Imperial County Air Pollution Control District Rule 400.2

400.2- 1

RULE 400.2 BOILERS, PROCESS HEATERS AND STEAM GENERATORS

(Adopted 02/23/2010)

A. Applicability

A.1 This rule limits emissions of oxides of nitrogen (NOx) from Boilers, 

Process Heaters, or Steam Generators.

A.2 This rule shall apply to any new or existing Process Heaters, Boilers or 

Steam Generators with a heat input rating of 5 million British Thermal 

Units (Btu) per hour or more, unless exempted pursuant to Section D of 

this rule.

A.3 Boilers, Process Heaters and Steam Generators that are subject to the 

provisions of this rule shall not be subject to Rule 400.

B. Definitions

Terms applicable to this rule are defined in Rule 101-Definitions and incorporated 

them to ICAPCD Rule 101–Definitions.

C. Requirements

C.1 All Boilers, Process Heaters and Steam Generators unless exempted 

pursuant to Sections C.3 or C4, shall not emit NOx in excess of the 

following:

C.1.a 30 parts per million by volume (ppmv) or 0.036 pounds per million 

BTU of heat input when operated on gaseous fuels.

C.1.b 40 ppmv or 0.052 pounds per million BTU of heat input when 

operated on liquid fuels.

C.1.c The heat-input weighted average of the limits specified in C.1.a and 

C.1.b, when operated on combinations of gas and liquid fuels.

Where: G = annual heat input from gaseous fuel

L = annual heat input from liquid fuel

C.2 All ppmv emission limits are referenced at dry stack-gas conditions 

and 3.0% by volume stack-gas oxygen as an hourly average.

Weighted Average Limit = (NOx limit for gaseous fuel x G) + (NOx limit for liquid fuel x L)

G + L
Imperial County Air Pollution Control District Rule 400.2

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C.3 All Boilers, Process Heaters, and Steam Generators, with an Annual 

Capacity Factor (ACF) less than or equal to 30%, shall not emit NOx in 

excess of the following:

C.4 Biomass boilers or process heaters shall not emit NOx in excess of the 

following:

C.4.a An exhaust concentration of 120 ppmv corrected to 12 percent by 

volume stack gas carbon dioxide (CO2) on a three-hour average dry 

basis, or

C.4.b NOx emissions shall be reduced minimum 80 percent of the 

uncontrolled NOx emission concentration in the exhaust gas 

stream. A corresponding controlled limit shall be established in the 

Authority to Construct/Permit to Operate condition(s) for the 

purpose of demonstrating continuous compliance with the 80 

percent emission reduction. 

D. Exemptions

D.1 The provisions of this rule shall not apply to the following:

D.1.a Waste Heat Recovery Boilers that are used to recover heat from 

the exhaust of Stationary Gas Turbines or Internal Combustion 

Engines.

D.1.b Furnaces, Kilns, and any combustion equipment where the material 

being heated is in direct contact with the products of combustion.

D.1.c Thermal Oxidizers and associated waste heat recovery equipment.

D.1.d Boilers, Process Heaters and Steam Generators used exclusively 

in connection with a structure that is designed for and used 

exclusively as a dwelling for not more than four families.

D.1.e Coal fired units, installed or erected prior to December 31, 2009.

D.2 Boilers, Process Heaters, or Steam Generators, during Startup, Shutdown 

or a change in load, when bringing the combustion process up to 

operating levels, may not exceed twelve hours (12) for Boilers and 

ACFcu ≤ 30% ppmv

Gaseous Fuel 70

Liquid Fuel 70
Imperial County Air Pollution Control District Rule 400.2

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Process Heaters of more than 40 MM Btu per hour or six (6) hours per 

Boilers and Process Heaters of equal to or less than 40 MM Btu per hour, 

or as specified on the permit to operate.

D.3 Section C.1.b shall not apply to Boilers while forced to burn nongaseous 

fuel during times of natural gas curtailment. This exemption shall not 

exceed 168 cumulative hours of operation per calendar year excluding 

equipment testing time not exceeding 24 hours per calendar year.

E. Monitoring and Recordkeeping Requirements

E.1 The owner or operator of Boilers, Process Heaters or Steam Generators 

with a continuous emission monitoring system (CEMS) which has been 

installed to measure NOx emissions pursuant to any federal regulation 

shall certify, calibrate and maintain the CEMS in accordance with 

applicable federal regulations including the reporting requirements of 

Sections 60.7(c), 60.7(d), and 60.13 of Title 40, Code of Federal 

Regulations Part 60 (40 CFR 60), performance specifications of Appendix 

B, quality assurance procedures of Appendix F, and a protocol approved 

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

E.2 The owner or operator of Boilers, Process Heaters or Steam Generators 

subject to this rule shall maintain an operating log and record actual times 

and duration of all Startups, Shutdowns and Fuel Changes, and the type 

and quantity of each fuel used.

E.3 For the purposes of a compliance determination based on CEMS data, the 

averaging period to calculate NOx emissions concentration shall be one 

clock hour.

E.4 For the purpose of determine compliance with Section C.4.b to evaluate 

percentage NOx emission reductions, the owner or operator has the 

option to run a one-time uncontrolled NOx emission source testing and 

use these results as reference for future annual compliance testing 

determination.

F. Test Methods

F.1 Compliance with the NOx emission limits in Section C shall be determined 

using United States Environmental Protection Agency (U.S. EPA) Method 

7, 7A, 7C, 7E, California Air Resources Board (CARB) Method 100, or any 

other applicable U.S. EPA approved test method.
Imperial County Air Pollution Control District Rule 400.2

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G. Source Test Requirements

G.1 Any required source testing shall be performed at no less than 80% of the 

power rating. If an owner or operator of a Boilers, Process Heaters or 

Steam Generators demonstrates to the satisfaction of the APCO that the 

equipment cannot operate at these conditions, then emissions sources 

testing shall be performed at the highest achievable continuous power 

rating.

G.2 Boilers, Process Heaters or Steam Generators subject to the requirements 

of Section C shall demonstrate compliance through emission compliance 

testing not less than once every 12 months. All emission rates shall be 

based on an hourly average. 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 36 months for Boilers, Process Heaters, or Steam 

Generators which operate less than 100 hours per a 12 month 

period (as demonstrated by operational logs) and which emit less 

than 5 tons of NOx per a 12 month period.

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

than every five (5) years for secondary fuel testing for Boilers, 

Process Heaters, or Steam Generators which operate less than 

100 hours per a 12 month period operating secondary fuel (as 

demonstrated by operational logs) and which emit less than 5 tons 

of NOx per a 12 month period operating secondary fuel. This period 

may be extended if a source can prove no secondary fuel has been 

fired.

G.3 Test reports shall include the operational characteristics recommended by 

the manufacturer to ensure compliance with the applicable emission limits 

of this rule for Boilers, Process Heaters and Steam Generators and all 

add-on NOx control systems.

G.4 For the purposes of a compliance determination based on source testing, 

the NOx emissions concentration shall be calculated as an average of 

three test runs.

G.5 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 (7) 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 60 

days following the actual source test date.
Imperial County Air Pollution Control District Rule 400.2

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H. Records Retention

H.1 The owner or operator of Boilers, Process Heaters and Steam Generators 

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 Boilers, Process Heaters and Steam Generators 

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 On or before June 30, 2010, an owner or operator shall submit for 

approval by the APCO, an Authority to Construct (ATC)/Permit to 

Operate (PTO) application amendment. The application shall 

include the following supplemental information:

I.1.a.1 Permit to Operate number.

I.1.a.2 Fuel Type.

I.1.a.3 Annual fuel consumption (BTU/yr).

I.1.a.4 Current emission level, including method used to 

determine emission level, and

I.1.a.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

I.1.a.6 Any other information the ICAPCD deems necessary 

for the completion of the application. 

I.1.b Any Boilers, Process Heaters, and Steam Generators 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 June 30, 2011.

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

of this rule upon initial installation and Startup.