 85 51 

20 Linear Transition Linear Transition 

272 75 33 

20 Linear Transition Linear Transition 

28 Warm Idle 0 

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Technical Amendments 

1 Percent speed is percent of maximum test speed. 2

 Advance from one mode to the next within a 20-second transition phase. During the

transition phase, command a linear progression from the torque setting of the current 

mode to the torque setting of the next mode.

3 Percent torque is percent of maximum test torque at maximum test speed.

Ramped-modal Cycle for Testing Recreational Engines (§1051.615) 

RMC Time Speed Torque 

Mode (percent) 1,2 (percent) 2,3 

1a Steady-state 

1b Transition 

2a Steady-state 

2b Transition 

3a Steady-state 

3b Transition 

4a Steady-state 

4b Transition 

5a Steady-state 

5b Transition 

6a Steady-state 

6b Transition 

7 Steady-state 

41 Warm Idle 0 

20 Linear Transition Linear Transition 

135 85 100 

20 85 Linear Transition 

112 85 10 

20 85 Linear Transition 

337 85 75 

20 85 Linear Transition 

518 85 25 

20 85 Linear Transition 

494 85 50 

20 Linear Transition Linear Transition 

43 Warm Idle 0 

1 Percent speed is percent of maximum test speed. 2

 Advance from one mode to the next within a 20-second transition phase. 

During the transition phase, command a linear progression from the torque

setting of the current mode to the torque setting of the next mode.

3 Percent torque is percent of maximum test torque at the commanded test speed.

14. Other Changes 

We adopted emission standards for recreational vehicles in November 2002 (67 FR 68242). 

The regulations in 40 CFR part 1051 were our first attempt to draft emission-control regulations 

in plain-language format. In the recent final rule for nonroad diesel engines, we went through a 

similar process, including extensive interaction with a different set of manufacturers. This 

process led us to adopt regulatory provisions in 40 CFR part 1039 that differ from those in part 

1051. Since the process of meeting standards, applying for certificates, and complying with 

other emission-related requirements has a lot of commonality across programs, we have a strong 

interest in adopting consistent provisions and uniform terminology as much as possible. As a 

result, we are proposing extensive changes in part 1051 to align with the regulations in part 

1039. 

Many of the changes we are proposing for part 1051 involve relatively minor wording 

differences. Several other changes involve new or revised language to express a regulatory 

provision more clearly without changing the underlying policy. There are also some minor 

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Draft Technical Support Document 

organizational changes to move certain provisions to a different location that better reflects their 

relationship to the overall process of certifying engines. We believe it is important to make these 

changes to avoid a situation where we unintentionally apply slightly different provisions to 

different categories of engines. These changes that are intended to involve no change in policy 

are not listed here.13 

The following tables highlight many of the specific changes we are proposing to part 1051. 

I. Subpart A—Overview and Applicability 

Reference Proposed Change 

1051.1 We now state that the part 1051 requirements apply to recreational vehicles, rather than to the 

manufacturers of recreational vehicles. 

II. Subpart B—Emission Standards and Related Requirements 

Reference Proposed Change 

1051.120(a) The scope of the warranty now explicitly includes secondary purchasers to make clear that the 

emission-related warranty is fully transferrable throughout the specified warranty period. 

Also, the scope of the warranty includes the engine and all its emission-related components. 

1051.120(b) Warranty periods are clarified: (1) If mechanical warranties are offered without charge, the 

emission-related warranty for the corresponding components (or the whole engine, as 

applicable) may not be shorter than the mechanical warranty. (2) If manufacturers offer an 

extended warranty for an extra charge, the emission-related warranty may not be shorter than 

that, but only for those particular engines. (3) We clarify that the warranty period starts when 

the engine is first placed into service. 

1051.120(c) We clarify that the warranty includes components such as catalysts that are manufactured by 

another company, even if the component is shipped separately and the certifying manufacturer 

never takes possession of those components. 

1051.120(e) We add a requirement for manufacturers to describe the emission-related warranty provisions 

that apply to their engines in the owners manual. 

1051.125(c) The rule originally allowed for extra maintenance for special situations. We are clarifying this 

to point out that manufacturers must make clear to the operator that this additional maintenance 

is tied to some special situation. 

1051.125(g) This provision was originally adopted as §1051.120(d). We have modified this to more 

carefully track provisions in the Clean Air Act. In particular, this provision now clarifies that 

owners must generally pay for scheduled maintenance, with an exception for relatively 

expensive parts that have been added to meet emission standards and that are not needed for 

proper engine performance. 

1051.125(h) Consistent with §1051.125(g), we now require manufacturers to communicate the owner’s 

obligations to properly maintain their engines. 

13 See “Redline Version of 40 CFR Part 1051 Showing Proposed Changes,” EPA memo 

from Alan Stout to Docket OAR-2004-0017, July 5, 2004. 

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Technical Amendments 

1051.130(d) We have added a provision allowing manufacturers to communicate installation instructions to 

engine installers other than sending a copy of the instructions along with each engine. 

Manufacturers would describe in their application for certification that they would, for 

example, post their installation instructions on a publicly available web site. 

1051.135(c) We have modified the requirements for the emission control information label: (1) We now 

allow manufacturers to apply the corporate name and trademark from another company, (2) 

The manufacturing date need not be on the label, as long as the manufacturer keeps records 

that allow us to find out the manufacturing date, or stamp the date on the engine and print it in 

the owners manual, (3) Only the exhaust emissions must be printed on the label. 

1051.135(d) We are adding a provision to specifically allow manufacturers to include additional label 

information related to meeting other emission standards, or properly maintaining engines. 

1051.135(g) We are adding a requirement for engine manufacturers to supply duplicate labels to equipment 

manufacturers that need them and to keep basic records to document the transactions. We 

have already adopted corresponding limits on what equipment manufacturers must do to 

properly apply these duplicate labels and prevent abuse, such as proliferation of counterfeit 

labels. 

1051.145(c) We are correcting the provision related to waived production-line testing for engines that do 

not generate or use ABT credits; the corrected language refers to all the different emission 

standards to which this applies. 

III. Subpart C—Certifying Engine Families 

Reference Proposed Change 

1051.201(g) We are including a clearer statement that we may require manufacturers to deliver test engines 

to a particular facility for our testing. 

1051.205(a) We are clarifying the direction to describe emission-control systems to require that 

manufacturers identify each unique configuration. 

1051.205(b) We are adding a clarifying note to include part numbers for emission-related components. 

This information, which is already commonly included in applications, helps us to manage the 

information related to the certified configuration, especially as it relates to running changes in 

an engine family. 

1051.205(b)(11) The instructions for completing the certification application now include detailed items related 

to auxiliary emission-control devices. This clarifies the manufacturers’ existing responsibility 

to describe their emission-control systems. 

1051.205(k) Add a requirement to include the hang-tag label with normalized emission rates in the 

application for certification. 

1051.205(t) In addition to the existing requirement to describe adjustable parameters, we are including a 

requirement to describe how the adjustment limits are effective in preventing operators from 

making inappropriate adjustments. 

1051.250(b) We are adding a requirement to keep records related to production figures by separate 

assembly plants and lists of engine identification numbers in each engine family. 

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Draft Technical Support Document 

IV. Subpart D—Testing Production-Line Engines 

Reference Proposed Change 

1051.310(g) Clarify that the maximum testing rate of 1 percent for production-line testing applies only after 

testing the minimum number of engines specified. 

1051.345 Change reporting requirements based on calendar quarters to refer instead to the test period. 

This addresses small-volume families for which the test period is the full model year. 

V. Subpart F—Test Procedures 

Reference Proposed Change 

1051.501(a) We no longer specify that testing must include measurement of CO2 emissions. However, if 

manufacturers use equipment and procedures that require measurement of CO2 emissions, then 

this information must be included in the application for certification (see §1051.205). 

1051.520 The provisions that were adopted under this section are now included under §1051.243. 

VI. Subpart G—Compliance Provisions 

Reference Proposed Change 

1051.605 We have made changes to this section to clarify the responsibilities of the original 

manufacturer of the engine and that of the “engine dressing” company. We also clarify the 

ABT responsibilities relative to engines or vehicles that are certified under the motor-vehicle 

program and used in recreational vehicles. 

1051.610 This section includes the same changes made in 1051.605 and adds a criterion such that adding 

500 pounds to the weight of the vehicle is considered to be a substantial change to the engine. 

This is consistent with the approach we have taken in guidance documents under current 

regulations. The requirement to avoid changing the emission-control system now includes the 

refueling controls, since the vehicle is being used in nonroad service in its certified 

configuration; no engine installation is required. 

1051.635 We are adding provisions that will allow manufacturers to place another company’s brand 

name on the emission control information label. This is consistent with provisions we have 

adopted for nonroad diesel engines. 

VI. Subpart H—ABT Provisions 

Reference Proposed Change 

1051.701 We clarify the limits on using emission credits across families and model years, especially as it 

relates to noncompliant engines. 

1051.705 We clarify the process for reconciling the balance of emission credits at the end of the model 

year. 

1051.710 We clarify the process for banking emission credits and using banked emission credits. 

1051.715 We clarify the process for trading emission credits. 

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Technical Amendments 

1051.725 - 735 We clarify the requirements for sending us ABT-related information in the application for 

certification and the end-of-year report, and for keeping such records. 

1051.745 We clarify the legal liabilities associated with using ABT provisions to comply with emission 

standards. 

VII. Subpart I—Definitions and Other Reference Information 

Reference Proposed Change 

1051.801 Brake power: We are revising the definition to focus on power required to fuel, lubricate, heat, 

and cool the engine, rather than on the components that do these things. This is necessary to 

address the ambiguity that would result from a single component such as a heat exchanger that 

cools the engine in addition to providing cooling for other purposes. 

1051.801 Round: We are changing our rounding specification from ASTM E29 to NIST Special 

Publication 811. Our understanding is that these two publications have equivalent 

specifications. 

1051.820 We are revising these provisions to clarify that we handle confidential information that we 

gather from manufacturers during inspections the same way that we handle what 

manufacturers send us. 

1051.825 We are adding details to better define the process for requesting hearings under part 1051. For 

example, manufacturers would need to send a written request within 30 days of an EPA 

judgment. Also, we would limit hearings to substantial factual issues. These are consistent 

with longstanding regulatory provisions from other programs. 

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Draft Technical Support Document 

Chapter 8: Test Procedures (40 CFR part 1065) 

The following tables describe the changes we are proposing for 40 CFR part 1065. The table 

entries generally describe the background and rationale for provisions we are adopting. We also 

cite the source of many of these provisions, including other parts of the Code of Federal 

Regulations and the standards adopted by the International Organization for Standardization 

(ISO). 

Subpart A– Applicability and General Provisions 

§1065.1 Applicability 

Reference Description Source 

(a ) and (b) We broadened applicability of Part 1065 to include Model year 2008 

and later heavy-duty highway engines we regulate under 40 CFR Part 

86. For model years 2006 and 2007, manufacturers may use the test 

procedures in this part or those specified in 40 CFR Part 86, Subpart 

N. 

§1065.2 Statements in applications and approvals 

Reference Description Source 

We reiterated anyone’s obligation to report truthful information to us 

and to reiterate our treatment of confidential business information. 

§1068.101 

§1068.10 

§1065.5 Overview and relationship to standard setting parts 

Reference Description Source 

(a) We revised the list of information needed from standard setting parts to 

conduct emissions testing according to this part. We revised the list to 

reflect a broader set of field testing requirements among the standard 

setting parts. 

§1065.10 Other procedures 

Reference Description Source 

(c)(3) We provided guidance on how to gradually update your test 

procedures to eventually comply with Part 1065 based on §86.1306-

07(c)(3). 

§86.1306-07(c) 

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Technical Amendments 

§1065.12 Approval of alternate procedures 

Reference Description Source 

We incorporated and revised text from §86.1306-07(d). We revised 

§86.1306-07(d) text to provide additional guidance on how to use 

statistical tests and how to use the statistics for field testing.(3) 

§86.1306-07(d) 

§1065.15 Overview of procedures for lab and field testing 

Reference Description Source 

We described lab testing and field testing in a similar context. 

(c)(1) We described engine operation during lab and field testing. 

(c)(2) We allowed both continuous and batch (e.g. bag, PM filter) sampling 

of emissions. In Part 1065 we incorporate specifications in Part 86, 

Part 89, and ISO 8178. 

40 CFR Part 86 

40 CFR Part 89 

ISO 8178 

(c)(3) We allowed work determination via chemical balances of fuel and 

exhaust. This enables field testing without a direct torque 

measurement and without a flow measurement that is accurate to flow, 

but only linearly proportional to flow. 

§1065.20 Units of measure and overview of calculations. 

Reference Description Source 

(a) We adopted the international system of units (SI) for all calculations. 

We revised Part 1065 to comply with a federal agency requirement to 

adopt SI. 

15 CFR 1170 

(a) We adopted a molar basis for calculating ideal gas flows, which 

includes intake air, dilution air and raw and diluted exhaust. We 

deleted the volume and mass bases to eliminate the associated 

confusion from different datums of standard pressure and standard 

temperature. 

(f) We revised equipment and measurement instrument specifications in 

Part 1065 to scale with our emissions standards and with the power of 

your engine. We revised these specifications to enable Part 1065 to be 

applicable across a wide range of emissions standards and engine 

sizes. 

§1065.25 Recordkeeping 

Reference Description Source 

We added a minimum 1-year requirement to keep records, which may 

be superceded by requirements in the standard-setting part. 

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Draft Technical Support Document 

Subpart B– Equipment Specifications 

§1065.101 Overview 

Reference Description Source 

We revised this subpart to only describe equipment specifications. We 

described measurement instrument specifications in their own subpart: 

Subpart C. 

§1065.110 Dynamometers and operator demand. 

Reference Description Source 

(a) We revised dynamometer specifications for different applications, 

including duty cycles with motoring commands. We broadened 

specifications for standard setting parts that have motoring in their 

duty cycles. 

§86.1308 

§89.306 

ISO 8178-1 §7.2 

(b) We described of how to control engine operator demand (e.g. throttle) 

to help ensure representative testing in the lab. 

§1065.120 Fuels and fuel temperature and pressure 

Reference Description Source 

(b) We allowed manufacturers to specify the fuel temperature and pressure 

to the engine to help ensure representative testing in the lab. ISO 8178-1 §6 

§1065.122 Engine fluids, heat rejection, and engine accessories 

Reference Description Source 

(c) We described how to use engine accessories and how to account for 

power to those accessories. 

§86.1327-98 

8178-11 §5.3 

§1065.125 Engine intake air 

Reference Description Source 

We allowed emissions testing with a production intake air system to 

help ensure representative testing in the lab. 

(b) We allowed use of a central barometer within 1 % of pressure at 

engine, instead of 0.1 % in §86.1344(e)(4), which is overly stringent 

considering exhaust conditions are only held within 1 % of barometric 

(e.g. within 4 inches of water column). 

§86.1344(e)(4) 

(c) We allowed engine manufacturers to specify a range of intake 

restriction, noting manufacturers’ liability up to the maximum 

allowable restriction. 

(d) We allowed the use of coolant as cool as 25 °C. 

We required the use of a cooler with a typical charge air volume to 

help ensure representative testing in the lab. 

8178-11 §5.2 

40
Technical Amendments 

§1065.130 Engine exhaust 

Reference Description Source 

(a) through (d) We scaled the exhaust system material, design, and component 

specifications in Part 86 Subpart N to enable Part 1065 to be applicable 

across a wide range of engine powers. 

CFR 86 Subpart N 

(e) We allowed forced aftertreatment cool-down based on guidance we 

issued in the past (1), (2). 

§86.1335-90 

(f) We allowed engine manufacturers to specify a range of exhaust 

restriction, noting manufacturers’ liability up to the maximum 

allowable restriction. 

(g) We added specifications on how to route open crankcase emissions to 

accommodate standard setting parts that require open crankcase 

emissions measurements. 

§1065.140 Dilution for gases and PM. 

Reference Description Source 

(a) We adopted a minimum dilution air temperature of 15 C from 

§86.1310-2007.(3) 

§86.1310-2007 

(b)(1) We recommended HEPA filtration, and we limited PM background if 

HEPA filtration is not used to improve PM measurement repeatability. 

§86.1310-2007 

(c) We revised the CVS specifications, which we based on §86.1310-

2007, to scale across a broad range of engine powers to enable Part 

1065 to be applicable across a broad range of engine powers. 

§86.1310-2007 

(d) We allowed constant-dilution ratio partial flow dilution samplers such 

as CVS secondary dilution systems. Previously we allowed this 

according to §86.1310-2007. We also allowed varying dilution ratio 

samplers for gaseous emissions, such as bag mini-diluters. We only 

allowed varying dilution ratio PFD systems for PM measurement as an 

alternate procedure, where we required prior approval from us 

according to §1065.10 and §1065.12. 

§86.1310-2007 

(e) We specified temperature control during PM sampling the same as we 

specified in 86.1310-2007.(3) 

§86.1310-2007 

§1065.145 Gaseous and PM probes, transfer lines, and sample conditioning components 

Reference Description Source 

(b) We defined a probe as only that section of a sampling system inside 

the raw or dilute exhaust duct. Note that this is a change from some of 

our other regulations where we allowed up to 1 meter of transfer line to 

be considered part of the probe. 

41
Draft Technical Support Document 

(b) We allowed single port or multiport probes oriented in any direction 

for gaseous emissions sampling. Note that this is a change from some 

of our other regulations where we required certain probes and 

orientations for gas sampling. We allowed a wider variety of probes. 

because gas sampling is insensitive to the previous specifications. 

(b) We required a more prescriptive design and orientation of for PM 

probes to ensure proper PM sampling. 

(c) We recommended how to install transfer lines, and we specified 

materials and temperatures of transfer lines based on §86.1310-2007, 

which were for diesel emissions sampling. We extended these 

specifications to include some spark-ignition engines.(3) 

§86.1310-2007 

(d) We allowed sample conditioning components in-line with transfer 

lines based on §86.1310-2007.(3) 

§86.1310-2007 

§1065.170 Batch sampling for gaseous and PM constituents 

Reference Description Source 

(a) and (b) We allowed gaseous batch sampling (e.g. bag sampling) based on Part 

86 subpart B, and we revised batch sampling to include high 

temperature batch sampling (i.e. 191 C) based on 86.1310-2007.(3) 

40 CFR Part 86 

Subpart B 

§86.1310-2007 

(c) We required the same PM sample media (i.e filters) that we required in 

86.1310-2007. In addition we required a more prescriptive filter 

specification for standards below 0.05 g/kW-hr. We required this to 

prevent gas-phase hydrocarbon adsorption onto the PM sample media, 

which would cause an incorrect result.(3) 

§86.1310-2007 

(c) We added PM sample media and PM batch sampling specifications 

based on 86.1310-2007.(3) 

§86.1310-2007 

§1065.190 PM stabilization and weighing environments for gravimetric analysis 

Reference Description Source 

We added PM stabilization and weighing environmental specifications 

based on §86.1312-2007.(3) 

§86.1312-2007 

(b) We revised our recommended clean room specification from an 

obsolete federal standard to an ISO standard. We reduced the 

stringency of this recommendation by an order of magnitude to reflect 

best practices. We recommend deviating from the ISO standard to 

control air velocities near a balance. 

§86.1312-2007 

(c) We adopted §86.1312-2007 specifications for temperature and 

humidity, and we added guidance on humidity control as a function of 

sulfuric acid in PM.(3) 

§86.1312-2007 

(d) We adopted §86.1312-2007 specifications for temperature and 

humidity monitoring, but we are less prescriptive on the averaging of 

these parameters to allow for other acceptable system designs.(3) 

§86.1312-2007 

42
Technical Amendments 

(e) and (f) We adopted §86.1312-2007 specifications for balance installation and 

balance accessories and tools. We added recommendations based on 

previous guidance we issued to engine manufacturers. (1), (2) 

§86.1312-2007 

§1065.195 PM stabilization environment for in-situ analyzers 

Reference Description Source 

We described the stabilization environment for in-situ PM analyzers, 

based on §86.1312 for gravimetric balances.(3) We expected that these 

instruments are likely to be used for field-testing PM measurement. 

§86.1312-2007 

(b) We required HEPA filtration of equilibration air based on §86.1310.(3) 

§86.1310-2007 

(c) We adopted a (42 to 52) °C equilibration temperature range to align insitu PM measurement temperature with the PM sampling temperature 

in §86.1310-2007.(3) We adopted this temperature range to ensure fast 

equilibration and measurement in-situ. We added guidance on 

humidity control as a function of sulfuric acid in PM to align in-situ 

PM measurement guidance with gravimetric PM measurement 

guidance. 

§86.1310-2007 

Subpart C– Measurement Instruments 

§1065.201Overview and general provisions 

Reference Description Source 

(d) We allowed combining results of redundant measurements a single test 

based on §86.1310-2007.(3) 

§86.1310-2007 

(e) We allowed using an instrument’s response if it is greater than 100 % 

of the instrument’s range, but we required additional testing, which is 

similar to §86.1338-2007. 

§86.1338-2007 

(f) We required continuous analyzer signals to be matched to other 

continuous signals to improve repeatability and correlation between 

continuous sampling and batch sampling systems. We defined this 

matching as “dispersion”. 

§1065.202 Data recording and control 

Reference Description Source 

(a) We required minimum recording frequencies of data. We took into 

account recent research that indicated that significant changes in raw 

exhaust flow can occur over a period as short as 200 milliseconds.(4) 

Combined with the signal dispersion and time alignment that we 

required in §1065.201, we improved repeatability and correlation 

between continuous sampling and batch sampling. 

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Draft Technical Support Document 

§1065.205 Performance specifications. 

Reference Description Source 

(a) We recommended performance specifications for individual 

instruments, and we relied on the calibrations and performance 

checks in Subpart D to ensure that complete measurement systems 

perform adequately. We recommended performance specifications 

based on calibration requirements in 40 CFR 86 Subpart N, 40 CFR 

89 Subpart D Appendix A, and ISO 8178-1. We defined accuracy, 

repeatability, and noise in Part 1065 Subpart D. We defined these 

values relative to emissions levels at a standard; not a lower value 

such as at 2 % of the standard, which is how some of our 

regulations previously specified accuracy. Essentially we allowed 

instruments to be matched to their application without forcing the 

use of higher performing instruments than required. 

40 CFR 86 Subpart N 

40 CFR 89 Subpart D 

Appendix A 

ISO 8178-1 

§1065.210 Speed and torque transducers 

Reference Description Source 

We required the same speed and torque transducer as §86.1308-84. §86.1308-84 

§1065.215 Pressure, temperature, and dewpoint transducers 

Reference Description Source 

We recommended specific transducers as guidance for future 

procurement of such transducers. 

§1065.220 Fuel flow 

Reference Description Source 

We allowed fuel flow to be directly measured or calculated by 

chemical balances of fuel, intake air, and exhaust, plus either an intake 

air flow or exhaust flow measurement. We allowed both options to 

help facilitate field testing and redundant measurements for lab testing. 

§89.415 

§89.416 

§1065.225 Intake air flow 

Reference Description Source 

We allowed intake air flow to be directly measured or calculated by 

chemical balances of fuel, intake air, and exhaust, plus either a fuel or 

exhaust flow measurement. We allowed both options to help facilitate 

field testing and redundant measurements for lab testing. 

§89.414 

§1065.230 Raw exhaust flow 

Reference Description Source 

44
Technical Amendments 

We allowed exhaust flow to be directly measured or calculated by 

chemical balances of fuel, intake air, and exhaust, plus either a fuel or 

intake air flow measurement. We allowed both options to help 

facilitate field testing and redundant measurements for lab testing. We 

created this section because new exhaust flow measurement 

technology has matured since we last revised our regulations. 

Combined with a new way to calculate brake-specific emissions that 

we allowed in §1065.650, a signal that is not absolutely calibrated-­

but just linearly proportional to exhaust flow--may be used to 

determine brake-specific emissions. 

§1065.240 Dilution air and diluted exhaust flow 

Reference Description Source 

We required the same flow meters as in §86.1310-2007 for CVS 

systems, and we added a new CVS flow meter, an ultrasonic air flow 

meter, because this technology has matured since we last updated our 

regulations.(3) 

§86.1310-2007 

§1065.245 Sample flow 

Reference Description Source 

We required the same flow meter performance as specified in 

§86.1320-90, and we provided additional guidance on flow meter 

selection. 

§86.1320-90 

§1065.248 Gas divider 

Reference Description Source 

We required the same flow meter performance as specified in 

§86.1314-94 for gas dividers. We also required a periodic gas divider 

linearity check. 

§86.1314-94 

§1065.250 Nondispersive infra-red CO analyzer 

Reference Description Source 

We required the same CO measurement technology as Part 86 and Part 

89. 

§86.1322-84 

§89.309 

§1065.255 Nondispersive infra-red CO2 analyzer 

Reference Description Source 

We required the same CO2 measurement technology as Part 86 and 

Part 89. 

§86.1324-84 

§89.309 

§1065.260 Flame ionization detector analyzer for THC, NMHC, CH4 

Reference Description Source 

45
Draft Technical Support Document 

We required the same THC, NMHC measurement technology as Part 

86 and Part 89 and we allowed a flame ionization detector to be 

coupled with a nonmethane cutter to facilitate CH4 measurement 

according to ISO 8178-1 §16.4. 

§86.1321-84 

§89.309 

ISO 8178-1 §16.4 

§1065.265 Nonmethane cutter for CH4 

Reference Description Source 

We adopted the same nonmethane cutter performance specification as 

ISO 8178-1 to provide an alternative to the gas chromatograph we 

specified in §1065.267. We allowed this to facilitate continuous 

sampling of NMHC because the gas chromatograph is only applicable 

to batch (e.g. bag) measurements. 

ISO 8178-1 §16.4 

§1065.267 Gas Chromatograph for CH4 

Reference Description Source 

We adopted a gas chromatograph performance specification based on 

the methane analyzer descriptions in §86.1325-94 and §89.324. 

§86.1325-94 

§89.324 

§1065.270 Chemiluminescent detector analyzer for NOx 

Reference Description Source 

We adopted the chemiluminescent detector analyzer specification in 

§86.1323-2007 §89.321. 

§86.1323-2007 

§89.321 

§1065.272 Nondispersive ultraviolet analyzer for NOx (NO and NO2) 

Reference Description Source 

We allowed the nondispersive ultraviolet detector NOx analyzer 

because it has matured since we last updated our regulations. We 

allowed this technology to provide more measurement options, 

especially for field testing. 

§1065.274 Zirconia sensor for NOx 

Reference Description Source 

We allowed the zirconia sensor NOx analyzer because it has matured 

since we last updated our regulations. We allowed this technology to 

provide more measurement options, especially for field testing. 

§1065.280 Paramagnetic detector analyzer for oxygen 

Reference Description Source 

We adopted the paramagnetic detector analyzer specification for 

oxygen measurement from ISO 8178-1. 

ISO 8178-1 §8.9.4 

46
Technical Amendments 

§1065.284 Zirconia sensor for oxygen 

Reference Description Source 

We allowed the zirconia sensor O2 analyzer because it has matured 

since we last updated our regulations. We allowed this technology to 

provide more measurement options, especially for field testing. 

§1065.290 Gravimetric balance for PM 

Reference Description Source 

We adopted the gravimetric balance for PM specification from 

§86.1312-2007.(3) We provided additional recommendations for 

features to consider when procuring a PM balance. 

§86.1312-2007 

§1065.295 Inertial balance for PM 

Reference Description Source 

We allowed the inertial balance for PM because it has matured since 

we last updated our regulations. We allowed this technology to 

provide more measurement options, especially for field testing. 

Subpart D– Calibrations and performance checks for complete measurement systems 

§1065.301 Overview 

Reference Description Source 

(a) through (c) We required calibrations and performance checks on complete 

laboratory and field testing measurement systems, which include the 

probes, transfer lines, sample conditioning equipment, analyzers, and 

any analog to digital conversion and data acquisition devices. We 

replaced some calibrations in 40 CFR Part 86 and 40 CFR Part 89 with 

performance checks. 

(d) We required the use of NIST traceable standards, but we noted that 

you may ask to use other standards. 

§1065.305 Accuracy, repeatability, and noise performance check. 

Reference Description Source 

We defined accuracy, repeatability, and noise by the procedure that we 

specify for determining these values. We defined these values 

procedurally to prevent sellers and buyers of measurement systems 

from misinterpreting our specifications. We defined noise is a limit 

value, below which you may set recorded values to zero. 

§1065.306 Summary of periodic calibration and performance checks 

Reference Description Source 

47
Draft Technical Support Document 

We summarized how frequently each check in this subpart must be 

performed. We provided this summary so that laboratories and field 

test operators might use it as a template for part of a preventive 

maintenance plan. 

§1065.307 Linearity check. 

Reference Description Source 

We replaced many calibrations that we required according to 40 CFR 

Part 86 and 40 CFR Part 89. We revised our approach toward 

instrument calibration because it did not apply to modern instruments 

that use other signals to correct for interferences. 

§1065.308 Response check for gas analyzers 

Reference Description Source 

We added a performance check to determine the response of analyzers 

and the alignment of any compensation signals. We added this check 

to verify that analyzer response and recording rate were matched and 

that other signals used to compensate for interferences were aligned 

with the primary emissions signal. 

§1065.310 Torque calibration 

Reference Description Source 

We adopted the calibration specifications in §86.1308-84, §89.306, 

and §89.307, but we scaled them to the maximum torque of an engine 

to make Part 1065 applicable across a wide range of maximum engine 

torques. 

§86.1308-84 

§89.306 

§89.307 

§1065.315 Pressure, temperature, and dewpoint calibration. 

Reference Description Source 

We provided guidance on pressure, temperature, and dewpoint 

calibration. We allowed laboratories to develop their own calibration 

procedures because of the diversity of measurement technologies. We 

relied on performance checks such as the linearity check to ensure 

measurement system performance. 

§1065.320 Fuel flow calibration. 

Reference Description Source 

We provided guidance on fuel flow calibration. We allowed 

laboratories to develop their own calibration procedures because of the 

diversity of measurement technologies. We relied on performance 

checks such as the linearity check to ensure measurement system 

performance. 

48
Technical Amendments 

§1065.325 Intake air flow calibration 

Reference Description Source 

We provided guidance on intake air flow calibration. We allowed 

laboratories to develop their own calibration procedures because of the 

diversity of measurement technologies. We relied on performance 

checks such as the linearity check to ensure measurement system 

performance. 

§1065.330 Exhaust flow check. 

Reference Description Source 

We provided guidance on exhaust flow calibration. We allowed 

laboratories to develop their own calibration procedures because of the 

diversity of measurement technologies. We relied on performance 

checks such as the linearity check to ensure measurement system 

performance. 

§1065.340 CVS calibration 

Reference Description Source 

We adopted CVS calibration specifications from §86.1319-90 and 

especially §86.1319-90(e)(3), which specified calculations that assume 

isentropic compressible flow. We adopted molar flow reference 

signals for calibration to eliminate the use of standard pressure and 

temperature values, which have been a frequent source of 

confusion–especially across different regulations. We recognized that 

40 CFR Part 86, 40 CFR Part 89, and ISO 8178-1 all have different 

standard conditions specified in different sections. 

§86.1319-90 

(e) We adopted PDP calibration specifications from §86.1319-90, but we 

reformulated the equations to make them easier to understand. 

§86.1319-90 

(f) We adopted CFV calibration specifications from §86.1319-90 CFV, 

but we reformulated the calibration to take into account isentropic 

compressible flow. We specified the new calibration formulation to 

extend use of the calibration data to a wider range of molar masses of 

an exhaust mixture. We allowed assumptions to be made in order to 

reduce the new formulation to the formulation in §86.1319-90, but we 

restricted use of the §86.1319-90 formulation to a range of molar 

masses of flow. We provided similar guidance to this effect in the 

past.(1),(2) 

§86.1319-90 

(g) We adopted the SSV calibration in §86.1319-90, but we used a molar 

reference signal. 

§86.1319-90 

§1065.341 Propane check 

Reference Description Source 

49
Draft Technical Support Document 

We adopted the propane check of §1319-90(f), but we extended its use 

to check secondary dilution systems, and we added an option to use a 

flow-based reference instead of the gravimetric reference in §1319-

90(f) . We recognized that the flow-based reference has been used 

successfully in light-duty CVS applications, and we allowed this 

reference to provide more options to engine dynamometer CVS 

laboratories. 

§1319-90(f) 

§1065.345 Vacuum side leak check 

Reference Description Source 

We adopted the leak checks from §86.1337-90 and 89.316, but we 

revised this check to include two step-by-step procedures to perform 

the check. We allowed either form of the check to provide more 

options to engine dynamometer laboratory operators and field test 

system operators. 

§86.1337-90 

§89.316 

§1065.350 CO2 NDIR analyzer H2O interference check. 

Reference Description Source 

We adopted the performance specification in §89.318, and we 

described a step-by-step procedure for this check. 

§89.318 

§1065.355 CO NDIR analyzer CO2 and H2O interference check. 

Reference Description Source 

We adopted the performance specification in §89.318, and we 

described a step-by-step procedure for this check. 

§89.318 

§1065.362 FID calibration, response optimization, CH4 response factor determination and FID flow check 

Reference Description Source 

We adopted the performance specification in §89.318, and we 

described a step-by-step procedure for this check. We allowed a 

simplified check that when completed successfully, significantly 

reduced the burden of the complete check. We currently use this 

simplified check successfully at our EPA labs; therefore, we allowed 

others to use it. 

§89.318 

§1065.362 FID O2 interference check 

Reference Description Source 

We incorporated by reference ISO 8178-1 §8.8.3, which is the oxygen 

interference check for raw exhaust flame ionization detector analyzers, 

which is the same check specified in §89.318. 

§89.318 

ISO 8178-1 §8.8.3 

50
Technical Amendments 

§1065.365 Nonmethane cutter penetration determination. 

Reference Description Source 

We adopted a revised version of the nonmethane cutter efficiency 

determination, which is specified in ISO 8178-1 §8.8.4. We revised 

this section to include a more prescriptive step-by-step procedure, and 

a simplified calculation to detemine nonmethane cutter penetration. 

ISO 8178-1 §8.8.4 

§1065.370 CLD H2O and CO2 interference check 

Reference Description Source 

We adopted the CLD H2O and CO2 interference check from §86.1323-

2007.(3) 

§86.1323-2007 

§1065.372 NDUV NOx analyzer performance check 

Reference Description Source 

We required a performance check specifically for nondispersive 

ultraviolet detector NOx analyzers. We required this check because of 

its limitations. We required this check to ensure that these instruments 

are designed and operated appropriately. 

§1065.374 Zirconia analyzer performance check 

Reference Description Source 

We required a performance check specifically for zirconia detector 

NOx analyzers. We required this check because of its limitations. We 

required this check to ensure that these instruments are designed and 

operated appropriately. 

§1065.376 Thermal chiller NO2 penetration check 

Reference Description Source 

We required this performance check if a thermal chiller is used 

upstream of an NO2 detector or NO2 to NO converter. We required 

this check because of its limitations. We required this check to ensure 

that these instruments are designed and operated appropriately. 

§1065.378 NO2 to NO converter check 

Reference Description Source 

We adopted the NO2 to NO converter efficiency specifications in 

§86.1323-84 and ISO 8178-1 §8.7, however we scaled performance to 

the level of NO2 expected during testing. We scaled this check to 

make it less stringent for emissions tests that are not affected by its 

performance and more stringent for emissions tests that are 

significantly affected by its performance. 

§86.1323-84 

ISO 8178-1 §8.7 

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Draft Technical Support Document 

§1065.390 PM weighing process performance check 

Reference Description Source 

We adopted the PM weighing process performance check from 

§86.1312-2007.(3), however we scaled this check to the PM emissions 

expected at the standard. This prevents an unnecessarily stringent 

requirement for PM weighing. 

§86.1312-2007 

Subpart E– Engine selection, preparation, and maintenance. 

§1065.405 Test engine preparation and maintenance. 

Reference Description Source 

We required specifications for engine selection, preparation, and 

maintenance; however we stated that any requirements in any 

standard- setting part take precedence over the specifications in this 

subpart. 

We allowed a default value 125 hours of engine service accumulation 

for compression-ignition engines without emissions measurement. 

Subpart F– Running an emissions test in a laboratory 

§1065.501 Overview 

Reference Description Source 

We summarized all of the step-by-step procedures for running an 

emissions test in a laboratory, and we reiterated that standard setting 

parts specify other information required to run an emissions test. We 

required variable speed and constant speed engines subject to 

steady-state, ramped modal, and transient testing to be tested 

according to this subpart, including any cold-start testing, hot-start 

testing, and warmed-up running engine testing. We adopted 

procedures in §86.1327 through §86.1337 (3), §89.404 through 

§89.408 and ISO 8178-1 §11. We added requirements and options to 

the specifications in §86.1327 through §86.1337 (3), §89.404 through 

§89.408 and ISO 8178-1 §11. 

§86.1327-§86.1337 

§86.1341 

§89.404-§89.408 

§89.410 

ISO 8178-1 §11 

§1065.510 Engine mapping 

Reference Description Source 

We adopted §86.1332-90 for variable speed engines. We added 

new requirements for constant-speed engines, which rely on the 

engine’s governor or simulated governor to select the engine speed 

during an emissions test. We required this to ensure that constant 

speed engines are tested in a representative way. 

§86.1332-90 

52
Technical Amendments 

§1065.512 Duty cycle generation. 

Reference Description Source 

We adopted §86.1333-90, §89.410, ISO 8178-1 §11.5, and ISO 

8178-1 §11.7 to combine the requirements for steady-state, ramped 

modal, and transient test cycle generation. We allowed constant 

speed engines to operate at the speed selected by the engine’s 

governor or simulated governor. 

§86.1333-90, 

§89.410, 

ISO 8178-1 §11.5, 

ISO 8178-1 §11.7 

§1065.514 Cycle validation criteria 

Reference Description Source 

We adopted the cycle validation criteria of §86.1341-90, but we 

revised the point omission criteria easier to understand. We revised 

some of the statistics to reflect the dependence of power on speed and 

torque. We revised the statistics to reflect the capabilities of modern 

dynamometer and operator demand control systems. We required only 

torque validation criteria for constant speed engines because we allow 

constant speed engines to be governed by their governor or simulated 

governor during emissions testing. 

§86.1341-90 

§1065.520 Pre-test verification procedures and pre-test data collection 

Reference Description Source 

We adopted §86.1330-90, §86.1334-84 and §89.406, including the 

preconditioning cycle we added to §86.1330-90 in January of 2001.(3) 

We replaced the hydrocarbon overflow zero and span procedure with a 

hydrocarbon sampling system contamination check. Up to a certain 

amount of contamination, we allowed emissions results correction by 

subtracting the contamination determined with an overflow zero check 

performed after an analyzer port zero and span. We required this to 

prevent excessive hydrocarbon contamination from biasing results. 

We allowed some contamination to be appropriately subtracted from 

emissions results, which is how the original overflow procedure 

worked, except that it had no limits on contamination. We required 

this procedure to improve test repeatability. 

§86.1330-90 

§86.1334-84 

§89.406 

§1065.525 Engine starting, restarting and shutdown 

Reference Description Source 

We adopted §86.1334-84, but we have simplified the requirements 

because §86.1334-84 described some starting procedures with obsolete 

engine components. We revised §86.1334-84 to achieve the same 

intent. 

§86.1334-84 

§1065.530 Emission test sequence. 

Reference Description Source 

53
Draft Technical Support Document 

We adopted §86.1337-90, §89.407, and ISO 8178-1 §11.7.1 and 

combined them to include PM sampling, continuous and batch 

sampling, and raw and dilute sampling. We required procedures to 

check for analyzer drift. We allowed collecting and correcting for 

background emissions in dilution air. We required procedures for 

cold-starts, hot-starts, soak periods, and hot running tests. 

§86.1337-90, 

§89.407, 

ISO 8178-1 

§11.7.1. 

§1065.545 Validation of proportional flow control for batch sampling 

Reference Description Source 

We adopted the performance specification of §86.1310-2007 for PM 

sampling systems.(3) We incorporated additional options for validating 

proportional sampling based on the principles of CVS sampling. 

§86.1310-2007 

§1065.550 Emissions analyzer range and drift validation. 

Reference Description Source 

We adopted the performance specifications in §86.1340-90, §89.406, 

and ISO 8178-1 §11.8. We allowed for correction of a limited amount 

of analyzer drift. We developed this procedure jointly with 

measurement instrument manufacturers and engine manufactures. 

§86.1340-90, 

§89.406, 

ISO 8178-1 §11.8. 

§1065.590 PM sample preconditioning and tare weighing 

Reference Description Source 

We adopted §86.1312-2007.(3) We added an option to perform 

substitution weighing, which has been used in ambient PM sampling 

successfully–especially when PM concentrations are very low. 

§86.1312-2007 

§1065.595 PM sample post-conditioning and total weighing. 

Reference Description Source 

We adopted §86.1312-2007.(3) We added an option to perform 

substitution weighing, which has been used in ambient PM sampling 

successfully–especially when PM concentrations are very low. 

§86.1312-2007 

Subpart G– Calculations and data requirements 

§1065.601 Applicability. 

Reference Description Source 

We consolidated calculations that were specified multiple times in this 

part (i.e. Part 1065). For example we consolidated statistical 

calculations for instrument performance, alternate system approval, 

and duty cycle validation in §1065.602. 

We adopted SI units for all calculations, except for one set of example 

calculations in §1065.640 where we showed how to convert different 

reference flow meter signals to molar reference signals. 

54
Technical Amendments 

We provided completely worked-out examples for every calculation, 

including conversion factors for various engineering units. 

§1065.602 Statistics 

Reference Description Source 

We consolidated statistics calculations that were specified multiple 

times in this part (i.e. Part 1065). For example we consolidated 

statistical calculations for instrument performance, alternate system 

approval, and duty cycle validation. We added examples on how to 

calculate flow-weighted average concentrations at a given standard for 

various engines. We provided these examples because we scale many 

measurement instrument specifications to this value tto ensure that Part 

1065 is applicable across a wide range of emissions standards and 

sampling techniques (e.g. raw, dilute, continuous, and batch sampling) 

§1065.605 Field test system overall performance check 

Reference Description Source 

We required that field test systems pass an overall check versus 

laboratory measurements. We provided a complete example of the 

specialized data reduction techniques to perform this check. 

§1065.610 Test cycle generation 

Reference Description Source 

We consolidated all of the calculations for steady-state, ramped modal, 

and transient test cycle generation from §86.1333-90, §89.410, ISO 

8178-1 §11.5, and ISO 8178-1 §11.7. We allowed constant speed 

engines to operate at the speed(s) selected by the engine’s governor or 

simulated governor. 

§86.1333-90, 

§89.410, 

ISO 8178-1 §11.5, 

ISO 8178-1 §11.7 

§1065.630 1980 International gravity formula 

Reference Description Source 

We adopted this formula to prescribe what we meant in previous 

regulations when we required that you account for local effects on 

gravity at your location, such as in § 86.1308-84(e)(1)(i). We 

recommended to use this formula when conducting dynamometer 

torque calibration and torque linearity checks according to §1065.308 

and §1065.310. 

§86.1308-

84(e)(1)(i) 

§1065.340 CVS calibration equations 

Reference Description Source 

55
Draft Technical Support Document 

We adopted CVS calibration calculations from §86.1319-90 and 

especially §86.1319-90(e)(3), which specified calculations that assume 

isentropic compressible flow. We adopted molar flow reference 

signals for calibration to eliminate the use of standard pressure and 

temperature values, which have been a frequent source of 

confusion–especially across different regulations. We recognized that 

40 CFR Part 86, 40 CFR Part 89, and ISO 8178-1 all have different 

standard conditions specified in different sections. 

§86.1319-90 

(b) We adopted PDP calibration calculations from §86.1319-90, but we 

reformulated the equations to make them easier to understand. 

§86.1319-90 

(c) We adopted CFV calibration calculations from §86.1319-90 CFV, but 

we reformulated the equations to take into account isentropic 

compressible flow. We specified the new calibration equation to 

extend use of the calibration data to a wider range of molar masses of 

an exhaust mixture. We allowed assumptions to be made in order to 

reduce the new equation to the equation in §86.1319-90, but we 

restricted use of the §86.1319-90 equation to a range of molar masses 

of flow. We provided similar guidance to this effect in the past.(1),(2) 

§86.1319-90 

(d) We adopted the SSV equation in §86.1319-90, but we rearranged it to 

use a molar reference signal. 

§86.1319-90 

§1065.340 CVS flow rate equations 

Reference Description Source 

We adopted CVS flow rate calculations from §86.1319-90 and 

especially §86.1319-90(e)(3), which specified calculations that assume 

isentropic compressible flow. We adopted molar flow rates to 

eliminate the use of standard pressure and temperature values, which 

have been a frequent source of confusion–especially across different 

regulations. We recognized that 40 CFR Part 86, 40 CFR Part 89, and 

ISO 8178-1 all have different standard conditions specified in different 

sections. 

§86.1319-90 

(a) We adopted PDP flow rate calculations from §86.1319-90, but we 

reformulated the equations to make them easier to understand. 

§86.1319-90 

(b) We adopted CFV flow rate calculations from §86.1319-90 CFV, but 

we reformulated the equations to take into account isentropic 

compressible flow. We specified the new flow rate equation to extend 

use of the flow meter to a wider range of molar masses of an exhaust 

mixture. We allowed assumptions to be made in order to reduce the 

new flow rate equation to the equation in §86.1319-90, but we 

restricted use of the §86.1319-90 flow rate equation to a range of molar 

masses of flow. We provided similar guidance to this effect in the 

past.(1),(2) 

§86.1319-90 

(c) We adopted the SSV flow rate equation in §86.1319-90, but we 

rearranged it to calculate a molar flow rate. 

§86.1319-90 

56
Technical Amendments 

§1065.645 Amount of water in an ideal gas. 

Reference Description Source 

We consolidated several other sections’ requirements to calculate this 

value, such as those sections that required an amount of water removed 

correction, a buoyancy correction, a background emissions correction, 

chemical balances of fuel, exhaust, and intake air, and flowmeter 

calibrations and performance checks. We specified this calculation 

only once in Part 1065 to ensure that this value is calculated in only 

one way. We adopted an internationally accepted formulation for this 

value from the World Meteorological Organization. 

§1065.650 Emissions calculations 

Reference Description Source 

We adopted emissions calculations from §86.1342-94, §89.418, 

§89.419, and ISO 8178-1 §12 though §16 to combine steady-state, 

ramped modal, and transient testing calculations. We included raw, 

dilute, continuous, and batch sampling. We added a new way to 

calculate brake-specific emissions based on the ratio of a value 

proportional to an emissions mass and another value similarly 

proportional to work. 

§86.1342-94, 

§89.418, 

§89.419, 

ISO 8178-1 §12 

though §16. 

§1065.655 Chemical balances 

Reference Description Source 

We adopted the chemical balances from §89.418 and ISO 8178-1 

Annexe A. We specified how to use chemical balances to determine 

the amount of water in exhaust, the amount of carbon-containing 

emissions in exhaust, and the dilution fraction of dilution air in diluted 

raw exhaust. 

§89.418 

ISO 8178-1 

Annexe A 

§1065.657 Drift validation and correction. 

Reference Description Source 

We adopted the drift performance specification from §86.1340-90, 

§89.406, and ISO 8178-1 §11.8. We added a drift correction to 

account for a limited amount of analyzer drift. We developed this 

procedure with instrument manufacturers and engine manufactures. 

We added this correction to improve repeatability. 

§86.1340-90, 

§89.406, 

ISO 8178-1 §11.8. 

§1065.658 Noise correction. 

Reference Description Source 

57
Draft Technical Support Document 

We allowed values lower than a critical noise limit to be set to zero. 

We specified that this noise limit is the lower of two values: the 

instrument noise specification that we recommend in Subpart C for lab 

instruments (Subpart J for field testing instruments) and the actual 

noise of an instrument as determined according to Subpart D. We 

allowed this correction for all instruments with the expectation that it 

will be most beneficial for field test instruments because they are 

subject to more external sources of instrument noise. 

§1065.659 Removed water correction. 

Reference Description Source 

We adopted the corection in §86.1342-90, §89.418, , ISO 8178-1 

A.2.4, but we have revised it to take into account any condensation 

that occurs upstream of a flow meter. 

§86.1342-90, 

§89.418, 

ISO 8178-1 A.2.4 

§1065.660 THC and NMHC determination 

Reference Description Source 

We adopted the THC and NMHC determination from §86.1342-94, 

ISO 8178 §15.4. We allowed multiplying THC by 0.98 as an 

approximation for NMHC. We replaced the hydrocarbon overflow 

zero and span procedure with a hydrocarbon sampling system 

contamination check. Up to a certain amount of contamination, we 

allowed emissions results correction by subtracting the contamination 

determined with an overflow zero check performed after an analyzer 

port zero and span. We required this to prevent excessive hydrocarbon 

contamination from biasing results. We allowed some contamination 

to be appropriately subtracted from emissions results, which is how the 

original overflow procedure worked, except that it had no limits on 

contamination. We required this procedure to improve test 

repeatability. 

§86.1342-94, 

ISO 8178 §15.4 

§1065.665 NMHCE determination 

Reference Description Source 

We adopted the THCE and NMHCE determination from §86.1342-94 

and ISO 8178-1 §15.5 and §15.6. We allowed multiplying THC by 

0.98 as an approximation for NMHC. We replaced the hydrocarbon 

overflow zero and span procedure with a hydrocarbon sampling system 

contamination check. Up to a certain amount of contamination, we 

allowed emissions results correction by subtracting the contamination 

determined with an overflow zero check performed after an analyzer 

port zero and span. We required this to prevent excessive hydrocarbon 

contamination from biasing results. We allowed some contamination 

to be appropriately subtracted from emissions results, which is how the 

original overflow procedure worked, except that it had no limits on 

contamination. We required this procedure to improve test 

repeatability. 

§86.1342-94, 

ISO 8178-1 §15.5 

and §15.6 

58
Technical Amendments 

§1065.667 Dilution air background correction 

Reference Description Source 

We adopted the dilution air background correction from §86.1342-94, 

§89.420, and ISO 8178-1 §13.5. We recommend when to remove 

background emissions from dilution air. 

§86.1342-94, 

§89.420 

ISO 8178-1 §13.5 

§1065.670 NOx intake air humidity correction 

Reference Description Source 

We adopted the NOx intake air humidity correction from §86.1342-94, 

§89.418, and ISO 8178-1 §13.4, but we revised the equation. We used 

a linear fit to a recent set of comprehensive data collected for the 

purpose of determining a NOx humidity correction factor.(5) We 

generated the equation with a least squares linear regression line of 

more than 300 data points generated with six different engines over a 

broad range of humidity conditions. We forced the correction to pass 

through a value of one (1) at 75 grains of water per pound of dry air 

(10.71 g/kg dry air) to align it with the correction from §86.1342-94, 

§89.418, and ISO 8178-1 §13.4. This correction is significantly more 

consistent with computer NOx models versus the previous correction. 

For example, from the range of (0 to 95) % relative humidity at 30 °C 

ambient temperature, the NOx correction from §86.1342-94, §89.418, 

and ISO 8178-1 §13.4 was 1.70 while the linear correction we adopted 

was 1.48. A computer NOx model, ALAMO,(6) predicted a correction 

of 1.42 for an engine at rated conditions across the same humidity. For 

this example the linear correction is 4 % higher than the model, but the 

correction from §86.1342-94, §89.418, and ISO 8178-1 §13.4 is 20 % 

high. We based this revised equation on data and verified it with a 

computer model to improve test repeatability. Below is an illustration 

of the uncorrected data(5), the data corrected according to §86.1342-94, 

§89.418, and ISO 8178-1 §13.4,(5) the data corrected to the equation we 

adopted in Part 1065, and lines depicting the corresponding correction 

factors. 

§86.1342-94, 

§89.418, 

ISO 8178-1 §13.4. 

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Draft Technical Support Document

60

§1065.672 CLD quench check calculations.

Reference Description Source

We adopted the chemiluminescent detector Nox analyzer quench

check performance specification from §86.1323-2007.(3)

§86.1323-2007

§1065.690 PM sample media buoyancy correction.

Reference Description Source

We adopted the bu §86.1312-2007,(3) but we eliminated the

temperature and humidity portions of the correction because we

specified tight humidity and temperature control in the PM weighing

environment. e determined that making corrections based on small

changes in temperature and humidity might induce error due to the

measurement error associated with them. We revised the correction so

that it only accounts for changes in barometric pressure, which is the

dominant parameter that causes a change in PM sample media

buoyancy.

§86.1312-2007.

 Normalized Brake-specific NOx versus Amount of Water in Intake Air

Uncorrected NOx, Corrected NOx, and Correction Factors

0.8

0.9

1.0

1.1

1.2

1.3

1.4

0 0.01 0.02 0.03 0.04

Amount of water in intake air, x H2O (mol/mol)

N

ormalized NOx, eNOx (

g/h

p-hr)

Uncorrected NOx

Part 86

correction

(overcorrection)

Part 1065

correction

W
Technical Amendments 

§1065.695 Required data. 

Reference Description Source 

We adopted the data requirements from §86.1344-94, and we combied 

these with required data from various standard setting parts and our 

most recent application formats for certification. 

§86.1344-94 

EPA’s most recent 

application formats 

for certification. 

Subpart H– Engine fluids, test fuels, analytical gases, and other calibration standards 

§1065.701 General requirements for test fuels 

Reference Description Source 

We adopted the general requirements for test fuels that was originally 

in Part 1065. 

§1065.703 Distillate diesel fuel 

Reference Description Source 

We deleted specific ranges of fuel parameters for diesel service 

accumulation fuel, which is different from §86.1313-2007. We 

adopted a 10 mg/kg minimum limit for aromatics, which is the same 

as the nonroad diesel engine Tier IV rule,(7) instead of 25 mg/kg, which 

was in §86.1313-2007. We eliminated the specification for Cetane 

Index because it is obsolete and because we require Cetane Number, 

which is a more accurate determination of Cetane. 

§86.1313-2007 

§1065.705 Residual fuel [reserved] 

Reference Description Source 

We reserved this section for a future marine residual fuel specification. 

§1065.710 Gasoline. 

Reference Description Source 

We adopted the test fuels that were originally in Part 1065. Current Part 1065 

§1065.715 Natural gas. 

Reference Description Source 

We adopted the test fuels that were originally in Part 1065. Current Part 1065 

§1065.720 Liquefied propane gas 

Reference Description Source 

We adopted the test fuels that were originally in Part 1065. Current Part 1065 

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Draft Technical Support Document 

§1065.740 Lubricants. 

Reference Description Source 

We adopted the lubricant specification in §89.330. §89.330 

§1065.745 Coolants. 

Reference Description Source 

We adopted the coolant specification in §86.1327-98 §86.1327-98 

§1065.750 Analytical gases. 

Reference Description Source 

We adopted the analytical gas specifications in §86.1314-94 and 

§89.312, however, we allowed zero gas contamination to scale with 

the concentration expected at the standard. In some cases this will be a 

decrease in stringency, however, we significantly increased the 

stringency on the level of contaminants when very low levels of 

emissions are expected at the standard. We adopted these changes to 

improve test repeatability. 

§86.1314-94, 

§89.312 

§1065.790 Mass standards 

Reference Description Source 

We adopted the dynamometer calibration weight specifications in 

§86.1308-84 and §89.305. We specified new requirements for 

calibration weights for PM balances. 

§86.1308-84 

§89.305 

Subpart I– Testing with oxygenated fuels. 

§1065.801 Applicability. 

Reference Description Source 

We applied this subpart to engines tested with a fuel that has a 25 % or 

greater concentration of oxygenate. 

§1065.805 Sampling systems. 

Reference Description Source 

We allowed a photo-acoustic analyzer to be used to measure methanol 

and ethanol in exhaust. We provided similar guidance in the past,(8) 

which is consistent with regulations published by the California Air 

Resources Board.(9) 

62
Technical Amendments 

§1065.660 Calculations. 

Reference Description Source 

We relocated the calculations to §1065.665. 

Subpart J– Field Testing 

§1065.901 Applicability 

Reference Description Source 

We applied this subpart to engines with field testing requirements, 

including manufacturer-run on-vehicle testing requirements. Refer to 

the standard setting part for applicability. 

We superceded the current field testing subpart in Part 1065 with a 

new subpart. 

§1065.905 General provisions. 

Reference Description Source 

We provided a list of information needed from standard setting parts to 

conduct field testing according to this part. We indicated that much of 

this subpart relies on specifications in other subparts of Part 1065. 

§1065.910 Field testing equipment 

Reference Description Source 

We specified the equipment we require for field testing. We included 

equipment for routing exhaust for sampling and flow measurement, 

mounting hardware, and power supplies. 

§1065.915 Measurement instruments. 

Reference Description Source 

We specified the measurement instruments we require for field testing 

by referring to Subpart C. We explained how to use signals from an 

engine’s electronic control module. We specified how to use 

redundant measurements. We specified how to address the effects of 

ambient conditions on field test measurement systems. We specified 

how to estimate torque in the field. 

§1065.920 Calibrations and performance checks 

Reference Description Source 

We referred to Subpart D for performance checks. We specified an 

overall field test system performance check against a laboratory that 

meets Part 1065. 

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Draft Technical Support Document 

§1065.925 Measurement instrument and equipment preparation 

Reference Description Source 

We specified a step-by-step set of instructions for preparing a field test 

measurement system for use. We based the instructions on a generic 

field test system by drawing on our own field testing experience and 

reports outlining similar instructions.(10), (11) 

§1065.930 Engine starting, restarting, and shutdown 

Reference Description Source 

We specified a step-by-step set of instructions for engine starting, 

restarting and shutdown based on lab testing, except that an engine 

may be shut down and restarted any number of times during a field 

test. 

§1065.935 Emission test sequence. 

Reference Description Source 

We specified a step-by-step set of instructions for running a field test. 

We based the instructions on a generic field test system by drawing on 

our own field testing experience and reports outlining similar 

instructions.(10), (11) 

§1065.940 Emission calculations. 

Reference Description Source 

We specified the same emissions calculations as used in a laboratory 

according to §1065.650. We noted that information from the standard 

setting parts are required to define individual test intervals within a 

field test. 

Subpart K– Definitions and other reference information 

§1065.1001 Definitions. 

Reference Description Source 

We defined terms that we use in Part 1065. We revised definitions 

from 40 CFR Part 86 and 40 CFR Part 89. We revised definitions to 

reflect the use of Part 1065 test procedures and the application of 

modern emissions control technology such as aftertreatment systems. 

§1065.1005 Symbols, abbreviations, acronyms, and units of measure. 

Reference Description Source 

64
Technical Amendments 

We defined the symbols, abbreviations, acronyms, and units of 

measure that we use in Part 1065. We minimized repeating symbols 

for different quantities. We used symbols consistent with ISO 31. We 

revised symbols, abbreviations, acronyms, and units of measure to 

reflect the use of Part 1065 test procedures and the application of SI 

units, and molar flow rates. 

§1065.1010 Reference materials. 

Reference Description Source 

We revised Part 1065 reference materials to include new ISO and 

NIST publications. 

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Draft Technical Support Document 

References for Chapter 8 

(1) Letter from EPA to EMA, “Guidance Regarding Test Procedures for Heavy-Duty OnHighway and Non-Road Engines”, Gregory Green, Division Director, Certification and 

Compliance Division, Office of Transportation and Air Quality, United States Environmental 

Protection Agency, December 3, 2002. 

(2) “Supporting Document for Letter to EMA Regarding Acceptable Interpretations and 

Alternatives to the Rules and Regulations published in the Federal Register, Vol. 66, No. 12, 

Thursday, January 18, 2001", Matthew Spears, Assessment and Standards Division, Office of 

Transportation and Air Quality, United States Environmental Protection Agency, December 3, 

2002. 

(3) “Description of Changes to the Test Procedures Specified in 40 CFR Part 86 for Model Year 

2007 and Later Heavy-Duty Engines”, Air Docket A-99-06, IV-B-11, Matthew Spears, 

Assessment and Standards Division, Office of Transportation and Air Quality, United States 

Environmental Protection Agency, December 6, 2000. 

(4) “Performance of Partial Flow Sampling Systems Relative to Full Flow Cvs for Determination 

of Particulate Emissions Under Steady-State and Transient Diesel Engine Operation”, Khalek 

Imad A., et al., Southwest Research Institute, Society of Automotive Engineers Technical Paper 

2002-01-1718, May 2002. 

(5) “Heavy-Duty Diesel Engine NOx

Research Institute, San Antonio, TX, July 27, 1999. 

and PM Correction Factors”, Project 08-2597, Southwest 

(6) “A PC-Based Model for Predicting Nox Reductions in Diesel Engines”, Dodge, Lee G., 

Leone, Douglas M., Naegeli, David W., Dickey Daniel, W., Swenson, Kendall R., Southwest 

Research Institute Society of Automotive Engineers Technical paper 962060, 1996. 

(7) Nonroad Diesel Tier IV Rule, EPA420-F-04-037, May 2004. 

(8)“Approval of the Request to Use the Innova 1312 Photoacoustic Multi-gas Monitor in the 

Measurement of Ethanol in Exhaust and Evaporative Emissions”, Gregory Green, Division 

Director, Certification and Compliance Division, Office of Transportation and Air Quality, 

United States Environmental Protection Agency, January 25, 2002. 

(9) Use of Innova Photoacoustic Multi-gas Monitor to Measure Ethanol Exhaust and Evaporative 

Vehicle Emissions”, Mail-Out #MSO 2000-08, Summerfield, R.B, Mobile Source Operations 

Division, California Air Resources Board, June 29,2000. 

(10) “On-vehicle, In-use, Heavy Duty Diesel Engine (HDDE) Protocol”, Czachura Barry S. J., 

Analytical Engineering Incorporated, September 2, 2003. 

66
Technical Amendments 

(11) “Protocol for Measurement of Air Pollutant Emissions from Ferry Boats”, Culnane Mary, San 

Francisco Water Transit Authority, August 19, 2002. 

67