SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

(Adopted December 1, 1978)(Amended July 8, 1983)(Amended November 6, 2009)

(Amended September 5, 2014)

RULE 1111 – REDUCTION OF NOx EMISSIONSFROM NATURAL-GAS- FIRED, FAN-TYPE CENTRAL FURNACES

(a) Purpose and Applicability

The purpose of this rule is to reduce NOx emissions from natural gas-fired, fantype central furnaces, as defined in this rule. This rule applies to manufacturers, 

distributors, sellers and installers of residential and commercial fan-type central 

furnaces, requiring either single-phase or three-phase electric supply, used for 

comfort heating with a rated heat input capacity of less than 175,000 BTU per 

hour, or, for combination heating and cooling units, a cooling rate of less than

65,000 BTU per hour. 

(b) Definitions

(1) ANNUAL FUEL UTILIZATION EFFICIENCY (AFUE) is defined in 

Section 10.1 of Code of Federal Regulations, Title 10, Part 430, Subpart 

B, Appendix N.

(2) BTU means British thermal unit or units.

(3) CONDENSING FURNACE means a high-efficiency furnace that uses a 

second heat exchanger to extract the latent heat in the flue gas by cooling 

the combustion gasses to near ambient temperature so that water vapor 

condenses in the heat exchanger, is collected and drained.

(4) FAN TYPE CENTRAL FURNACE is a self-contained space heater

providing for circulation of heated air at pressures other than atmospheric 

through ducts more than 10 inches in length that have:

(A) a RATED HEAT INPUT CAPACITY of less than 175,000 BTU

per hour; or

(B) for combination heating and cooling units, a cooling rate of less 

than 65,000 BTU per hour.

(5) HEAT INPUT means the higher heating value of the fuel to the furnace

measured as BTU per hour. 

(6) NOx EMISSIONS means the sum of nitrogen oxide and nitrogen dioxide

(oxides of nitrogen) in the flue gas, collectively expressed as nitrogen 

dioxide. 

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Rule 1111 (Cont.) (Amended September 5, 2014)

(7) RATED HEAT INPUT CAPACITY means the gross HEAT INPUT of the 

combustion device. 

(8) RESPONSIBLE OFFICIAL means: 

(A) For a corporation: a president or vice-president of the corporation 

in charge of a principal business function or a duly authorized 

person who performs similar policy-making functions for the 

corporation, or

(B) For a partnership or sole proprietorship: general partner or 

proprietor, respectively.

(9) SINGLE FIRING RATE means the burners and control system are 

designed to operate at only one fuel input rate and the control system 

cycles burners between the maximum heat output and no heat output.

(10) USEFUL HEAT DELIVERED TO THE HEATED SPACE is the AFUE 

(expressed as a fraction) multiplied by the heat input.

(11) VARIABLE FIRING RATE means the burners and control system are

designed to operate at more than one fuel input rate and the control system 

cycles burners between two or more heat output rates and no heat output.

(12) WEATHERIZED means designed for installation outside of a building, 

equipped with a protective jacket and integral venting, and labeled for 

outdoor installation.

(c) Requirements

(1) A manufacturer shall not, after January 1, 1984, manufacture or supply for 

sale or use in the South Coast Air Quality Management District naturalgas-fired, fan-type central furnaces, unless such furnaces meet the 

requirements of paragraph (c)(3).

(2) A person shall not, after April 2, 1984, sell or offer for sale within the 

South Coast Air Quality Management District natural-gas-fired, fan-type 

central furnaces unless such furnaces meet the requirements of paragraph 

(c)(3).

(3) Natural-gas-fired, fan-type central furnaces shall:

(A) not emit more than 40 nanograms of oxides of nitrogen (calculated 

as NO2) per joule of useful heat delivered to the heated space; and

(B) be certified in accordance with subdivision (d) of this rule.

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Rule 1111 (Cont.) (Amended September 5, 2014)

(4) On or after October 1, 2012, a person shall not manufacture, supply, sell, 

offer for sale, or install, for use in the South Coast Air Quality 

Management District, natural-gas-fired, fan-type central furnaces subject 

to this rule, unless such furnace complies with the applicable emission 

limit and compliance date set forth in Table 1 and is certified in 

accordance with subdivision (d) of this rule. 

Table 1 – Furnace NOx Limits and Compliance Schedule

* Nanograms of oxides of nitrogen (calculated as NO2) per joule of useful heat delivered to the 

heated space

(5) Any manufacturer of fan-type central furnaces regulated by this rule may 

elect to pay a per unit mitigation fee of $200 for each condensing furnace 

and $150 for each non-condensing, weatherized or mobile home furnace 

distributed or sold into the SCAQMD in lieu of meeting the 14 

nanogram/Joule NOx emission limit in Table 1 of paragraph (c)(4) of this 

rule. A manufacturer may elect to pay the per unit mitigation fee for a 

time period of no more than 36 months after the applicable compliance 

date in Table 1 of paragraph (c)(4). A manufacturer shall submit an 

alternate compliance plan for each 12 month time period after the 

applicable compliance date during which the manufacturer elects to pay 

the mitigation fee in lieu of meeting the NOx emission limit. 

(A) Any manufacturer electing to comply using this mitigation fee 

option shall submit to the SCAQMD an alternate compliance plan 

no later than 60 days prior to the applicable compliance date that 

includes the following:

(i) a letter with the name of the manufacturer requesting the 

mitigation fee compliance option signed by a responsible 

official identifying the category of fan-type central furnaces 

Compliance Date Equipment Category NOx Emission Limit 

(nanograms/Joule *)

October 1, 2012 Mobile Home Furnace 40

April 1, 2015 Condensing Furnace 14

October 1, 2015 Non-condensing Furnace 14

October 1, 2016 Weatherized Furnace 14

October 1, 2018 Mobile Home Furnace 14

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Rule 1111 (Cont.) (Amended September 5, 2014)

and the 12 month alternate compliance period that the 

mitigation fees cover;

(ii) an estimate of the quantity of applicable Rule 1111 fantype central furnaces to be distributed or sold into the 

SCAQMD during the alternate compliance period, which 

estimate shall be based on total distribution and sales 

records or invoices of condensing, non-condensing, 

weatherized or mobile home fan-type central furnaces that 

were distributed or sold into the SCAQMD during the 12 

month period of July 1 to June 30 prior to the applicable 

compliance date, along with supporting documentation;

(iii) a completed SCAQMD Form 400A with company name, 

identification that application is for an alternate compliance 

plan (section 7 of form), identification that the request is 

for the Rule 1111 mitigation fee compliance option (section 

9 of form), and signature of the responsible official;

(iv) a check for payment of the alternate compliance plan filing 

fee (Rule 306, section (c)).

(B) The manufacturer shall submit to the Executive Officer a report 

signed by the responsible official for the manufacturer identifying 

by model number the quantity of Rule 1111 fan-type central 

furnaces actually distributed or sold into SCAQMD and a check 

for payment of mitigation fees for the applicable 12 month 

alternate compliance period for the quantity of applicable Rule 

1111 fan-type central furnaces distributed or sold into the 

SCAQMD during the alternate compliance period. The report and 

the payment of mitigation fees must be submitted to the SCAQMD 

no later than thirty (30) days after the end of each 12-month 

mitigation fee alternate compliance period.

(d) Certification

(1) The manufacturer shall have each appliance model tested in accordance 

with the following:

(A) Oxides of nitrogen measurements, test equipment, and other 

required test procedures shall be in accordance with AQMD 

Method 100.1.

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Rule 1111 (Cont.) (Amended September 5, 2014)

(B) Operation of the furnace shall be in accordance with the 

procedures specified in Section 4.0 of Code of Federal 

Regulations, Title 10, Part 430, Subpart B, Appendix N.

(2) One of the two formulas shown below shall be used to determine the 

nanograms of oxides of nitrogen per joule of useful heat delivered to the 

heated space:

N = 4.566 x 104 x P x U, N = 3.655 x 1010 x P

H x C x E (20.9-Y) x Z x E

Where:

N = nanograms of emitted oxides of nitrogen per joule of useful 

heat.

P = concentration (ppm volume) of oxides of nitrogen in flue 

gas as tested.

U = volume percent CO2 in water-free flue gas for stoichiometric 

combustion.

H = gross heating value of fuel, BTU/cu.ft. (60oF, 30-in. Hg).

C = measured volume percent of CO2 in water-free flue gas, 

assuming complete combustion and no CO present.

E = AFUE, percent (calculated using Table 2).

Y = volume percent of O2 in flue gas.

Z = heating value of gas, joules/cu. meter (0.0oC, 1 ATM).

(3) At least 120 days prior to the date a furnace model is first shipped to a 

location in the AQMD for use in the District, the manufacturer shall 

submit to the Executive Officer the following:

(A) A statement that the model is in compliance with subdivision (c). 

(The statement shall be signed by a responsible official and dated, 

and shall attest to the accuracy of all statements.)

(B) General Information

(i) Name and address of manufacturer.

(ii) Brand name.

(iii) Model number, as it appears on the furnace rating plate.

(C) A description of the furnace and specifications for each model 

being certified.

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Rule 1111 (Cont.) (Amended September 5, 2014)

(D) Executive Officer approved emission test protocol and emission 

test results verifying compliance with the applicable NOx limit 

specified in Table 1.

(e) Identification of Compliant Units

(1) The manufacturer of the furnace complying with subdivisions (c) and (d)

shall display the following on the shipping container label and rating plate

of the furnace:

(A)Model number;

(B) Heat input capacity;

(C) Applicable NOx emission limit in Table 1; and

(D)Date of manufacture or date code.

(2) Any non-certified furnace shipped to a location in the South Coast Air 

Quality Management District for distribution or sale outside of the District 

shall have a label on the shipping container identifying the furnace as not 

certified for use in the District.

(f) Enforcement

The Executive Officer may periodically conduct such tests as are deemed 

necessary to ensure compliance with subdivision (c), (d), (e) and (h).

(g) Exemptions

(1) The provisions of this rule shall not apply to furnaces installed in mobile 

homes before October 1, 2012.

(2) For furnaces manufactured, purchased and delivered to the South Coast 

Air Quality Management District prior to the applicable compliance date 

in Table 1, any person may, until 300 days after the applicable compliance 

date, sell, offer for sale, or install such a furnace in the District, so long as 

the furnace meets the requirements of paragraph (c)(3) and subdivisions 

(d) and (e).

(h) Rebate Incentives for Early Compliance

Any manufacturer of natural gas-fired, fan-type central furnaces subject to this 

rule that distributes and sells into the District furnaces that comply with the 14 

nanograms/Joule emission limit 90 days prior to the applicable compliance date in 

Table 1 of paragraph (c)(4) may submit a compliance plan for early compliance to 

the Executive Officer and to receive on a first-come first-served basis from the 

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Rule 1111 (Cont.) (Amended September 5, 2014)

AQMD a rebate payment of $75 for each 14 nanograms/Joule certified furnace 

and $90 for each high efficiency 14 nanograms/Joule certified furnace with AFUE 

of 90% or greater distributed and sold into the District, provided funds are 

available on the date documentation on the number of units distributed and sold is 

submitted to the AQMD. Total rebate payments to all manufacturers shall not 

exceed $3,000,000.

(i) Technology Assessment

On or before April 1, 2013, the Executive Officer shall conduct a technology 

assessment and shall report to the Governing Board on the status of 

manufacturers’ progress towards compliance with the 14 nanograms/Joule 

emission limit for nitrogen oxides. 

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