UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX AIR DIVISION

Technical Support Document 

for

EPA’s Direct Final Rulemaking

for the

California State Implementation Plan

San Joaquin Valley Unified Air Pollution Control District Rule 4308

Boilers, Steam Generators, and Process Heaters – 0.075 MMBtu/hr to less than 

2.0 MMBtu/hr

Prepared by: Nicole Law

November 2014
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Agency: San Joaquin Valley Unified Air Pollution Control 

District (SJVUAPCD)

SIP Approved Rule: Rule 4308 - Boilers, Steam Generators, and Process 

Heaters – 0.075 MMBtu/hr to less than 2.0 MMBtu/hr

Amended – December 17, 2009

Submitted – May 17, 2010

EPA Approved – December 30, 2010 (76 FR 5276)

Superseded Submittals: none

Subject of this TSD: Rule 4308 - Boilers, Steam Generators, and Process 

Heaters – 0.075 MMBtu/hr to less than 2.0 MMBtu/hr

Amended – November 14, 2013

Submitted – May 13, 2014

RULE SUMMARY -

Rule 4308 establishes emissions limits for criteria air pollutants, including NOx

and CO limits and certification requirements for boilers, steam generators, and 

process heaters. It also describes related compliance reporting, labelling, and test 

methods. Rule 4308 does not apply to existing units, as it is a point of sale rule. 

Changes from the approved SIP include:

1. Added carbon monoxide (CO) to section 1.0 Purpose to clarify that the rule 

also controls emissions from CO.

2. Removed the terms California Public Utility Commission (PUC) Quality 

Natural Gas and Heat Output and added the terms EPA, Hot Water 

Pressure Washer, PUC Quality Natural Gas, and SCAQMD to section 3.0 

Definitions.

3. Added hot water pressure washers to the section 4.0 Exemptions.

4. Revised the compliance dates in section 5.0 Requirements to make the 

Table 1 requirements effective until December 31, 2014 and the Table 2 

requirements effective starting January 1, 2015.

5. Removed the Tier 1, 2, and 3 categories of units. The rule limits are 

unchanged and now divided by size of unit and type of fuel in Table 1. 

6. Added a Table 2 which introduces a lower limit for instantaneous water 

heaters between the heating capacity of 0.075 and 0.4 MMBtu/hr.
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7. Revised section 6.1 to remove language that units certified by SCAQMD 

need to comply with the emission limits and compliance schedule in rule 

4308.

8. Revised section 6.2.3 to include that for natural gas fired units, a specific 

SCAQMD test method shall be used.

9. Removed section 7.0 Compliance Schedule from the rule.

EVALUATION CRITERIA - The following criteria were used to evaluate the 

submitted rule. 

1. Enforceability - The Bluebook (Issues Relating to VOC Regulation 

Cutpoints, Deficiencies, and Deviations, EPA, May 25, 1988) and the Little 

Bluebook (Guidance Document for Correcting Common VOC & Other Rule 

Deficiencies, EPA Region 9, August 21, 2001) were used to help evaluate 

compliance with the CAA §110(a)(2)(A) requirement for enforceability. 

2. Stringency - EPA’s Alternative Control Techniques Document (ACT) titled, 

“NOx Emissions from Industrial/Commercial/Institutional (ICI) Boilers” (EPA453/R-94-022-1994/03, March 1994), CARB’s RACT/BARCT guidance 

titled, “Industrial, Institutional, and Commercial Boilers, Steam Generators, 

and Process Heaters” (July 18, 1991), and other state and local rules for 

this category were used to help evaluate the stringency of the rule’s control 

requirements. 

3. SIP Relaxation - CAA §110(l) prohibits EPA from approving any SIP revision 

that would interfere with any applicable requirement concerning attainment 

and reasonable further progress (RFP) or any other applicable requirement 

of the CAA. In addition, CAA §193 prohibits the modification of any SIPapproved control requirement in effect before November 15, 1990, in a 

nonattainment area.

EPA EVALUATION - A summary of our evaluation of the three criteria follows.

1. The rule requirements and applicability are clear, and the certification, 

compliance reporting and other provisions sufficiently ensure that affected 

sources and regulators can evaluate and determine compliance with Rule 

4308 consistently. 

2. The SJVUAPCD regulates an extreme nonattainment area for the 8-hour 

1997 and 2008 Ozone National Ambient Air Quality Standards and a nonattainment area for the 24-hr 1997 and 2006 PM2.5 NAAQS. As a result, 

Rule 4307 must fulfill RACT and RACM requirements.
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The submitted rule regulates boilers, steam generators, process heaters, 

and water heaters that are smaller than the applicable units under CARB’s 

RACT/BARCT guidance for NOx. The controls in rule 4308 are comparable 

to those in EPA’s ACT and other California District rules for this category for 

CO and NOx, including South Coast Air Quality Management District Rule 

1146.2 and Sacramento Metropolitan Air Quality Management District Rule 

414. While Rule 4308 does not have specific controls for PM2.5, the rule 

was evaluated for control of PM2.5 precursors such as NOx. Accordingly, 

we find that the control requirements in this rule represent RACT-level 

control for this source category for NOx and fulfill RACM requirements for 

PM2.5 precursors. 

3. We propose to determine that our approval of the submittal would comply 

with CAA §§110(l) and 193 because (1) 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 (2) the submitted rule has 

introduced a lower limit for instantaneous water heaters with rated heat 

input capacity equal to 0.075 but less than or equal to 0.4 MMBtu/hr.

Therefore, overall, the rule is more stringent than the existing SIP approved 

rule.

The rule has added an exemption for hot water pressure washers. These 

units fall under the definition of instantaneous water heaters, but it was not 

the intent of the District to include hot water pressure washers as they are 

generally portable units fueled with diesel fuel. Because of their portable 

nature, it would be difficult to install controls on these units. Rule 4308 is a 

point of sale rule and these units currently are not subject to an emission 

limit. SCAQMD Rule 219 similarly exempts these units.

RULE DEFICIENCIES – We have identified no deficiencies with Rule 4308

sufficient for EPA to propose less than full approval.

ADDITIONAL RECOMMENDATIONS FOR THE NEXT RULE REVISION - The 

following revisions are not currently the basis for rule disapproval, but are 

recommended for the next time the rule is amended.

1. Section 4.2 provides an exemption for units installed in recreational 

vehicles. Consider removing this exemption. 

2. Rule 4308 is a point of sale rule and applies to any person who supplies, 

sells, offers for sale, installs, or solicits the installation of boilers, steam 

generators, process heaters or water heaters. Consider expanding the 

applicability to include existing units with rated heat input capacity greater 
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than 0.4 and less than or equal to 2 MMBtu/hr as is done in SCAQMD Rule 

1146.2.

3. Section 4.3 gives a full exemption for hot water pressure washers. 

Consider limiting this exemption to hot water pressure washers within a 

specific rated heat input capacity as is done in SCAQMD Rule 219 section 

(b)(4).

EPA ACTION -

The submitted Rule 4308 strengthens the SIP, and the associated District staff 

report projects it will reduce NOx emissions by 1.82 tons per year within the next 

20 years. The rule satisfies the applicable CAA §110 requirements. Therefore, 

EPA staff recommends a full approval of Rule 4308 pursuant to CAA §110(k)(3). 

REFERENCES -

1. SJVUAPCD Rule 4308, Boilers, Steam Generators, and Process Heaters –

0.075 MMBtu/hr to less than 2.0 MMBtu/hr, as amended November 14, 

2013 and submitted to EPA on May 13, 2014.

2. SJVUAPCD Rule 4308, Boilers, Steam Generators, and Process Heaters –

0.075 MMBtu/hr to less than 2.0 MMBtu/hr,, as approved into the SIP on 

December 30, 2010. 

3. “Alternative Control Techniques Document- NOx Emissions from 

Industrial/Commercial/Institutional (ICI) Boilers” EPA-453/R-94-022-

1994/03, March 1994. 

http://www.epa.gov/groundlevelozone/SIPToolkit/ctg_act/199403_nox_epa

453_r-94-022_ici_boilers.pdf

4. “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.

5. “Issues Relating to VOC Regulation Cutpoints, Deficiencies, and 

Deviations,” (a.k.a., Bluebook) EPA OAQPS, May 25, 1988 (web citation).

6. “Guidance Document for Correcting Common VOC & Other Rule 

Deficiencies,” (a.k.a., Little Bluebook), EPA Region 9, August 21, 2001 

(http://www.epa.gov/region09/air/sips/littlebluebook2001.pdf).