June 23, 2015 Revision RULE 74.15.1: 1

VENTURA COUNTY AIR POLLUTION CONTROL DISTRICT

RULE 74.15.1 - BOILERS, STEAM GENERATORS, AND PROCESS HEATERS

(Adopted 5/11/93, Revised 6/13/95, 6/13/00, 9/11/12,6/23/15)

A. Applicability

The provisions of this rule apply to any gaseous fuel or liquid fuel fired boiler, steam 

generator, or process heater with a rated heat input capacity equal to or greater than 1

million BTU per hour and less than 5 million BTU per hour. Both stationary and portable 

process heaters are subject to this rule. Applicable gaseous fuels include natural gas, 

landfill gas, biogas, liquefied petroleum gas (LPG), and produced oilfield gas.

B. Requirements

1. No person shall allow the discharge into the atmosphere, from any boiler, steam 

generator, or process heater with an annual heat input rate of equal to or greater 

than 1.8 x 109 BTU, oxides of nitrogen (NOx) emissions in excess of 30 parts per 

million volume (ppmv). Carbon monoxide (CO) emissions from units subject to 

this rule shall not exceed 400 ppmv.

2. Emission Limits for New and Replacement Boilers and Steam Generators

and Process Heaters:

a. After January 1, 2013, nNo person shall allow the discharge into the 

atmosphere, from any new or replacement natural gas-fired boiler, steam 

generator, or process heater with a rated heat input capacity of equal to or 

greater than 1,000,000 million BTU/hr and less than or equal to 2,000,000

million BTU/hr, oxides of nitrogen emissions in excess of 20 ppmv or 

0.025 lbs/MMBTU heat input. Carbon monoxide emissions shall not 

exceed 400 ppmv. In addition prior to installation, each device shall be 

certified by the South Coast Air Quality Management District in 

accordance with the requirements of SCAQMD Rule 1146.2, adopted May 

5, 2006. 

b. After January 1, 2016, no person shall allow the discharge into the 

atmosphere, from any new or replacement boiler, steam generator, or 

process heater fired with a rated heat input capacity of greater than 2

million BTU/hr and less than 5 million BTU/hr oxides of nitrogen 

emissions in excess of the following limits:

CATEGORY LIMITS

Units fired on Natural Gas- Atmospheric 12 ppm or 0.015 lbs/MMBTU heat input 

Units fired on Natural Gas- Pressurized 9 ppm or 0.011 lbs/MMBTU heat input

Units fired on Landfill Gas 25 ppm or 0.031 lbs/MMBTU heat input

Units fired on Biogas 15 ppm or 0.019 lbs/MMBTU heat input

Units fired on Liquefied Petroleum Gas 20 ppm or 0.025 lbs/MMBTU heat input

Units fired on Produced Oilfield Gas - Atmospheric 15 ppm or 0.019 lbs/MMBTU heat input

Units fired on Produced Oilfield Gas – Pressurized 12 ppm or 0.015 lbs/MMBTU heat input
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Carbon monoxide emissions shall not exceed 400 ppmv or 0.30 

lbs/MMBTU.

3. Any boiler, steam generator, or process heater with an annual heat input rate of 

equal to or greater than 0.3 x 109 BTU and less than 1.8 x 109 BTU (less than 2.8 

x 109 BTU for portable oil well dewaxing process heaters) shall comply with one 

of the following requirements:

a. The unit shall be tuned every 6 months or after 750 hours of operation 

since the previous tune-up, whichever occurs last, but in no case less than

once per calendar year. The unit shall be tuned in accordance with the 

procedure described in Attachment 1 for forced draft-fired equipment or 

Attachment 2 for natural draft-fired equipment; or

b. The unit shall comply with the emission and testing requirements of 

Subsection B.4.

4. Test Requirements

a. Units with a rated heat input capacity of greater than 2 million BTU/hr, 

and subject to the provisions of Subsection B.1, shall test for compliance

upon initial installation and then not less than once every 24 months.

b. Units with a rated heat input capacity of greater than 2 million BTU/hr, 

and subject to the provisions of Subsection B.2.b shall test for compliance 

upon initial installation and then not less than once every 48 months. 

bc. Units with a rated heat input capacity of less than or equal to 2 million 

BTU/hr, and subject to the provisions of Subsection B.1 or B.2.a, shall test 

for compliance upon initial installation and then not less than once every 

48 months. The first source test on this test schedule shall be 48 months 

after the last source test conducted prior to September 11, 2012.

cd. All units subject to emission limits shall perform an annual screening 

analysis of NOx and CO emissions unless a source test specified in either 

Subsection B.4.a, or B.4.b, or B.4.c is required that year. The deadline for 

performing this annual screening is no later than the yearly anniversary 

date of the last source test. The operator shall notify the APCD by 

telephone, fax, or email, 24 hours prior to any screening analysis.

C. Exemptions

1. The provisions of Section B of this rule shall not apply to any unit operated on 

alternate fuel under the following conditions:
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1.a. Alternate fuel use is required due to the curtailment of natural gas service 

to the individual unit by the natural gas supplier. Alternate fuel use in this 

case shall not exceed the period of natural gas curtailment.

2.b. Alternate fuel use is required to maintain the alternate fuel system. 

Alternate fuel use in this case shall not exceed 50 hours per year.

2. The emission limits in Subsection B.1 shall not apply to any portable oil well 

dewaxing process heater if the annual heat input rate is less than 2.8 x 109 BTU. 

D. Recordkeeping Requirements

1. Any person owning and/or operating a boiler, steam generator, or process heater 

with an annual heat input rate of less than 1.82.8 x 109 BTU and not complying 

withsubject to the requirements of Subsection B.1 shall install a totalizing fuel 

meter for each applicable unit and for each fuel. Meters shall be accurate to ± one 

(1) percent, as certified by the manufacturer in writing. Fuel consumption for 

each unit shall be compiled monthly into a rolling twelve (12) calendar month 

report.

2. Any person subject to the provisions of Subsection B.3.a shall submit a report to 

the Air Pollution Control Officer (APCO) within forty-five (45) days after 

achieving first compliance with Subsection B.3.a. Reports shall continue to be 

submitted every twelve (12) months. The report shall verify that each tune-up has 

been performed and the results were satisfactory. The report shall contain all 

information and or documentation that the APCO may determine, in writing, to be 

necessary.

3. Any person subject to the provisions of Subsection B.4.cd shall submit a report to 

the APCO within forty-five (45) days after first achieving compliance with the 

subsection. Reports shall continue to be submitted every twelve (12) months. 

The report shall contain all information and or documentation that the APCO may 

determine, in writing, to be necessary. Any person subject to the provisions of 

Subsection B.4.d, shall record the results of all screenings in an annual test log,

and this log shall be made available to APCD personnel upon request. This log

shall indicate the date of the screening, the NOx and CO emissions measured at 

3% Oxygen (calculated as NO2), the applicable NOx and CO limits for the unit, 

and any action taken, if applicable.

4. Any person utilizing alternate fuel, pursuant to the provisions of Subsection C.1 of 

this rule, shall maintain daily records of each occurrence. Each record shall 

include the type of fuel, the quantity of fuel, and the duration of the occurrence.

5. All records required by Subsections D.1 and D.4 shall be maintained for a period 

of four (4) years and shall be available for inspection by the APCO upon request.
June 23, 2015 Revision RULE 74.15.1: 4

E. Test Methods

1. Compliance with the emission requirements in Section B shall be determined 

using ARB Method 100 for Oxides of Nitrogen, Carbon Monoxide, and Stack Gas 

Oxygen. An alternative procedure for determining emission compliance in units 

of lb/MMBTU heat input shall be determined using the South Coast AQMD 

“Compliance Protocol for the Measurement of Nitrogen Dioxide, Carbon 

Monoxide, and Oxygen From Sources Subject to SCAQMD Rules 1146 and 

1146.1” dated March 10, 2009.

2. Emission tests resulting in compliance determinations for the requirements of 

Subsection B.1 or B.2 shall be conducted on units in "As-found" operating 

condition.

3. The NOx parts per million emission limitation specified in Subsection B.1 and 

B.2 is expressed as nitrogen dioxide. The limitations for both NOx and CO are 

referenced at three (3) percent volume stack gas oxygen on a dry basis averaged 

over 15 consecutive minutes.

4. Screening analyses required pursuant to Subsection B.4.cd shall be performed 

using a portable analyzer calibrated, maintained, and operated in accordance with 

the manufacturer’s specifications or as approved in writing by the APCO. 

Portable analyzer operators shall undergo training, on the operation and 

maintenance of the analyzer.

F. Violations

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

rule.

2. Any unit subject to the provisions of Subsection B.3 shall comply with the 

provisions of Subsection B.1 if the unit operates during any rolling twelve (12) 

month period at a total annual heat input rate greater than the applicable annual 

heat input rate specified in Subsection B.3.

3. Any unit previously operating at an annual heat input rate of less than 0.3 x 109

BTU shall comply with the applicable provisions of Subsection B.1 or Subsection 

B.3 if the unit operates during any rolling twelve (12) month period at a total 

annual heat input rate greater than 0.3 x 109 BTU.

4. An applicable unit shall be in violation if, according to a screening analysis, it is 

operated out-of-compliance with the requirements of either Subsection B.1 or B.2

as follows. AnAll out-of-compliance screening analysies shall be reported to the 

District within seven (7) calendar days. The unit shall be corrected and a second 

screening analysis or source test shall be performed within fourteen (14) calendar 
June 23, 2015 Revision RULE 74.15.1: 5

days of the initial screening analysis. The results of the second analysis shall be 

reported to the District within seven (7) days. If the unit remains out-ofcompliance, a violation has occurred.

G. Definitions

1. "Alternate Fuel": Any fuel that is not natural gas permitted to be used due to 

natural gas curtailment by the natural gas supplier because of limited availability.

2. “Atmospheric Unit”: Any natural gas or produced oilfield gas fired unit with a 

non-sealed combustion chamber in which natural draft is used to exhaust 

combustion gases.

2.3 "Annual Heat Input": The actual amount of heat released by fuels burned in a unit 

during a twelve (12) calendar month rolling period, based on the fuel's higher 

heating value. The annual heat input shall be calculated as the sum of the 

previous 12 monthly fuel use rates multiplied by the fuel's higher heating value.

4. “Biogas”: A gaseous mixture of methane and carbon dioxide produced by the 

bacterial decomposition of organic waste and used as a fuel, including, but not 

limited to, digester gas.

3.5 "Boiler or Steam Generator": Any external combustion equipment fired with 

liquid and/or gaseous fuel and used to produce steam or to heat water. Boiler or 

Steam Generator does not include any unfired waste heat recovery boiler that is 

used to recover sensible heat from the exhaust of any combustion equipment.

6. “Landfill Gas”: Any gas derived through any biological process from the 

decomposition of waste buried within a waste disposal site.

7. “Liquefied Petroleum Gas (LPG)”: An organic compound having a vapor 

pressure not exceeding that allowed for commercial propane that is composed 

predominantly of the following hydrocarbons, either by themselves or as 

mixtures: propane, propylene, butane, and to a lesser extent butylenes, and that is 

stored and transported under pressure in a liquid state.

8. “Natural Gas”: Any mixture of gaseous hydrocarbons containing at least 80 

percent methane by volume, as determined using Standard Method ASTM D1945-

03(2010) or later revision.

9. "New or Replacement Boiler, Steam Generator, or Process Heater": Any 

applicable unit sold, offered for sale, or installed after January 1, 2013, pursuant to

Subsection B.2.a or after January 1, 2016, pursuant to Subsection B.2.b. 

10. “Open Heated Tank”: Any non-pressurized self-heated tank that may include a 

cover or doors that can be opened or detached to put in or remove parts, 
June 23, 2015 Revision RULE 74.15.1: 6

components or other material for processing in the tank. Tanks heated solely by 

an electric heater, boiler, thermal fluid heater, or heat recovered from another 

process using heat exchangers are excluded from this definition.

11. “Portable Oil Well Dewaxing Process Heater”: Any portable process heater 

mounted on a truck or trailer that is used to heat and circulate fluid (usually crude 

oil) around oil well production tubing or oil flow lines to remove paraffin wax (a 

natural occurring constituent of crude oil) to prevent loss of oil production caused 

by wax plugging of the unit. 

12. “Pressurized Unit”: Any unit that does not meet the criteria needed to qualify as

an atmospheric unit.

5.13. "Process Heater": Any external combustion equipment fired with liquid and/or 

gaseous fuel and which transfers heat from combustion gases to water or process 

streams. For the purpose of rule applicability, Pprocess Hheater does not include

any of the following combustion sources:

a. any kKiln, or oven, open heated tank, dehydrator, dryer, crematory, 

incinerator, calciner, cooker, roaster, or furnace. used for drying, baking, cooking, 

calcining or vitrifying,

b. any uUnfired waste heat recovery heater that is used to recover sensible 

heat from the exhaust of any combustion equipment, 

orc. any fFuel-fired degreasing or metal finishing equipment including parts 

washers and metal heat treating or metal furnaces,

d. Afterburner, vapor incinerator, or thermal or catalytic oxidizers used as an 

emission control device.

e. Glass melting furnace,

f. Tenter frame, fabric or carpet dryer.

14. “Produced Oilfield Gas”: Any mixture of gaseous hydrocarbons produced in the 

oil field containing less than 80 percent methane by volume, as determined using 

Standard Method ASTM D1945-03(2010) or later revision.

6.15. "Rated Heat Input Capacity": The heat input capacity specified on the nameplate 

of the combustion unit. If the combustion unit has been altered or modified such 

that its maximum heat input is different than the heat input capacity specified on 

the nameplate, the new maximum heat input shall be considered as the rated heat 

input capacity. This alteration or modification can be through either burner 

alteration or modification or installation of a fixed orifice. The new maximum 

heat input must be certified, in writing, by the manufacturer or installer and 

engineering calculations supporting the new maximum heat input rating must be 

submitted to the APCO.

16. “Tenter Frame Dryer”: Any cloth dryer that hold the edges of the material as it is 

dried in order to control shrinkage.
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7.17. "Therm": 100,000 BTU.

8.18. "Unit": Any boiler, steam generator, or process heater as defined in Subsections 

G.25, G.9, and G.313 of this rule.