April 10, 2003 

Placer County APCD 242-1 Rules and Regulations 

RULE 242 STATIONARY INTERNAL COMBUSTION ENGINES 

Adopted 4-10-03 

CONTENTS 

100 GENERAL 

101 PURPOSE 

102 APPLICABILITY 

103 EXEMPTIONS 

200 DEFINITIONS 

201 ANNUAL FUEL USAGE 

202 APCO 

203 CALENDAR YEAR 

204 DIESEL ENGINE 

205 EMERGENCY STAND-BY ENGINE 

206 ENGINE RATING 

207 EXISTING ENGINE 

208 LEAN-BURN ENGINE 

209 MAINTENANCE OPERATION 

210 NITROGEN OXIDES (NOx) 

211 OUTPUT 

212 PERMITTED CAPACITY FACTOR 

213 RICH-BURN ENGINES 

214 PEAK LOAD 

215 START OF CONSTRUCTION 

216 STATIONARY INTERNAL COMBUSTION ENGINE 

217 STOICHIOMETRIC AIR/FUEL RATIO 

300 STANDARDS

301 LIMITS 

302 ENGINE OPERATOR INSPECTION PLAN 

400 ADMINISTRATIVE REQUIREMENTS

401 COMPLIANCE SCHEDULES 

402 REPORTING REQUIREMENTS 

403 EMISSION SOURCE TESTING 

404 VIOLATIONS

500 MONITORING AND RECORDKEEPING

501 RECORDKEEPING-GENERAL 

502 RECORDKEEPING-EXEMPTIONS 

503 RECORDKEEPING-RETENTION 

504 TEST METHODS 
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Rules and Regulations 242-2 Placer County APCD 

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Placer County APCD 242-3 Rules and Regulations 

100 GENERAL 

101 PURPOSE: To limit the emission of nitrogen oxides (NOx) and carbon monoxide (CO) from 

stationary internal combustion engines. 

102 APPLICABILITY

102.1 Geographic: The provisions of this rule apply to facilities located anywhere in Placer 

County. 

102.2 Application: This rule applies to any stationary internal combustion engine rated at 

more than 50 brake horsepower and using any gaseous fuel or liquid fuel, including 

liquid petroleum gas (LPG), gasoline or diesel fuel. This rule shall not apply to 

engines used directly and exclusively for agricultural operations necessary for the 

growing of crops or the raising of fowl and animals. 

102.3 Severability: If any section, subsection, sentence, clause, phrase or portion of this 

rule is, for any reason, held invalid, unconstitutional, or unenforceable by any court of 

competent jurisdiction, that portion shall be deemed as a separate, distinct and 

independent provision, and the holding shall not affect the validity of the remaining 

portions of the rule. 

103 EXEMPTIONS: 

103.1 Exemption, Operating Hours: The provisions of this rule shall not apply to any 

engine operated less than 200 hours per calendar year. 

103.2 Exemption, Emergency Stand-By Engines: The provisions of this rule shall not apply 

to permitted emergency stand-by engines operated either during an emergency or 

maintenance operation. Maintenance operation is limited to 100 hours per calendar 

year. 

103.3 Exemption, Research, Testing and Evaluation: The provisions of this rule shall not 

apply to: 

103.3.1 Engines used in research or teaching programs; 

103.3.2 Test-stands used for evaluating engine performance. 

103.4 Exemption, Low Capacity: The provisions of this rule shall not apply to diesel 

engines with a permitted capacity factor of 15 percent or less. 

103.5 Exemption, Cranes and Welding: The provisions of this rule shall not apply to 

engines used to power cranes and welding equipment. 

200 DEFINITIONS 

201 ANNUAL FUEL USAGE: The amount of fuel an internal combustion engine consumes in a 

calendar year.

202 APCO: District Air Pollution Control Officer. 

203 CALENDAR YEAR: Twelve (12) consecutive months beginning January 1 and ending 

December 31. 

204 DIESEL ENGINE: A compression-ignited two or four-stroke engine in which liquid fuel 

injected into the combustion chamber ignites when the air charge has been compressed to a 

temperature sufficiently high for auto-ignition. 
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Rules and Regulations 242-4 Placer County APCD 

205 EMERGENCY STAND-BY ENGINE: An internal combustion engine used only as follows: 

205.1 When normal power line or natural gas service fails; 

205.2 For the emergency pumping of water for either fire protection or flood relief. 

An emergency stand-by engine may not be operated to supplement a primary power source 

when the load capacity or rating of the primary power source has either been reached or 

exceeded. 

 206 ENGINE RATING: The output of an engine as determined by the engine manufacturer and 

listed on the nameplate of the engine, regardless of any de-rating. 

 207 EXISTING ENGINE: A stationary internal combustion engine whose installation commenced 

prior to the date of adoption of this rule.

208 LEAN-BURN ENGINE: A spark-ignited engine that is designed to operate with an air-to-fuel 

ratio that is greater than 1.1 times the stoichiometric air-to-fuel ratio. 

209 MAINTENANCE OPERATION: The use of an emergency stand-by engine and fuel system 

during testing, repair and routine maintenance to verify its readiness for emergency stand-by 

use. 

210 NITROGEN OXIDES (NOx): The sum of nitric oxide and nitrogen dioxide compounds in the 

exhaust gas stream of an internal combustion engine. 

211 OUTPUT: The shaft work output from an engine, plus the energy reclaimed by any useful 

heat recovery system. 

212 PERMITTED CAPACITY FACTOR: Calculated in percent by (1) taking the annual permitted 

fuel use and dividing it by the product of the manufacturer’s specified maximum hourly fuel 

consumption times 8760 hours per year, and (2) multiplying that result by 100. 

213 RICH-BURN ENGINE: A spark-ignited engine that is designed to operate with an air-to-fuel 

ratio that is less than or equal to 1.1 times the stoichiometric air-to-fuel ratio. 

214 PEAK LOAD: Maximum instantaneous operating load. 

215 START OF CONSTRUCTION: The time when the owner has: 

215.1 Begun a continuous program of on-site construction of the source, to be completed 

within a reasonable time. 

or 

215.2 Entered into binding agreements or contractual arrangements to undertake 

construction, which cannot be cancelled or modified without substantial loss to the 

owner or operator. 

216 STATIONARY INTERNAL COMBUSTION ENGINE: Any internal combustion engine of the 

reciprocating type that is operated at a site for more than one year or is attached to a 

foundation, not including engines used for self-propulsion. 

217 STOICHIOMETRIC AIR/FUEL RATIO: The chemically correct air-to-fuel ratio where all fuel 

and all oxygen in the air-to-fuel mixture will be consumed. 
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Placer County APCD 242-5 Rules and Regulations 

300 STANDARDS 

301 LIMITS

301.1 After the applicable compliance date specified in Section 401 of this rule, the owner 

or operator of an existing stationary internal combustion engine to which this rule is 

applicable, shall limit the emissions from that engine to no more than the following: 

301.1.1 Rich-burn stationary internal combustion engine NOx emissions shall not 

exceed 90 ppmv and CO emissions shall not exceed 2,000 ppmv. 

301.1.2 Lean-burn stationary internal combustion engine NOx emissions shall 

not exceed 150 ppmv and CO emissions shall not exceed 2,000 ppmv, if 

the engine rating is greater than 100 horsepower. 

301.1.3 Lean-burn stationary internal combustion engine NOx emissions shall 

not exceed 300 ppmv and CO emissions shall not exceed 2,000 ppmv, if 

the engine rating is equal to or less than 100 horsepower. 

301.1.4 Diesel-fired stationary internal combustion engine NOx emissions shall 

not exceed 600 ppmv and CO emissions shall not exceed 2,000 ppmv. 

Where: ppmv = parts per million by volume at 15% oxygen on a dry basis 

 NOx = nitrogen oxides 

 CO = carbon monoxide 

301.2 The owner or operator of any new or replacement stationary internal combustion 

engine shall limit the emissions from that engine to those levels established in 

Section 301.1. 

301.3 In lieu of meeting the emission limits specified in Sections 301.1 of this rule, an 

owner or operator of an internal combustion engine may elect to replace the unit with 

an electric motor or permanently remove the engine from service in accordance with 

the applicable compliance schedule specified in Section 401.4 of this rule.

301.4 All engines subject to this rule shall be equipped with a non-resettable fuel 

consumption meter or a non-resettable elapsed time meter. 

302 ENGINE OPERATOR INSPECTION PLAN: The operator of an engine subject to the 

provisions of Section 301 of this rule shall submit to the APCO an Engine Operator 

Inspection Plan. The plan shall be approved in writing by the APCO and updated after any 

change in operation. For new engines and modifications to existing engines, the plan shall 

be submitted to and approved by the APCO prior to issuance of the Permit to Operate. The 

operator may request a change to the plan at any time. The plan shall include the following: 

302.1 The manufacturer, model number, rated horsepower and combustion method (i.e., 

rich-burn, lean-burn, or diesel) of the engine. 

302.2 A description of the NOx control system installed on the engine, if any, including type 

(e.g., nonselective catalyst, “clean-burn” combustion, etc.), manufacturer, and a 

description of any ancillary equipment related to the control of emissions (e.g., 

automatic air/fuel ratio controller, fuel valves, etc.). 

302.3 The company identification and location of the engine by a schematic diagram of the 

affected facilities. 

302.4 A specific emission inspection procedure to assure that the engine is operated in 

continual compliance with the provisions of this rule. The procedure shall include an 
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Rules and Regulations 242-6 Placer County APCD 

inspection schedule. Inspections shall be conducted every quarter or after every 

2,000 hours of engine operation. In no event shall the frequency of inspections be 

less than once per year. Testing results from individual engines in terms of rated 

brake horsepower, operational conditions, fuel used and control method, may satisfy 

these inspection requirements. Prior to implementation of testing, test plans shall be 

submitted to and approved in writing by the APCO. 

302.5 A description of each preventive or corrective maintenance procedure or practice that 

will be used to maintain the engine and NOx control system in continual compliance 

with the provisions of this rule. 

400 ADMINISTRATIVE REQUIREMENTS 

401 COMPLIANCE SCHEDULES

401.1 Compliance Schedule-Existing: Owners or operators of existing engines shall 

comply, with the applicable provisions of Section 301 of this rule in accordance with 

the following schedule: 

 No later than 90 days after the date of adoption of this rule, submit to the APCO: 

401.1.1 An Engine Operator Inspection Plan pursuant to Section 302 of this rule and 

a complete application for an Authority to Construct, if applicable; 

or 

401.1.2 Support documentation for each exempt engine, pursuant to Section 

502.1 of this rule. 

No later than 120 days after the date of adoption of this rule, demonstrate full 

compliance with all provisions of this rule. 

401.2 Compliance Schedule – Retrofit: Owners or operators of existing engines that 

require retrofit or additions to meet requirements of this rule, shall comply with the 

applicable provisions of Section 301.1 of the rule in accordance with the following 

schedule: 

No later than 90 days after adoption of this rule, submit to the APCO: 

401.2.1 An Engine Operator Inspection Plan pursuant to Section 302 of this rule; or 

401.2.2 Support documentation for each exempt engine, pursuant to Section 502.1 

of this rule. 

401.2.3 A complete application for an Authority to Construct for all modifications. 

No later than July 1, 2004, start construction of all retrofits and/or additions of new 

control equipment, as approved by the APCO. 

No later than December 1, 2004, demonstrate full compliance with the applicable 

provisions of this rule. Engines equipped with non-selective catalytic control 

reduction have until the next catalyst recharge or three (3) years, whichever occurs 

first, to comply with the requirements of Section 301.1. 

401.3 Compliance Schedule – New Construction: Any owner or operator of a new or 

replacement unit that is constructed on or after date of adoption of this rule, shall 

complete an application for an Authority to Construct prior to beginning construction 

of the unit. The owner or operator shall demonstrate that the unit will be operated in 
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Placer County APCD 242-7 Rules and Regulations 

compliance with all applicable provisions of this rule within 60 days after the date of 

initial startup of the unit. 

401.4 Compliance Schedule – Permanent Removal/Replacement: An owner or operator 

who elects to replace a stationary internal combustion engine with an electric motor 

as specified in Section 301.3 of this rule, or who permanently removes the engine 

from service shall demonstrate compliance with all the applicable requirements of 

this rule no later than December 1, 2004. The owner or operator shall submit written 

notification to the District for either conversion to electric power or permanent 

removal no later than December 1, 2003. The owner or operator shall start electric 

motor conversion of the unit no later than May 1, 2004, or permanently remove the

engine from service by December 1, 2004. 

402 REPORTING REQUIREMENTS: Prior to the renewal of any Permit to Operate, each owner 

or operator subject to the provisions of this rule shall provide the APCO the following data: 

402.1 Actual annual usage (e.g., fuel consumption and operating hours) for each affected 

engine; 

402.2 Engine manufacturer, model number and permit number; 

402.3 Location of each engine; 

402.4 A summary of maintenance and testing reports per Section 302.4 of this rule, and an 

annual emission report. 

403 EMISSION SOURCE TESTING: Engines subject to the requirements of Sections 301.1, 

301.2 and 301.3 of this rule shall be source tested for NOx and CO emissions as follows: 

 403.1 The owner or operator shall arrange for and assure that an emissions source test is 

performed on each stationary internal combustion engine at least once every 24 

months. 

403.2 All emission readings shall be taken at an engine’s actual peak load and under the 

engine’s typical duty cycle. Determination of emissions shall be made in accordance 

with the test methods listed in Sections 504.1, 504.2 and 504.3. 

403.3 Prior to any source test required by this rule, a source test protocol shall be prepared 

and submitted to the APCO. The source test protocol shall be approved by the 

APCO prior to any testing. In addition to other information, the source test protocol 

shall describe which critical parameters will be established and incorporated into the 

Engine Operator Inspection Plan described in Section 302. Source test protocol 

shall conform to the requirements in Section 504.5. Emissions under normal 

operating conditions before any controls are considered to be Baseline emissions. 

Source test reports shall be submitted to the APCO or designee. 

404 VIOLATIONS

404.1 Failure to comply with any provision of this rule shall constitute a violation of this rule. 

404.2 It is the responsibility of the engine owner or operator to demonstrate to the 

satisfaction of the APCO, that an engine subject to this rule is being operated in 

continuous compliance with all applicable provisions of this rule. 

404.3 An engine shall be in violation if is operated out of compliance with the operating 

parameters of an approved Engine Operator Inspection Plan. If, however, data from 

a source test of the engine operating under identical conditions indicates that the 

engine is in compliance with the requirements of this rule, then a violation will not 

have occurred. The source test shall be conducted at the engine operator’s 
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Rules and Regulations 242-8 Placer County APCD 

expense. The Engine Operator Inspection Plan shall be then amended to reflect the 

information from this source test. 

500 MONITORING AND RECORDKEEPING 

501 RECORDKEEPING-GENERAL: The owner or operator of any engine subject to Section 301 

of this rule shall maintain an inspection log containing, at a minimum, the following data: 

 501.1 Identification and location of each engine subject to the provisions of this rule. 

501.2 Date and results of each emission inspection. 

501.3 A summary of any corrective maintenance measures taken to ensure compliance 

with the emission limits or reductions, specified in Section 301 of this rule. 

501.4 The readings of the non-resettable fuel consumption and the non-resettable elapsed 

operating time indicators. 

501.5 Any additional information required in the Engine Operator Inspection Plan. 

502 RECORDKEEPING – EXEMPTIONS: Any owner or operator claiming an exemption under 

Section 103 of this rule shall keep support documentation identifying reasons for the 

exemption. Such documentation shall contain a list that provides the following for each 

engine: 

 502.1 Permit to Operate number, if applicable 

 502.2 Engine manufacturer 

 502.3 Engine model designation 

 502.4 Rated brake horsepower 

 502.5 Type of fuel and type of ignition 

502.6 A log of operating hours for each engine. 

503 RECORDKEEPING - RETENTION: The owner or operator shall maintain the records 

required in Sections 501 and 502 for a period of two (2) years after the date of each entry. 

The log shall be made available for inspection by the APCO, upon request. 

 504 TEST METHODS 

504.1 Nitrogen Oxides: NOx emissions for compliance source tests shall be determined in 

accordance with EPA Method 7E or CARB Method 100. 

504.2 Carbon Monoxide: CO emissions for compliance source tests shall be determined in 

accordance with EPA Method 10 or CARB Method 100. 

504.3 Oxygen: Oxygen content for compliance source tests shall be determined in 

accordance with EPA Method 3A or CARB Method 100. 

504.4 Testing Protocol: NOx emission limitations specified in Sections 301.1 and 301.2 of 

this rule shall be expressed as nitrogen dioxide. All ppmv emission limitations are 

referenced at 15 percent volume stack gas oxygen, measured on a dry basis. 

Source test data point intervals shall be no greater than five (5) minutes and data 

points shall be averaged over 15 consecutive minutes.