Bay Area Air Quality Management District July 30, 2008

 9-7-1 

REGULATION 9 

INORGANIC GASEOUS POLLUTANTS 

RULE 7 

NITROGEN OXIDES AND CARBON MONOXIDE FROM INDUSTRIAL, 

INSTITUTIONAL, AND COMMERCIAL BOILERS, STEAM GENERATORS, 

AND PROCESS HEATERS 

INDEX 

9-7-100 GENERAL 

9-7-101 Description 

9-7-110 Exemptions 

9-7-111 Limited Exemption, Low Fuel Usage – Section 9-7-301 

9-7-112 Limited Exemption, Low Fuel Usage 

9-7-113 Limited Exemption, Natural Gas Curtailment and Testing 

9-7-114 Limited Exemption, Tune-up 

9-7-115 Limited Exemption, Startup and Shutdown 

9-7-116 Limited Exemption, Compliance Extension for Facilities Subject to Regulation 9, Rule 

9 

9-7-117 Limited Exemption, Devices Rated 75 MM BTU/hr and Higher Limited to 9 PPMV 

NOx 

9-7-200 DEFINITIONS 

9-7-201 Annual Heat Input 

9-7-202 Annual Maximum Heat Capacity 

9-7-203 Boiler or Steam Generator 

9-7-204 British Thermal Unit (BTU) 

9-7-205 Digester Gas 

9-7-206 Digester Gas-Fired Device 

9-7-207 Gaseous Fuel 

9-7-208 Heat Input 

9-7-209 Heat-Input Weighted Average 

9-7-210 Higher Heating Value (HHV) 

9-7-211 Landfill Gas 

9-7-212 Landfill Gas-Fired Device 

9-7-213 Load-Following Unit 

9-7-214 Natural Gas 

9-7-215 Natural Gas Curtailment 

9-7-216 Nitrogen Oxide (NOx) Emissions 

9-7-217 Process Heater 

9-7-218 Rated Heat Input 

9-7-219 Shutdown Period 

9-7-220 Startup Period 

9-7-221 Therm 

9-7-300 STANDARDS 

9-7-301 Interim Emission Limits 

9-7-302 Deleted 

9-7-303 Deleted 

9-7-304 Interim Low Fuel Usage Requirements 

9-7-305 Deleted 

9-7-306 Deleted 

9-7-307 Final Emission Limits 
Bay Area Air Quality Management District July 30, 2008

 9-7-2 

9-7-308 Compliance Schedule 

9-7-309 Final Low Fuel Usage Requirements 

9-7-310 Prohibition of Commerce in Uncertified Devices 

9-7-311 Insulation Requirements 

9-7-312 Stack Gas Temperature Limits 

9-7-313 Tune-Up Requirements 

9-7-400 ADMINISTRATIVE REQUIREMENTS 

9-7-401 Deleted 

9-7-402 Deleted 

9-7-403 Initial Demonstration of Compliance 

9-7-404 Registration 

9-7-405 Compliance with Emissions Standards – Devices Rated Less Than 10 Million BTU/hr 

Input 

9-7-406 Application for Certification 

9-7-407 Identification 

9-7-408 Designation of Load-Following Units 

9-7-500 MONITORING AND RECORDS 

9-7-501 Combinations of Different Fuels 

9-7-502 Deleted 

9-7-503 Records 

9-7-504 Low Fuel Usage - Monitoring and Records 

9-7-505 Original Manufacture Date 

9-7-506 Periodic Testing 

9-7-600 MANUAL OF PROCEDURES 

9-7-601 Determination of Nitrogen Oxides 

9-7-602 Determination of Carbon Monoxide and Stack-Gas Oxygen 

9-7-603 Compliance Determination 

9-7-604 Tune-Up Procedures 

9-7-605 Determination of Higher Heating Value 

ATTACHMENT 1 – PORTABLE ANALYZER PROTOCOL 
Bay Area Air Quality Management District July 30, 2008

 9-7-3 

REGULATION 9 

INORGANIC GASEOUS POLLUTANTS 

RULE 7 

NITROGEN OXIDES AND CARBON MONOXIDE FROM INDUSTRIAL, 

INSTITUTIONAL, AND COMMERCIAL BOILERS, STEAM GENERATORS, 

AND PROCESS HEATERS 

(Adopted September 16, 1992) 

9-7-100 GENERAL 

9-7-101 Description: This rule limits the emissions of nitrogen oxides (NOx) and carbon 

monoxide (CO) from industrial, institutional, and commercial boilers, steam 

generators, and process heaters. 

9-7-110 Exemptions: The requirements of this rule shall not apply to the following: 

110.1 Boilers, steam generators, and process heaters with a rated heat input of 2 

million BTU/hour or less, if fired exclusively with natural gas, liquefied 

petroleum gas, or any combination thereof; 

110.2 Boilers, steam generators and process heaters with a rated heat input less 

than 1 million BTU/hour fired with any fuel; 

110.3 Boilers, steam generators, and process heaters that are used in petroleum 

refineries; 

110.4 Boilers used by public electric utilities or qualifying small power production 

facilities, as defined in Section 228.5 of the Public Utilities Code, to generate 

electricity; 

110.5 Waste heat recovery boilers that are used to recover sensible heat from the 

exhaust of combustion turbines or reciprocating internal combustion engines; 

110.6 Kilns, ovens, and furnaces used for drying, baking, heat treating, cooking, 

calcining, or vitrifying. 

(Amended July 30, 2008) 

9-7-111 Limited Exemption, Low Fuel Usage - Section 9-7-301: The requirements of 

Section 9-7-301 shall not apply to the use of any boiler, steam generator, or process 

heater with an annual heat input less than 90,000 therms during each consecutive 

12-month period after July 1, 1993, or that accepts a limiting condition in their 

operating permit to limit the annual heat input to less than 90,000 therms, provided 

the requirements of Sections 9-7-304 and 504 are satisfied. 

(Amended July 30, 2008) 

9-7-112 Limited Exemption, Low Fuel Usage: The requirements of Sections 9-7-307 

(except as specified below), 311 and 312 shall not apply to the use of any boiler, 

steam generator, or process heater provided that all of the following conditions are 

met: 

112.1 For devices with a rated heat input less than 10 million BTU/hr, the device 

uses less than 10% of its annual maximum heat capacity in each 

consecutive 12-month period beginning January 1, 2011 and the 

requirements of Section 9-7-309 are satisfied; 

112.2 For devices with a rated heat input of 10 million BTU/hr or more, the device 

uses less than 10% of its annual maximum heat capacity in each 

consecutive 12-month period beginning January 1, 2012 and the 

requirements of Section 9-7-307.10 are satisfied. 

An operator of a boiler, steam generator, or process heater that loses eligibility for 

this exemption by using more than the specified amount of fuel in any consecutive 

12-month period shall comply with the applicable standards of Section 9-7-307 within 

24 months. 

(Adopted July 30, 2008) 

9-7-113 Limited Exemption, Natural Gas Curtailment and Testing: The requirements of 

Section 9-7-307 shall not apply to any boiler, steam generator or process heater 

while it burns LPG or other non-gaseous fuel during a natural gas curtailment or 
Bay Area Air Quality Management District July 30, 2008

 9-7-4 

during testing to verify readiness for such a curtailment, provided that all of the 

following conditions are met: 

113.1 The device does not burn LPG or other non-gaseous fuel for more than 168 

total hours in each consecutive 12-month period, plus 48 hours in each 

consecutive 12-month period for oil-burn readiness testing or state, federal, 

or local agency-required performance testing, 

113.2 The device does not exceed a NOx exhaust concentration of 150 ppmv, and 

113.3 The records specified in Section 9-7-503.3 are maintained. 

(Adopted July 30, 2008) 

9-7-114 Limited Exemption, Tune-Up: The emission limits of Section 9-7-307 shall not 

apply during the tune-up of a boiler, steam generator or process heater required by 

Section 9-7-313. Emissions shall be minimized to the extent possible during the 

exemption period and the tune-up shall be completed in as little time as necessary. 

(Adopted July 30, 2008) 

9-7-115 Limited Exemption, Startup and Shutdown: The emission limits of Section 9-7-

307 shall not apply during startup and shutdown periods provided that all of the 

following conditions are met: 

115.1 Each startup and shutdown period shall not exceed two hours, unless 

otherwise allowed in a District Permit to Operate. In no case shall the startup 

period exceed 12 hours, or the shutdown period exceed 9 hours. 

115.2 All emission control systems shall be in operation and emissions shall be 

minimized, to the extent possible, during startup and shutdown periods. 

(Adopted July 30, 2008) 

9-7-116 Limited Exemption, Compliance Extension for Facilities Subject to Regulation 

9, Rule 9: Boilers, steam generators or process heaters located at the same facility 

as a turbine that is subject to Regulation 9, Rule 9 and that is modified or replaced to 

comply with Section 9-9-301.2 of that regulation, shall comply with the requirements 

of Section 9-7-307 no later than 24 months after the date otherwise specified for 

compliance in Section 9-7-308. 

(Adopted July 30, 2008) 

9-7-117 Limited Exemption, Devices Rated 75 MM BTU/hr or Higher Limited to 9 PPMV 

NOx: The emission limits of Section 9-7-307.6 shall not apply to any boiler, steam 

generator or process heater that is limited to 9 ppmv NOx or less by a District Permit 

to Operate in effect on or before July 30, 2008 as long as that permit limit remains in 

effect. 

(Adopted July 30, 2008) 

9-7-200 DEFINITIONS 

9-7-201 Annual Heat Input: The total heat input of fuels burned by a combustion source 

during any consecutive 12-month period, as determined from the higher heating 

value and cumulative annual usage of each fuel. 

9-7-202 Annual Maximum Heat Capacity: The amount of heat input that a device would 

have if it operated at its rated heat input continuously for 365 consecutive days. 

(Adopted July 30, 2008) 

9-7-203 Boiler or Steam Generator: Any combustion equipment used to produce steam or 

to heat water. 

(Renumbered July 30, 2008) 

9-7-204 British Thermal Unit (BTU): The amount of heat required to raise the temperature 

of one pound of water from 59o

 to 60oF at one atmosphere. 

(Renumbered July 30, 2008) 

9-7-205 Digester Gas: Gas derived from the decomposition of organic matter in a digester. 

(Adopted July 30, 2008) 

9-7-206 Digester Gas-Fired Device: A boiler, steam generator or process heater that fires 

or co-fires digester gas at least 90% of its operating time, on a calendar year basis. 

(Adopted July 30, 2008) 

9-7-207 Gaseous Fuel: Any fuel that is a gas at 68oF and one atmosphere. 

(Adopted July 30, 2008) 

9-7-208 Heat Input: The heat of combustion released due to burning a fuel in a source, 

using the higher heating value of the fuel. This does not include the sensible heat of 

incoming combustion air. 
Bay Area Air Quality Management District July 30, 2008

 9-7-5 

(Renumbered July 30, 2008) 

9-7-209 Heat-Input Weighted Average: The heat input of the gaseous fuel per unit time 

divided by the total heat input per unit time and the heat input per unit time of the 

non-gaseous fuel divided by the total heat input per unit time. The calculated 

fractions are used to calculate the applicable weighted average ppmv emission limit 

of Section 9-7-301.3. 

(Amended, Renumbered July 30, 2008) 

9-7-210 Higher Heating Value (HHV): The total heat liberated per mass of fuel burned (BTU 

per pound), when fuel and dry air at standard conditions undergo complete 

combustion and all resultant products are brought to their standard states at standard 

conditions. The HHV is determined as specified in Section 9-7-605. 

(Renumbered July 30, 2008) 

9-7-211 Landfill Gas: Gas derived from the decomposition of waste in a landfill. 

(Adopted July 30, 2008) 

9-7-212 Landfill Gas-Fired Device: A boiler, steam generator or process heater that fires or 

co-fires landfill gas at least 90% of its operating time, on a calendar year basis. 

(Adopted July 30, 2008) 

9-7-213 Load-Following Unit: A unit that cannot be operated in a base-loaded mode, and 

that has normal operational load fluctuations and requirements, imposed by 

fluctuations in the process(es) served by the unit, that exceed the operational 

response range of a Ultra-Low NOx burner system operating at 9 ppmv NOx, as 

determined by the District and indicated on the device’s permit to operate. 

(Adopted July 30, 2008) 

9-7-214 Natural Gas: Any mixture of gaseous hydrocarbons containing at least 80 percent 

methane by volume, as determined according to Standard Method ASTM D1945-64. 

(Renumbered July 30, 2008) 

9-7-215 Natural Gas Curtailment: A shortage in the supply of pipeline natural gas, due 

solely to supply limitations or restrictions in distribution pipelines by the utility 

supplying the gas, and not due to the cost of natural gas. 

(Adopted July 30, 2008) 

9-7-216 Nitrogen Oxide (NOx) Emissions: The sum of nitric oxide (NO) and nitrogen 

dioxide (NO2) in the flue gas, collectively expressed as nitrogen dioxide. 

(Renumbered July 30, 2008) 

9-7-217 Process Heater: Any combustion equipment that transfers heat from combustion 

gases to water or process streams. A process heater does not include any kiln, 

furnace or oven that is used for drying, baking, heat treating, cooking, calcining, or 

vitrifying. A process heater also does not include a space heating device that is 

primarily intended to only heat ambient air. 

(Amended, Renumbered July 30, 2008) 

9-7-218 Rated Heat Input: The heat input capacity specified on the nameplate of the boiler, 

steam generator or process heater, or the sum of the capacities on the nameplates 

of the burners in the boiler, steam generator or process heater, whichever is greater. 

(Amended, Renumbered July 30, 2008) 

9-7-219 Shutdown Period: The period of time during which a unit is taken from an 

operational to a non-operational status. 

(Adopted July 30, 2008) 

9-7-220 Startup Period: The period of time during which a unit is brought from a nonoperational status to operating temperature, including the time required for the unit’s 

emission control system to reach full operation. 

(Adopted July 30, 2008) 

9-7-221 Therm: One hundred thousand (100,000) BTU's. 

(Renumbered July 30, 2008) 

9-7-300 STANDARDS 

9-7-301 Interim Emission Limits: No person shall operate a boiler, steam generator or 

process heater with a rated heat input greater than or equal to 10 million BTU per 

hour unless the following emission limits are met: 

301.1 Nitrogen oxide (NOx) emissions shall not exceed 30 ppmv, dry at 3 percent 

oxygen when gaseous fuel is used; 
Bay Area Air Quality Management District July 30, 2008

 9-7-6 

301.2 Nitrogen oxide (NOx) emissions shall not exceed 40 ppmv, dry at 3 percent 

oxygen when non-gaseous fuel is used; 

301.3 Nitrogen oxide (NOx) emissions shall not exceed the heat-input weighted 

average of the limits in Sections 9-7-301.1 and 301.2 when a combination of 

gaseous and non-gaseous fuel is used; 

301.4 Carbon monoxide (CO) emissions shall not exceed 400 ppmv, dry at 3 

percent oxygen. 

This section shall not apply to any boiler, steam generator, or process heater subject 

to a NOx or CO emission limit in Section 9-7-307. 

(Amended July 30, 2008) 

9-7-302 Deleted July 30, 2008 

9-7-303 Deleted July 30, 2008

9-7-304 Interim Low Fuel Usage Requirements: No person shall operate any boiler, steam 

generator or process heater under the limited exemption in Section 9-7-111, or with 

rated heat input less than 10 million BTU per hour with the capability of firing any 

non-gaseous fuel, without doing at least one of the following: 

304.1 Operate in a manner that maintains stack-gas oxygen concentrations at less 

than or equal to 3 percent by volume on a dry basis; or 

304.2 Perform an inspection and tune-up at least once every 12 months by a 

technician in accordance with the procedure specified in Section 9-7-604; or 

304.3 Meet the emission limits specified in Sections 9-7-301. 

(Amended July 30, 2008) 

9-7-305 Deleted July 30, 2008

9-7-306 Deleted July 30, 2008 

9-7-307 Final Emission Limits: No person shall operate a boiler, steam generator or 

process heater with a rated heat input listed in the table below that exceeds the 

corresponding NOx and CO emission limits on or after the corresponding effective 

date specified in Section 9-7-308. Where more than one NOx limit applies to a 

device, the device will be subject only to the higher (less restrictive) NOx limit. 

Emission 

Limit 

Rated Heat Input 

(million BTU/hr) 

NOx Limit 

(ppmv) 

CO Limit 

(ppmv) 

307.1 >2 to 5 30 400 

307.2 >5 to <10 15 400 

307.3 10 to <20 15 400 

307.4 20 or more, load-following unit 15 400 

307.5 20 to <75 9 400 

307.6 75 or more 5 400 

307.7 10 or more, landfill gas-fired or 

digester gas-fired device 

30 400 

307.8 1 or more while firing only nongaseous fuel 

40 400 

307.9 

1 or more while firing a 

combination of gaseous and nongaseous fuel 

heat-input weighted 

average of gaseous 

& non-gaseous limit 

400 

307.10 10 or more, while operated under 

exemption 9-7-112.2 

30 400 

(Adopted July 30, 2008) 

9-7-308 Compliance Schedule: Boilers, steam generators and process heaters subject to 

the requirements of Section 9-7-307 shall comply with those requirements in 

accordance with the schedule in the table below. 
Bay Area Air Quality Management District July 30, 2008

 9-7-7 

Section At least 33% of devices at a 

single facility 

At least 66% 

of devices at a 

single facility 

100% of 

devices at a 

single facility 

9-7-307.1 

Effective Date: Later of January 1, 

2011 OR 10 years after original 

manufacture date if manufactured 

prior to January 1, 2011 

One year after 

Effective Date 

Two years after 

Effective Date 

9-7-307.2 

9-7-307.3 

Effective Date: Later of January 1, 

2012 OR 10 years after original 

manufacture date if manufactured 

prior to January 1, 2012 

One year after 

Effective Date 

Two years after 

Effective Date 

9-7-307.4 

9-7-307.5 

9-7-307.6 

Effective Date: Later of January 1, 

2012 OR 5 years after original 

manufacture date if manufactured 

prior to January 1, 2012 

One year after 

Effective Date 

Two years after 

Effective Date 

9-7-307.7 

9-7-307.10 July 30, 2008 July 30, 2008 July 30, 2008 

9-7-307.8 

9-7-307.9 

Effective Date: January 1, 2011 for 

devices with rated input <10 MM 

BTU/hr; July 30, 2008 for devices 

with rated input ≥10 MM BTU/hr 

One year after 

Effective Date 

Two years after 

Effective Date 

(Adopted July 30, 2008) 

9-7-309 Final Low Fuel Usage Requirements: No person shall operate any boiler, steam 

generator or process heater under the limited exemption in Section 9-7-112.1 without 

doing at least one of the following: 

309.1 Operate in a manner that maintains stack-gas oxygen concentrations at less 

than or equal to 3 percent by volume on a dry basis; or 

309.2 Perform an inspection and tune-up at least once per calendar year by a 

technician in accordance with the procedure specified in Section 9-7-604; or 

309.3 Meet the applicable emission limits in Section 9-7-307. 

(Adopted July 30, 2008) 

9-7-310 Prohibition of Commerce in Uncertified Devices: No person shall sell, offer for 

sale, or install any boiler, steam generator or process heater subject to Section 9-7-

307.1 or 307.2 unless the device is certified in accordance with Sections 9-7-405 and 

406. 

(Adopted July 30, 2008) 

9-7-311 Insulation Requirements: Effective January 1, 2010, no person shall operate a 

boiler or steam generator unless the exposed, external surface of the device, 

including all pipes and ducts heated by the device, does not exceed a temperature of 

120oF. This requirement shall not apply to any of the following: 

311.1 Any device that meets the definition of a high-temperature water boiler in 

California Code of Regulations, Title 8. 

311.2 Any surface or appurtenance that must remain un-insulated for safety or 

operational reasons. 

311.3 Any surface that has at least one inch of insulation, or that does not exceed a 

temperature of 140oF with no insulation. 

311.4 Any surface heated by a source other than the boiler or steam generator, 

including sunlight. 

311.5 Any exhaust stack surface. 

(Adopted July 30, 2008) 

9-7-312 Stack Gas Temperature Limits: Effective January 1, 2011, no person shall operate 

a boiler or steam generator with a stack gas temperature (downstream of any 

economizer) that exceeds the indicated maximum temperature: 
Bay Area Air Quality Management District July 30, 2008

 9-7-8 

Heater 

Design 

Maximum Temperature (oF) 

Gaseous Fuel Non-Gaseous Fuel 

firetube 100oF over saturated steam 

temperature for steam boiler, 

100oF over hot water 

temperature for hot water boiler 

OR 250 oF greater than ambient 

temperature, whichever is higher 

100oF over saturated steam 

temperature for steam boiler, 

100oF over hot water temperature 

for hot water boiler OR 300 oF 

greater than ambient 

temperature, whichever is higher 

watertub

e 

150oF over saturated steam 

temperature for steam boiler, 

150oF over hot water 

temperature for hot water boiler 

OR 250 oF greater than ambient 

temperature, whichever is higher 

150oF over saturated steam 

temperature for steam boiler, 

150oF over hot water temperature 

for hot water boiler OR 300 oF 

greater than ambient 

temperature, whichever is higher 

(Adopted July 30, 2008) 

9-7-313 Tune-Up Requirements: Effective January 1, 2009, no person shall operate a 

boiler, steam generator or process heater unless they do at least one of the following 

each calendar year: 

313.1 Operate at less than 10% of its annual maximum heat capacity during the 

calendar year; or 

313.2 Perform an inspection and tune-up at least once per calendar year by a 

technician in accordance with the procedure specified in Section 9-7-604. 

(Adopted July 30, 2008) 

9-7-400 ADMINISTRATIVE REQUIREMENTS 

9-7-401 Deleted July 30, 2008

9-7-402 Deleted July 30, 2008

9-7-403 Initial Demonstration of Compliance: No person shall operate a boiler, steam 

generator or process heater that is subject to the requirements of Sections 9-7-307.3, 

307.4, 307.5, 307.6 or 309.1 unless an initial source test to verify compliance with 

these requirements is conducted in accordance with Sections 9-7-601 or 602 within 1 

year of the date these requirements are effective. Alternatively, devices subject to 

Sections 9-7-307.3, 307.4 or 309.1 may be tested using a portable analyzer that 

meets the specification standards and using the testing protocol in Attachment 1. 

This section does not apply to any device required to perform verification testing to 

establish compliance with applicable requirements of Sections 9-7-307.3, 307.4, 

307.5, 307.6 or 309.1 in accordance with a District Authority to Construct issued on 

or after January 1, 2011. 

(Amended July 30, 2008) 

9-7-404 Registration: Effective January 1, 2011, no person shall operate any boiler, steam 

generator or process heater subject to Section 9-7-307.1 or 307.2 unless the device 

is registered in accordance with Regulation 1, Section 410. Any person registering a 

device shall pay the fees specified in Regulation 3. This registration requirement 

shall not apply to any device for which the operator holds a District Permit to 

Operate. 

(Adopted July 30, 2008) 

9-7-405 Compliance with Emissions Standards – Devices Rated Less Than 10 Million 

BTU/hr Input: The manufacturer shall obtain confirmation from an independent 

testing laboratory that each boiler, steam generator or process heater model it sells 

or distributes for sale into the District that is subject to the requirements of Section 9-

7-307.1 or 307.2 has been tested in accordance with the procedures in Sections 9-7-

601 and 602. This requirement shall not apply to burner assemblies sold as retrofit 

packages. 

(Adopted July 30, 2008) 

9-7-406 Application for Certification: 

406.1 Each manufacturer shall submit an application to the APCO for certification 

of their compliant boiler, steam generator or process heater model. The 

application must: 
Bay Area Air Quality Management District July 30, 2008

 9-7-9 

1.1 Provide the following general information: name and address of 

manufacturer, brand name, trade name, model number and heat input 

rating as it appears on the water heater rating plate. 

1.2 Provide a description of the model being certified 

1.3 Include a complete certification source test report demonstrating that 

the boiler or water heater model was tested in accordance with 

procedures in Sections 9-7-601 and 602 and a written statement that 

the model complies with Section 9-7-307.1 or 307.2 and is tested in 

accordance with procedures in Sections 9-7-601 and 602. 

1.4 Be submitted to the District no more than 90 days after the date of the 

emissions compliance test conducted in accordance with Section 9-7-

405. 

1.5 Be submitted to the District no less than 90 days before the first sale or 

distribution within the District that occurs on or after January 1, 2011, 

of a boiler, steam generator or process heater model. 

406.2 After completing review of the application for certification and source test 

report, the APCO will approve, or will deny approval of the device. 

406.3 Certification status shall be valid for three years from the date of approval by 

the APCO. After the third year, recertification shall be required according to 

the requirements in 9-7-406. 

(Adopted July 30, 2008) 

9-7-407 Identification: The boiler, steam generator or process heater manufacturer shall 

display the model number and the certification status of the boiler, steam generator 

or process heater on the shipping carton and on the rating plate of each unit. 

(Adopted July 30, 2008) 

9-7-408 Designation of Load-Following Units: To be eligible for the load-following 

emission standard in section 9-7-307, a unit must be designated a load-following unit 

by the APCO on the unit Permit to Operate. In order to support this designation, the 

unit operator shall include the following information with an application for an 

Authority to Construct or an application for a modification to a Permit to Operate, as 

specified in Regulation 2: 

408.1 A description of the processes the unit serves and the normal operational 

load fluctuations and load requirements imposed on the unit, verifying that 

the unit cannot be operated in a base-loaded mode. 

408.2 A detailed report on the design and condition of the unit, burner(s), burner 

controls, and any other subsystem that may affect the ability of the unit to 

comply with a 9 ppmv NOx limit, including a verification that the unit is free of 

air leaks, and is operated within normal design parameters, and is otherwise 

free of significant design defects and physical defects and is operated within 

reasonable parameters. This report shall verify that the inability of the unit to 

comply with a 9 ppmv NOx limit is substantially caused by the system load 

fluctuations and the limitations of state-of-the-art, commercially-available, 9 

ppmv burners and burner controls, rather than any other factor. 

408.3 Technical data such as steam demand charts or other information to support 

the description and report described above. 

(Adopted July 30, 2008) 

9-7-500 MONITORING AND RECORDS 

9-7-501 Combinations of Different Fuels: No person shall simultaneously fire 

combinations of different fuels in a device subject to the requirements of Sections 9-

7-301.3 or 307.9 without first installing a non-resettable totalizing fuel meter in each 

fuel line for each source. 

(Amended July 30, 2008) 

9-7-502 Deleted July 30, 2008

9-7-503 Records: Any person subject to the requirements of this rule shall keep records of 

the following: 

503.1 Documentation verifying tune-ups performed in accordance with Sections 9-

7-304.2, 309.2 or 313.2. 
Bay Area Air Quality Management District July 30, 2008

 9-7-10 

503.2 In the event that the limited exemption in Section 9-7-113 is invoked, 

documentation from the natural gas supplier verifying that natural gas was 

unavailable due to a natural gas curtailment. 

503.3 Documentation verifying the hours of equipment testing using non-gaseous 

fuel, and of total operating hours using non-gaseous fuel during each 

calendar month. 

503.4 The results of any testing required by Sections 9-7-403 or 506. 

503.5 Digester gas-fired and landfill gas-fired devices operating under Section 9-7-

307.7 shall maintain records of total operating hours and operating hours 

firing or co-firing digester or landfill gas. 

 Such records shall be retained for a minimum of 24 months from date of entry and be 

made available to District staff upon request. 

(Amended July 30, 2008) 

9-7-504 Low Fuel Usage - Monitoring and Records: Any person who operates a boilers, 

steam generator or process heater under the limited exemption of Section 9-7-111 or 

112 shall comply with the following requirements: 

504.1 Operate a non-resettable totalizing meter for each fuel that demonstrates 

that the source operated at or below the applicable heat input level, or 

receive APCO approval for using utility service meters, purchase or tank fill 

records, or any other acceptable methods for measuring the cumulative 

annual usage of each fuel; and 

504.2 Have available for inspection by the APCO annual fuel use data and the 

Higher Heating Value of each fuel used, for the prior consecutive 12-month 

period. Records shall be maintained and made accessible to the APCO for a 

period of 24 months from the date the record is made. 

An operator of a boiler, steam generator or process heater who claims eligibility for 

the limited exemption in Section 9-7-111 or 112, but who fails to maintain records to 

allow verification of fuel usage shall have the burden of proof to establish eligibility for 

the limited exemption. 

(Amended July 30, 2008) 

9-7-505 Original Manufacture Date: Any person who operates a boiler, steam generator or 

process heater that is subject to a standard in Sections 9-7-307.1 through 307.6 and 

that elects to use an effective date for this standard that is based on the original 

manufacture date of the device shall make available the original manufacture date of 

the device on the original manufacturer’s identification or rating plate permanently 

fixed to the device, or else on a copy of the manufacturer’s invoice. 

(Adopted July 30, 2008) 

9-7-506 Periodic Testing: No person shall operate a boiler, steam generator or process 

heater subject to an emission limit specified in the table below unless they verify 

compliance with the limit at the specified intervals. Testing shall be performed in 

accordance with Sections 9-7-601 and 602. Alternatively, devices may be tested 

using a portable analyzer that meets the specification standards and using the 

testing protocol in Attachment 1. No person shall operate a device that use nongaseous fuel unless they perform testing using non-gaseous fuel to verify compliance 

with Section 9-7-307.8 or 307.9, in addition to testing to verify compliance with any 

other applicable standard in Section 9-7-307. This section does not apply to any 

device required to perform periodic testing in accordance with a District Permit to 

Operate or to any device that verifies compliance with an emission limit with a 

District-approved continuous emission monitor. 

Emission Limit Testing Interval 

9-7-307.3 Every two years (no less than 18 months and no more than 24 

months), beginning with the effective date in Section 9-7-308. 

9-7-307.4, 

9-7-307.5, 

9-7-307.6, or 

9-7-309.1 

Every year (no less than 10 months and no more than 12 

months), beginning with the effective date in Section 9-7-308. 
Bay Area Air Quality Management District July 30, 2008

 9-7-11 

9-7-307.8 or 

9-7-307.9 

Within 60 days of the first use of non-gaseous fuel in any 

calendar year in which non-gaseous fuel is used. Use of nongaseous fuel for oil-burn readiness testing or state, federal, or 

local agency-required performance testing, not exceeding a 

total of 48 hours in a calendar year, will not trigger periodic 

testing. 

(Adopted July 30, 2008) 

9-7-600 MANUAL OF PROCEDURES 

9-7-601 Determination of Nitrogen Oxides: The methods by which samples of exhaust 

gases are collected and analyzed to determine concentrations of nitrogen oxides are 

set forth in the District Manual of Procedures, Volume IV, ST-13 A or B. 

9-7-602 Determination of Carbon Monoxide and Stack-Gas Oxygen: Compliance with the 

carbon monoxide emission requirements of Sections 9-7-301 and 307 and the stackgas oxygen concentration requirement of Sections 9-7-304.1 and 309.1 shall be 

determined as set forth in the District Manual of Procedures, Volume IV, ST-6 

(carbon monoxide) and ST-14 (oxygen). 

(Amended July 30, 2008) 

9-7-603 Compliance Determination: All emission determinations shall be made in the asfound operating condition, except that no compliance determination shall be 

established during startup or shutdown. 

(Amended July 30, 2008) 

9-7-604 Tune-Up Procedures: The tune-up procedure required by Section 9-7-304.2, 309.2 

and 313.2 shall be performed in accordance with the procedure set forth in the 

District Manual of Procedures, Volume I, Chapter 5. 

(Adopted 9/15/93; Amended 7/30/08) 

9-7-605 Determination of Higher Heating Value: If certification of the Higher Heating Value 

is not provided by the third-party fuel supplier, it shall be determined by one of the 

following test methods: (1) ASTM D2015-85 for solid fuels; (2) ASTM D240-87 or 

ASTM D2382-88 for liquid hydrocarbon fuels; or (3) ASTM D1826-88, or ASTM 

D1945-81 in conjunction with ASTM D3588-89, for gaseous fuels. 
Bay Area Air Quality Management District July 30, 2008

 9-7-12 

Attachment 1 

Portable Analyzer Protocol 

Emission readings using a portable analyzer 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 over the 15-consecutive-minute period. If the results of the 

portable analyzer show that the NOx or CO emissions from the unit exceed the applicable limits, 

then the unit shall be source tested no later than 60 days from the date of discovering such 

exceedance. 

Portable Analyzer Specifications 

A. General: A portable analyzer consists of a sample interface, a gas detector, and a data 

recorder, and is used to quantitatively analyze stack gas for one or more components. A 

portable analyzer for CO, O2, or NOx shall be considered approved by the District if it 

adheres to the standards that are set forth in this section, is used in accordance with the 

standards of this section, and is used in accordance with the manufacturer's specifications. 

Other portable analyzers and techniques are approvable on a case by case basis. 

B. Definitions: 

Sample interface: That portion of the portable analyzer used for one or more of the 

following: sample acquisition, sample transport, sample conditioning, or protection of the 

portable analyzer from the effects of the stack effluent. 

Gas detector: That portion of the portable analyzer that senses the gas to be measured and 

generates an output proportional to the gas concentration. 

Data recorder: A strip chart recorder, digital recorder, or any other device used for recording 

or displaying measurement data from the gas detector output. 

Resolution: The smallest increment of output that the gas detector will provide. This value 

should be reported by the equipment manufacturer. 

Error: The maximum standard measurement error over the measurement range. This value 

should be reported by the equipment manufacturer. 

Detection Limit: The lowest concentration of gas that can be detected by the gas detector. 

This value should be reported by the equipment manufacturer. 

Response Time: The amount of time required for the portable analyzer to display 95% of a 

step change in gas concentration on the data recorder. 

C. Equipment: The portable analyzer shall adhere to the standards tabulated below for each of 

the pollutants that it is intended to measure. All values in the table refer to maximum values. 

In addition to the parameters contained in the table, the minimum upper limit of the 

measurement range shall be equal to 1.5 times the emission limit for the species being 

measured. 

Detector Resolution Error Detection Limit Response Time

CO 20 ppm ± 50 ppm 50 ppm 1 min 

O2 0.5% ± 1.0% 0% 1 min 

NOx 1 ppm ± 1 ppm 5 ppm 1 min 

D. Calibration: Each gas detector shall be calibrated a minimum of once every six months and 

all instrument calibration data shall be kept on file with the monthly analyses. If the 

manufacturer recommends calibration more than once every six months, then the instrument 

calibration shall follow the manufacturer’s recommended interval. Two calibration gases are 

required, the upper limit calibration gas shall have a concentration of 60-100% of the upper 

limit of the measurement range and the lower limit calibration gas shall have a concentration 

from 0-10% of the upper limit of the measurement range. Ambient air may be used as the 

upper limit calibration gas for O2 and may be used as the lower limit calibration gas for both 
Bay Area Air Quality Management District July 30, 2008

 9-7-13 

NOx and CO. The system response time shall be determined during the gas detector 

calibration. The portable analyzer shall first be purged with ambient air. Calibration gas is 

then provided to the portable analyzer through a tubing length typically used during analysis. 

The time necessary for the data recorder to display a concentration equal to 95% of the final 

steady state concentration shall be recorded as the response time. 

E. Measurement: 

1. Concentration measurements shall not be taken until the sample acquisition probe has been 

exposed to the stack gas for at least 150% of the response time. Measurements shall be 

taken in triplicate. 

2. If water vapor is not removed prior to measurement, the absolute humidity in the gas stream 

must be determined so that the gas concentrations may be reported on a dry basis. If water 

vapor creates an interference with the measurement of any component, then the water vapor 

must be removed from the gas stream prior to concentration measurements. 

3. The concentration of NOx is calculated as the sum of the volumetric concentrations of both 

NO and NO2. The portable analyzer used to detect NOx must either convert NO2 to NO and 

measure NO, convert NO to NO2 and measure NO2, or measure both NO and NO2. An 

NO2 to NO converter is not necessary if data are presented to demonstrate that the NO2 

portion of the exhaust gas is less than 5 percent of the total NOx concentration.