APPENDIX C: VERIFICATION PROCEDURE 

Part 2 

Proposed Verification Procedures for Retrofit Emission Control Systems 

for Off-Road Industrial Engines 

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APPENDIX C, PART 2: 

VERIFICATION PROCEDURE DISCUSSION 

The Air Resources Board (ARB or Board) and equipment manufacturers share the 

responsibility to ensure that emission control systems for retrofit use on existing engines 

and equipment are functional and durable. This responsibility is greater yet when 

ARB’s regulations directly require the systems end users to achieve emission 

reductions from the equipment and engines they own and operate as with the proposed 

LSI fleet requirements. ARB staff, based on significant input from industry and related 

trade groups, has developed a procedure to verify and ensure that control equipment is 

durable and effective in reducing emissions. 

This document describes the verification procedure that the ARB will use to evaluate 

retrofit technologies and the claimed emission reductions of oxides of nitrogen (NOx) 

and hydrocarbons (HC) from off-road large spark-ignition LSI engines. The proposed 

Verification Procedure (Procedure) establishes a way for manufacturers to demonstrate 

to the ARB that their retrofit emission control system provides real and durable emission 

reductions while not increasing carbon monoxide (CO) above existing established 

levels. Resulting emissions benefits when using these retrofit systems will be used to 

meet SIP requirements or for calculating cost effectiveness for applicants to incentive 

programs. 

The ARB’s role is to ensure that the reduction claims for a given retrofit emissions 

control system are real, quantifiable, and durable. The ARB must also establish the 

emission reduction level, as well as verify that the equipment has passed rigorous field 

tests and investigate any secondary emissions of concern. 

While developing the Procedure staff addressed important issues such as verifying the 

reduction claims, including durability, warranty, and in-use emissions. The durability 

and warranty requirements ensure that manufacturers are building retrofit emission 

control systems (RECS) with sufficient durability to meet the verified emission levels as 

the systems age. In-use compliance testing is a way to show ARB staff that the unit 

produced remains consistent with verified designs and continues to function as 

designed after it has left the manufacturing plant. 

1. PROPOSED REGULATION 

Participation in the verification process is voluntary. The proposed Procedure outlines 

the requirements to which an applicant must fully comply: conduct emission tests, 

conduct durability and field demonstrations and submit the results to the ARB along with 

other information in the prescribed application format. 

 

When the ARB completes the evaluation of a RECS, and is satisfied that the RECS 

reduces emissions, the Executive Officer will notify the applicant in writing and issue an 

Executive Order. The Executive Order states the verified emission reduction level and 

any conditions that are necessary to support or sustain that verification. The verification 
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also requires that the applicant provide a detailed warranty, conduct in-use compliance 

testing of the system after having sold or leased a specified number of units and report 

the results to the Executive Officer. 

2. Applicability and Purpose 

The Verification Procedures apply to retrofit control systems, which through the use of 

sound, proven science and engineering will control emissions HC, NOx and CO from 

off-road LSI engines. The use of control systems verified in accordance with the 

proposed verification procedure may be a means of complying with other state board 

regulations applicable to LSI engines, to the extent provided for in those regulations. 

3. APPLICATION PROCESS 

3.1 Letter of Intent – Proposed Verification Plan 

Prior to submitting a formal application for verification, the applicant must submit a letter 

of intent to apply for verification of their retrofit system. This will ensure that the 

applicant includes all information necessary for the ARB staff to conduct an initial 

evaluation. Providing such information will also ensure that the applicant understands 

the requirements and thus not spend extra time and resources conducting unnecessary 

testing. The letter should include: 

• Identification of the contact persons, phone numbers, names and addresses of the 

responsible party proposing to submit an application 

• A general description of the technical principles of the retrofit operation 

• Plans for meeting the testing and other verification requirements or existing test data 

• A percent emission reduction and/or brake-specific emission limit that the system is 

expected to achieve throughout the emission durability period 

• Proposed emission control group and parameters 

• Plans for meeting the testing and other verification requirements – including any 

existing test data 

• Previous test data 

• A brief statement that the applicant agrees to provide a warranty 

3.2 Plan Review Timeframe

During the initial review, ARB staff may be requesting more information and 

understanding of how the RECS functions on the target equipment. If the Executive 

Officer determines that the applicant has not made a satisfactory demonstration that the 

product designed to achieve the claimed emission reductions is based on sound 

principles of science and engineering, the Executive Officer shall notify the applicant in 

writing. The applicant has 60 days from the date of the notification letter to decide 

whether to submit additional materials and clarifications or discontinue their participation 

in the verification process. 
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If the ARB staff determines that the retrofit system appears to be technologically sound 

and appropriate for the identified emission control group, the applicant will be notified of 

this finding. The applicant may then proceed with satisfying the remaining requirements 

for full verification of their RECS. Once the applicant and staff agree on the proposed 

verification plan any modifications to the prescribed test equipment and/or test 

procedures must be approved in advance by the Executive Officer and described later 

in the formal verification application. 

3.3 Formal Application

When all prescribed verification testing is complete, the applicant may then submit a 

formal application. The test results along with other information should be submitted in 

the approved application format included in the proposed verification procedure. The 

ARB has 30 days to review this application for completeness and to determine whether 

additional information is required. Within 60 days after an application has been deemed 

complete, the staff will determine whether the RECS merits verification. 

The Executive Officer shall notify the applicant of the decision in writing and issue an 

Executive Order specifying the Verification level and state absolute emissions or 

percentage reduction. 

If the retrofit system passes the verification process, a performance classification level 

will be assigned by the Executive Officer. The level will be either the percentage 

reduction or the absolute emissions as shown in Table 1 below. 

 

3.4 Data Submission

Any data submission must be in an electronic file that is column-delimited format or an 

alternative format approved by the Executive Officer. The appropriateness of allowing 

alternatives to the prescribed requirements will be taken into consideration at this time. 

Emission tests used to support emission reduction claims must be reported in total 

hydrocarbons, oxides of nitrogen, and carbon monoxide. Emission test units must be 

reported in grams/brake horsepower-hour (g/bhp-hr.)

4. Classification of Retrofit Emission Control Levels 

Achieving large reductions in emissions with retrofit emissions control systems may not 

be a pragmatic proposal for all LSI engines and equipment. In recognition of this, and 

to facilitate the implementation of current emission control strategies, the ARB has 

proposed a procedure that would allow multiple levels of system verifications rather than 

a single level. The proposed levels are based on the performance of current LSI retrofit 

emission control system technology and input from industry. A multi-level approach 

gives a hierarchy for emission reduction technologies. 
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The multi-level verification classification consists of four HC + NOx reduction levels as 

shown in Table 1. The proposed levels should broaden both the spectrum of control 

technologies available and the number of applications that can be controlled. It should 

be noted that while staff is recommending a multi-level approach to verification, ARB is 

not deviating from the goal to realize the maximum reductions in HC + NOx emissions 

from LSI equipment that is economically and technologically feasible. 

Table 1. LSI Engine Retrofit System Verification Levels 

Classification Percentage Reduction 

(HC+NOx)

Absolute Emissions 

(HC+NOx) 

LSI Level 1 (1) > 25% (2) Not Applicable 

LSI Level 2 (1) > 75%(3) 3.0 g/bhp-hr (3) 

LSI Level 3a (1) > 85% (4) 0.5, 1.0, 1.5, 2.0, 2.5 g/bhp-hr 

LSI Level 3b (5) Not Applicable 0.5, 1.0, 1.5, 2.0 g/bhp-hr 

 

 (1) Applicable to uncontrolled engines only 

(2) The allowed verified emission reduction is capped at 25% regardless of actual 

emission test values 

 (3) The allowed verified reduction for LSI Level 2 is capped at 75% or 

3.0 g/bhp-hr regardless of actual emission test values 

(4) Verified in 5% increments, applicable to LSI Level 3a classifications only 

(5) Applicable to emission-controlled engines only 

4.1 Emission Control Groups

An emission control group is a set of LSI engines or applications that is determined by a 

group of common parameters that affect the performance of particular RECS. An aftermarket system would likely be flexible enough for use on a diverse group of engine 

models and equipment, including different engine makes, years, and fuel types. 

Categorizing the engine “universe” in this way is an effective method for reducing the 

amount of testing needed and allows ARB to evaluate diverse technologies with a single 

verification Procedure. 

Significant parameters for the RECS of both the engine and application are considered 

in creating “emission control groups.” The exact parameters depend on the nature of 

the RECS and may include, but are not limited to, baseline or certification levels of 

engine emissions, displacement, horsepower rating, duty cycle, fuel delivery systems 
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and fuel. The emission control group may be comprised of several engine families, 

applications and engine manufacturers. 

Staff expects that the procedure will be used for a wide range of technologies, each with 

its own nature, strengths and weaknesses. Because the applicant is most acquainted 

with the engines and equipment the RECS will work on, ARB staff recognizes the 

importance of applicant input in the early stages of the application process when the 

emission control group is identified for verification. 

The applicant should submit its proposed emission control group and parameters for the 

RECS with their proposed verification plan. A RECS system that employs two or more 

individual sub-systems or components would be tested and submitted for evaluation as 

one system. This coordination with staff will also help identify appropriate use of any 

existing data and potentially reduce the amount of testing that would be required under 

an emission control group system. 

Emission control groups are fully integrated into the procedure for both initial 

verifications and extensions of existing verifications. For the initial verification of a 

RECS, the applicant must restrict its application to a single emission control group. By 

restricting the scope of the first application, staff is better able to conduct a thorough 

review of the retrofit emission control system. 

 

4.2 Extensions of a Verification 

After the RECS has been successfully verified for one emission control group, the 

applicant may extend the verification by submitting data showing that the retrofit 

emission control system would be effective on other engines or equipment. Any 

information deemed necessary by the Executive Officer to address differences between 

the emission control group already verified and the additional emission control group(s) 

or engines could be required for the extension. 

If the applicant has design modifications of the RECS in the original verification, an 

extension of the original Executive Order or issuance of an additional Executive Order 

can be made through this same verification procedure. The applicant may use 

additional test data, engineering analysis or justification, and any other information 

deemed essential by staff. Processing time periods are consistent with initial 

verification. 

5. Verification Requirements 

5.1 Emissions Reductions Testing

The applicant’s proposed plan and the formal application must focus on testing the 

retrofit emission control system on engines representing a single identified emission 

control group. Some manufacturers of RECS have been conducting testing and 

evaluation of their emissions control systems for a number of years. That test 
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information has mainly been used to assist their customers in controlling exposure of 

individuals to CO emissions while operating power equipment in confined space 

environments. ARB staff anticipates that some applicants may request to use the 

existing test data for verification purposes. The applicant is encouraged to submit with 

their verification plan any existing test data or their plans for meeting the emission 

testing, durability testing, field compatibility and the later in-use compliance testing 

requirements of the procedure. Based on this information and discussions, staff will 

determine whether testing requirements are already partially or fully satisfied. 

The primary aim of emission testing is to ensure that retrofit emission control systems 

give real emission reductions while minimizing any generation of harmful secondary 

emissions by presenting test results for representative engines/equipment from the 

chosen emissions control group. Engine family name when available, make, model 

designation (e.g. name or number) and model year should be used for the test engine 

identification. 

Baseline emission test data must be collected for HC and NOx as well as the emission 

test data after the RECS is installed. If this verification is for a retrofit to be used on a 

certified engine, the certification emission standards can be used as the baseline 

emission test data. Baseline emissions data for CO is required to insure that the RECS 

does not cause the CO emissions to exceed the allowed limits. 

The appropriate test cycles to use in the testing are shown in Table 2 below. 

Table 2. Test Cycles for Emission Reduction Testing 

Test Type LSI Retrofit 

System 

Verification Date

Off-Road (including 

portable engines) 

Off-Road (constantspeed operation) 

Engine Pre-2007 

Steady-state test cycle 

from ARB off-road 

regulations 

or 

U.S. EPA transient test

Steady-state test cycle 

from ARB off-road 

regulations 

or 

U.S. EPA transient test 

Engine 2007 and later U.S. EPA transient test U.S. EPA transient test 

5.2 Test Engine Selection 

The applicant will identify the engine/s that best represent the chosen emission control 

group for testing. Appropriate identification of test engines would be the make, model, 

model year, HC, NOx, and CO baseline emission test levels for uncontrolled equipment, 

or HC, NOx, and CO certification standards and engine family name for engines subject 

to emission regulations. 
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The applicant must also describe the equipment applications on which the RECS is 

intended to be used, by giving examples of in-use equipment, characterizing typical duty 

cycles, indicating any fuel requirements, and/or providing other application-related 

information. 

5.3 Test Fuel

The testing fuel used shall be consistent with the fuel specifications as outlined in the 

"California Exhaust Emission Standards and Test Procedures for 2001 and Subsequent 

Model Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles," as referenced 

in Title 13, California Code of Regulations, section 1961 (d). If testing will be done 

using U.S. EPA fuel, as outlined in title 40, Code of Federal Regulations (CFR), part 

1065, the manufacturer shall demonstrate that the emission results are consistent with 

the above ARB test procedures. Manufacturers may, however use “commercially 

available fuels” to accumulate service hours. 

During all engine tests, the engine shall employ lubricating oil consistent with the engine 

manufacturer's specifications for that particular engine. These specifications shall be 

recorded and declared in the verification application. 

5.4 Test Cycle 

The test used for the verification should follow the test cycles specified in the Table 2 or 

with an alternative cycle(s) approved by the Executive Officer. For off-road engines 

used in constant-speed operation, the applicant must use the D-2 steady state test 

cycle or another appropriate off-road test cycle representing the operating conditions of 

the application, with approval from the Executive officer, or the U.S. EPA transient test. 

The applicant may request the Executive Officer approve an alternative test cycle or 

method in place of a required test cycle or method if the need arises. Some of the 

criteria staff will use in evaluating a proposed alternative are: 

• Similarity of characteristics to the specified test cycle or method and in-use duty 

cycle 

• Existing test data generated using the alternative test cycle or method 

• Technological necessity 

• Technical ability to conduct the required test 

5.5 Testing and Emissions Analysis 

A minimum of three hot start tests for the test cycle selected must be run for both the 

baseline configuration without emissions controls and with the implemented RECS 

configuration. For all test runs used to support emission reduction claims, the applicant 

must report emissions of total HC, NOx, and CO in grams per brake horsepower-hour. 
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Test data must be submitted in electronic file in comma-delimited columns or another 

format approved by the Executive Officer. 

The Executive Officer may require the applicant to perform additional analyses if there 

is reason to believe that the use of the RECS may result in the increase of toxic air 

contaminants, or other harmful compounds. In the determination, the Executive Officer 

may consider all relevant data, including but not limited to the following: 

• The nature of any substance added to the fuel, intake air, or exhaust stream 

• Whether a catalytic reaction is known or reasonably suspected to increase toxic air 

contaminants or ozone precursors 

• Results from scientific literature 

• Field experience 

5.6 Durability Demonstration 

The previous section on emission testing described the process ARB would use to 

evaluate the emission reductions for the RECS and to determine if the reductions are 

real. This section focuses on the process for verifying that the RECS emission 

reductions are durable. Testing conducted in the durability demonstration provides a 

picture of how the performance of the RECS may change over time. Testing gives 

further certainty that the emissions control system is durable and physically functional. 

The durability demonstration consists of operating the system in the field or in a 

laboratory for 2,500 hours. Emissions testing must be performed both at the beginning 

and end of the demonstration period. If the applicant chooses to conduct all the 

durability accumulation services in the laboratory, an in-field compatibility demonstration 

report would be required. 

If the applicant has demonstrated durability for an identical system in a prior verification 

or has demonstrated durability through field experience, the applicant may request ARB 

to accept the previous demonstration. In evaluating such a request, staff will consider 

relevant information including, but not limited to:

• Similarity of baseline emissions and application duty cycles 

• The relationship between the emission control group used in previous testing and 

the current emission control group 

• Number of engines tested 

• Evidence of successful operation and user acceptance 

• Published reports 

If the RECS fails to maintain the initial verified percent emission reduction or absolute 

emission level during the durability demonstration period, ARB will either deny the 

verification or downgrade the system to the verification level corresponding to the 

appropriate lower performance level. 
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If the RECS fails to maintain at least a 25% reduction, it cannot be verified. The 

applicant must submit a report explaining the circumstances of the failure. ARB will 

then determine if the applicant should continue the durability demonstration after fixing 

the failed system or begin a new durability demonstration. 

5.7 Test Engine Selection

The applicant may choose the engine and application to be used in the durability 

demonstration subject to ARB approval. The selected engine need not be the same 

engine used for emission reduction testing, but if the applicant does use the same 

engine, the emission reduction testing results can also be used for the zero hour 

durability test requirement. 

5.8 Service Accumulation

Durability demonstration consists of an extended service accumulation period in 

combination with emission reduction testing before and after the service accumulation. 

Service accumulation begins at the zero hour and concludes at 2,500 hours. The 

applicant could choose to satisfy the durability demonstration by complying with the 

requirements for a shorter durability period. The minimum durability demonstration 

period would be 1,000 hours if it can be correlated with or demonstrated to be 

equivalent to 2,500-hour in-use. 

The applicant must provide sufficient documentation to justify the request for a shorter 

durability demonstration period. The applicant may propose a sampling scheme for 

approval by the Executive Officer. The sampling scheme may include, but is not limited 

to, logging only significant changes in a parameter, averages or changes above some 

threshold value. Data must be submitted in an electronic file in comma-delimited 

columns or another format that is approved by the Executive Officer. 

5.9 Required Emission Testing for Durability Demonstration

The ARB staff proposes that emissions testing be conducted as part of the durability 

demonstration. The tests are intended to provide a picture of any change in 

performance of RECS over time. 

The RECS must be tested for baseline and control emissions once at the beginning and 

once at the end of the durability demonstration period. The applicant may elect to test 

for baseline emissions only once, either at the beginning of the durability demonstration 

period or at the end of the durability demonstration period. However, if this is the case, 

the applicant must use the same baseline test result for calculating emissions 

reductions for both the beginning and the end of the demonstration period. As an 

alternative to testing a single unit before and after the service accumulation period, the 

applicant may request that the Executive Officer consider the testing of two identical 

units, one that has been preconditioned and another that has completed the service 

accumulation period. 
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For service accumulation in the laboratory the duty cycle must be the same test cycle(s) 

as for the initial emissions reductions testing and a minimum of three hot-start tests is 

required. The applicant may request ARB to accept existing field demonstration data or 

waive the initial emission tests if there is substantial test data from previous 

demonstrations. 

5.10 Maintenance 

Except for emergency engine repairs, only scheduled maintenance on the engine and 

RECS may be performed during the durability demonstration. If normal maintenance 

includes replacement of any component of the engine emission control system, the time 

(years, or hours) between component change must be included with the results of the 

demonstration. 

If emergency repair was conducted on an engine equipped with the RECS within the 

durability demonstration period, the applicant must report to the Executive Officer, within 

30 days of the repair, on what repair was performed and what components were 

involved, and provide an explanation on the possible cause(s) for the engines and/or 

the RECS malfunction. Based on the information provided by the applicant, the 

Executive Officer will decide whether to allow that engine to continue to be used in the 

durability demonstration program, or to start a new durability demonstration period. 

5.11 Performance Requirements

Throughout the durability demonstration period, the RECS must meet the following 

requirements: 

(1) If the applicant claims a percent emission reduction, the percent emission 

reduction must exceed the minimum percent emission reduction associated with 

the LSI Level for which the applicant was seeking verification. 

(2) If the applicant claims a lower emission level, the emission level test results must 

not exceed the emission level associated with the LSI Level for which the 

applicant was seeking verification. 

(3) The RECS must maintain physical integrity. Its physical structure and all of its 

components not specified for regular replacement during the durability 

demonstration period must remain intact and fully functional. 

(4) The RECS must not cause any damage to the engine, vehicle, or equipment. 

(5) No maintenance of the RECS beyond that specified in its owner’s manual will be 

allowed without prior ARB approval. 

5.12 Performance Failures in Durability Demonstration Period 

If the retrofit emission control system does not maintain its initial emission reduction 

percent or emission reduction level over the durability period for any reason, the 

Executive Officer may downgrade the system to the verification level corresponding to 

the lowest degraded performance observed in the durability demonstration period. If 
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the RECS fails to maintain the emission reduction performance pursuant to the 

performance requirements described above during the demonstration period, the RECS 

will not be verified. If the system fails, and the applicant desires to proceed with the 

verification, the applicant must submit a report explaining the circumstances of the 

failure within 90 days of the event. ARB will then determine if the applicant should 

continue the current durability demonstration after fixing the failed system or begin a 

new durability demonstration. 

5.13 Field Demonstration Requirements

The applicant must demonstrate successful operation and compatibility of the retrofit 

emission control system in the field with at least one vehicle or engine belonging to the 

emission control group chosen for verification. The field demonstration test period is a 

minimum of 200 hours. ARB will consider existing field experience and engineering 

justification to determine whether additional emission control groups require separate 

field demonstrations. 

Field demonstrations are not required for the purpose of determining in-field emission 

reductions and have no emission-testing component. Instead, the purpose is to see if 

the RECS is compatible with the emission control group selected and how it withstands 

real-world conditions. Compatibility here incorporates many aspects. It is important to 

determine, for instance, if the operator notes any unusual effects, how the system 

handles real-world vibrations, jolts, and variable exhaust flows, and what maintenance 

issues may turn up. The field demonstration, therefore, would verify that the applicant’s 

system is technologically mature and ready for real-world application. 

Compatibility is determined by the Executive Officer based on a third-party statement 

(described below) and any other data submitted. A control system will be considered 

compatible with the chosen application if it does not: 

• cause engine damage or engine malfunction or 

• hinder or detract from the vehicle or equipment’s ability to perform its normal 

functions. 

The RECS would be deemed to fail the field demonstration requirements if it could not 

comply with the above-specified criteria during the demonstration period. 

Field demonstration is required if all durability was conducted in the laboratory. 

If the durability demonstration selected is an in-field test, it may be used to satisfy the 

field demonstration requirement for that emission control group. In this case the field 

demonstration requirements need only be a written statement from an ARB-approved 

third party such as the owner or operator of the vehicle or equipment. 

The statement must describe overall performance, maintenance required, problems 

encountered, the results of a visual inspection and any other relevant comments. The 

results of a visual inspection conducted by the third party at the end of the 
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demonstration period must also be described. This should comment on whether the 

RECS is physically intact, securely mounted, or leaking any fluids and should include 

any other evaluative observations. If the RECS fails in the course of the field 

demonstration, the applicant must notify ARB within 15 days of the failure and then 

submit a report explaining the circumstances of the failure within 90 days of the failure. 

ARB may then determine whether to deny verification or allow the applicant to correct 

the failed RECS and either continue the field demonstration or begin a new field 

demonstration. 

5.14 Other Requirements 

In addition to the emission testing, durability testing and field demonstration, the 

applicant must meet a number of other requirements and provide additional information, 

much of which depends on the nature of the retrofit emission control system. This type 

of information would be explored with ARB staff and the applicant in the proposed 

verification plan. 

5.15 Fuel and Oil Requirements

The applicant must specify the fuel and lubricating oil requirements necessary for 

proper functioning of the RECS in the owner’s manual. The applicant must also specify 

any consequences that will be caused by failure to comply with these requirements, as 

well as methods for reversing any negative consequences. 

5.16 Maintenance Requirements

The applicant must identify all normal maintenance requirements for the RECS. The 

applicant must specify the recommended intervals for cleaning and/or replacing 

components. Any components to be replaced within the defects warranty period must 

be included with the original RECS package or provided free of charge including freight 

and handling fees, to the customer at the appropriate maintenance intervals. 

Any normal maintenance items that the applicant does not intend to provide free of 

charge must be approved by the Executive Officer (the applicant is not required to 

submit cost information for these items). In addition, if applicable, the applicant must 

specify procedures for proper handling of spent components and/or materials removed 

from the RECS. If any materials are hazardous, the applicant must identify them as 

such in the owner’s manual. 

5.17 System Labeling

Certain emissions-critical or emissions-related parts and/or engines must be properly 

identified for the end users. This will enable users to determine their compliance with 

any regulations. Also, the label will assist the applicants to identify a representative 

sample of retrofit emission control systems for in-use compliance testing. By using LSI 

emission control group names, ARB will be able to clearly identify given RECS and 
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distinguish significant differences in design from superficial changes that are, for 

instance, employed by the applicant for marketing purposes. 

The applicant must provide legible and durable labels to be affixed on both the RECS 

and the engine on which the RECS is installed except as noted in below. The required 

labels must identify the verification level as well as the percent reduction or absolute 

emission level. The label must also include name, address, and phone number of the 

manufacturer, the LSI retrofit emission control group name. A unique identification 

comprising the serial number for the RECS and the month and year of manufacture are 

also required for this label. The month and year of manufacture are not required on the 

label if this information can be readily obtained from the applicant by reference to the 

serial number. A scale drawing of a sample label must be submitted with the 

verification application. Unless an alternative is approved by the Executive Officer, the 

label information must be in the following format: 

Name, Address, and Phone Number of Manufacturer 

LSI Retrofit Emission Control Group Name 

Product Serial Number 

ZZ-ZZ (Month and Year of manufacture, e.g., 11-05) 

(2) LSI Retrofit Emission Control Group Name. Each RECS shall be 

assigned a name defined as below: 

CA/V/MMM/LL##/NHP## or NHL##/APP/XXXXX 

Where: 

CA: Designates a RECS verified in California 

V: Year of verification 

 LL##: Verified LSI Level (e.g., LL2 means the retrofit system was verified to the “LSI 

Level 2”, LL3a means the retrofit system was verified to “LSI Level 3a). 

 NHP##: Verified HC + NOx reduction percent (e.g., NH75 means HC + NOx reduction of 

75 percent). 

NHL##: Verified HC + NOx absolute emissions in units of g/bhp-hr, (e.g., NH3.0 means 

verified HC + NOx emission level of 3.0 g/bhp-hr). 

APP: Verified application includes a combination of Off-road (OF),or Stationary (ST) 

XXXXX: Five alphanumeric character code issued by the Executive Officer 

The applicant may request that the Executive Officer approve an alternative label format 

to the RECS or engine as described in this section. In reviewing this request, the 

Executive Officer may consider all relevant information including, but not limited to, the 

informational content of an alternative label as proposed by the applicant. 
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5.18 Noise Level Control

Applicants must ensure that the RECS is in compliance with all applicable noise limits 

for which the RECS is intended. All RECS must be in compliance with applicable local 

government requirements for noise control. 

5.19 Limits on CO

In order for the RECS to be verified, it must comply with the following limits on CO: 

(1) If installed on engines not emission-certified, the system must not cause the CO 

emissions to exceed the greater of: 

 (a) 37 g/bhp-hr or 

 (b) ten percent above the engine’s baseline CO emission level. 

(2) If installed on an emission-certified engine, the system must not cause the CO 

emission to exceed the CO emission standard applicable to the engine at the 

time of the engine’s certification 

5.20 Emission Sampling Ports

To facilitate in-field emission measurements, the applicant may design the RECS to 

have two sampling ports where emissions measurements can be made. 

5.21 Owner’s Manual

The applicant must provide a copy of the owner’s manual for the retrofit emission 

control system. At a minimum, the following information must be clearly specified. 

• Warranty statement including the warranty period over which the applicant is 

liable for any defects 

• Installation procedure and maintenance requirements for the RECS 

• Any fuel consumption improvement or penalty 

• Any fuel requirements 

• Requirements for lubrication oil quality and maximum consumption rate 

• Contact information for replacement components and cleaning agents 

5.22 Determination of Emissions Reduction

The ARB verification of the emission reductions from the RECS will be based on the 

average of the entire valid baseline and control emission and durability test results (i.e., 

before and after the installation of the RECS). For applicants that are verifying to 

absolute emission levels, an average of the control test results will be used. 

For durability testing: if the applicant chooses to perform either the zero hour or the 

2500 hour baseline test, but not both, then those results must be used in the calculation 

of the reductions for the zero hour and the 2500 hour control tests. 
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6. Post-Verification Responsibilities 

After a control system has been verified for use with an emission control group, it may 

be sold in California as such, participate in incentive programs in which verification is 

required, or be used to satisfy the requirements of ARB in-use control regulations. After 

verification, applicants have the responsibility to perform in-use compliance testing and 

to honor the warranty. 

7. Warranty Requirements 

The applicant must provide a minimum defects and emissions performance and product 

warranty with a minimum coverage of 2,500 hours or three years, whichever comes 

first. Because the emissions benefits must be real and durable for a specified length of 

time, an installation warranty will also be required, ensuring that nothing has been 

compromised by an incorrect installation. The applicant must also include a copy of this 

warranty statement in the owner’s manual. 

7.1 Product Warranty 

The applicant must provide a transferable warranty to all owners, for ownership within 

the warranty period, and lessees, within the lease contract warranty period. The 

warranty should state that the verified RECS is free from defects in design, materials, 

workmanship, or operation of the RECS which would cause the RECS to fail to conform 

to at least 90 percent of the lower bound of all the test values used to determine 

percentage verification levels or 90 percent of the upper bound of all test values used to 

determine absolute verification levels. 

The minimum warranty period should be three years or 2,500 hours, provided the 

operation of and conditions of use for the equipment, engine, and RECS conform with 

the operation and conditions specified in the ARB’s Executive Order and stated in the 

owner’s manual. 

The warranty must cover the full repair or full replacement costs of the RECS, including 

parts and labor. The warranty must also cover the full repair or replacement cost of 

returning the engine components to the condition they were in prior to the failure, 

including parts and labor, for damage to the engine proximately caused by the verified 

RECS. Repair or replacement of any warranted part, including the engine, must be 

performed at no charge to the equipment or engine owner. This includes only those 

relevant diagnostic expenses in the case in which a warranty claim is valid. The 

applicant may, at its option, instead pay the fair market value of the engine prior to the 

time the failure occurs. 

The repair or replacement of any warranted part otherwise eligible for warranty 

coverage may be excluded from the warranty if the RECS or engine has been abused, 

neglected, or improperly maintained. If such abuse, neglect, or improper maintenance 
16

was the direct cause of the need for the repair or replacement of the part it’s repair or 

replacement would be excluded from the warranty. Failure of the equipment or engine 

owner to ensure scheduled maintenance or to keep maintenance records for the 

equipment, engine, or RECS may, but shall not, per se, be grounds for disallowing a 

warranty claim. 

7.2 Installation Warranty

A person or company who installs a verified RECS must warrant that the installation is 

free from defects in workmanship or any materials which cause the RECS to fail to 

conform to the emission control performance level it was verified to for three years or 

2,500 hours, whichever occurs first. 

The extent of the warranty coverage provided by installers must be the same as the 

warranty provided by the applicant as established by the Product Warranty section 

(discussed above) and the same exclusions must apply. 

7.3 Product Warranty Statement

The applicant must furnish a copy of the warranty statement in the owner’s manual. 

The applicant may include descriptions of circumstances that may result in a denial of 

warranty coverage, but these descriptions shall not limit warranty coverage in any way. 

7.4 Retrofit Emission Control System Warranty Reports 

7.4.1 Annual Warranty Claims Reports

The applicant must submit an annual warranty report to the Executive Officer by 

February 1 of each calendar year including the following information: 

 

• Annual and cumulative sales, and annual and cumulative leases of equipment 

installed with RECS in California. 

• Annual and cumulative production of RECS is required for California only. 

• Annual summary of warranty claims in California only must include: 

− A description of the nature of the claims and of the warranty replacements or 

repairs. The applicant must categorize warranty claims for each LSI retrofit 

emission control group by the component(s) part number(s) replaced or repaired. 

− The number and percentage of RECS of each model for which a warranty 

replacement or repair was identified. 

− A short description of the RECS component that was replaced or repaired under 

warranty and the most likely reason for its failure. 

• Date the warranty claims were filed and the engine family and application in which 

the RECS were used. 

• Delineate the reason(s) for any instances in which warranty service is not provided 

to end-users that file warranty claims. The applicant may also report instances 

where the applicant chose to make repairs for the user even though the applicant 
17

has determined that those warranty claims were unsubstantiated or that they were 

not required under Section 2757 of the Verification Procedure. 

7.4.2 Periodic Warranty Claims Reports 

The applicant is required to submit a periodic warranty report within 30 calendar days if 

there are three or more warranty claims for the same component or same part number 

that is repaired or replaced; or, if there are four or more total warranty claims, or four 

percent of the cumulative number of RECS subject to these warranty provisions, 

whichever is greater. Throughout the year the applicant must continue to comply with 

the periodic warranty reporting as more warranty claims were made. The periodic 

warranty report must include the following information: 

• Description of the nature of the claims and of the warranty replacements or repairs. 

The applicant must categorize warranty claims for each LSI retrofit emission control 

group by the component(s) part number(s) replaced or repaired. 

• The number and percentage of RECS of each model for which a warranty 

replacement or repair was identified. 

• A short description of the RECS component that was replaced or repaired under 

warranty and the most likely reason for the component failure. 

• Date the warranty claims were filed and the engine family and application that were 

installed with the RECS. 

• The reason(s) for any instances in which warranty service is not provided to endusers that file warranty claims. The applicant may also want to report instances 

where the applicant chose to make repairs for the user even though it determined 

that those warranty claims were unsubstantiated or that they were not required. 

7.5 In-Use Compliance

An in-use compliance test requirement was included to ensure that RECS sold to endusers are as effective during normal operation as those tested for the initial verification. 

The in-use compliance testing is required when at least 50 units of a specific RECS 

group have been sold in the California market. 

For each RECS control group, the Executive Officer will identify a representative sample 

of engines or equipment fitted with RECS for the in-use compliance testing from each 

emission control group. As with any in-use emission testing, all properly maintained 

engines would be expected to sustain the verified emission levels. Good maintenance 

records for the engines or equipment with the selected RECS installed will be an 

important part of the compliance information. Accumulated hours of usage, 

maintenance records (to the extent practicable), operating conditions and a description 

of any unscheduled maintenance that may affect the emission results would be 

important to present. 

Applicants must obtain and test a minimum of four RECS that have operated between 

1,500 and 2,000 hours or between 22 and 29 months. This testing would allow ARB to 
18

identify and assist in resolving any problems associated with the RECS before having 

widespread application of those systems in the market. A tune-up or regular 

maintenance prior to testing is allowed. 

An applicant is required to follow the same testing procedure as used for initial emission 

testing, including the same test cycle(s). Doing so would eliminate any variations in 

emission reduction performance that occur with different test cycles. ARB could then 

make a more meaningful comparison of the emission reductions between the in-use 

RECS and those that were originally verified. After all testing is completed, the 

applicant must submit an in-use compliance report that summarizes the results of in-use 

testing. 

7.5.1 In-Use Compliance Report 

The applicant must submit an in-use compliance report to the Executive Officer within 

three months of completing each phase of testing. These reports are important so that 

ARB may be brought in early if there are problems that would need to be addressed that 

affect the verification of the RECS. The following information must be reported for each 

of the minimum of four RECS tested: 

• Parties involved in conducting the in-use compliance tests. 

• Quality control and quality assurance information for the test equipment. 

• RECS group name and manufacture date. 

• Equipment and type of engine the RECS was applied (engine family name, make, 

model year, model, displacement, etc.) 

• Estimated hours that the RECS were used. 

• Results of all emission testing. 

• Summary of maintenance, modifications, and repairs performed on the RECS. 

 

REFERENCES 

ARB, 2002. "Staff Report: Initial Statement of Reasons, Proposed Regulation for the 

Verification Procedure for In-use Strategies to Control Emission From Diesel Engines," 

California Air Resources Board, March 29, 2002. 

ARB, 1998a. "Public Hearing to Consider Adoption of Emission Standards and Test 

Procedures for New 2001 and Later Off-Road Large Spark-Ignition Engines," California 

Air Resources Board, September 4, 1998. 

EPA, 2001. "Evaluation of Emissions Durability of Off-road LPG Engines Equipped 

With Three-way Catalyst,” United States Environmental Protection Agency, 

September, 1998. 

EPA, 2005. "Test Procedures for Highway and Nonroad Engines and Omnibus 

Technical Amendments,” United States Environmental Protection Agency, June, 2005.