DAQ-2024-007670

State of Utah
Administrative Rule Analysis
Revised May 2023

NOTICE OF PROPOSED RULE
TYPE OF FILING: Amendment
Title No. - Rule No. - Section No.
Rule or Section Number: R307-315 Filing ID: Office Use Only

Agency Information
1. Department: Environmental Quality
Agency: Air Quality
Room number:
Building: MASOB
Street address: 195 N 1950 W
City, state and zip: Salt Lake City
Mailing address: PO BOX 144820
City, state and zip: Salt Lake City, UT 84114-4820
Contact persons:
Name: Phone: Email:
Ryan Bares 801-536-4216 [e-mail]
Erica Pryor 385-499-3416 [e-mail]

Please address questions regarding information on this notice to the persons listed above.

General Information
2. Rule or section catchline:
R307-315. NOx Emission Controls for Natural Gas-Fired Boilers 2.0-5.0 MMBtu

3. Purpose of the new rule or reason for the change:
Based on feedback received from the Air Quality Board during original adoption of Rule R307-315, from engagement with
manufacturers, and from sources complying with the original rule, the Division is proposing changes to provide clarifying
language for the applicability and compliance of Rule R307-315.

4. Summary of the new rule or change:
The proposed amendments modify and add additional definitions and language intended to clarify compliance and applicability
of Rule R307-315. These amendments: 1) add a carbon monoxide limit which provides clarity for compliance with the rule, 2)
adds in the definition of “combustion analysis” to provide additional guidance for compliance, 3) modifies the definitions of
“modification” and “construction” to clarify the intent of the rule, the applicability of the rule, and makes these definitions more
consistent with federal definitions, and 4) moves applicability language from Subsection R307-315-4 to the applicability
Subsection in R307-315-2 to provide additional clarity for when the rule is applicable.

Fiscal Information
5. Provide an estimate and written explanation of the aggregate anticipated cost or savings to:
A) State budget:
There are no anticipated costs or savings to the state budget as the amendments will have no impact on how the Division of Air
Quality functions. The proposed amendments provide additional clarity around applicability and compliance with the rule;
however, do not expand the applicability beyond the original intent of the rule. Therefore, the changes do not result in any costs
or savings beyond those identified with the original adoption of Rule R307-315, nor do the changes to the rule result in any
functional changes to how the Division implements the rule.

B) Local governments:
There are no anticipated costs or savings to local governments associated with the amendments. The proposed amendments
provide additional clarity around applicability and compliance with the rule; however, do not expand the applicability beyond the
original intent of the rule. Therefore, the changes do not result in any costs or savings beyond those identified with the original
adoption of Rule R307-315.

C) Small businesses ("small business" means a business employing 1-49 persons):
There are no anticipated costs or savings for small businesses associated with the amendments. The proposed amendments
provide additional clarity around applicability and compliance with the rule; however, do not expand the applicability beyond the
original intent of the rule. Therefore, the changes do not result in any costs or savings beyond those identified with the original
adoption of Rule R307-315.

D) Non-small businesses ("non-small business" means a business employing 50 or more persons):
There are no anticipated costs or savings to non-small businesses associated with the amendments. The proposed
amendments provide additional clarity around applicability and compliance with the rule; however, do not expand the
applicability beyond the original intent of the rule. Therefore, the changes do not result in any costs or savings beyond those
identified with the original adoption of Rule R307-315.

E) Persons other than small businesses, non-small businesses, state, or local government entities ("person" means
any individual, partnership, corporation, association, governmental entity, or public or private organization of any character
other than an agency):
There are no anticipated costs or savings to persons other small businesses, non-small businesses, state, or local government
entities associated with the amendments. The proposed amendments provide additional clarity around applicability and
compliance with the rule; however, do not expand the applicability beyond the original intent of the rule. Therefore, the changes
do not result in any costs or savings beyond those identified with the original adoption of Rule R307-315.

F) Compliance costs for affected persons (How much will it cost an impacted entity to adhere to this rule or its changes?):
There are no anticipated compliance costs or savings for affected persons associated with the amendments. The proposed
amendments provide additional clarity around applicability and compliance with the rule; however, do not expand the
applicability beyond the original intent of the rule. Therefore, the changes do not result in any costs or savings beyond those
identified with the original adoption of Rule R307-315.

G) Regulatory Impact Summary Table (This table only includes fiscal impacts that could be measured. If there are
inestimable fiscal impacts, they will not be included in this table. Inestimable impacts will be included in narratives above.)
Regulatory Impact Table
Fiscal Cost FY2024 FY2025 FY2026
State Government $0 $0 $0
Local Governments $0 $0 $0
Small Businesses $0 $0 $0
Non-Small Businesses $0 $0 $0
Other Persons $0 $0 $0
Total Fiscal Cost $0 $0 $0
Fiscal Benefits FY2024 FY2025 FY2026
State Government $0 $0 $0
Local Governments $0 $0 $0
Small Businesses $0 $0 $0
Non-Small Businesses $0 $0 $0
Other Persons $0 $0 $0
Total Fiscal Benefits $0 $0 $0
Net Fiscal Benefits $0 $0 $0
H) Department head comments on fiscal impact and approval of regulatory impact analysis:
The Executive Director of Environmental Quality, Kim D. Shelley, has reviewed and approved this regulatory impact analysis.

Citation Information
6. Provide citations to the statutory authority for the rule. If there is also a federal requirement for the rule, provide a
citation to that requirement:
Section 19-2-104 U.S.C. Title 42 Chapter 85 Subchapter I
Part A Section 7410 (a)(1) 2 (A)

Incorporations by Reference Information
7. Incorporations by Reference (if this rule incorporates more than two items by reference, please include additional tables):
A) This rule adds, updates, or removes the following title of materials incorporated by references (a copy of materials
incorporated by reference must be submitted to the Office of Administrative Rules; if none, leave blank):
Official Title of Materials Incorporated
(from title page)

Publisher
Issue Date
Issue or Version

B) This rule adds, updates, or removes the following title of materials incorporated by references (a copy of materials
incorporated by reference must be submitted to the Office of Administrative Rules; if none, leave blank):
Official Title of Materials Incorporated
(from title page)

Publisher
Issue Date
Issue or Version

Public Notice Information
8. The public may submit written or oral comments to the agency identified in box 1. (The public may also request a
hearing by submitting a written request to the agency. See Section 63G-3-302 and Rule R15-1 for more information.)
A) Comments will be accepted until: 06/14/2024
B) A public hearing (optional) will be held:
Date (mm/dd/yyyy): Time (hh:mm AM/PM): Place (physical address or URL):
06/12/2024 2:00-3:00 PM R307-315/316 Public Hearing

Wednesday, June 12 · 2:00 – 3:00pm

In Person

Multi-Agency State Office Building (MASOB) 195 N
1950 W, Salt Lake City, UT 84116, USA
Air Quality Board Room 1015, 1st Floor

Or attend virtually:

Time zone: America/Denver

Google Meet joining info:

Video call link: https://meet.google.com/ovb-vgei-uun

Or dial: 1158-408-(US) +1 224 PIN: 317 060 602#

More phone numbers: https://tel.meet/ovb-vgei-
uun?pin=6012657426852

In accordance with 63G-3-302, please note that if no
requests for a public hearing for R307-315 and/or
R307-316 are received by 2:00pm on Jun 11th, 2024,
then we will cancel this hearing.

To determine if the hearing has been cancelled
and/or view the cancellation notice, you can visit:

https://deq.utah.gov/air-quality/air-quality-rule-plan-
changes-open-public-comment

To the agency: If more space is needed for a physical address or URL, refer readers to Box 4 in General Information. If more
than two hearings will take place, continue to add rows.

9. This rule change MAY become effective on: 06/21/2024
NOTE: The date above is the date the agency anticipates making the rule or its changes effective. It is NOT the effective date.

Agency Authorization Information
To the agency: Information requested on this form is required by Sections 63G-3-301, 63G-3-302, 63G-3-303, and 63G-3-
402. Incomplete forms will be returned to the agency for completion, possibly delaying publication in the Utah State Bulletin
and delaying the first possible effective date.
Agency head or
designee and title:
Bryce C. Bird, Director, Division of Air
Quality
Date: 04/16/2024

R307. Environmental Quality, Air Quality.
R307-315. NOx and CO Emission Controls for Natural Gas-Fired Boilers 2.0-5.0 MMBtu.
R307-315-1. Purpose.
Rule R307-315 establishes maximum emission thresholds for the emissions of oxides of nitrogen (NOx) and carbon monoxide
(CO) for new or modified natural gas-fired boilers with a total rated heat input of at least 2.0 million British Thermal Units per hour
(MMBtu/hr) and not more than 5.0 MMBtu/hr.

R307-315-2. Applicability.
(1) Rule R307-315 applies to each boiler that[ begins construction or modification after the compliance date defined in Section
R307-315-6 that]:
(a) is fueled exclusively by natural gas;
(b) has a total rated heat input greater than 2.0 MMBtu/hr and not more than 5.0 MMBtu/hr;
(c) is an industrial boiler, institutional boiler, or commercial boiler;
(d) is located in Salt Lake, Utah, Davis, Weber, or Tooele County; and
(e) [is not a temporary boiler.]undergoes one of the following after the compliance date defined in Subsection R307-315-6(3):
(i) begins construction, or modification of a boiler;
(ii) replaces a burner in a boiler having only a single burner; or
(iii) replaces 50% or more of the burners in a multi-burner boiler.
(2) Exemptions to this rule include:
(a) residential boilers as defined in this rule;
(b) CO boilers as defined in this rule;
(c) waste heat boilers as defined by this rule;[ and]
(d) process heaters as defined by this rule[.]; and
(e) temporary boilers as defined by this rule.

R307-315-3. Definitions.
As used in this rule:
"Boiler" means an enclosed device using controlled flame combustion of natural gas, as defined by this rule, in which water is
heated to recover thermal energy in the form of steam or hot water. Controlled flame combustion refers to a steady-state, or near
steady-state, process wherein fuel or oxidizer feed rates are controlled.
"Burner" means the functional component of a boiler that provides the heat input by combustion of a fossil fuel, with air or
oxygen. Burners are available either as part of the boiler package from the manufacturer, as stand-alone products for custom
installations, or as replacement products.
"CO boiler" means a boiler that is fired with gaseous fuel with an integral waste heat recovery system used to oxidize CO-rich
waste gases generated by a Fluid Catalytic Cracking Unit.
“Combustion analysis” means an analysis performed on flue gases using a portable instrument which measures a range of
variables relevant to the byproducts of combustion including temperatures, draft pressure, concentrations of oxygen, and
concentrations of pollutants.
"Commercial boiler" means a boiler used in commercial establishments such as hotels, restaurants, and laundries to provide
electricity, steam, or hot water.
"Construction" means any physical change or change in method of operation including fabrication, erection, installation,
demolition, or modification of an emission unit [boiler which] that would result in a[n] potential increase in [actual NOx ]emissions.
"Industrial boiler" means a boiler used in manufacturing, processing, mining, and refining or any other industry to provide
steam, hot water, or electricity.
"Institutional boiler" means a boiler used in institutional establishments such as medical centers, nursing homes, research
centers, institutions of higher education, elementary and secondary schools, libraries, religious establishments, and governmental
buildings to provide electricity, steam, or hot water.
"Modification" means any planned change in a [boiler]source which results in a[n increase of actual NOx] change in emissions.
"Natural gas" means:
(1) a mixture of gaseous hydrocarbons, with at least 80% methane by volume, and of pipeline quality, such as the gas sold or
distributed by any utility company regulated by the Utah Division of Public Utilities;
(2) liquefied petroleum gas, as defined by the American Society for Testing and Materials in ASTM D1835, or propane,
propane-derived synthetic natural gas, or mixtures thereof; or
(3) propane or propane-derived synthetic natural gas.
"Process Heater" means an enclosed device using controlled flame, and the unit's primary purpose is to transfer heat indirectly
to a process material such as liquid, gas, or solid, or to a heat transfer material such as glycol or a mixture of glycol and water, for use
in a process unit, instead of generating steam. Process heaters are devices in which the combustion gases do not come into direct
contact with process materials. Process heaters include units that heat water and water mixtures for pool heating, sidewalk heating,
cooling tower water heating, power washing, or oil heating.
"Propane" means a colorless gas derived from petroleum and natural gas, with the molecular structure C3H8.
"Residential boiler" means a boiler used to provide heat or hot water or as part of a residential combined heat and power
system. This definition includes boilers located at an institutional facility such as a university campus, military base, church grounds, or
a commercial, or industrial, such as a farm, used primarily to provide heat or hot water for:
(1) a dwelling containing four or fewer families; or
(2) a single unit residence dwelling that has since been converted or sub-divided into condominiums or apartments.
"Temporary boiler" means any gaseous or liquid fuel-fired steam generating unit that is designed to, and is capable of, being
carried or moved from one location to another by wheels, skids, carrying handles, dollies, trailers, or platforms. A steam generating unit
is not a temporary boiler if any one of the following conditions exists:
(1) the equipment is attached to a foundation;
(2) the steam generating unit or a replacement remains at a location for more than 180 consecutive days and any temporary
boiler that replaces a temporary boiler at a location and performs the same or similar function shall be included in calculating the
consecutive time period;
(3) the equipment is located at a seasonal facility and operates during the full annual operating period of the seasonal facility,
remains at the facility for at least two years, and operates at that facility for at least three months each year; or
(4) the equipment is moved from one location to another in an attempt to circumvent the residence time requirements of this
definition.
"Waste heat boiler" means a device that recovers normally unused energy such as hot exhaust gas and converts it to usable
heat. Waste heat boilers are also referred to as heat recovery steam generators. Waste heat boilers are heat exchangers generating
steam from incoming hot exhaust gas from an industrial or power equipment such as thermal oxidizers, kilns, furnaces, combustion
turbines, and engines. Duct burners are sometimes used to increase the temperature of the incoming hot exhaust gas.

R307-315-4. Requirements.
(1) An [person ]owner or operator of a boiler subject to this rule shall[ that]:
[ (a) begins construction, or modification of a boiler;
(b) replaces a burner in a boiler having only a single burner; or
(c) replaces 50% or more of the burners in a multi-burner boiler for a boiler meeting the requirements of Section R307-315-2
shall install a burner that meets a NOx emission rate of nine parts per million by volume (ppmv) or less at 3% volume stack gas oxygen
on a dry basis.]
(a) install a burner that meets a NOx emission rate of nine parts per million by volume (ppmv) or less at 3% volume stack gas
oxygen on a dry basis; and
(b) meet a CO emission rate of 200 ppmv or less at 3% volume stack gas oxygen on a dry basis.
(2) An owner or operator of a boiler subject to Subsection R307-315-4(1) shall:
(a) operate and maintain the boiler and boiler subsystems, including burners, according to the manufacturer's instructions;
(b) determine continued compliance based on Section R307-315-6; and
(c) meet the applicable recordkeeping requirements for any control device.

R307-315-5. Recordkeeping.
(1) The owner or operator of any boiler subject to [Rule]Section R307-315-4 shall:
(a) retain documentation of the unit's emission rate specifications;
(b) retain a copy of the manufacturer's recommendations for proper operation and maintenance of units covered by Rule
R307-315; and
(c) maintain records showing proper operation and maintenance of units covered by Rule R307-315 following manufacturer's
recommendations.
(2) Operation and maintenance records shall be retained for five years and shall be made available to the director upon
request.

R307-315-6. Compliance Schedule.
(1) Compliance with the NOx emission requirement listed in Subsection R307-315-4(1)(c) shall be determined according to the
following procedures:
(a) U.S. EPA Reference Method 7E, Determination of Nitrogen Oxides Emissions from Stationary Sources;
(b) other EPA-approved testing methods acceptable to the Director; or
(c) combustion analysis as part of a regular maintenance schedule.
(2) Compliance Determination shall be conducted once every five years.
(3) The compliance schedule for this rule shall begin on May 1, 2024.

KEY: air pollution, boiler, NOx, nitrogen oxides
Date of Last Change: July 10, 2023
Authorizing, and Implemented or Interpreted Law: 19-2-104