Imperial County Air Pollution Control District Rule 400.3

RULE 400.3 INTERNAL COMBUSTION ENGINE(S)

(Adopted 10/22/2013)

A APPLICABILITY

A.1 The provisions of this Rule shall apply to any Internal Combustion 

Engine(s) with a brake horsepower (bhp) rating greater than 50 that 

requires a Permit to Operate (PTO), except as provided in Section D.

A.2 Internal Combustion Engine(s) subject to the provisions of this Rule shall 

not be subject to Rule 400.

B DEFINITIONS

The following definitions apply to all terms applicable to this Rule. If a term is not 

defined in this Rule, then the definitions provided in Rule 101 shall apply.

INTERNAL COMBUSTION ENGINE: any spark or compression ignited 

reciprocating Internal Combustion Engine that is attached to a foundation at a 

location, or is portable and operated at a location for more than 90 days in any 

consecutive twelve (12) month period, excluding engines used for self propulsion 

of a vehicle. 

LEAN-BURN ENGINE: any spark or compression ignited Internal Combustion 

Engine that is operated with an exhaust gas stream oxygen concentration of four 

percent (4%) by volume, or greater. The exhaust gas oxygen content shall be

determined from the uncontrolled exhaust gas stream.

RATED BRAKE HORSEPOWER: the maximum Rated Brake Horsepower 

specified for the engine by the manufacturer and listed on the units nameplate, 

regardless of any derating, unless limited by the engine's PTO.

RICH-BURN ENGINE: any spark or compression ignited Internal Combustion 

Engine that is operated with an exhaust gas stream oxygen concentration of less 

than four percent (4%) by volume. The exhaust gas oxygen content shall be 

determined from the uncontrolled exhaust gas stream.

VALID: under the provisions of this Rule, as long as the certification is current 

and does not exceed the maximum hours. 

C REQUIREMENTS

C.1 The emission concentration of NOx in ppmv, calculated as nitrogen

dioxide (NO2) at 15% oxygen on a dry basis, are not greater than the limits 

in Table 400.3-1.

400.3-1
Imperial County Air Pollution Control District Rule 400.3

C.2 For all engines subject to Subsection C.1 of this Rule, emissions of carbon 

monoxide (CO), calculated at 15% oxygen on a dry basis shall not exceed 

2500 ppmv.

D EXEMPTIONS

The provisions of this Rule shall not apply to the following engine(s): 

D.1 The operation of any engine while being used to preserve or protect 

property, human life, or public health during the existence of a disaster or

state of emergency;

D.2 Engines used directly and exclusively for the growing of crops or the 

raising of animals that are located within facilities that are not exempt 

under Rule 202, Exemptions, Section E.10;

D.3 Gas turbine engines;

D.4 New or existing emergency stand-by engines which operate 100 hours or 

less per calendar year for the purpose of testing and maintenance shall be 

exempt from the requirements of Section C, and;

D.5 Existing Internal Combustion Engines to be permanently replaced with 

electric motors or removed from service by April 22, 2014 based upon a 

permit condition, contract, or binding agreement with the District.

E RECORDKEEPING REQUIREMENTS

E.1 The Owner or Operator of any Internal Combustion Engine subject to the 

provisions of this Rule shall maintain an engine operating log on-site for 

each month or any part of a month that the device is operated that includes 

the following:

E.1.a Engine(s) manufacturer name and model number, brake 

horsepower output rating, combustion method (i.e. Rich or Lean 

Burn or diesel).

Table 400.3-1

Engine Type NOx Limits

Rich-Burn 90

Lean-Burn 150

Diesel 600

400.3-2
Imperial County Air Pollution Control District Rule 400.3

E.1.b A manual of recommended maintenance as provided by the 

engine(s) manufacturer or other maintenance procedure as 

approved in writing by the Air Pollution Control Officer (APCO).

E.1.c Record of routine engine(s) maintenance, including date(s) and type 

of maintenance performed.

E.1.d 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 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.

E.1.e Total recorded hours of operation or calculated hours of operation 

based upon fuel usage.

E.1.f Type of fuel combusted. 

E.2 In addition to the records required in Subsection E.1, an Owner or 

Operator of an engine(s) subject to this Rule shall install a non-resettable 

fuel consumption meter or a non-resettable elapsed time meter.

F TEST METHODS

F.1 Compliance with the requirements of Section C shall be determined In 

accordance with the following test procedures or any other method 

approved by the United States Environmental Protection Agency (US 

EPA) and/or the California Air Resources Board (CARB).

F.1.a NOx emissions for compliance source tests shall be determined by 

using CARB Method 100 or US EPA Method 7E.

F.1.b Oxygen content for compliance source tests shall be determined by 

using CARB Method 100 or US EPA Method 3A.

F.1.c Carbon monoxide emissions for compliance source tests shall be

determined by using CARB Method 100 or US EPA Method 10.

G COMPLIANCE TESTING

G.1 The Owner or Operator of any Internal Combustion Engine with a bhp 

rating less than 500 shall demonstrate compliance using one of the 

following:

400.3-3
Imperial County Air Pollution Control District Rule 400.3

G.1.a For diesel fueled engines, off-road engine certification data for the 

stationary diesel-fueled engine, or

G.1.b Engine manufacturer test data, or

G.1.c Engine emission compliance source test.

G.2 The Owner or Operator of any Internal Combustion Engine with a bhp 

rating of 500 or greater shall demonstrate compliance through emission 

compliance testing not less than once every 36 months. All emission 

rates shall be based on an hourly average. The Owner or Operator shall 

perform initial source test to demonstrate compliance within one year of 

start up or adoption of this Rule, thereafter frequency of compliance 

testing may be extended under the following:

G.2.a The frequency of compliance testing may be extended to not less 

than every 60 months for Internal Combustion Engine(s) which 

operate less than 500 hours per 12 month period (as demonstrated 

by operational logs) and which emit less than 5 tons of NOx per 12

month period. This period may be extended if a source can prove 

that the engine(s) has not been operated during the calendar year.

G.2.b The frequency of compliance testing may be extended to not less 

than every 60 months for Internal Combustion Engine(s) which use 

a portable NOx analyzer to take NOx emission readings to verify 

compliance with the emission limits in Section C during each 

quarter in which a source test is not performed. All emission 

reading shall be taken with the engine operating either at conditions 

representative of normal operations or conditions specified in the 

PTO. The analyzer shall be calibrated, maintained, and operated in 

accordance with the manufacturer’s specifications and 

recommendations and the Protocol for the Periodic Monitoring of 

Nitrogen Oxides, Carbon Monoxide, and Oxygen from Stationary 

Engines Subject to South Coast Air Quality Management District 

Rule 1110.2, approved on February 1, 2008, or subsequent 

protocol approved by US EPA and the APCO. NOx emission 

readings taken pursuant to this section shall be averaged over a 15 

consecutive-minute period by either taking a cumulative 15 

consecutive-minute sample reading or by taking at least five (5) 

readings, evenly spaced out over the 15 consecutive-minute period.

G.3 For the purpose of a compliance determination based on source testing, 

the NOx emissions concentration shall be calculated as an average of 

three test runs.

400.3-4
Imperial County Air Pollution Control District Rule 400.3

G.4 At least 30 days prior to the scheduled source test date, the Owner or 

Operator of a unit subject to this Rule shall submit a source test plan to 

the APCO. At least seven days prior to the source test, the Owner or 

Operator shall notify the APCO of the exact date and time of the source 

test. A final source test result shall be submitted to the APCO within 30 

days following the actual source test date.

H RECORDS RETENTION

H.1 The Owner or Operator of any Internal Combustion Engine(s) subject to 

this Rule shall maintain all records required by this Rule for a minimum of 

two (2) calendar years. Title V facilities shall maintain these records for 

five (5) calendar years. These records shall be maintained on the 

premises and made available to the District upon request.

I COMPLIANCE SCHEDULE 

I.1 The Owner or Operator of any Internal Combustion Engine(s) subject to 

the requirements of this Rule which are not in compliance with the 

thresholds pursuant to Section C, may be granted an extension for 

compliance provided the following criteria is met:

I.1.a No later than six (6) months after Rule adoption, an Owner or 

Operator shall submit for approval by the APCO an Authority to 

Construct (ATC)/PTO application amendment. The application shall 

include the following supplemental information:

1. PTO number.

2. Fuel Type;

3. Annual fuel consumption (Btu/yr);

4. Current emission level, including method used to determine 

emission level; and

5. Plan of actions, including a schedule of increments of 

progress, which will be taken to satisfy the requirements of 

Section C and the compliance schedule in Section I.1.b; and

6. Any other information the District deems necessary for the 

completion of the application. 

I.1.b Any Internal Combustion Engine(s) not in compliance with the 

thresholds in Section C shall demonstrate full compliance with all 

applicable standards and requirements of this Rule no later than 

one year after Rule adoption. 

I.2 Any person installing a new unit shall comply with all applicable provisions 

of this Rule upon initial installation and startup.

400.3-5