### SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

(Adopted September 9, 1988)(Amended January 6, 1989) (Amended May 13, 1994)(Amended June 16, 2000) (Amended November 17, 2000) ( Amended September 5 , 2008 ) ( Amended November 1 , 2013 )

RULE 1146 EMISSIONS OF OXIDES OF NITROGEN FROM INDUSTRIAL, INSTITUTIONAL, AND COMMERCIAL BOILERS, STEAM GENERATORS, AND PROCESS HEATERS

(a) Applicability This rule applies to boilers, steam generators, and process heaters of equal to or greater than 5 million Btu per hour rated heat input capacity used in all industrial, institutional, and commercial operations with the exception of: (1) boilers used by electric utilities to generate electricity; and (2) boilers and process heaters with a rated heat input capac ity greater than 40 million Btu per hour that are used in petroleum refineries; and (3) sulfur plant reaction boilers. (4) RECLAIM facilities (NOx emissions only)

( b ) Definitions (1) ADSORPTION CHILLER U NIT means any natural gas fired unit that captures and uses waste heat to provide cold water for air conditioning and other process requirements. (2) ANNUAL CAPACITY FACTOR means the ratio of the amount of fuel burned by a unit in a calendar year to the amoun t of fuel it could have burned if it had operated at the rated heat input capacity for 100 percent of the time during the calendar year. (3) ANNUAL HEAT INPUT means the actual amount of heat released by fuels burned in a unit during a calendar year. (4) AT MOSPHERIC UNIT means any natural gas fired unit with a heat input less than or equal to 10 million Btu per hour with a non

- sealed combustion
chamber in which natural draft is used to exhaust combustion gases

. (5) BOILER or STEAM GENERATOR means any combustion equipment fired with liquid and/or gaseous (i ncluding landfill and digester ga s) and/or solid fossil fuel and used to produce steam or to heat water and that is not used exclusively to produce electricity for sale. Boiler or Steam

1146

- 1Rule 1146 (Cont.) (Amended November 1, 2013 )

Generator does not include any open heated tank, adsorption chiller unit,

or waste heat recovery boiler that is used to recover sensible heat from the exhaust of a combustion turbine or any unfired waste heat recovery boiler
that is used to recover sensible heat from the exhaust of any combustion equipment. (6) BTU means British thermal unit. (7) COMMERCIAL OPERATION means any office building, lodging place, or similar location designed for tenancy by one or more business entities

or residential occupants. (8) GROUP I UNIT means any unit burning natural gas with a rated heat input greater than or equal to 75 million Btu per hour , excluding thermal
fluid heaters

. (9) GROUP II UNIT means any unit burning gaseous fuels , excluding digester and landfill gases, with a rated heat input less than 75 million Btu per hour down to and including 20 million Btu per hour , excluding
thermal fluid heaters

. (10) GROUP III UNIT means any unit burning gaseous fuels

, excluding digester and landfill gases, and thermal fluid heaters with a rated heat input less than 20 million Btu per hour down to and includi ng 5 million Btu per hour, and all units operated at schools and universities greater than or equal to 5 million Btu per hour

. (11) HEALTH FACILITY has the same meaning as defined in Section 1250 of the California Health and Safety Code. (12) HEAT INPUT means the chemical heat released due to fuel combustion in a unit, using the higher heating value of the fuel. This does not include the
sensible heat of incoming combustion air. (13) INDUSTRIAL OPERATION means any entity engaged in the production and/or provision of chemicals, foods, textiles, fabricated metal products, real estate, personal services or other kindred or allied products or
services. (14) I NSTITUTIONAL OPERATI ON means any public or private establishment constituted to provide medical

, educational, governmental, or other similar services to promote safety, order, and welfare. (15) NOx EMISSIONS means the sum of nitric oxide and nitrogen dioxi de in the flue gas, collectively expressed as nitrogen dioxide.

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- 2Rule 1146 (Cont.) (Amended November 1, 2013 )

(16) OPEN HEATED TANK means a non

- pressurized self

- heated tank that may include a cover or doors that can be opened or detached to put in or remove parts, components or other material for processing in the tank. Tanks heated solely by an electric heater, boiler, thermal fluid heater or heat recovered from another process using heat exchangers are excluded
from this definition. (17) PROCESS HEATER means any combustion equipment fired with l iquid
and/or gaseous (i ncluding landfill and digester ga s) and/or solid fossil fuel and which transfers heat from combustion gases to water or process streams. Process Heater does not include any kiln or oven used for drying, curing, baking, cooking, calcining, or vitrifying; or any unfired waste heat recovery heater that is used to recover sensible heat from the exhaust of any combustion equipment. (18) RATED HEAT INPUT CAPACITY means the heat input capacity specified on the nameplate of the combustio n unit. If the combustion unit has been altered or modified such that its maximum heat input is different than the heat input capacity specified on the nameplate, the new maximum heat input shall be considered as the rated heat input capacity. (19) SCHOOL means any public or private school, including juvenile detention facilities with classrooms, used for purposes of the education of more than 12 children at the school, including in kindergarten and grades 1 to 12, inclusive, but does not include any priva t e school in which education is primarily conducted in private homes. The term includes any building or structure, playground, athletic field, or other area o f school property, but
does not include unimproved school property. (20) STANDBY BOILER is a boi ler which operates as a temporary replacement for primary steam or hot water while the primary steam or hot water supply unit is out

- of

- service. (21) THERM means 100,000 Btu. (22) THERMAL FLUID HEATER means a PROCESS HEATER in which a process is heated ind irectly by a heated fluid other than water. (23) UNIT means any boiler, steam generator, or process heater as defined in paragraph ( b )( 5 ) or ( b )( 17 ) of this subdivision.

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- 3Rule 1146 (Cont.) (Amended November 1, 2013 )

(c) Requirements (1) The owner or operator shall subject all of the units within th e facility to
the NOx emission limits and schedule s specified in Table 1146

- 1 :



### Table 1146

- 1

– Standard Compliance Limits and Schedule

(2) In lieu of complying with the NOx emission limits and schedule s specified in paragraph (c)(1), t he owner or operator may elect to subject all of the units within the facility to the requirements specified in Table 1146

- 2

. The owner or operator that fails to submit a Compliance Plan or Application for Permit to Construct pursuant to the schedule specified in
Table 1146

- 1 for any of the Group II units shall be subject to the NOx limits and schedule specified in Table 1146

- 2. Rule Reference Category Limit Submit Compliance Plan on or

before Submit Application for Permit to Construct on or before Unit Shall be in Full Compliance

on or before

(c)(1)(A) All Units Fired on Gaseous Fuels 30 ppm or for natural gas fired units 0.036 lbs/10 6 Btu - - September 5, 2008

(c)(1)(B) Any Units Fired on Non

- gaseous Fuels 40 ppm

- - September 5, 2008

(c)(1)(C) Any Units Fired on Landfill Gas 25 ppm

- - January 1, 2015

(c)(1)(D) Any Units Fired on Digester Gas 15 ppm

- - January 1, 2015

(c)(1)(E) Atmospheric Units 12 ppm or 0.015 lbs/10 6 Btu January 1, 2010 January 1, 2013 January 1, 2014

(c)(1)(F) Group I Units 5 ppm or 0.0062 lbs/10 6 Btu - January 1, 2012 January 1, 2013

(c)(1)(G) Group II Units 75% or more of units (by heat input) January 1, 2010 January 1, 2011 January 1, 2012

(c)(1)(H) Group II Units 100% of units (by heat input) 9 ppm or January 1, 2010 January 1, 2013 January 1, 2014

(c)(1)(I) Group III Units 75% or more of units (by heat input) 0.011 lbs/10 6 Btu January 1, 2011 January 1, 2012 January 1, 2013

(c)(1)(J) Group III Units 100% of units (by heat input) January 1, 2011 January 1, 2014 January 1, 2015

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- 4Rule 1146 (Cont.) (Amended November 1, 2013 )



### Table 1146

- 2

– Enhanced Compliance Limits and Schedule

Rule Reference Category Limit Submit Compliance Plan on or before Submit Application for Permit to Construct on or before Unit Shall be in Full Compliance on or before (c)(2)(A) Group II Units 75% or more of units (by heat input) 5 ppm or 0.0062 lbs/10 6 Btu January 1, 201 1 January 1, 2013 January 1, 2014

(c)(2)(B) Group II Units 100% of units (by heat input) January 1, 201 1 January 1, 2015 January 1, 2016

( 3 ) For dual fuel co

- fired combustion a weighted average limit calculated by Equation 1146

- 1 may be used provided a totalizing fuel flow meter is installed pursuant to paragraph (c)( 8 ), for units burning a combination of
both fuels.

(CL A x Q A ) + (CL B x Q B ) Weighted Limit =

______________________ Equation 1146

- 1
Q A + Q B

Where:
CL A = compliance limit for fuel A
CL B = compliance limit for fuel B Q A = heat input from fuel A Q B = heat input from fuel B

( 4 ) The owner or operator of any unit(s) with a heat input capacity greater than or equal to 5 million Btu per hour shall not discharge into the atmosphere carbon monoxide (CO) emissions in excess of 400 ppm or for natural gas fired units 0.30 lbs/10 6 Btu

. ( 5 ) In lieu of complying wit h the applicable emission limits specified in paragraphs (c)(1), (c)(2), (c)(3) , and (c)(4) , t he owner or operator of any unit(s) in operation prior to September 5, 2008 with an annual heat input less than or equal to 9.0 x 10 9 Btu (90,000 therms ) per year, shall:

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- 5Rule 1146 (Cont.) (Amended November 1, 2013 )

(A) operate the unit(s) in a manner that maintains stack gas oxygen concentrations at less than or equal to 3 percent on a dry basis for any 15

- consecutive

- minute averaging period; or (B) tune the unit(s) at least twice per year, (at in tervals from 4 to 8 months apart) in accordance with the procedure described in Attachment 1 or the unit manufacturer's specified tune

- up procedure. If a different tune

- up procedure from that described in Attachment 1 is used then a copy of this procedure shall be kept on
site. The operator of any unit(s) selecting the tune

- up option shall
maintain record s for a rolling twenty four month period verifying
that the required tune

- up s ha ve been performed. If the unit does not operate throughout a continuous six

- month period within a twelve month period , only one tuneup is required for the twelve month period that includes the entire period of non

- operation

. For this case, the tune

- up shall be conducted within thirty (30) days of

start

- up. No tune

- up is requi red during a rolling twelve month period for any unit that is not operated during that rolling twelve month period ; this unit may be test fired to verify availability of the unit for its intended use but once the test firing is completed the
unit shall be shutdown. Records of test firings shall be maintained
for a rolling twenty four month period, and shall be made accessible to an authorized District representative upon request

. ( 6 ) Any unit(s) with a rated heat input capac ity greater than or equal to 40

m illion Btu per hour and an annual heat input greater than 200 x 10 9 Btu per year shall have a continuous in

- stack nitrogen oxides monitor or equivalent verification system in compliance with 40 CFR part 60 Appendix B Specification 2. Maintenance and emiss ion records shall be maintained and made accessible for a period of two years to the Executive
Officer. ( 7 ) An owner or operator that has installed or modified a Group III natural gas fired unit prior to September 5, 2008 complying with the applicable BACT emission limit of 12 ppm or less of NOx may defer compliance with
sub paragraphs (c)(1)( I ) or (c)(1)( J ) until the unit’s burner(s) replacement

. ( 8 ) Any owner or operator who chooses the pound per million Btu compliance option specified in paragraph(s) (c)( 1) (c)(2), or (c)(4) or chooses the weighted average emission limit using Equation 1146

- 1 under paragraph

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- 6Rule 1146 (Cont.) (Amended November 1, 2013 )

(c )(3) shall install a non

- resettable totalizing fuel meter to measure the total of each fuel used by each individual unit, as approved by the
Execut ive Officer. ( 9 ) The owner or operator of Group II or III unit s shall submit for the approval of the Executive Officer a compliance plan in accordance with the requirements of Rule 221

– Plans and Rule 306

– Plan Fees by the applicable date specified in Tables 1146

- 1 or 1146

- 2. The compliance plan shall include the following information: (A) Owner/operator contact information (company name, AQMD facility identification number, contact name, phone number, address, e

- mail address). (B) Number and size (mm b tu/hr) of Group II and III units located at the facility. (C) Selection of the Standard (Table 1146

- 1) or Enhanced (Table
1146

- 2) compliance schedule by Group II and III units. (D) The owner or operator of more than one unit located within th e same facility that have opted to divide the units by heat input for the purpose of separate compliance dates according to Tables
1146

- 1 or 1146

- 2 shall indicate which units are categorized 75 percent or more of the heat input and which units make up the remaining 100 percent of the heat input. (10) On or after January 1, 2015, an owner operator of any landfill or digester gas (biogas) unit co

- fired with natural gas shall not operate the unit in a
manner that exceeds the emission concentration limits specified in subparagraphs (c)(1)(C) or (c)(1)(D), provided that the facility monthly average biogas usage by the biogas units is 90% or more, based on the higher heating value of the fuels used. (A) The Executive Officer may approve the burning of more th an 10% up to: (i) 25% natural gas in a biogas fired unit at the 15 ppm (digester gas) or 25 ppm (landfill gas) NOx level, when it is necessary, if the only alternative to limiting natural gas to 10% would be shutting down the unit and flaring more biogas. (ii) 50% natural gas in a digester gas

- fired unit at the 15 ppm NOx level, when it is necessary as specified in clause (c)

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- 7Rule 1146 (Cont.) (Amended November 1, 2013 )

(10)(A)(i) and for units installed on or after September 5,
2008 provided the unit has demonstrated compliance with
the NOx limits in paragraph (c)(1) applicable to units fired exclusively on natural gas. For units subject to this subparagraph, the percent natural gas usage shall be based on the facility monthly average biogas usage by the biogas units and the higher heating value of th e fuels used. (B) Any biogas

- fired unit burning more than the approved percent natural gas as determined under subparagraph (c)(10)(A) shall comply with the weighted average NOx limit specified in paragraph (c)(3).

(d) Compliance Determination (1) An owner or operator of any unit(s) shall have the option of complying with either the pound per million Btu or parts per million emission limits specified in paragraphs (c)(1)

, (c)(2) , (c)(3)

, and (c)(4)

. (2) All emission determinations shall be made in the as

- found operating condition, except no compliance determination shall be established during

start

- up, shutdown, or under breakdown conditions. C ompliance
determination as specified in paragraph (d)(6) shall be conducted at least 250 operating hours, or a t least thirty days subsequent to the tuning or servicing of any unit , unless it is an unscheduled repair

. (3) All parts per million emission limits specified in subdivision (c) are referenced at 3 percent volume stack gas oxygen on a dry basis averaged over a period of 15 consecutive minutes. (4) Compliance with the NO x and CO emission requirements of par agraphs (c)(1), (c)(2), (c)(3), and (c)(4) and the stack

- gas oxygen concentration requirement of sub paragraph (c)( 5 )(A) shall be determined using a Dis trict approved contractor under the Laboratory Approval Program according to the following procedures : (A) District Source Test Method 100.1

- Instrumental Analyzer Procedures for Continuous Gaseous Emission Sampling (March 1989), or (B) District Source Test Method 7.1

- Determination of Nitrogen Oxide Emissions from Stationary Sources (March 1989) and

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- 8Rule 1146 (Cont.) (Amended November 1, 2013 )

District Source Test Method 10.1

- Carbon Monoxide and Carbon Dioxide by Gas Chromatograph/Non

- Dispersive Infrared Detector (GC/NDIR)

- Oxygen by Gas Chrom atograph

- Thermal Conductivity (GC/TCD) (March 1989) ; or (C) United States Environmental Protection Agency Conditional Test
Method CTM

- 030, Determination of Nitrogen Oxides, Carbon Monoxide, and Oxygen Emissions from Natural Gas

- Fired Engines, Boilers and Process Heaters Using Portable Analyzers; or (D) ASTM D6522

- 00(2005) Standard Test Method for Determination of Nitrogen Oxides, Carbon Monoxide, and Oxygen
Concentrations in Emissions from Natural Gas

- Fired Reciprocating Engines, Combustion Turbines, Boil ers, and Process Heaters Using Portable Analyzers ( E ) any other test method determined to be alternative and approved before the test in writing by the Executive Officers of the District and the California Air Resources Board and the Regional
Administrato r of the United States Environmental Protection Agency, Region IX ; or ( F ) a continuous in

- stack nitrogen oxide monitor or equivalent verification system as specified in paragraph ( c )( 6 ).

Records of all source tests shall be made available to District personnel
upon request. Emissions determined to exceed any limits established by this rule through the use of any of the above

- referenced test methods shall
constitute a violation of this rule. (5) For any operator who chooses the pound per million Btu of hea t input compliance opti on of paragraph (c)(1)

, (c)(2), (c)(3), or (c)(4)

, NO x emissions in pounds per million Btu of heat input shall be calculated using procedures in 40 CFR Part 60, Appendix A, Method 19, Sections 2 and 3 and CO emissions in pounds per m illion Btu of heat input shall be calculated according to the Protocol for the Periodic Monitoring of Nitrogen Oxides, Carbon Monoxide, and Oxygen from Units Subject to South Coast Air Quality Management District Rules 1146 and 1146.1

.

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- 9Rule 1146 (Cont.) (Amended November 1, 2013 )

(6) Compliance determi nation with the NOx emission requirements in paragraph (d)(4) shall be conducted on ce : (A) every three years for units with a rated heat input greater than or equal to 10 million Btu per hour , except for units subject to paragraph (c)(6)

. (B) every five years for units with a rated heat input less than 10
million Btu per hour down to and including 5 million Btu per hour. (7) Provided the emissions test is conducted within the same calendar year as the test required in paragraph (d)(6), an owner or opera tor may use the following emissions tests to comply with paragraph (d)(6): (A) Periodic monitoring or testing of a unit as required in a Title V permit pursuant to Regulation XXX, or (B) Relative accuracy testing for continuous emissions monitoring verification p ursuant to Rule 218. 1 or 40 CFR part 60 Appendix B Specification 2

. (8) Any owner or operator of units subject to this rule shall perform diagnostic
emission check s of NOx emissions with a portab le NOx, CO and oxygen analyzer according to the Protocol for the Periodic Monitoring of Nitrogen Oxides, Carbon Monoxide, and Oxygen from Units Subject to South Coast Air Quality Management District Rules 1146 and 1146.1 according to the following schedule: (A) On or after July 1, 2009

, the owner or operator of units subject to paragraphs (c)(1), (c)(2), (c)(3), and (c)(4) shall check NOx emissions at least monthly or every 750 unit operating hours,
whichever occurs later

. If a unit is in compliance for three
consecutive diagnostic emission checks, without any a djustments to the oxygen sensor set points, then the unit may be checked quarterly or every 2,000 unit operating hours, whichever occurs later, until the resulting diagnostic emission check exceeds the applicable limit specified in paragraphs (c)(1), (c)( 2), or (c)(3)

. (B) On or after January 1, 201 5 or during burner replacement,
whichever occurs later

, the owner or operator of units subject to paragraph (c)( 5 ) shall check NOx emissions according to the tune

up schedule specified in subparagraph (c)(5)(B). (C) Rec ords of all monitoring data required under subparagraphs (d)(8)(A) and (d)(8)(B) shall be maintained for a rolling twelve

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- 10Rule 1146 (Cont.) (Amended November 1, 2013 )

month period of two years (5 years for Title V facilities) and shall
be made available to Di strict personnel upon request. (D) The portable analyzer diagnostic emission checks required under subparagraph (d)(8)(A) and (d)(8)(B) shall only be conducted by a person who has completed an appropriate District

- approved training program in the operation of portable analyzers and has

rece ived a certification issued by the District. (9) An owner or operator shall comply with the requirements as applied to CO emissions specified in paragraph (d)(8) and subparagraph: (A) (d)(6)(A) for units greater than or equal to 10 mmbtu/hr, or (B) (d)( 6)(B) for units less than 10 mmbtu/hr. ( 10 ) A diagnostic emission check conducted under the requirements specified in paragraph (d)(8) that finds emissions in excess of those allowed by this rule or a permit condition shall not constitute a violation of th is rule if the
owner or operator correct s the problem and demonstrate compliance with
another emission check within 72 hours from the time the owner or operator knew of excess emissions, or reasonably should have known, or shut down the unit by the end of an operating cycle, whichever is sooner

. (11) Notwithstanding the requirements specified in paragraph (d)(10) any diagnostic emission check conducted by District staff that finds emissions in excess of those allowed by this rule or a permit condition is a violation

. ( 12 ) A n owner or operator may opt to lower the unit’s rated heat input capacity.
The lower ed rated heat input capacity shall not be less than or equal to 2
million Btu per hour and shall be based on manufacturer’s identification or rating p late or permit condition.

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- 11Rule 1146 (Cont.) (Amended November 1, 2013 )

(e) Compliance Schedule (1) An o wner or operator of units subject to paragraph (c)(1) shall comply
with the schedule specified in Table 114 6

- 1. (2) An owner or operator of units subject to paragraph (c)(2) shall com p ly
with the schedule specified in Table 1146

- 2. ( 3 ) On or after January 1, 201 5 or during burner replacement, whichever
occurs later , no person shall operate in the District any unit subject to paragraph (c)( 5 ) whi ch does not meet the emissions limits specified in
sub paragraph (c)(1) (A) of Table 1146

- 1

. ( 4 ) Any unit subject to the requirements specified in paragraph (c)( 5 ) that exceeds 90,000 therms of heat input from all fuels used in any twelve month period, the operators shall: (A) within 4 months after exceeding 90,000 therms of heat input in any twelve month period, submit required applications for permits to construct and operate; and (B) within 18 months after exceeding 90,000 therms of heat input in any twelve month period, dem onstrate and maintain compliance with all applicable requirements of paragraphs (c)(1), (c)(2), (c)(3), and (c)( 6 ) for the life of the unit

. ( 5 ) T he Executive Officer shall grant a time extension to the full compliance date with the applicable NOx complian ce limits specified in subparagraphs (c)(1)( E ) through (c)(1)( J ) and paragraph (c)(2) for any health facility as defined in Section 1250 of the California Health and Safety Code that can demonstrate that the Office of Statewide Health Planning and Developm ent has approved an extension of time to comply with seismic safety requirements pursuant to Health and Safety Code
Sections 130060 and 130061.5. The extension of time granted by the Executive Officer shall be consistent with the time extension granted

pu rsuant to Health and Safety Code Section 130060 but not to exceed January 1, 2015 and shall be consistent with the time extension granted pursuant to Health and Safety Code Section 130061.5 but not to exceed January 1, 2020. Those health facilities grante d a time extension shall submit a compliance plan to the Executive Officer on or before January 1,
201 0

.

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- 12Rule 1146 (Cont.) (Amended November 1, 2013 )

ATTACHMENT 1

A. Equipment Tuning Procedure 1 for Forced

- Draft Boilers, Steam Generators, and Process Heaters

Nothing in this Equipment Tuning Procedure shall be construed to require any act or

o mission that would result in unsafe conditions or would be in violation of any regulation or requirement established by Factory Mutual, Industrial Risk Insur e rs, National Fire Prevention Association, the California Department of Industrial Relations (Occup ational Safety and Health Division), the Federal Occupational Safety and Health Administration, or other relevant regulations and requirements. Should a different tuning procedure be used, a copy of this procedure should be kept with
the unit records for t wo years and made available to the District personnel on request.

1. Operate the unit at the firing rate most typical of normal operation. If the unit experiences significant load variations during normal operation, operate it at its average firing rate.
2. At this firing rate, record stack gas temperature, oxygen concentration, and CO concentration (for gaseous fuels) or smoke

- spot number 2 (for liquid fuels), and observe flame conditions after unit operation stabilizes at the firing rate selected.
If th e excess oxygen in the stack gas is at the lower end of the range of typical
minimum values 3 , and if CO emissions are low and there is not smoke, the unit is probably operating at near optimum efficiency

- at this particular firing rate.

However, complete the remaining portion of this procedure to determine whether still lower oxygen levels are practical.

3. Increase combustion air flow to the furnace until stack gas oxygen levels increase by one to two percent over the level measured in Step 2. As in Step 2, record the

1 This tuning procedure is based on a tune

- up procedure developed by KVB, Inc. for the United

States EPA.

2 The smoke

- spot number can be determined with ASTM Test Method D

- 2156 or with the

Bacharach method. ASTM Test Method D

- 2156 is included in a tuneup kit that can be purchased from the Bacharach Company.

3 Typical minimum oxygen levels for boilers at high firing rates are: 1. For natural gas: 0.5%

- 3% 2. For liquid fuels: 2%

- 4%

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- 13Rule 1146 (Cont.) (Amended November 1, 20 13 )

stack gas temperature, CO concentration (for gaseous fuels) or smoke

- spot number (for liquid fuels), and observe flame conditions for these higher oxygen levels after boiler operation stabilizes.
4. Decrease combustion air flow unt il the stack gas oxygen concentration is at the level measured in Step 2. From this level gradually reduce the combustion air flow, in small increments. After each increment, record the stack gas temperature, oxygen concentration, CO concentration (for g aseous fuels) and
smoke

- spot number (for liquid fuels). Also observe the flame and record any changes in its condition.
5. Continue to reduce combustion air flow stepwise, until one of these limits is
reached:

a. Unacceptable flame conditions

- such as fl ame impingement on furnace walls or burner parts, excessive flame carryover, or flame instability.
b. Stack gas CO concentrations greater than 400 ppm.

c. Smoking at the stack.
d. Equipment

- related limitations

- such as low windbox/furnace pressure
differe ntial, built in air

- flow limits, etc.
6. Develop an O 2 /CO curve (for gaseous fuels) or O 2 /smoke curve (for liquid fuels) similar to those shown in Figures 1 and 2 using the excess oxygen and CO or
smoke

- spot number data obtained at each combustion air flow setting.

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- 14Rule 1146 (Cont.) (Amended November 1, 20 13 )

7. From the curves prepared in Step 6, find the stack gas oxygen levels where the
CO emissions or smoke

- spot number equal the following values:
Fuel Measurement Value
Gaseous CO Emissions 400 ppm #1 and #2 oils smoke

- spot number number 1 #4 oil smoke

- spot number number 2 #5 oil smoke

- spot number number 3 Other oils smoke

- spot number number 4
The above conditions are referred to as the CO or smoke thresholds, or as the minimum excess oxygen level. Compare this minimum value of excess oxygen to the expected value provided by the combustion unit manufacturer. If the minimum level found is substantially higher than the value provided by the combustion unit manufacturer, burner adjustments can probably be made to improve f uel and air mixing, thereby allowing operation with less air.
8. Add 0.5 to 2.0 percent O2 to the minimum excess oxygen level found in Step 7 and reset burner controls to operate automatically at this higher stack gas oxygen level. This margin above the m inimum oxygen level accounts for fuel variations, variations in atmospheric conditions, load changes, and nonrepeatability or play in
automatic controls.

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- 15Rule 1146 (Cont.) (Amended November 1, 20 13 )

9. If the load of the combustion unit varies significantly during normal operation, repeat Steps 1

- 8 f or firing rates that represent the upper and lower limits of the range of the load. Because control adjustments at one firing rate may affect conditions at other firing rates, it may not be possible to establish the optimum excess oxygen level at all firi ng rates. If this is the case, choose the burner control settings that give best performance over the range of firing rates. If one firing rate predominates, settings should optimize conditions at that rate.
10. Verify that the new settings can accommoda te the sudden load changes that may occur in daily operation without adverse effects. Do this by increasing and decreasing load rapidly while observing the flame and stack. If any of the conditions in Step 5 result, reset the combustion controls to provi de a slightly higher level of excess oxygen at the affected firing rates. Next, verify these new settings in a similar fashion. Then make sure that the final control settings are recorded at steady

- state operating conditions for future reference.
11. Whe n the above checks and adjustments have been made, record data and attach combustion analysis data to boiler, steam generator, or heater records indicating name and signature of person, title, and date the tuneup was performed.

B. Equipment Tuning Procedu re for Natural Draft

- Fired Boilers, Steam Generators, and Process Heaters.

Nothing in this Equipment Tuning Procedure shall be construed to require any act or omission that would result in unsafe conditions or would be in violation of any regulation

or re quirement established by Factory Mutual, Industrial Risk Insurers, National Fire Prevention Association, the California Department of Industrial Relations (Occupational Safety and Health Division), the Federal Occupational Safety and Health Administration, or other relevant codes, regulations, and equipment manufacturers specifications and operating manuals.

Should a different tuning procedure be used, a copy of this procedure should be kept with the unit records for two years and made available to the Dis trict personnel on request.

1. PRELIMINARY ANALYSIS

a. CHECK THE OPERATING PRESSURE OR TEMPERATURE. Operate the boiler, steam generator, or heater at the lowest acceptable pressure or temperature that will satisfy the load demand. This will minimize heat and radiation losses. Determine the pressure or temperature

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- 16Rule 1146 (Cont.) (Amended November 1, 20 13 )

that will be used as a basis for compar ative combustion analysis before and after tuneup.
b. CHECK OPERATING HOURS. Plan the workload so that the boiler, steam generator, or process heater operates only the minimum hours and days necessary to perform the work required. Fewer operating hours wi ll reduce fuel use and emissions. For units requiring a tuneup to comply with the rule, a totalizing non

- resettable fuel meter will be required for each fuel used and for each boiler, steam generator, and heater to prove fuel consumption is less than the heat input limit in therms per year specified in the rule.

c. CHECK AIR SUPPLY. Sufficient fresh air supply is essential to ensure optimum combustion and the area of air supply openings must be in compliance with applicable codes and regulations. Air open ings must be kept wide open when the burner is firing and clear from restriction to flow.
d. CHECK VENT. Proper venting is essential to assure efficient combustion. Insufficient draft or overdraft promotes hazards and inefficient burning. Check to be

sur e that vent is in good condition, sized properly and with no
obstructions.

e. COMBUSTION ANALYSIS. Perform an "as is" combustion analysis (CO, O2, etc.) with a warmed up unit at high and low fire, if possible. In addition to data obtained from
combustion analysis, also record the following:
i. Inlet fuel pressure at burner (at high & low fire)
ii. Draft at inlet to draft hood or barometric damper 1) Draft hood: high, medium, and low 2) Barometric Damper: high, medium, and low
iii. Steam pressure, water tem perature, or process fluid pressure or temperature entering and leaving the boiler, steam generator, or process heater.
iv. Unit rate if meter is available.

With above conditions recorded, make the following checks and corrective actions as necessary:

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2. CHECKS & CORRECTIONS

a. CHECK BURNER CONDITION. Dirty burners or burner orifices will cause boiler, steam generator, or process heater output rate and thermal efficiency to decrease. Clean burners and burner orifices thoroughly. Also, ensure that fuel filters and moisture traps are in place, clean, and operating properly, to prevent plugging of gas orifices. Confirm proper location and orientation of burner diffuser spuds, gas canes, etc. Look for any burned

- off or missing burner parts, and replace a s needed.
b. CHECK FOR CLEAN BOILER, STEAM GENERATOR, OR PROCESS
HEATER TUBES & HEAT TRANSFER SURFACES.
External and internal build

- up of sediment and scale on the heating surfaces creates an insulating effect that quickly reduces unit efficiency.
Excessi ve fuel cost will result if the unit is not kept clean. Clean tube surfaces, remove scale and soot, assure proper process fluid flow and flue gas flow.

c. CHECK WATER TREATMENT & BLOWDOWN PROGRAM. Soft water and the proper water or process fluid treatment must be uniformly used to minimize scale and corrosion. Timely flushing and periodic blowdown must be employed to eliminate sediment and scale
build

- up on a boiler, steam generator or process heater.
d. CHECK FOR STEAM, HOT WATER OR PROCESS FLUID LEAKS. Repair all leaks immediately since even small high

- pressure leaks quickly lead to considerable fuel, water and steam losses. Be sure there are no leaks through the blow

- off, drains, safety valve, by

- pass lines or at the feed pump, if used.

3. SAFETY CHE CKS

a. Test primary and secondary low water level controls.
b. Check operating and limit pressure and temperature controls.

c. Check pilot safety shut off operation.
d. Check safety valve pressure and capacity to meet boiler, steam generator or process hea ter requirements.

e. Check limit safety control and spill switch.

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- 18Rule 1146 (Cont.) (Amended November 1, 20 13 )

4. ADJUSTMENTS While taking combustion readings with a warmed up boiler, steam generator, or process heater at high fire perform checks and adjustments as follows:

a. Adjust unit to fire at rate; record fuel manifold pressure.
b. Adjust draft and/or fuel pressure to obtain acceptable, clean combustion at both high, medium and low fire. Carbon Monoxide (CO) value should always be below 400 parts per million (PPM) at 3% 02. If CO is high
mak e necessary adjustments. Check to ensure boiler, steam generator, or process heater light offs are smooth and safe. A reduced fuel pressure test at both high and low fire
should be conducted in accordance with the manufacturers instructions
and maintenanc e manuals.

c. Check and adjust operation of modulation controller. Ensure proper, efficient and clean combustion through range of firing rates.

When above adjustments and corrections have been made, record all data.

5. FINAL TEST
Perform a final combust ion analysis with a warmed up boiler, steam generator, or process heater at high, medium and low fire, whenever possible. In addition to data from combustion analysis, also check and record:

a. Fuel pressure at burner (High, Medium, and Low).
b. Draft abo ve draft hood or barometric damper (High, Medium and Low).

c. Steam pressure or water temperature entering and leaving boiler, steam generator, or process heater.
d. Unit rate if meter is available. When the above checks and adjustments have been made, rec ord data and attach combustion analysis data to boiler, steam generator, or process heater records indicating name and signature of person, title, company name, company address and date the tuneup was performed.

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