UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX AIR DIVISION

Technical Support Document 

for

EPA’s Rulemaking

for the

California State Implementation Plan

Ventura County Air Pollution Control District Rule 74.15.1

Boilers, Steam Generators, and Process Heaters

Prepared by: Kevin Gong

April 1, 2016
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RULE IDENTIFICATION

Agency Ventura County Air Pollution Control District (VCAPCD)

SIP Approved 

Rule

Rule 74.15.1 – Boilers, Steam Generators, and Process Heaters

Revised – September 11, 2012

Submitted – April 22, 2013

EPA Approved - May 19, 2014 (79 FR 28612)

Subject of this 

TSD

Rule 74.15.1 – Boilers, Steam Generators, and Process Heaters

Revised – June 23, 2015

Submitted – November 13, 2015

Completeness 

Finding

Determination of Completeness Letter: January 19, 2016

BACKGROUND 

VCAPCD regulates the Ventura County nonattainment area, which is classified as a 

“Severe” nonattainment area (NAA) for the 1994 1-hour ozone National Ambient Air 

Quality Standard (NAAQS), and as “Serious” for the 1997 8-hour ozone and 2008 8-hour 

ozone NAAQS (see 40 CFR part 81). The Clean Air Act (CAA) requires that for areas 

classified as moderate or above nonattainment, the State must submit revisions to the 

State Implementation Plan (SIP) requiring the implementation of reasonably available 

control technology (RACT) (see sections 182(b)(2) and 182(f)). This rule was revised in 

part to ensure continued compliance with the CAA RACT requirement and to fulfil the 

commitment for additional emission reductions from this category found in VCAPCD’s 

2007 Air Quality Management Plan.

RULE SUMMARY 

Rule 74.15.1 establishes emission limits for oxides of nitrogen (NOx) and carbon 

monoxide (CO) for boilers, steam generators and process heaters with a rated heat input 

capacity between 1 million BTU and 5 million BTU. It also describes related 

recordkeeping, reporting, and monitoring requirements. Changes from the approved SIP 

rule include:

1. Clarifications to section A to define units as fired by certain gaseous or liquid 

fuels, and to include both stationary and portable process heaters.

2. Revisions at section B.2 to include new emission limits for new or replacement 

units installed after January 1, 2016 broken down by fuel type.

3. Revisions at section B.4 to reduce testing frequency for units with a rated heat 

input capacity of greater than 2 million BTU/hr, and subject to the new emission 
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limits at B.2 to no less than once every 48 months, provided they meet annual 

screening requirements.

4. A new exemption at C.2 for low use portable oil well dewaxing process heaters 

from emission limits in B.1.

5. Additional recordkeeping requirements at D.3 for the maintenance of records 

from annual screenings required under B.4.

6. Additional approved test method at E.1, South Coast Air Quality Management 

District (SCAQMD) “Compliance Protocol for the Measurement of Nitrogen 

Dioxide, Carbon Monoxide, and Oxygen from Sources Subject to SCAQMD Rules 

1146 and 1146.1” dated March 10, 2009, to ensure compliance with 

requirements in B.

7. Clarified definition for the term “process heater” to clearly exclude specified 

combustion sources from applicability to this rule.

8. Additional definitions for terms previously undefined in this rule.

9. Various corrections to update references changed due to re-numbering of rule 

provisions, and several grammatical changes for clarity.

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 - SIPs must require RACT for each category of sources covered by a 

Control Technique Guideline (CTG) document as well as each major source in 

ozone nonattainment areas (see sections 182(b)(2) and 182(f)). EPA’s CTGs titled 

“Control Techniques for Nitrogen Oxides Emissions from Stationary Sources –

Second Edition” (EPA-450/1-78-001, January 1978), and “Alternative Control 

Techniques Document – NOx Emissions from Process Heaters (Revised)” (EPA453/R-93-034, September 1993), CARB’s RACT/BARCT guidance titled, 

“Determination of Reasonably Available Control Technology and Best Available 

Retrofit Control Technology for 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 RACT requirements of CAA 

§182(b)(2) and §182(f). 
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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 SIP-approved 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 provisions of VCAPCD Rule 74.15.1 are generally clear and enforceable. 

VCAPCD reduced the testing frequency of full source tests for newer large units (2 

million BTU/hr and larger, constructed or replaced after January 1, 2016), to align 

with the same testing regime for smaller units. The District has justified this 

reduction in frequency with the requirement that all applicable units undergo 

annual emissions screenings with portable analyzers for each year that a full 

source test is not conducted. Operators are required to maintain records of these 

screenings, and to inform the District when they are conducted. We believe that 

this change is an overall improvement to the enforceability of the requirements in 

this rule as it requires more frequent testing overall. EPA has determined that 

testing conducted by trained operators with properly calibrated portable analyzers

is credible evidence (although somewhat less accurate) in determining compliance 

with emission limits. More frequent screenings are more robust overall as a 

warning mechanism for operators or the District against non-compliance with 

emission limits.

2. The submitted rule is as stringent as other California district’s rules for this 

category, including SCAQMD Rule 1146.1 for units fueled by natural gas, landfill 

gas and biogas, and San Joaquin Valley Unified Air Pollution Control District 

(SJVUAPCD) Rule 4307 for natural gas sources. It is also more stringent than 

CARB’s RACT/BARCT guidance. The District’s staff report estimated that the more 

stringent emission limits for new and replacement units for most fuel categories 

would reduce NOx emissions by 9.3 tons per year.

3. Revisions to section C.2 exempt portable oil well dewaxing process heaters with an 

annual heat input rate of less than 2.8 million BTUs from the emission limits for 

existing units in B.1. The District estimates that this exemption (which currently 

applies to a single existing source) would result in 0.29 tons per year of uncaptured 

NOx. This is a small increase in comparison to the estimated reductions, and would 

not interfere with overall progress towards attainment.

Additionally, section G.13 is amended to clarify the types of combustion sources 

that are excluded from the definition of “process heater,” including kilns, ovens, 
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open heated tanks, dehydrators, dryers (including tenter frame, fabric, and carpet 

dryers), crematories, incinerators, calciners, cookers, roasters, and furnaces 

(including metal heat treating or metal furnaces, and glass melting furnaces). The 

District states that this clarifies existing policy. We agree that sources such as kilns, 

dryers, cookers, calciners, and incinerators are generally exempt from similar 

process heater rules in other Districts.

1 These Districts regulate these sources in 

other SIP-approved rules specifically applicable to these sources.

2

The District has clarified via phone and email that they have never considered any 

of these exempted sources to be “process heaters” and have never regulated any 

such sources under Rule 74.15.1.3 The District also confirmed that units defined 

under subsections G.13 e and f do not currently exist in Ventura County. Thus, this 

clarification does not constitute backsliding under §110(l).

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 ongoing process for ensuring that requirements for RFP and attainment of 

the NAAQS are met, and (2) the emission limits in the submitted rule are more 

stringent than the existing SIP-approved control requirements that they would 

replace.

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. Consider standardizing the use of scientific notation or the term “million” in 

reference to BTU terms, for example in sections B.1 and B.2.

EPA ACTION

The submitted Rule 74.15.1 strengthens the SIP, and the associated District staff report 

projects it will reduce yearly NOx emissions. The rule largely fulfils the relevant CAA §110 

and part D requirements. Therefore, EPA staff recommends approval of Rule 74.15.1

pursuant to CAA §110(k)(3) and §301(a). 

REFERENCES

1. “Issues Relating to VOC Regulation Cutpoints, Deficiencies, and Deviations,” 

(a.k.a., Bluebook) EPA OAQPS, May 25, 1988.

2. “Guidance Document for Correcting Common VOC & Other Rule Deficiencies,” 

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

 

1 See, for example, SJVUAPCD Rule 4307, section 3.19 and SCAQMD Rule 1146.1, (b)(12).

2 See, for example, SJVUAPCD Rules 4309, 4313, and 4354, and SCAQMD Rules 1117 and 1147.

3 Emails between Stan Cowen, VCAPCD and Kevin Gong, EPA Region 9 on March 22, March 24, and 

March 29.
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3. “Control Techniques for Nitrogen Oxides Emissions from Stationary Sources –

Second Edition,” EPA-450/1-78-001, January 1978.

4. “Alternative Control Techniques Document – NOx Emissions from Process Heaters 

(Revised),” EPA-453/R-93-034, September 1993.

5. “Determination of Reasonably Available Control Technology and Best Available 

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

Steam Generators, and Process Heaters,” California Air Resources Board 

RACT/BARCT guidance, July 18, 1991.

6. SJVUAPCD Rule 4307, “Boilers, Steam Generators, and Process Heaters –

2.0MMBtu/hr to 5.0 MMBtu/hr,” as amended October 16, 2008.

7. SJVUAPCD Rule 4309, “Dryers, Dehydrators, and Ovens,” as adopted December 

15, 2005.

8. SJVUAPCD Rule 4313, “Lime Kilns,” as adopted March 27, 2003.

9. SJVUAPCD Rule 4354, “Glass Melting Furnaces,” as amended May 19, 2011.

10. SCAQMD Rule 1117, “Emissions of Oxides of Nitrogen from Glass Melting 

Furnaces,” as amended January 6, 1984.

11. SCAQMD Rule 1146.1 “Emissions from Small Industrial, Institutional, and 

Commercial Boilers, Steam Generators, and Process Heaters,” as amended 

November 1, 2013.

12. SCAQMD Rule 1147, “NOx Reductions from Miscellaneous Sources,” as adopted 

on December 5, 2008.