PLACER COUNTY AIR POLLUTION CONTROL DISTRICT 

 

 

 

 

 

 

RULE 233 BIOMASS BOILERS

Adopted 10-06-94 

 

 

100 GENERAL 

 

101 APPLICABILITY: This rule applies to boilers and steam generators which have a potential to 

emit, as defined in Rule 502, NEW SOURCE REVIEW, 25 tons or more of NOxemissions 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. 

 

105 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 206. 

 

106 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 BRITISH THERMAL UNIT (BTU) - The amount of heat required to raise the temperature of one 

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

204 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. 

 

205 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: 

205.1 ASTM D 2015-85 for solid fuels; or 

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

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

fuels. 

 

206 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, nonmanufacturing 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. 

 

207 NOXEMISSIONS - The sum of nitric oxides and nitrogen dioxide in the flue gas, collectively 

expressed as nitrogen dioxide (NO2). 

 

208 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. 

 

209 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. 

 

210 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: 

210.1 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: 

a. The facilities employ more than 250 persons or have gross annual sales or expenditures 
exceeding $25 million (in second quarter 1980 dollars); or 

b. The delegation of authority to such representative is approved in advance by the Air 

Pollution Control Officer; 

210.2 For a partnership or sole proprietorship, a general partner or the proprietor, respectively; or 

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

or a ranking elected official; or 

210.4 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. 

 

211 SHUTDOWN - The period of time a unit is cooled from its normal operating temperature to cold or 

ambient temperature. 

212 STARTUP - The period of time a unit is heated from cold or ambient temperature to its normal 

operating temperature as specified by the manufacturer. 

213 UNIT - Any biomass boiler or steam generator as defined in Sections 202. 

214 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 NOxemissions into the atmosphere from a biomass 

boiler or steam generator in excess of the following standards, whichever is less stringent: 

a. An exhaust concentration of 115 parts per million (ppmv) corrected to 12 percent by 

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

b. 50 percent of the uncontrolled NOxemission concentration in the exhaust gas stream. A 

corresponding controlled concentration limit, expressed in ppmv corrected to 12 percent by 

volume stack gas CO2 on a three-hour average dry basis, shall be established in a Permit to 

Operate for the purpose of demonstrating continuous compliance with the 50 percent 

emission reduction. 

301.2 A person operating a biomass boiler or steam generator subject to this rule shall establish a 

carbon monoxide (CO) emission limitation that represents good operating and combustion 

practices. No person shall allow the discharge of CO into the atmosphere in excess of 120 percent 

of the CO exhaust concentration established by an initial compliance test conducted in accordance 

with Section 503. The CO concentration in ppmv shall be corrected to 12 percent by volume stack 

gas CO2 on a 3-hour average dry basis. 

 

400 ADMINISTRATIVE REQUIREMENTS 

 
401 COMPLIANCE SCHEDULE

401.1 Any person operating a unit subject to this rule shall demonstrate full compliance with the 

emission limitations of Section 300 by May 31, 1995. Subject to the approval of the Air Pollution 

Control Officer, testing conducted in the 18 months preceding May 31, 1995, may be used to 

demonstrate compliance provided such testing meets the requirements of Sections 503.1 or 

Section 503.2, using the test methods specified in Section 504. 

401.2 Any person operating a unit subject to this rule shall demonstrate compliance with the 

continuous emissions monitoring requirements of Section 502 in accordance with the following 

schedule: 

a. By April 6, 1995, submit plans and specifications for the Continuous Emissions Monitoring 

System, including milestones for installation and certification of the proposed system. 

b. By October 6, 1996, achieve full compliance with all requirements of Section 502. Full 

compliance shall be achieved no later than 60 days after installation of the Continuous 

Emissions Monitoring System. 

402 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. 

402.1 The Operation and Maintenance Plan shall specify: 

a. Operation and maintenance procedures that will demonstrate continuous operation of the 

emission control device during emission-producing operations; and 

b. Records that must be kept to document the operation and maintenance procedures. 

402.2 The records must comply with Sections 501, 502, and 505. 

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

Pollution Control Officer. 

402.4 Subsequent to the construction of any emission control device used for demonstrating 

compliance with the emission limitation of Section 301, a 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. 

 

403 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. 

 

404 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. 

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 NOxemission concentration (expressed as NO2and corrected to 12 

percent by volume stack gas CO2). 

501.9 Three-hour average CO emission concentration (corrected to 12 percent by volume stack 

gas CO2). 

501.10 Identification of time periods during which NOxand CO emission limitations are 

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

501.11 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. 

 

502 CONTINUOUS EMISSIONS MONITORING

502.1 By the compliance date in Section 401.2, 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: 

a. Continuous exhaust gas NOxand CO concentrations corrected to 12 percent by volume 

stack gas CO2 dry basis. 

b. Average NOxand CO concentrations calculated on a three-hour 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. 

 

503 INITIAL COMPLIANCE TEST

503.1 A person who elects to comply with the limitation specified in Section 301.1.a shall conduct 

an initial compliance test no later than the applicable final compliance date in Section 401.1. The 

source test shall also be used to establish the CO limitation in accordance with Section 301.2. 

a. Each emission test run shall be conducted while the unit is operated within 10% of the rated 

heat input capacity. No emission test shall be conducted during startup, shutdown, or under 

breakdown conditions for the purpose of the initial compliance test. 

b. The initial compliance test shall be conducted for NOxand CO using the test methods 

specified in Section 504. 

503.2 A person who chooses to comply with the limitation specified in Section 301.1.b shall 

conduct an initial compliance test no later than the applicable final compliance date in Section 

401.1. The source test shall also be used to establish the CO limitation in accordance with Section 

301.2. 

a. Each emission test run shall be conducted while the unit is operated within 10% of the rated 

heat input capacity. No emission test shall be conducted during startup, shutdown, or under 

breakdown conditions for the purpose of the initial compliance test. 
b. The initial compliance test shall be conducted for NOx

and CO using the test methods 

specified in Section 504. 

c. The 50 percent NOxemission reduction specified in Section 301.1.b shall be calculated 

based on the pre- and post-controlled NOxconcentration corrected to 12 percent by volume 

stack gas CO2. The pre-controlled concentration to be used in demonstrating the 50 percent 

reduction shall be obtained using the test methods specified in Section 504. The precontrolled concentration shall be submitted to the Air Pollution Control Officer in the 

application for Authority to Construct specified in Section 401.2 or in a previously 

submitted application for Authority to Construct for an existing unit. 

503.3 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 TEST METHODS - A person conducting source tests in accordance with Section 503 shall use the 

following test methods: 

504.1 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. 

504.2 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. 

504.3 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. 

 

505 CORRECTION OF EMISSION CONCENTRATIONS: NOxand CO concentrations may be 

corrected to 8 percent by volume stack gas O2instead of 12 percent by volume stack gas CO2if 

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

506 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.