United States Environmental Protection Agency, Region 9 

Air Division 

Technical Support Document 

for 

EPA’s Notice of Rulemaking 

for the 

California State Implementation Plan 

Placer County Air Pollution Control District’s 

Rule 231, Industrial, Institutional and Commercial Boiler, Steam Generator and Process 

Heaters 

Prepared by: Idalia Perez 

September 2011 
1 

Placer County Air Pollution Control District (PCAPCD) 

Submitted Rule 

PCAPCD Rule 231, Industrial, Institutional and Commercial Boiler, Steam Generator 

and Process Heaters: 

§ Amended: October 9, 1997 

§ Submitted: March 17, 2009 

§ Determined complete: April 20, 2009 

Previous Rule Submittals 

Another version of Rule 231 was previously submitted to EPA on 10/19/94 as a revision 

to the State Implementation Plan (SIP) but was later withdrawn from submission by 

ARB. 

SIP-Approved Rule 

There is currently no SIP-approved version of Rule 231. 

Rule Summary 

This rule limits emission of nitrogen oxides (NOx) and carbon monoxide (CO) from 

boilers, steam generators and process heaters fueled on liquid or gas fuels that are 5 

MMBtu/hour or larger. 

Section 103 states the units that are exempt from the rule. 

Section 300 has the standards in the rule. For units with an annual heat input of 90,000 

therms or more, the NOx emission limits are: 

30 ppm or 0.036 lbs/MMBtu for units fired on gaseous fuels; 

40 ppm or 0.052 lbs/MMBtu for units fired on liquid fuels. 

Units with a annual heat input lower than 90,000 therms can meet the above limits or are 

required to keep a 3% oxygen concentration in the flue gas or be tuned once a year. 

Section 400 has the rule’s administrative requirements. 

Section 500 includes monitoring and recordkeeping requirements. 

Section 600 describes the tuning procedure for low-use units that are tuned once a year to 

meet the requirements of Section 300. 

Effects on Emissions 

Supporting information that was included in the SIP-submittal indicates that no emission 

reduction will result from this version of Rule 231 since it does not include changes in the 

emission limits. Email correspondence with the John Finnell on 12/17/09 (attached) 

indicates that the emission reductions obtained from the previous version of Rule 231 

was 0.09 tons NOx/day. 

Rule Evaluation 
2 

Generally, SIP rules must be enforceable (see section 110(a) of the Act), must require 

Reasonably Available Control Technology (RACT) for major sources in nonattainment 

areas (see sections 182(b)(2) and 182(f)), and must not relax existing requirements (see 

sections 110(l) and 193). In addition, Section 172(c)(1) of the Clean Air Act (CAA) 

requires nonattainment areas to implement all reasonably available control measures 

(RACM), including such reductions in emissions from existing sources in the area as may 

be obtained through the adoption, at a minimum, of reasonably available control 

technology (RACT), as expeditiously as practicable. 

The PCAPCD regulates ozone nonattainment areas (40 CFR 81), thus, submitted Rule 

231 must fulfill RACT and RACM requirements1. 

Guidance and policy documents that we used to define specific RACT, RACM and 

enforceability requirements include the following: 

• Issues Relating to VOC Regulation, Cutpoints, Deficiencies, and Deviations (the 

"Blue Book"), US EPA, OAQPS (May 25, 1988). 

• Guidance Document for Correcting Common VOC and Other Rule Deficiencies, 

EPA Region IX (August 21, 2001, the “Little Bluebook”). 

• State Implementation Plans; General Preamble for the Implementation of Title I 

of the Clean Air Act Amendments of 1990, 57 FR 13498 (April 16, 1992); 57 FR 

18070 (April 28, 1992). 

• State Implementation Plans; Nitrogen Oxides Supplement to the General 

Preamble for the Implementation of Title I of the Clean Air Act Amendments of 

1990 (the "NOX Supplement to the General Preamble"), US EPA, 57 FR 55620 

(November 25, 1992). 

• Clean Air Fine Particle Implementation Rule, 72 FR 20586 (April 25, 2007) 

• Determination of Reasonably Available Control Technology and Best Available 

Retrofit Control Technology for Industrial, Institutional, and Commercial Boilers, 

Steam Generators, and Process Heaters, CARB (July 18, 1991). 

http://www.arb.ca.gov/ractbarc/boilers.pdf

• Alternative Control Techniques Document-- NOx Emissions from 

Industrial/Commercial/Institutional (ICI) Boilers, US EPA 453/R-94-022 (March 

1994). http://www.epa.gov/ttn/catc/dir1/icboiler.pdf 

• Alternative Control Techniques Document-- NOx Emissions from Utility Boilers, 

US EPA 452/R-93-008 (March 1994). 

http://www.epa.gov/ttn/catc/dir1/utboiler.pdf

We believe Rule 231 implements RACT for reasons including: 

 

1

PCAPCD also regulates a nonattainment area under the 2006 24-Hour PM2.5 National Ambient Air 

Quality Standard (NAAQS). 40 C.F.R. § 81.305 (2010). By December 14, 2012, California must submit a 

revision to the State Implementation Plan (SIP) for this nonattainment area that provides for, among other 

things, implementation of all RACM as expeditiously as practicable (including RACT for existing sources). 

CAA § 172(a)(2)(A), (b) & (c)(1), 74 FR 58689 (Nov. 13, 2009). EPA will take action on this RACM 

demonstration in a separate rulemaking. 
3 

- Both 1994 ACT documents mentioned above provide technical information 

including control techniques and achievable controlled NOx emission levels 

from boilers. Rule 231 requirements are more stringent than the ACT. 

- The submitted rule is as stringent as CARB’s RACT/BARCT guidance. 

Since no CTG has been issued for this activity, we do not have clear national guidance 

defining presumptive RACT. However, we believe the analysis summarized above 

sufficiently demonstrates that Rule 231 implements RACT. 

CAA §172(c)(1) requires nonattainment areas to implement all reasonably available 

control measures, including such reductions in emissions from existing sources in the 

area as may be obtained through the adoption, at a minimum, of RACT, as expeditiously 

as practicable. Boilers can emit direct PM2.5, as well as SOx, which is a precursor to 

PM2.5, and NOx, which is a precursor to both PM2.5 and ozone. Therefore, PCAPCD 

must implement RACM for boilers if those measures will advance attainment of the 

National Ambient Air Quality Standard (NAAQS) for PM2.5 or ozone, when considered 

collectively with other reasonable measures. Additional control measures may be 

required pursuant to CAA §172(c)(1) if both: (1) additional measures are reasonably 

available; and (2) these additional reasonably available measures will advance attainment 

in the area when considered collectively. In separate rulemakings, EPA will take action 

on the State’s RACM demonstration for PM2.5 and ozone based on an evaluation of the 

control measures submitted as a whole and their overall potential to advance the 

applicable attainment dates in the District. See 40 CFR §§ 51.1010, 51.912(d). 

Recordkeeping and other compliance provisions in the rule ensure that the requirements 

are adequately enforceable. Lastly, since there is currently no rule in the SIP that 

regulates this source category for PCAPCD, the emission limitations in the submitted rule 

strengthen the SIP. We propose to determine that our approval of the submittal would 

comply with CAA sections 110(l) and 193, because the proposed SIP revision would not 

interfere with the on-going process for ensuring that requirements for RFP and attainment 

of the NAAQS are met, and the submittal strengthens the SIP as there is no rule for this 

category currently in the SIP and would insure equivalent or greater emission reductions 

of NOx. 

Additional Recommendation 

Although not currently basis for rule disapproval, EPA recommends that the PCAPCD 

make the following revisions to Rule 231: 

1. Section 103.1 refers to Rule 232 that has not been submitted to be included in the 

SIP. The rule should be submitted or this reference should be eliminated. 

2. Section 103.6 incorrectly refers to Section 206 as the definition of municipal solid 

waste. This section should refer to 207. 

3. The district should consider lowering the emission limits in Section 301 to be 

consistent with South Coast Rule 1146 (adopted September 5, 2008) and 

analogous rules in other areas. 
4 

4. Section 302.1 does not specify how a 3% or less stack oxygen content would be 

verified. This provision should be eliminated and Section 302.2 should be used 

instead. 

5. Section 502.2 should clarify the definition of “as-found operating conditions”. It 

could specify that operating conditions that are prevalent more than 90% of the 

time or it could state that “as-found operating conditions” must be defined in the 

permit. For units with varying loads, the tests should span the loads the unit varies 

throughout operations. 

6. Section 601.1 and Section 602.9 should clarify normal operations and significant 

load variations. Definitions can be based on percentage of time spent at a given 

firing rate. 

Recommended Action 

EPA staff recommends approval for incorporation into the California Applicable SIP. 

Other References 

1. Submitted Rule 231 (Clean Copy) 

2. SIP submittal package 

3. Email from John Finnell to Idalia Perez indicating emission reductions, dated 

December 17, 2009. 
1 Attachment

Hi Idalia,

Regarding RULE 231 INDUSTRIAL, INSTITUTIONAL, AND COMMERCIAL BOILERS, STEAM GENERATORS, AND PROCESS

HEATERS, the emission reductions obtained at the time the Rule 231 was adopted are estimated to be 0.09 tons per day.

Attached is a spreadsheet showing the results. These reductions required modifications of boilers. Low NOx burners and

flue gas recirculation were used.

John Finnell

Sr. Air Pollution Control Engineer

Placer County APCD

3091 County Center Drive, Suite 240

Auburn, CA 95603

(530) 745-2324

CONFIDENTIALITY NOTICE: This communication with its contents may contain confidential and/or legally privileged

information. It is solely for the use of the intended recipient(s). Unauthorized interception, review, use or disclosure is

prohibited and may violate applicable laws including the Electronic Communications Privacy Act. If you are not the intended

recipient, please contact the sender and destroy all copies of the communication.

Placer Rule 231

John Finnell

to:

Idalia Perez

12/17/2009 07:42 AM

Hide Details

From: John Finnell <JFinnell@placer.ca.gov>

To: Idalia Perez/R9/USEPA/US@EPA

History: This message has been replied to.

Reduction in Emissions from Boilers from Rule 231.xlsx
Boiler

Reductions MMBtu/hr

Reductions

lbs/hr lbs/year tons/day

NEC AC-95-16 M-Line Boilers 20.9 MMBtu/hr 1.45 12702 0.0174

AC-95-16 M-Line Boilers 20.9 MMBtu/hr 1.45 12702 0.0174

AC-97-34 K-Line Boilers 8.4 MMBtu/hr 0.42 3679.2 0.0050

AC-97-34 K-Line Boilers 8.4 MMBtu/hr 0.42 3679.2 0.0050

AC-97-34 K-Line Boilers 8.4 MMBtu/hr 0.42 3679.2 0.0050

Kaiser AC-98-36 8 MMBtu/hr 0.4 3504 0.0048

8 MMBtu/hr 0.4 3504 0.0048

8 MMBtu/hr 0.4 3504 0.0048

HB Fuller AC-96-74 6.277 MMBtu/hr 0.65 5694 0.0078

Sutter Roseville AC-96-10 7.499 MMBtu/hr 0.4 3504 0.0048

7.499 MMBtu/hr 0.4 3504 0.0048

7.499 MMBtu/hr 0.4 3504 0.0048

7.499 MMBtu/hr 0.4 3504 0.0048

Total tons/yr Tons/day Total

33.3 0.0913