PROPOSED May 19, 2011 

4307 - 1 Proposed Amendments to Rule 4307

RULE 4307 BOILERS, STEAM GENERATORS, AND PROCESS HEATERS – 2.0 

MMBtu/hr to 5.0 MMBtu/hr (Adopted December 15, 2005; Amended April 20, 

2006; Amended October 16, 2008, Amended [rule adoption date]) 

1.0 Purpose 

The purpose of this rule is to limit emissions of oxides of nitrogen (NOx), carbon 

monoxide (CO), oxides of sulfur (SO2), and particulate matter 10 microns or less (PM10)

from boilers, steam generators, and process heaters. 

2.0 Applicability 

This rule applies to any gaseous fuel or liquid fuel fired boiler, steam generator, or 

process heater with a total rated heat input of 2.0 million Btu per hour (MMBtu/hr) up to 

and including 5.0 MMBtu/hr. 

3.0 Definitions 

3.1 Air Pollution Control Officer (APCO): as defined in Rule 1020 (Definitions). 

3.2 Air Resources Board (ARB): as defined in Rule 1020 (Definitions). 

3.3 Annual Heat Input: the actual, total heat input of fuels burned by a unit in a 

calendar year, as determined from the higher heating value and cumulative annual 

usage of each fuel. 

3.4 Atmospheric Unit: any unit with a non-sealed combustion chamber in which the 

combustion air and flue gases are drawn through the unit without the use of a fan. 

3.5 Boiler or Steam Generator: any external combustion equipment fired with any 

fuel used to produce hot water or steam. 

3.6 British Thermal Unit (Btu): the amount of heat required to raise the temperature 

of one pound of water from 59°F to 60°F at one atmosphere. 

3.7 California Public Utility Commission (PUC) Quality Natural Gas: any gaseous 

fuel, gas-containing fuel where the sulfur content is no more than one-fourth 

(0.25) grain of hydrogen sulfide per one hundred (100) standard cubic feet and no 

more than five (5) grains of total sulfur per one hundred (100) standard cubic feet. 

PUC quality natural gas also means high methane gas of at least 80% methane by 

volume. 
PROPOSED May 19, 2011 

4307 - 2 Proposed Amendments to Rule 4307

3.8 Certified Unit or Certified Retrofit Control Technology: any unit, any control 

technology, or any burner and ancillary controls or blowers, that has been 

demonstrated to comply with the emissions limits of this rule and which has been 

approved by the APCO pursuant to Section 9.0 of this rule. 

3.9 Dryer: any unit in which material is dried in direct contact with the products of 

combustion. 

3.10 US Environmental Protection Agency (EPA): the United States Environmental 

Protection Agency or any person authorized to act on its behalf. 

3.11 Gaseous Fuel: any fuel which is a gas at Standard Conditions. 

3.12 Heat Input: the heat (hhv basis) released due to fuel combustion in a unit, not 

including the sensible heat of incoming combustion air and fuel. 

3.13 Higher Heating Value (hhv): the total heat liberated per mass of fuel burned 

(expressed as Btu per pound), when fuel and dry air at standard conditions 

undergo complete combustion and all resulting products are brought to their 

standard states at standard conditions. 

3.14 Humidifier: a device or system that uses an air stream heated by a direct contact 

combustion process in combination with a water spray to produce warm air of 

high humidity in order to maintain or increase the moisture content of the 

material being processed or conveyed by the air stream. 

3.15 Liquid Fuel: any fuel which is a liquid at Standard Conditions. 

3.16 NOx Emissions: the sum of oxides of nitrogen expressed as NO2 in the flue gas. 

3.17 NOx Exhaust Control: a device or technique used to treat a unit’s exhaust 

combustion gas to reduce NOx emissions. Such a device or technique includes, 

but is not limited to, selective catalytic reduction or nonselective catalytic 

reduction. 

3.18 Parts Per Million by Volume (ppmv): as defined in Rule 1020 (Definitions). 

3.19 Process Heater: any combustion equipment fired with liquid and/or gaseous fuel 

and which transfers heat from combustion gases to water or process streams. This 

definition excludes: kilns or ovens used for drying, baking, cooking, calcining, or 

vitrifying; and unfired waste heat recovery heaters used to recover sensible heat 

from the exhaust of combustion equipment. 
PROPOSED May 19, 2011 

4307 - 3 Proposed Amendments to Rule 4307

3.20 Qualified Technician: a stationary source employee or any personnel contracted 

by a stationary source operator who has a documented training and a demonstrated 

experience performing tune-ups on a unit to the satisfaction of the APCO. The 

documentation of tune-up training and experience shall be made available to the 

APCO upon request. 

3.21 Rated Heat Input (expressed as million Btu per hour): the heat input capacity 

specified on the nameplate of the unit. If the unit has been physically modified 

such that its maximum heat input differs from what is specified on the nameplate, 

the modified maximum heat input shall be considered as the rated heat input and 

made enforceable by Permit to Operate. 

3.22 Re-ignition: the relighting of a unit after an unscheduled and unavoidable 

interruption or shut off of the fuel flow or electrical power, for a period of less 

than 30 minutes, due to reasons outside the control of the operator. 

3.23 School: any public or private school used for the purpose of education and 

instruction of school pupils in Kindergarten through Grade 12, but does not 

include any private school in which education and instruction are primarily 

conducted in private homes. 

3.24 Shutdown: the period of time during which a unit is taken from an operational to 

a non-operational status by allowing it to cool down from its operating 

temperature to a cold or ambient temperature as the fuel supply is turned off. A 

unit is considered in shutdown status when the fuel supply to the unit is turned off 

for a continuous period of at least 30 minutes. 

3.25 Solid Fuel: any fuel which is a solid at Standard Conditions. 

3.26 Standard Conditions: as defined in Rule 1020 (Definitions). 

3.27 Start-up: the period of time during which a unit is brought from a shutdown status 

to its operating temperature and pressure. 

3.28 Stationary Source: as defined in Rule 2201 (New and Modified Stationary Source 

Review Rule). 

3.29 Tree Nut Pasteurizer: a unit, designed to remove pathogens from tree nuts, which 

is operated at a tree nut processing facility subject to any part of Title 7 Section 

900 through 999 of the Code of Federal Regulations (7 CFR 900 through 7 CFR 

999). 

3.30 3.29 Unit: any boiler, steam generator or process heater as defined in this rule. 
PROPOSED May 19, 2011 

4307 - 4 Proposed Amendments to Rule 4307

4.0 Exemptions 

This rule shall not apply to: 

4.1 Solid fuel fired units. 

4.2 Dryers and glass melting furnaces. 

4.3 Kilns, humidifiers, and smelters where the products of combustion come into 

direct contact with the material to be heated. 

4.4 Unfired or fired waste heat recovery boilers that are used to recover or augment 

heat from the exhaust of combustion turbines or internal combustion engines. 

4.5 Units used at a school. On and after July 1, 2015, units used at a school shall 

comply with all applicable requirements of this rule. 

4.6 The requirements of Sections 5.1 shall not apply to a unit when burning any fuel 

other than PUC quality natural gas during a PUC quality natural gas curtailment 

provided all of the following conditions are met: 

4.6.1 Fuels other than PUC quality natural gas are burned no more than 168 

cumulative hours in a calendar year plus 48 hours per calendar year for 

equipment testing, as limited by Permit to Operate or Permit-Exempt 

Equipment Registration. 

4.6.2 NOx emission shall not exceed 150 ppmv or 0.215 lb/MMBtu. 

Demonstration of compliance with this limit shall be made by either source 

testing, continuous emission monitoring system (CEMS), an APCO 

approved Alternate Monitoring System, or an APCO approved portable 

NOx analyzer. 

5.0 Requirements 

All ppmv emission limits specified in this section are referenced at dry stack gas 

conditions and 3.00 percent by volume stack gas oxygen. Emission concentrations shall 

be corrected to 3.00 percent oxygen in accordance with Section 8.1. 

5.1 NOx and CO Emission Limits 

5.1.1 Except for units subject to either Section 5.1.2 or Section 5.2, no unit shall 

be operated unless it is certified, according to Section 9.0, or source tested 

in accordance with the test methods in Section 6.2, to comply with the 

applicable emission limits specified in Table 1 and Table 2. 
PROPOSED May 19, 2011 

4307 - 5 Proposed Amendments to Rule 4307

Table 1 NOx and CO limits 

Type of Unit NOx Limit CO Limit 

(ppmv) 

Gaseous Fuel-Fired Unit 30 ppmv or 

0.036 lb/MMBtu 400 

Liquid Fuel-Fired Unit 40 ppmv or 

0.052 lb/MMBtu 400 

Table 2 NOx and CO limits for New and Replacement Units 

I. Atmospheric Units 

Type of Unit NOx Limit CO Limit 

(ppmv) Effective Date 

A. A new or replacement unit that is not 

included in Section I. B. 

12 ppmv or 

0.014 lb/MMBtu 400 

Upon Installation 

of a new or 

replacement unit 

on and after 

January 1, 2010 

B. A new or replacement unit that is one 

of the following: 

1. a unit used at a school; or 

2. a unit in an oilfield or refinery; or 

3. a glycol reboiler; or 

4. a unit with a heat input greater than 

1.8 billion Btu but less than 5.0 

billion Btu per calendar year 

12 ppmv or 

0.014 lb/MMBtu 400 

Upon Installation 

of a new or 

replacement unit 

on and after 

January 1, 2016 

II. Non-Atmospheric Units 

Type of Unit NOx Limit CO Limit 

(ppmv) Effective Date 

A. A new or replacement unit that is not 

included in Section II. B. 

9 ppmv or 

0.011 lb/MMBtu 400 

Upon Installation 

of a new or 

replacement unit 

on and after 

January 1, 2010 

B. A new or replacement unit that is one of 

the following: 

5. a unit used at a school; or 

6. a unit in an oilfield or refinery; or 

7. a glycol reboiler; or 

8. a unit with a heat input greater than 

1.8 billion Btu but less than 5.0 

billion Btu per calendar year 

9 ppmv or 

0.011 lb/MMBtu 400 

Upon Installation 

of a new or 

replacement unit 

on and after 

January 1, 2016 
PROPOSED May 19, 2011 

4307 - 6 Proposed Amendments to Rule 4307

5.1.2 Tree nut pasteurizers shall be fired exclusively on PUC quality natural gas. 

5.1.2.1 All tree nut pasteurizers shall be operated and maintained 

according to manufacturer’s specifications or APCO-approved 

alternative procedures. 

5.1.2.2 Operation and maintenance records and manufacturer’s 

specifications/APCO-approved alternative procedures shall be 

maintained in accordance with Section 6.1.5. 

5.1.2.3 During PUC quality natural gas curtailments, operators of tree 

nut pasteurizers shall abide by the provisions of Section 4.6, if 

the unit is operated during the curtailment. 

5.2 Operators shall meet the following requirements as applicable. 

5.2.1 Until June 30, 2015, for each existing atmospheric unit operated in an 

oilfield or refinery; each glycol reboiler; or each unit limited to no more 

than 5.0 billion Btu per calendar year heat input pursuant to a Permit to 

Operate or Permit-Exempt Equipment Registration, the operator shall 

comply with Section 5.5.2, Section 7.3, Section 7.4, and either Section 

5.2.1.1, 5.2.1.2, or 5.2.1.3. 

5.2.1.1 Tune the unit at least twice per calendar year, (from four to eight 

months apart) using a qualified technician in accordance with the 

procedure described in Rule 4304 (Equipment Tuning Procedure 

for Boilers, Steam Generators, and Process Heaters). If the unit 

does not operate throughout a continuous six-month period within 

a calendar year, only one tune-up is required for that calendar 

year. No tune-up is required for any unit that is not operated 

during that calendar year; this unit may be test fired to verify 

availability of the unit for its intended use, but once the test firing 

is completed the unit shall be shutdown; or 

5.2.1.2 Operate the unit in a manner that maintains exhaust oxygen 

concentrations at less than or equal to 3.00 percent by volume on 

a dry basis; or 

5.2.1.3 Certify the unit according to Section 9.0 to comply with the 

applicable emission requirements of Section 5.1 Table 1. 
PROPOSED May 19, 2011 

4307 - 7 Proposed Amendments to Rule 4307

5.2.2 On and after July 1, 2015, for each unit limited to no more than 1.8 billion 

Btu per calendar year heat input pursuant to a Permit to Operate or PermitExempt Equipment Registration, the operator shall comply with Section 

5.5.2, Section 7.3, Section 7.4, and either Section 5.2.1.1, 5.2.1.2, or 

5.2.1.3. 

5.2.3 On and after July 1, 2015, for each existing atmospheric unit in an 

oilfield or refinery; each glycol reboiler; or each unit with a heat input 

greater than 1.8 billion Btu to less than 5.0 billion Btu per calendar year, 

the operator shall comply with the applicable emission requirements of 

Section 5.1 Table 1. The operator shall comply with the compliance 

requirements and deadlines specified for Group 3 units in Section 7.1 

Table 3. 

5.3 Particulate Matter Control Requirements 

5.3.1 To limit particulate matter emissions, an operator shall comply with one of 

the following requirements: 

5.3.1.1 On and after July 1, 2015, operators shall fire units exclusively 

on PUC quality natural gas, commercial propane, butane, or 

liquefied petroleum gas, or a combination of such gases; or 

5.3.1.2 On and after July 1, 2015, operators shall limit fuel sulfur 

content to no more than five (5) grains of total sulfur per one 

hundred (100) standard cubic feet; or 

5.3.1.3 On and after July 1, 2015, operators shall install and properly 

operate an emission control system that reduces SO2 emissions by 

at least 95% by weight; or limit exhaust SO2 to less than or equal 

to 9 ppmv corrected to 3.0% O2. 

5.3.2 On and after July 1, 2015, liquid fuel shall be used only during a PUC 

quality natural gas curtailment period provided it contains no more than 

15 ppm sulfur as determined by the test method specified in Section 6.2.7. 

An operator shall comply with the recordkeeping requirement of Section 

6.1.3. In lieu of testing the sulfur content of liquid fuel, an operator may 

demonstrate compliance with the 15 ppm sulfur content by obtaining a 

copy of the fuel sulfur content specification data from the fuel 

manufacturer or vendor. 
PROPOSED May 19, 2011 

4307 - 8 Proposed Amendments to Rule 4307

5.4 Start-Up and Shutdown Requirements 

The applicable emission limits of Sections 5.1 and 5.2.1.2 shall not apply during 

start-up or shutdown provided an operator complies with the requirements 

specified below. 

5.4.1 For units not equipped with a NOx exhaust control, the duration of each 

start-up and each shut down shall not exceed one hour, except as provided 

in Section 5.4.4. 

5.4.2 For units equipped with a NOx exhaust control, the duration of each 

start-up and each shut down shall not exceed two hours, except as 

provided in Section 5.4.4. 

5.4.3 The emission control system shall be in operation and emissions shall be 

minimized insofar as technologically feasible during start-up or shutdown. 

5.4.4 Notwithstanding the requirements of Section 5.4.1 or Section 5.4.2, t The 

APCO, ARB, and EPA may approve a longer start-up or shutdown 

duration than the duration specified in Section 5.4.1 or 5.4.2 (as 

applicable), if an operator submits an application for a Permit to Operate 

or Permit-Exempt Equipment Registration which provides a justification 

for the requested additional duration. 

5.4.4.1 The maximum allowable duration of start-up or shutdown will be 

determined by the APCO, ARB, and EPA. 

5.4.4.2 At a minimum, a justification for increased start-up or shutdown 

duration shall include the following: 

5.4.4.2.1 A clear identification of the control technologies or 

strategies to be utilized; and 

5.4.4.2.2 A description of what physical conditions prevail 

during start-up or shutdown periods that prevent the 

controls from being effective; and 

5.4.4.2.3 A reasonably precise estimate as to when the 

physical conditions will have reached a state that 

allows for the effective control of emissions; and 

5.4.4.2.4 A detailed list of activities to be performed during 

start-up or shutdown and a reasonable explanation 

for the length of time needed to complete each 

activity; and 
PROPOSED May 19, 2011 

4307 - 9 Proposed Amendments to Rule 4307

5.4.4.2.5 A description of the material process flow rates and 

system operating parameters, etc., the operator 

plans to evaluate during the process optimization; 

and an explanation of how the activities and process 

flow affect the operation of the emissions control 

equipment; and 

5.4.4.2.6 Basis for the requested additional duration of startup or shutdown. 

5.4.5 Permit to Operate (PTO) changes solely to include start-up or shutdown 

conditions may be exempt from Best Available Control Technology 

(BACT) and emission offset requirements if the PTO changes meet the 

requirements of Rule 2201 (New or Modified Stationary Source Review 

Rule) Section 4.2 (BACT Exemptions) and Rule 2201 Section 4.6 (Offset 

Exemptions). 

5.5 Monitoring Provisions 

5.5.1 For units subject to the emission limits of Section 5.1 the operator shall;: 

5.5.1.1 Monitor, at least once a month, the operational characteristics 

recommended by the manufacturer and approved by the APCO; 

and 

5.5.1.2 Tune the unit at least twice per calendar year, (from four to 

eight months apart) using a qualified technician in accordance 

with the procedure described in Rule 4304 (Equipment Tuning 

Procedure for Boilers, Steam Generators, and Process Heaters). 

If the unit does not operate throughout a continuous six-month 

period within a calendar year, only one tune-up is required for 

that calendar year. No tune-up is required for any unit that is 

not operated during that calendar year; this unit may be test 

fired to verify availability of the unit for its intended use, but 

once the test firing is completed the unit shall be shutdown. In 

lieu of tuning the unit, operators shall monitor the emissions with 

a portable NOx analyzer and adjust the unit’s operating 

parameters accordingly to assure compliance with the emission 

limits of this rule. 

5.5.2 The operator of any unit limited to the annual heat input specified in 

Section 5.2.1 or Section 5.2.2 shall install and maintain an operational 

non-resettable, totalizing mass or volumetric flow meter in each fuel line 

to each unit. Volumetric flow measurements shall be periodically 

compensated for temperature and pressure. A master meter, which 
PROPOSED May 19, 2011 

4307 - 10 Proposed Amendments to Rule 4307

measures fuel to all units in a group of similar units, may satisfy these 

requirements if approved by the APCO in writing. The cumulative 

annual fuel usage may be verified from utility service meters, purchase 

or tank fill records, or other acceptable methods, as approved by the 

APCO. 

5.5.3 Monitoring SOx Emissions 

5.5.3.1 Operators complying with Section 5.3.1.3 by installing and 

operating a control device with 95% SOx reduction shall 

propose the key system operating parameters and frequency of 

the monitoring and recording. The monitoring option proposed 

shall be submitted for approval by the APCO. 

5.5.3.2 Operators complying with Sections 5.3.1.1 or 5.3.1.2 shall 

provide an annual fuel analysis to the District unless a more 

frequent sampling and reporting period is included in the Permit 

To to Operate or Equipment Registration condition. Sulfur 

analysis shall be performed in accordance with the test methods 

in Section 6.2. 

5.6 Compliance Determination 

5.6.1 For the purposes of certification, the operator of any unit shall have the 

option of demonstrating compliance with either the applicable heat input 

emission limits (lb/MMBtu) or the concentration emission limits (ppmv) 

specified in Section 5.1. The emission limits selected to demonstrate 

compliance shall be specified in the Permit to Operate or Permit-Exempt 

Equipment Registration. The emission limit selected in Section 5.1 shall 

also be specified in the source test proposal pursuant to Rule 1081 (Source 

Sampling). 

5.6.2 All emissions measurements shall be made with the unit operating either at 

conditions representative of normal operations or conditions specified in 

the Permit to Operate or Permit-Exempt Equipment Registration. 

5.6.3 Unless otherwise specified in the Permit to Operate or Permit-Exempt 

Equipment Registration no determination of compliance shall be 

established within two hours after a continuous period in which fuel flow 

to the unit is shut off for 30 minutes or longer, or within 30 minutes after a 

re-ignition as defined in Section 3.0. 
PROPOSED May 19, 2011 

4307 - 11 Proposed Amendments to Rule 4307

5.6.4 Notwithstanding the requirements of Section 5.6.3, for units with a 

cyclical firing period that routinely interrupts fuel flow as part of its 

normal operation, source testing may commence sooner than specified in 

Section 5.6.3 and continue through its normal cyclical firing period. 

5.6.5 For emissions source testing performed pursuant to Section 6.3.1 for the 

purpose of determining compliance with an applicable standard or 

numerical limitation of this rule, the arithmetic average of three (3) 30-

consecutive-minute test runs shall apply. If two (2) of three (3) runs are 

above an applicable limit the test cannot be used to demonstrate 

compliance with an applicable limit. 

6.0 Administrative Requirements 

6.1 Recordkeeping 

The records required by Sections 6.1.1 through 6.1.5 6.1.4 shall be maintained, 

and retained for five calendar years., and The records shall be made available to 

the APCO, ARB, and EPA upon request. Failure to maintain records or 

information contained in the records that demonstrates noncompliance with the 

applicable requirements of this rule shall constitute a violation of this rule. 

6.1.1 The operator of any unit limited to the annual heat input specified in 

Section 5.2.1 or Section 5.2.2 shall record the amount of fuel use, at 

least once a month for each unit, or for a group of units as specified in 

Section 5.5.2. On and after the compliance schedule specified in Section 

7.0 Table 3, any unit that exceeds the annual heat input limit specified in 

Section 5.2.1 or Section 5.2.2, shall be brought into full compliance with 

this rule as specified in Section 7.3. 

6.1.2 The operator of any unit subject to the applicable requirements of Sections 

5.2.1.1, 5.5.1.1, and 5.5.1.2 shall maintain records to verify that tune-up 

and monitoring of the operational characteristics of the unit have been 

performed. 

6.1.3 Operators who operate a unit on liquid fuel during PUC-quality natural gas 

curtailment period shall record the sulfur content of the fuel, amount of 

fuel used, and duration of the natural gas curtailment period. 

6.1.4 The operator performing start-up or shutdown of a unit shall keep records 

of the duration of start-up or shutdown that exceed the applicable 

requirements of Sections 5.4.1 or 5.4.2. 
PROPOSED May 19, 2011 

4307 - 12 Proposed Amendments to Rule 4307

6.1.5 Tree Nut Pasteurizers Operations and Maintenance Records 

The operator of a tree nut pasteurizer shall maintain operation and 

maintenance records that demonstrate operation of the tree nut 

pasteurizer is within the limits of the manufacturer’s specification and 

maintenance according to manufacturer’s recommendation or APCOapproved alternative procedures. 

6.1.5.1 Operations records shall be maintained for the days on which 

the tree nut pasteurizer is operated. 

6.1.5.2 The operator shall keep maintenance records that verify that 

maintenance was performed in accordance with manufacturer’s 

specifications or APCO-approved alternative procedures. 

6.1.5.3 A copy of the manufacturer’s operation specifications and 

maintenance instruction manual or APCO-approved alternative 

procedures shall be maintained on-site during normal business 

hours. 

6.1.5.4 If the manufacturer’s operation specifications or maintenance 

instruction manual are not available, the operator of a tree nut 

pasteurizer shall submit alternative operation or maintenance 

procedures for approval by the APCO by [6 months after rule 

amendment date] or as part of the Authority to Construct 

application, whichever is later. 

6.1.5.5 The operator of a tree nut pasteurizer shall maintain records that 

demonstrate that the fuel used to fire the pasteurizer is PUC 

quality natural gas. 

6.2 Test Methods 

The following test methods shall be used unless otherwise approved by the APCO, 

ARB, and EPA. 

6.2.1 Oxides of nitrogen (ppmv) – EPA Method 7E, or ARB Method 100. 

6.2.2 Carbon monoxide (ppmv) – EPA Method 10, or ARB Method 100. 

6.2.3 Stack gas oxygen – EPA Method 3 or 3A, or ARB Method 100. 

6.2.4 NOx Emission Rate (Heat Input Basis) – EPA Method 19. 

6.2.5 Stack gas velocities – EPA Method 2. 
PROPOSED May 19, 2011 

4307 - 13 Proposed Amendments to Rule 4307

6.2.6 Stack gas moisture content – EPA Method 4. 

6.2.7 Sulfur content of liquid fuel – American Society for Testing and Materials 

(ASTM) D 6920-03 or ASTM D 5453-99. 

6.2.8 Determination of total sulfur as hydrogen sulfide (H2S) content – EPA 

Method 11 or EPA Method 15, as appropriate. 

6.2.9 Oxides of sulfur – EPA Method 6C, EPA Method 8, or ARB Method 100. 

6.2.10 The SOx emission control system efficiency shall be determined using the 

following: 

% Control Efficiency = [ (CSO2, inlet – CSO2, outlet) / CSO2, inlet ] X 100 

Where: 

CSO2, inlet = concentration of SOx (expressed as SO2) at the inlet side of 

the SOx emission control system, in lb/dscf 

CSO2, outlet = concentration of SOx (expressed as SO2) at the outlet side 

of the SOx emission control system, in lb/dscf 

6.3 Compliance Demonstration 

6.3.1 The operator shall conduct an initial source test at the time of installation 

and/or modification for each non-certified unit or each non-certified 

retrofit control technology to demonstrate compliance with the applicable 

certification emission limits in Section 5.1. Units demonstrating 

compliance are eligible for certification under the provisions of Section 

9.0. 

6.3.2 Source testing of a certified unit or certified retrofit control technology, as 

defined in Section 3.0, is not required provided the operator complies with 

the requirements of Sections 6.3.2.1 and 6.3.2.2. 

6.3.2.1 Operate the unit within range of operating parameters specified 

in the APCO-approved certification document. 

6.3.2.2 Operate and maintain the unit in accordance with the 

manufacturer’s instructions and conditions specified in the 

APCO-approved certification document. 
PROPOSED May 19, 2011 

4307 - 14 Proposed Amendments to Rule 4307

6.3.3 A unit or retrofit control technology that loses its certification status shall 

be source tested within 60 days after the date the certification status is lost 

to demonstrate compliance with the emission limits of this rule. The 

manufacturer or operator may request re-certification of a unit or retrofit 

control technology that lost its certification status provided the provisions 

of Section 9.0 are met. 

6.4 Equipment Registration Requirement 

Except for units that require a Permit to Operate pursuant to Rule 2020 

(Exemptions), the operator shall register with the District any unit subject to this 

rule no later than the applicable date shown in Table 3, in accordance with Rule 

2250 (Permit-Exempt Equipment Registration). 

7.0 Compliance Schedule 

7.1 An operator with multiple units at a stationary source shall comply with this rule in 

accordance with the schedule specified in Table 3. An operator with only one unit 

at a stationary source shall comply with the schedule specified in Table 3, Group 2. 

TABLE 3 - Compliance Schedule 

Quantity of Units to be in 

Compliance at a Stationary 

Source 

Authority to 

Construct 

Permit-Exempt 

Equipment 

Registration 

Full Compliance

Group 1: 

50% or more of the total 

number of units subject to this 

rule on July 1, 2008, excluding

Group 3 

January 1, 2008 April 1, 2008 July 1, 2008 

Group 2: 

100% of the total number of 

units subject to this rule on and 

after July 1, 2009, excluding 

Group 3 

January 1, 2009 April 1, 2009 July 1, 2009 

Group 3: 

100%of the total number of 

units subject to Section 5.2.3 

and 100% of the total number 

of units located at a school, 

subject to this rule on and after

July 1, 2015 

January 1, 2015 April 1, 2015 July 1, 2015 

Units are considered to be subject to this rule if the rule is applicable to the units pursuant 

to Section 2.0 and the units are not exempt pursuant to Section 4.0. 
PROPOSED May 19, 2011 

4307 - 15 Proposed Amendments to Rule 4307

7.2 As shown in Table 3, the column labeled: 

7.2.1 “Authority to Construct” identifies the date by which the operator shall 

submit an Application for Authority to Construct for each unit subject to 

this rule and which is required to have a Permit to Operate (PTO) pursuant 

to Rule 2020 (Exemptions). 

7.2.2 “Permit-Exempt Equipment Registration” identifies the date by which the 

owner or operator shall submit a complete Permit-Exempt Equipment 

Registration application for each unit subject to the registration 

requirements of Rule 2250 (Permit-Exempt Equipment Registration). 

7.2.3 "Full Compliance" identifies the date by which the owner shall demonstrate 

that each unit is in compliance with this rule regardless of whether the unit 

requires a Permit to Operate or a Permit-Exempt Equipment Registration. 

7.3 Any unit that becomes subject to the emission limits of this rule as a result of 

exceeding the annual heat input limit specified in Section 5.2.1 or Section 5.2.2, 

shall be in compliance with the emission limits specified in Section 5.1 Table 1 on 

and after the date the annual heat input limit is exceeded. 

7.4 When an existing unit, that is subject to Section 5.2, is replaced, the replacement 

unit shall be certified, according to Section 9.0, or source tested in accordance with 

the test methods in Section 6.2 to comply with the applicable emission limits 

specified in Section 5.1, on and after the date of initial operation. 

8.0 Calculations 

8.1 All ppmv emission limits specified in Section 5.1 are referenced at dry stack gas 

conditions and 3.00 percent by volume stack gas oxygen. Emission concentrations 

shall be corrected to 3.00 percent oxygen as follows: 

measured

measured

corrected x ppm NOx

O

ppm NOx [ ]

20 95. % [% ]2

17 95. %

[ ]

−

= 

measured

measured

corrected x ppmCO

O

ppmCO [ ]

20 95. % [% ]2

17 95. %

[ ]

−

=

8.2 All pounds per million Btu NOx emission rates shall be calculated as pounds of 

nitrogen dioxide per million Btu of heat input (hhv). 

9.0 Equipment Certification Requirements 

9.1 To be considered for APCO certification, the manufacturer or operator shall 

comply with the following requirements: 
PROPOSED May 19, 2011 

4307 - 16 Proposed Amendments to Rule 4307

9.1.1 Certification shall be based upon the emission source testing results of a 

specific unit, or a randomly selected unit of each model, or retrofit control 

technology. 

9.1.2 A source testing protocol shall be submitted in accordance with the 

provisions of Rule 1081 (Source Sampling) for approval by the APCO 

prior to conducting the source test. The source testing protocol 

approved by the APCO shall be strictly adhered to during certification 

source testing. 

9.1.3 Source testing shall be conducted over the range of operating parameters 

for which the unit(s) or retrofit control technology will be operated. 

9.1.4 The source testing results shall demonstrate compliance with the emission 

limits of this rule for each model of unit(s), or retrofit control technology 

to be certified. 

9.1.5 The source testing procedure and reports shall be prepared by an ARBapproved independent testing laboratory, and shall contain all the elements 

identified in the APCO-approved source testing protocol. 

9.1.6 Source testing shall be conducted no more than 90 days prior to the date of 

submission of request for certification by the APCO. 

9.2 The manufacturer or operator requesting certification shall submit to the APCO 

the following information: 

9.2.1 Copies of the source testing results conducted pursuant to the requirements 

of Section 9.1, and other pertinent technical data to demonstrate 

compliance with the emission limits of this rule. 

9.2.2 The applicant shall sign and date the statement attesting to the accuracy of 

all information in the statement. 

9.2.3 Name and address of the unit manufacturer or operator, brand name of the 

unit or retrofit control technology, model number, rated heat input as it 

appears in the unit nameplate, and description of model of unit(s), or 

retrofit control technology being certified. 

9.3 The APCO will only approve an application for certification to the extent that the 

requirements of Sections 9.1 through 9.2 are met and the source testing results 

demonstrate that the emission limits of this rule are met. 

9.4 The APCO-approved certification is valid only for the range of operating 

parameters for which certification is issued. 
PROPOSED May 19, 2011 

4307 - 17 Proposed Amendments to Rule 4307

9.5 A certified unit or a certified retrofit control technology that is operated outside 

the APCO-certified range of operating parameters shall lose its certification status. 

A unit or retrofit control technology that loses its certification status shall comply 

with the requirements of Section 6.3.3. 

9.6 The APCO shall publish a list of certified units or certified retrofit control 

technology after the certification process is completed.