STATE OF CALIFORNIA

ENVIRONMENTAL PROTECTION AGENCY

AIR RESOURCES BOARD

P. O. Box 2815

Sacramento, California 95812

April 13, 2006

Transmittal

of

ARB Staff Rule Review Comments

To: Mr. David Yang

Air Quality Engineer

Feather River Air Quality Management District

Telephone Number: (530) 634-7659 ext. 208

e-mail: dyang@fraqmd.org

From: Alex Krichevsky, (916) 324-6222

e-mail: akrichev@arb.ca.gov

The following draft rule, which is scheduled for a public workshop to be held by your 

District staff on April 20, 2006, was received by us on March 2, 2006, for our review:

Rule 3.21 Industrial, Institutional, and Commercial Boilers, Steam 

Generators, and Process Heaters

We have reviewed the rule and have the comments on the following pages. We believe

that our comments are important to the effectiveness and enforceability of Rule 3.21.

On March 16, 2006, Ms. Jill Locke and Mr. Eric Patton, both of our Program Review 

Section, Program Evaluation Branch, Stationary Source Division, discussed our

comments with you. 

If you have any questions about our comments, please contact Mr. Hardip Judge, 

Manager of the Program Review Section, at (916) 324-9512.

Rule review comments are on the following pages
2

Date: April 13 , 2006

Air Resources Board Staff Comments on

Feather River Air Quality Management District

Draft Rule 3.21

Rule 3.21 Industrial, Institutional, and Commercial Boilers, Steam Generators, and 

Process Heaters

1. Section B1: This section exempts units for which the permit restricts operation to 

an annual capacity factor of 15 percent or less. We are concerned that there could 

be business inequities and unnecessarily high emissions in that a relatively large 

source that operates at or below 15 percent capacity may be exempt while a small 

source that operates above 15 percent capacity must comply even though 

emissions from the latter may be much less. Operation under the capacity factor 

exemption could be continuous, or seasonal, such that a boiler operates at high 

capacity, but not for a long enough period to exceed the 15 percent limit over a 

one-year period. Thus, a large seasonally operated boiler can be exempted, even 

though it emits large amounts of NOx, perhaps at times when the District's air 

quality is poor.

We also believe that this exemption does not accurately reflect a reasonable costeffectiveness threshold for all units to which it could apply. The cost of retrofitting 

an existing unit to meet the emissions limits of Section D is not proportional to size, 

but is a weak function of size. A much better indicator of cost-effectiveness 

threshold is the annual fuel usage of a unit. In the ARB/CAPCOA-approved 

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, July 18, 

1991, (Determination), the fuel usage threshold for exemption from emission limits 

is 90,000 therms.

2. Section C: Consistent with Comment 1 above, we suggest adding the 

following definition: Therm: One hundred thousand (100,000) BTU.

3. Section B.1a and E: Consistent with Comment 1 above, we suggest that a fuel 

totalizing fuel meter be required for each applicable unit and each applicable fuel to 

validate the exemption. The fuel meter should be certified by the manufacturer in 

writing (Section E.1.a) and the fuel consumption for each unit should be compiled 

monthly into a rolling twelve calendar month report.
3

4. Section D.1C: This section does not require that the annual tune-up results be 

satisfactory. We recommend modifying the second sentence as follows:

The owner/operator of any unit(s) is required to submit an annual 

report verifying that the tune-up has been performed with

satisfactory results. 

5. Sections D1, D2, D3, D4: These sections are somewhat awkward and repetitive. 

We recommend that the District consider improving the clarity of sections D.1 

through D.4 by possibly having a section that applies to units between 1 and 5 

MMBtu/hr and those over 5 MMBtu/hr. 

6. Section D3: This section specifies a three-hour averaging time for emissions 

source testing, which is not consistent with the Determination. To maximize 

reductions of NOx emissions and provide consistency with the Determination, we 

recommend that the District replace the three-hour averaging time with the 

following: 

All emission concentrations and emission rates shall be based on 

15-consecutive- minute averages. The averages shall be 

calculated from no less than five data sets, recorded from 

samplings on intervals of no greater than three minutes.

7. Section F 2: This section requires units to be source tested for compliance once 

every three calendar years unless otherwise specified by the APCO. The 

Determination requires that units with rated heat inputs of greater than or equal to 

5 million Btu/per hour and annual heat input of greater than or equal to 9 billion Btu 

be source tested for compliance not less than once every 12 months. We suggest 

that a source test be require for every 8,760 hours of actual operation or two years 

whichever occurs more frequently.

In March 1995, the Tehama County Air Pollution Control District (TCAPCD) 

adopted a boiler rule TCAPCD Rule 4.31 with APCO discretion as to the frequency 

of compliance testing. After TCAPCD Rule 4.31 was submitted to the SIP, the 

U.S. Environmental Protection Agency partially disapproved the rule (65FR56486) 

because of the APCO compliance testing discretion. After the TCAPCD revised 

Rule 4.31, the U.S. Environmental Protection Agency approved the rule 

(67FR34405) because the rule no longer included the unapprovable APCO 

discretion. To make the rule approvable we suggest removing the phrase “or other 

test methods approved by the APCO.”

8. Section F3: This section denotes that no compliance determination shall be 

established within two (2) hours after a continuous period in which fuel flow to the 

unit is zero, or shut off, for fifteen (15) minutes or longer. The 15 minute time 

period does not agree with the Determination. We recommend that the 15 minute 
4

time period in section F.3 be replaced with 30 minutes to agree with the 

Determination.

9. Section D: This section contains the emission limits for NOx. We recommend that 

the District evaluate whether adoption of every feasible measure has been met by 

the rule by considering other regulations that have been implemented in other 

Districts.
1

Comments and Responses

Rule 3.21 Industrial, Institutional, Commercial Boilers, Steam Generators and 

Process Heaters

Written Comments

Air Resources Board Staff Comments:

Comment #1

Section B1: This section exempts units for which the permit restricts operation to an 

annual capacity factor of 15 percent or less. We are concerned that there could be 

business inequities and unnecessarily high emissions in that a relatively large source that 

operates at or below 15 percent capacity may be exempt while a small source that 

operates above 15 percent capacity must comply even though emissions from the latter 

may be much less. Operation under the capacity factor exemption could be continuous, 

or seasonal, such that a boiler operates at high capacity, but not for a long enough period 

to exceed the 15 percent limit over a one-year period. Thus, a large seasonally operated 

boiler can be exempted, even though it emits large amounts of NOx, perhaps at times 

when the District's air quality is poor.

We also believe that this exemption does not accurately reflect a reasonable costeffectiveness threshold for all units to which it could apply. The cost of retrofitting an 

existing unit to meet the emissions limits of Section D is not proportional to size, but is a 

weak function of size. A much better indicator of cost-effectiveness threshold is the 

annual fuel usage of a unit. In the ARB/CAPCOA-approved 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, July 18, 1991, (Determination), the fuel 

usage threshold for exemption from emission limits is 90,000 therms.

Response #1

Staff reviewed the exemption and concurred with ARB that the annual capacity factor 

does not reflect a reasonable cost-effectiveness threshold for all units. Staff concurred

that a better indicator is the fuel usage threshold of 90,000 therms as determined in the 

Determination. Staff revised the rule to indicate the exemption based on an annual fuel 

usage of a unit rather than the unit’s annual capacity factor. 

Furthermore, for consistency with the Determination, Staff revised the rule to only 

exempt units rated equal to or greater than 1 MMBtu/hr, but less than 5 MMBtu/hr with

an annual heat input less than 90,000 therms. Units greater than or equal to 5 MMBtu/hr 

with an annual heat input less than 90,000 therms will be subject to the requirements 

listed in the proposed rule, section D.1.a to D.1.d. 
2

Comment #2

Section C: Consistent with Comment 1 above, we suggest adding the following 

definition: Therm: One hundred thousand (100,000) BTU.

Response #2

Staff added the term “Therm” and defined it as “one hundred thousand (100,000) Btu” in 

Section C. 

Comment #3

Section B.1a and E: Consistent with Comment 1 above, we suggest that a fuel totalizing 

fuel meter be required for each applicable unit and each applicable fuel to validate the 

exemption. The fuel meter should be certified by the manufacturer in writing (Section 

E.1.a) and the fuel consumption for each unit should be compiled monthly into a rolling 

twelve calendar month report.

Response #3

Staff revised Section B.1.a to be consistent with the annual heat input exemption units. 

But Staff believed that either a totalizing fuel meter or a non-resettable hour meter will be 

sufficient to track the unit’s applicability to the exemption. 

However, hour meters may not be an accurate representation of the actual fuel used in a 

unit if the unit does not operate at 100% load. The annual hours will represent the unit’s

maximum annual heat input based on the rated heat input of the unit and the higher

heating value of the fuel. 

Staff concurred with CARB and added the phrase “in writing” in section E.1.a.

Comment #4

Section D.1C: This section does not require that the annual tune-up results be

satisfactory. We recommend modifying the second sentence as follows:

The owner/operator of any unit(s) is required to submit an annual report verifying 

that the tune-up has been performed with satisfactory results. 

Response #4

Staff revised the Section D.1.c to include “tune-up has performed with satisfactory results

in accordance to the tune-up procedures describe in Attachment 1.”

Comment #5

Sections D1, D2, D3, D4: These sections are somewhat awkward and repetitive. We 

recommend that the District consider improving the clarity of sections D.1 through D.4 

by possibly having a section that applies to units between 1 and 5 MMBtu/hr and those 

over 5 MMBtu/hr. 
3

Response #5

Staff reworded the language and renumbered each subsection in Sections D to be clear 

and concise. 

Comment #6

Section D3: This section specifies a three-hour averaging time for emissions source 

testing, which is not consistent with the Determination. To maximize reductions of NOx 

emissions and provide consistency with the Determination, we recommend that the 

District replace the three-hour averaging time with the following: 

All emission concentrations and emission rates shall be based on 15-consecutiveminute averages. The averages shall be calculated from no less than five data sets, 

recorded from samplings on intervals of no greater than three minutes.

Response #6

Staff removed the “three-hour averaging time” phrase from Section D. Staff 

added a new section in Section F., Compliance Determination, subsection F.5., 

Emission Averaging. Section F.5 is consistent with the Determination. 

Comment #7

Section F 2: This section requires units to be source tested for compliance once every 

three calendar years unless otherwise specified by the APCO. The Determination 

requires that units with rated heat inputs of greater than or equal to 5 million Btu/per hour 

and annual heat input of greater than or equal to 9 billion Btu be source tested for 

compliance not less than once every 12 months. We suggest that a source test be 

required for every 8,760 hours of actual operation or two years whichever occurs more 

frequently.

In March 1995, the Tehama County Air Pollution Control District (TCAPCD) adopted a 

boiler rule TCAPCD Rule 4.31 with APCO discretion as to the frequency of compliance 

testing. After TCAPCD Rule 4.31 was submitted to the SIP, the U.S. Environmental 

Protection Agency partially disapproved the rule (65FR56486) because of the APCO 

compliance testing discretion. After the TCAPCD revised Rule 4.31, the U.S. 

Environmental Protection Agency approved the rule (67FR34405) because the rule no 

longer included the unapprovable APCO discretion. To make the rule approvable we 

suggest removing the phrase “or other test methods approved by the APCO.”

Response #7

Staff concurred with ARB’s suggestion to require a source test for every 8,760 

hours of actual operation or two years, whichever occurs more frequently. Staff 

also removed the phrase “or other test methods approved by the APCO” to not 

allow APCO discretion. 

Comment #8

Section F3: This section denotes that no compliance determination shall be established 

within two (2) hours after a continuous period in which fuel flow to the unit is zero, or 
4

shut off, for fifteen (15) minutes or longer. The 15 minute time period does not agree 

with the Determination. We recommend that the 15 minute time period in section F.3 be 

replaced with 30 minutes to agree with the Determination.

Response #8

Staff revised the section to be consistent with the Determination. 

Comment #9

Section D: This section contains the emission limits for NOx. We recommend that the 

District evaluate whether adoption of every feasible measure has been met by the rule by 

considering other regulations that have been implemented in other Districts.

Response #9

Staff evaluated the standards in the rule against similar requirements adopted by other 

districts with similar attainment status. The proposed 2-tiered standards, depending on 

the area designation, will be consistent among most of the Northern Sacramento Valley 

Air Basin District. The proposed rule is based on CARB’s Determination for 

Reasonable Available Control Technology (RACT) and Best Available Retrofit Control 

Technology (BARCT) for Industrial, Institutional and Commercial Boilers, Steam 

Generators, and Process Heaters. Staff determined the standards are feasible and have 

been achieved in practice. 

EPA Comments-Approvability Issues

Comment #10

Section D.3 - This section requires that compliance with the emission limits in Table 1 be 

based on a three-hour averaging period. The California Air Resources Board's (CARB) 

Determination of Reasonably Available Control Technology (RACT) and Best Available 

Retrofit Control Technology (BARCT) for Industrial, Institutional, and Commercial 

Boilers, Steam Generators, and Process Heaters ("Determination") specifies a 15-minute 

averaging period. To meet RACT requirements, this section should be revised to specify 

a 15-minute averaging period.

Response #10

Staff revised the section to be consistent with the Determination.

Comment #11

Section F.1 - The provision on how to demonstrate initial compliance is imprecise, and 

therefore difficult to enforce. The term "verified manufacturer’s specification" should be 

defined within the rule or removed from this section. (Also see the following two 

comments.)

Response #11

Staff removed the term “verified manufacturer’s specification” from the rule.
5

Comments #12

Section F.1 - The phrase "or other methods/documents approved by the APCO" in this 

section allows APCO discretion. This phrase should be removed. If the District intends 

to allow initial compliance methods or documents other than source tests, the specific 

allowable methods or documents should be described.

Response #12

Staff removed the phrase “or other methods/documents approved by the APCO” to not 

allow APCO discretion. 

Comment #13

Section F.1 - The phrase "or other test methods approved by the APCO" allows APCO 

discretion. This phrase should be modified to read, "or other test methods approved 

before the test, in writing, by the APCO, the California Air Resources Board, and the 

U.S. Environmental Protection Agency."

Response #13

Staff removed the phrase “or other test methods approved by the APCO” to not allow 

APCO discretion. 

Comment #14

Section F.2 - This section requires that compliance be demonstrated every three years 

unless otherwise specified by the APCO. The Determination requires that units be tested 

for compliance at least once every 12 months. To meet RACT requirements, this section 

should be revised to require compliance testing at least once every 12 months.

Response #14

See Comment #7 and Response #7. The maximum operation in 12 months is 8,760 

hours. The Determination requires compliance testing at least once every 12 months. 

The Rule requires compliance testing once every 8,760 actual hours if operated within 2 

years. If the facility will not operate more than 8,760 hours in two year, the facility is

required to test every 2 year to show compliance. Staff believed this alternative to annual 

compliance testing meets the Determination based on hours of operation instead of 12-

month operating year. 

Comment # 15

Section F.2 - The phrase "unless otherwise specified by the APCO" allows APCO 

discretion. This phrase should be removed.

Response #15

Staff removed the phrase “unless otherwise specified by the APCO” to not allow APCO 

discretion. 
6

Comment #16

Section F.2 - The phrase "or other test methods approved by the APCO" allows APCO 

discretion. This phrase should be modified to read, "or other test methods approved 

before the test, in writing, by the APCO, the California Air Resources Board, and the 

U.S. Environmental Protection Agency."

Response #16

Staff removed the phrase “or other test methods approved by the APCO” to not allow 

APCO discretion.

EPA - Additional Recommendations

Comment #17

Section D.4 - The phrase, "shall meet the emission limits shown in Table 1 and also" is 

redundant and should be removed.

Response #17

Staff reworded the section and removed the phrase.

Comment #18

Section D.4, Table 1 - The word "firing" in the middle column label should be removed, 

so that the label reads "Gaseous & Non-Gaseous Fuel Co-Firing Units."

Response #18

Staff removed the word “firing” from the middle column of the table. 

Comment #19

Section D.3, Table 1 - Emission Limitations for NOx - This table indicates a 2-tiered set

of NOx emission limits for the District, depending on whether a facility is located in the 

Sacramento Federal Non-attainment Area (SFNA), which is in serious non-attainment, or 

in the northern portion of the District, which is in moderate non-attainment. EPA 

recommends that the more stringent limits listed for the SFNA be imposed on the entire 

District. Having different limits raises questions of equity as facilities in the SFNA are 

disadvantaged relative to facilities elsewhere in the District. In addition, emission 

reductions from boilers anywhere in the District are likely to have positive effects over 

the entire District.

Response #19

Staff reviewed the rule and the emission limitations for NOx. Staff decided to maintain 

the 2-tiered NOx emission standards within the jurisdiction of the District for three 

reasons. 

First, the 2-tiered NOx emission standards are consistent with CH&S Code Sections

40918 and 40919, California one-hour ozone attainment status designated by CARB. 

CARB has designated the District with dual one-hour ozone attainment status: moderate 

non-attainment for Yuba County and northern portion of Sutter County, and serious 
7

non-attainment for southern portion of Sutter County. CH&S Code Section 40918 

requires air districts to adopt control measures that will use reasonable available control 

technology (RACT) for all existing stationary sources in the “moderate” non-attainment 

area. CH&S Code Section 40919 requires air districts to adopt control measures that will 

use Best Available Retrofit Control Technology (BARCT) for all existing stationary 

sources in the “serious” non-attainment area. 

Furthermore, Yuba County and northern portion of Sutter County are designated as 

federal 8-hour ozone Attainment/Unclassified. The southern portion of Sutter County is 

only designated as federal 8-hour ozone non-attainment area for planning purposes. 

Central California Ozone Study (CCOS) has not indicated that the cause of nonattainment 

status for the Sacramento Federal Nonattainment Area was the result from transport of 

pollutants generated from the balance of the FRAQMD jurisdiction. Therefore, imposing 

an equally stringent rule to the balance of the FRAQMD for the purpose of improving the 

general air quality for the Sacramento Federal Nonattainment Area does not have

scientific support. 

Second, the balance of the FRAQMD jurisdiction complies with federal ambient air 

quality standards, which are health based. EPA has not provided a study supporting the 

outcome of further health benefits by reducing ambient pollution concentrations to lower 

standards than the current ones. In addition, there is also a lack of targeted lower federal 

ambient air quality standards after the current ones are met. 

And last, how business competitiveness is affected by regulatory stringency is still a 

debatable issue in both industry and academia. Some researchers believe that more 

stringent environmental standards could make companies more innovative, therefore, 

more profitable1. There is also empirical data supporting this hypothesis2. Therefore, 

having different standards does not necessarily generate inequity issues as you have 

suggested. 

Staff concluded that the District proposed a rule within the constraint of the CH&S Code 

and complies with federal ambient air quality standards. Staff also concluded that by 

imposing the more stringent emission standards on the balance of FRAQMD does not 

necessarily generate equity. Therefore, Staff decided to maintain the 2-tiered NOx 

emission standards within the jurisdiction of District. 

 

1 Michael E. Porter and Claas van der Linde. Toward a new conception of the environment-competitiveness 

relationship. Journal of Economic Perspectives, 9(4):97–118,1995.

2

Jaffe, A.B., S.R. Peterson, P.R. Portney, and R.N. Stavins, "Environmental regulation and the 

competitiveness of U.S. manufacturing: what does the evidence tell us?", Journal of Economic Literature 

33, 132-63, 1995
8

Comments from Placer County APCD

Comment #20

Have you considered setting the emission limit for firing on gaseous fuel for NOx to 30 

ppmv or lower? 70 ppmv may not obtain any reductions.

Response #20

See Response #9 and #19. 

Comment #21

I would show the 3% O2 correction in the same section as the emission limits. (Placer’s 

rule is written in a similar manner as your draft).

Response #21

Staff concurred with Placer APCD. Staff revised the proposed rule to include 3% O2 

corrected to all ppmv emission limits listed on Table 1 of proposed rule. The correction 

to 3% O2 is also reference in section F.4, Emissions Concentration. 

Comment #22 

Wood-fired boilers are often corrected to 12% CO2 by multiplying by 12/CO2 measured.

Response #22

Staff proposed a rule to allow FRAQMD to evaluate any solid fuel-fired unit on a case by 

case basis as stated in Section D.3 of the proposed rule. Upon reviewing an application 

for solid fueled-fired boiler, specific requirements will be listed on the Permit to Operate. 

Staff reviewed the sources within FRAQMD. There are no sources that operate woodfired boilers or solid fuel-fired boilers. 

Comment #23

Section F2 says “All emission determinations shall be made in the as-found operating 

condition at the maximum firing rate allowed by the District permit”.

This statement seems conflicting. As found is not normally maximum firing.

You might consider the following: All source tests shall be made in the as-found 

operating condition, except that source tests shall include at least one test conducted at

the maximum firing rate allowed by the District permit....OR you might consider source 

testing within 10% of the maximum allowed firing rate.

Response #23

Staff renumbered section F.2 to F.3, Emission Determination. Staff revised section F.3 to 

be consistent with the Determination. Section F.3 states, “All emission determinations 

shall be made in the as-found operating conditions, except that emission determinations 

shall include, at a minimum, one source test conducted at the maximum firing rate 

allowed by the District permit...”