RULE 233 BIOMASS BOILERS

Adopted 10-6-94

(Amended 10-11-07, 12-10-09, ,6-14-12)

CONTENTS

100 GENERAL

101 APPLICABILITY

102 FEDERAL REGULATIONS

103 EXEMPTION, BOILERS, STEAM GENERATORS, AND PROCESS HEATERS

104 EXEMPTION, BIOMASS SUSPENSION BOILERS

1054 EXEMPTION, MUNICIPAL SOLID WASTE

1065 EXEMPTION, WASTE HEAT RECOVERY BOILERS

200 DEFINITIONS

201 BIOMASS

202 BIOMASS BOILER OR STEAM GENERATOR

203 BLOCK 24-HOUR AVERAGE

2043 BRITISH THERMAL UNIT

2054 CIRCULATING FLUIDIZED BED BOILER

2065 CURING STARTUP

2076 HEAT INPUT

2087 HIGHER HEATING VALUE (HHV)

2098 MUNICIPAL SOLID WASTE

21009 NOX EMISSIONS 

2110 PARTS PER MILLION BY VOLUME (PPMV)

2121 RATED HEAT INPUT CAPACITY

2132 RESPONSIBLE OFFICIAL

2143 SHUTDOWN

2154 STARTUP

2165 STOKER BOILER

2176 UNIT

2187 WOOD

300 STANDARDS

301 LIMITATIONS

302 STARTUP AND SHUTDOWN PROVISIONS

400 ADMINISTRATIVE REQUIREMENTS

401 OPERATION AND MAINTENANCE PLAN

402 COMPLIANCE COSTS

403 CERTIFICATION

500 MONITORING AND RECORDS

501 RECORDKEEPING

502 CONTINUOUS EMISSIONS MONITORING

503 INITIAL COMPLIANCE TEST

504 TEST METHODS

505 CORRECTION OF EMISSION CONCENTRATIONS

5056 DURATION OF RECORDS
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Placer County APCD 233 - 3 Rules and Regulations

100 GENERAL

101 APPLICABILITY: This rule applies to stoker and circulating fluidized bed boilers and steam 

generators which have a heat input rating of less than 500 million Btu per hour and a 

potential to emit, as defined in Rule 502, NEW SOURCE REVIEW, 25 tons or more of NOx

emissions and which have a primary energy source of biomass consisting of a minimum of 75 

percent of the total annual heat input.

102 FEDERAL REGULATIONS: Compliance with this rule shall not exempt a person from 

complying with any federal regulation promulgated pursuant to the Clean Air Act (42 U.S.C. 

Section 7401 et seq.).

103 EXEMPTION, BOILERS, STEAM GENERATORS, AND PROCESS HEATERS: This rule 

shall not apply to boilers, steam generators, and process heaters subject to Rule 231, 

INDUSTRIAL, INSTITUTIONAL, AND COMMERCIAL BOILERS, STEAM GENERATORS, 

AND PROCESS HEATERS.

104 EXEMPTION, BIOMASS SUSPENSION BOILERS: This rule shall not apply to existing 

boilers and steam generators subject to Rule 232, BIOMASS SUSPENSION BOILERS.

1045 EXEMPTION, MUNICIPAL SOLID WASTE: This rule shall not apply to combustion units 

whose primary purpose is to burn municipal solid waste, as defined in Section 2098.

1056 EXEMPTION, WASTE HEAT RECOVERY BOILERS: The provisions of this rule do not 

apply to waste heat recovery boilers used to recover sensible heat from the exhaust of 

combustion turbines or unfired waste heat recovery boilers used to recover sensible heat 

from the exhaust of any combustion equipment.

200 DEFINITIONS

201 BIOMASS: Any organic material not derived from fossil fuels, such as agricultural crop 

residues, bark, lawn, yard and garden clippings, leaves, silvicultural residue, tree and brush 

pruning, wood and wood chips, and wood waste, including these materials when separated 

from other waste streams. Biomass does not include material containing sewage sludge, 

industrial sludge, medical waste, hazardous waste, or radioactive waste.

202 BIOMASS BOILER OR STEAM GENERATOR: Any combustion equipment used in any 

industrial, institutional, or commercial operation designed to burn biomass to produce steam, 

heat water or other fluids, and/or produce electricity.

203 BLOCK 24-HOUR AVERAGE: Tthe arithmetic average of the hourly air pollution emission 

rates of discharge as measured over 24 contiguous one-hour periods from 00:00:00 to 

23:59:59, 24-hour clock time.

2043 BRITISH THERMAL UNIT (BTU): The amount of heat required to raise the temperature of 

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

2054 CIRCULATING FLUIDIZED BED BOILER: A boiler that burns solid fuel in a moving 

suspension of inert materials, forced through upward blowing of air jets, and where the ash 

and inerts are captured and recirculated back into the moving fluidized bed.

2065 CURING STARTUP: A startup which includes heating the boiler at predetermined rate and 

holding temperature at several points to allow for insulating materials to cure in the boiler 

refractory. A curing startup shall not exceed 96 hours.

2076 HEAT INPUT: The chemical heat released due to fuel combustion in a boiler, using the 

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

combustion air.
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2087 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. HHV shall 

be determined by one of the following test methods:

2078.1 ASTM E711 for biomass; or

2078.2 ASTM D 240-87 or ASTM D 2382-82 for liquid hydrocarbon fuels; or

2078.3 ASTM D 1826-88 or ASTM D 1945-81 in conjunction with ASTM D 3588-89 for 

gaseous fuels.

2098 MUNICIPAL SOLID WASTE: Household, commercial/retail, and/or institutional waste. 

Household waste includes material discarded by single or multiple residential dwellings, 

hotels, motels, and other similar permanent or temporary housing establishments or facilities. 

Commercial/retail waste includes material discarded by stores, offices, restaurants, 

warehouses, non-manufacturing activities at industrial facilities, and other similar 

establishments or facilities. Institutional waste includes material discarded by schools, 

hospitals, prisons, and government facilities and other similar establishments or facilities.

21009 NOX EMISSIONS: The sum of nitric oxides and nitrogen dioxide in the flue gas, 

collectively expressed as nitrogen dioxide (NO2).

2110 PARTS PER MILLION BY VOLUME (PPMV): The ratio of the number of gas molecules of a 

given species, or group, to the number of millions of total gas molecules.

2121 RATED HEAT INPUT CAPACITY: The heat input capacity, in million BTU per hour, 

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 input capacity specified on the 

nameplate, and this alteration or modification has been approved by the Air Pollution Control 

Officer and made a limiting condition of operation, then the new maximum heat input shall be 

considered as the rated heat input capacity.

2132 RESPONSIBLE OFFICIAL: An individual with the authority to certify that a source complies 

with all applicable requirements, including the conditions of permits issued to sources in 

accordance with Regulation 5, PERMITS. A "responsible official" means one of the following:

2132.1 For a corporation, a president, secretary, treasurer, or vice-president of the 

corporation in charge of a principal business function, or any other person who 

performs similar policy or decision-making functions for the corporation, or a duly 

authorized representative of such person if the representative is responsible for the 

overall operation of one or more manufacturing, production, or operating facilities 

applying for or subject to a permit and either:

2132.1.1 The facilities employ more than 250 persons or have gross annual sales 

or expenditures exceeding $25 million (in second quarter 1980 dollars); or

2132.1.2 The delegation of authority to such representative is approved in 

advance by the Air Pollution Control Officer;

2132.2 For a partnership or sole proprietorship, a general partner or the proprietor, 

respectively; or

2123.3 For a municipality, state, federal, or other public agency, either a principal executive 

officer or a ranking elected official; or

2132.4 For an acid rain unit subject to Title IV (Acid Deposition Control) of the Clean Air Act, 

the "responsible official" is the designated representative of that unit for any purposes 

under Title IV and Rule 507, FEDERAL OPERATING PERMITS PROGRAM.
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2143 SHUTDOWN: A shutdown starts when fuel feed is curtailed and the unit begins cooling from 

the unit’s normal operating temperature, as specified by the manufacturer, and ends when 

steam flow is zero or 24 hours has elapsed since the start of the shutdown, whichever occurs 

first.

2154 STARTUP: The period of time a unit is heated to the normal operating temperature, as 

specified by the manufacturer. A normal startup shall not exceed 24 hours. A curing startup 

shall not exceed 96 hours.

2165 STOKER BOILER: A boiler that burns solid fuel on a stationary or moving grate located at 

the bottom of the furnace, and where the fuel is supplied and ash removed continuously.

2176 UNIT: Any biomass boiler or steam generator as defined in Sections 202.

2187 WOOD: Wood, wood residue, bark, or any derivative fuel or residue thereof, in any form, 

including but not limited to sawdust, sanderdust, wood chips, scraps, slabs, millings, 

shavings, and processed pellets made from wood or other forest residues.

300 STANDARDS

301 LIMITATIONS:

301.1 No person shall allow the discharge of NOx and CO emissions into the 

atmosphere from a biomass boiler or steam generator in excess of the following standards, 

excluding startup and shutdown conditions:

Type of Boiler NOx

(Emission limits effective 

until December 31, 

2012)

NOx

(Emission limits effective 

January 1, 2013)

CO

Circulating 

Fluidized Bed

(<500 MMBtu/hour)

115 ppmv corrected to 

12% CO2

(3 hour rolling average)

115 ppmv corrected to 12% 

CO2

(3 hour rolling average)

400 ppmv corrected 

to 12% CO2

(3 hour rolling 

68 ppmv corrected to 12% average)

CO2

(24 hour block average)

Stoker

(<500 MMBtu/hour)

115 ppmv corrected to 

12% CO2

(3 hour rolling average)

115 ppmv corrected to 12% 

CO2

(3 hour rolling average)

1000 ppmv 

corrected to 12% 

CO2

(3 hour rolling 

average)

68 ppmv corrected to 12% 

CO2

(24 hour block average)

302 STARTUP AND SHUTDOWN PROVISIONS

302.1 The emission limits of Section 301.1 shall not apply during startup or shutdown 

provided the following requirements are met:

1.302.1 CO2 emissions are 10 percent or less by volume stack gas on a one-hour average

dry basis.

302.2 During startup and shutdown, the mass emissions of NOx and CO shall not exceed 

the levels shown below. The block averaging time starts at the beginning of either the 

startup or the shutdown.

2.
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Type of Boiler NOx CO

Circulating Fluidized Bed

(<500 MMBtu/hour)

35 pounds per hour

(24 hour block average)

56 pounds per hour

(24 hour block average)

35 pounds per hour

(72 hour block average 

during curing startup)

56 pounds per hour

(72 hour block average 

during curing startup )

Stoker

(<500 MMBtu/hour)

37.6 pounds per hour 

(3 hour rolling average)

170 pounds per hour 

(3 hour rolling average)

302.3 302.1.3. A normal startup shall not exceed 24 hours. A startup which involves 

curing of refractory shall not exceed 96 hours.

400 ADMINISTRATIVE REQUIREMENTS

401 OPERATION AND MAINTENANCE PLAN: Any person installing an emission control device 

as a means of complying with the emission limitations of Section 301 shall submit an 

Operation and Maintenance Plan with the application for Authority to Construct for the 

emission control device.

401.1 The Operation and Maintenance Plan shall specify:

401.1.1. Operation and maintenance procedures that will demonstrate continuous 

operation of the emission control device during emission-producing 

operations; and

401.1.2 Records that must be kept to document the operation and maintenance 

procedures.

401.1.3. Each source must provide to the District a description of the actions that 

will be taken to minimize emissions during startup and shutdown events.

401.2 The records must comply with Sections 501, 502, and 5045.

401.3 The Operation and Maintenance Plan shall be implemented upon approval by the Air 

Pollution Control Officer.

401.4 Subsequent to the construction of any emission control device used for 

demonstrating compliance with the emission limitation of Section 301, an Operation 

and Maintenance Plan shall be submitted or resubmitted in conjunction with any 

changes in the procedures addressed in the plan, or upon the request of the Air 

Pollution Control Officer.

402 COMPLIANCE COSTS: A person operating a unit subject to this rule shall bear all expenses 

associated with compliance with the monitoring and reporting provisions of this rule.

403 CERTIFICATION: All reports submitted in accordance with this rule shall be signed by a

responsible official who shall certify the truth, accuracy, and completeness of the report.

500 MONITORING AND RECORDS

501 RECORDKEEPING: A person operating a unit subject to this rule shall keep the following 

records for each unit:

501.1 Calendar date of record.

501.2 Number of hours the unit is operated during each day.
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501.3 Boiler load.

501.4 Fuel types, including supplementary gaseous or liquid fuels.

501.5 Duration of startups and shutdowns.

501.6 Type and duration of maintenance and repairs.

501.7 Results of compliance tests.

501.8 Three-hour average NOx emission concentration (expressed as NO2 and corrected 

to 12 percent by volume stack gas CO2).

501.9 Twenty-four hour average NOx emission concentration (expressed as NO2 and 

corrected to 12 percent by volume stack gas CO2).

501.109 Three-hour average CO emission concentration (corrected to 12 percent by 

volume stack gas CO2).

501.110 Startup and shutdown emissions records using averaging periods as required in 

Section 302.1.

501.121 Identification of time periods during which NOx and CO emission limitations are 

exceeded, the reason for the exceedance, and a description of corrective action 

taken.

501.132 Identification of time periods during which operating condition and pollutant 

emission data were not obtained, the reason for not obtaining this information, and a 

description of corrective action taken.

501.143 If zero steam flow is used to determine the end of a shutdown, then steam flow 

must be recorded.

502 CONTINUOUS EMISSIONS MONITORING

502.1 A person operating a unit subject to this rule shall install, calibrate, operate, and 

maintain a Continuous Emissions Monitoring System (CEMS) in accordance with 

applicable requirements of Appendices B and F of Title 40 Code of Federal 

Regulations Part 60 (40 CFR 60).

502.2 The CEMS shall include equipment that measures and records the following:

502.2.1. Continuous exhaust gas NOx and CO concentrations corrected to 12 

percent by volume stack gas CO2 dry basis.

502.2.2. Average NOx and CO concentrations calculated on a three-hour rolling 

average basis.

502.2.3 Average NOx concentrations calculated on a twenty-four hour block 

average basis.

502.3 A person operating a CEMS shall submit an excess emissions and monitoring 

systems performance report to the Air Pollution Control Officer within 30 days after 

the end of each calendar quarter in accordance with 40 CFR 60, Section 60.7(c) and 

(d) and Section 60.13.

502.4 The enhanced monitoring requirements of Sections 113 and 114 of the Federal 

Clean Air Act shall take precedence over the requirements of this Section for facilities 

subject to Rule 507, FEDERAL OPERATING PERMIT PROGRAM.
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503 INITIAL COMPLIANCE TEST

503.1 An initial compliance test shall be conducted within 60 days of achieving the 

maximum firing rate at which the unit will be operated, but not later than 180 days 

after initial startup.

503.1.1 Each emission test run shall be conducted while the unit is operated within 

10% of the maximum steady-state steam production rate. No emission test 

shall be conducted during startup, shutdown, or under breakdown 

conditions for the purpose of the initial compliance test.

503.1.2. The initial compliance test shall be conducted for NOx and CO using the 

test methods specified in Section 504.

503.2 At least sixty (60) days prior to the initial compliance test, a written test plan detailing 

the test methods and procedures to be used shall be submitted for approval by the 

Air Pollution Control Officer. The plan shall cite the test methods to be used for the 

determination of compliance with the emission limitations of this rule. The plan shall 

provide the proposed procedures for the characterization of the representative 

biomass materials to be burned during testing.

504 CORRECTION OF EMISSION CONCENTRATIONS: NOx and CO concentrations may be 

corrected to 8 percent by volume stack gas O2 instead of 12 percent by volume stack gas 

CO2 if approved by the Air Pollution Control Officer in a Permit to Operate.

5054 TEST METHODS: A person conducting source tests shall use the following test methods:

5054.1 Nitrogen Oxides (NOX): ARB Test Method 100, Title 17, CCR, Section 94114, 

Procedures for Continuous Emission Stack Sampling, or EPA Test Method 7E, 

40 CFR 60, Appendix A. A violation determined by any of these test methods shall 

constitute a violation of this rule.

5054.2 Carbon Monoxide (CO): ARB Test Method 10, Title 17, CCR, Section 94109, 

Determination of Carbon Monoxide Emissions from Stationary Sources, or ARB Test 

Method 100, or EPA Test Method 10, 40 CFR 60, Appendix A. A violation determined 

by any of these test methods shall constitute a violation of this rule.

5045.3 Carbon Dioxide (CO2): ARB Test Method 100, Title 17, CCR, Section 94114, 

Procedures for Continuous Emission Stack Sampling, or EPA Test Method 3A, 

40 CFR 60, Appendix A.

5065 DURATION OF RECORDS: All records maintained pursuant to this rule shall be retained for 

at least two years from date of entry, with the exception that sources subject to the 

requirements of Rule 507, FEDERAL OPERATING PERMIT PROGRAM, shall retain records 

at least five years. Records shall be made available for inspection by the Air Pollution Control 

Officer upon request.