Santa Barbara County APCD Rule 352 352 - 1 October 20, 2011

RULE 352. NATURAL GAS-FIRED FAN-TYPE CENTRAL FURNACES AND SMALL WATER 

HEATERS. (Adopted 9/16/1999, revised 10/20/2011)

A. Applicability

This rule applies to any person who manufactures, supplies, sells, offers for sale, installs, or solicits the 

installation of any natural gas-fired fan-type central furnaces or water heaters for use within the District.

B. Exemptions

The provisions of this rule shall not apply to:

1. Units installed in manufactured housing (mobile homes).

2. Water heaters used exclusively in recreational vehicles.

3. Water heaters with a rated heat input of 75,000 British thermal units per hour or greater.

4. Water heaters used exclusively to heat swimming pools or hot tubs.

5. Fan-type central furnaces and water heaters using fuels other than natural gas.

C. Definitions

“Fan-Type Central Furnace” means 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 has a rated heat input 

capacity of less than 175,000 British thermal units per hour and, for combination heating and cooling units, 

a rated cooling capacity of less than 65,000 British thermal units per hour. 

“Heat Output (Central Furnace)” means the product obtained by multiplying the annual fuel utilization 

efficiency as defined by Section 10.1 of the Code of Federal Regulations (CFR), Title 10, Part 430, Subpart 

B, Appendix N, by the rated heat input capacity of the natural gas-fired central furnace. 

“Heat Output (Water Heater)” means the product obtained by multiplying the recovery efficiency as 

defined by Section 6.1.3 of 10 CFR 430, Subpart B, Appendix E, by the rated heat input capacity of the 

water heater. 

“Manufactured Home” has the same meaning as defined in 42 United States Code Section 5402 and 

California Health and Safety Code Section 18007.

“Natural Gas” means a mixture of gaseous hydrocarbons containing at least 80% methane by volume as 

determined by ASTM Method D1945-03(2010), “Standard Test Method for Analysis of Natural Gas by Gas

Chromatography,” ASTM International. 

“Rated Cooling Capacity” means the cooling capacity specified on the nameplate of the cooling unit. 

Cooling capacity is the amount of heat energy the cooling system can displace in one hour (British thermal 

units per hour). 

“Rated Heat Input Capacity” means the heat input capacity specified on the nameplate of the combustion 

unit. Heat input is the amount of energy consumed in one hour (British thermal units per hour). 

“Water Heater” means a device that heats water at a thermostatically-controlled temperature of no more 

than 210 degrees Fahrenheit for delivery on demand. 
Santa Barbara County APCD Rule 352 352 - 2 October 20, 2011

D. Requirements – General

1. Except as specified in Section D.2, no person shall supply, sell, offer for sale, install, or solicit the 

installation of any natural gas-fired fan-type central furnace or water heater for use within the 

District:

a. With emissions of oxides of nitrogen in excess of 40 nanograms per joule (0.093 pounds 

of oxides of nitrogen per million British thermal units) of heat output, or 55 parts per 

million at 3.00 percent stack gas oxygen by volume on a dry basis, and

b. That is not certified in accordance with Section E.

2. After July 1, 2012, no person shall supply, sell, offer for sale, install, or solicit the installation of 

any natural gas-fired water heater for use within the District:

a. With emissions of oxides of nitrogen in excess of 10 nanograms per joule (0.023 pounds 

of oxides of nitrogen per million British thermal units) of heat output, or 15 parts per 

million at 3.00 percent stack gas oxygen by volume on a dry basis, and

b. That is not certified in accordance with Section E.

E. Requirements – Certification and Identification

1. Each appliance model shall be tested in accordance with Section F. In lieu of such certification 

tests, the District will accept certifications issued under South Coast Air Quality Management 

District Rule 1111 or Rule 1121.

2. The central furnace manufacturer and water heater manufacturer shall display the model number of 

the appliance complying with Section D on the shipping carton and the rating plate of the 

appliance. 

3. Upon request of the Control Officer, each manufacturer shall submit to the District a statement 

confirming the appliance subject to this rule is in compliance with the emission limit specified in 

Section D. The statement shall be signed, dated, and shall attest to the accuracy of all information. 

The statement shall include: 

a. Name and address of manufacturer, and

b. Brand name, and

c. Model number, as it appears on the appliance rating plate, and

d. Heat input rating, British thermal units per hour, and

e. A source test report verifying compliance with the applicable emission limits in Section 

D.1.a or D.2.a.

F. Monitoring – Source Testing

1. During testing, each tested central furnace shall be operated in accordance with the procedures 

specified in 10 CFR 430, Subpart B, Appendix N.

2. During testing, each water heater shall be operated in accordance with Section 2.4 of American

National Standards ANSI Z21.10.1-1998 at normal pressure, input rates, and with a five-foot stack 
Santa Barbara County APCD Rule 352 352 - 3 October 20, 2011

installed during the oxides of nitrogen emissions tests.

3. Compliance with the oxides of nitrogen emission requirement in D shall be determined using Air 

Resources Board Method 100, or Environmental Protection Agency Methods 7E and 3A.

4. The following calculation shall be used to determine the nanograms of oxides of nitrogen per joule 

of heat output:

H C E

P U

N × ×

× × × =

4 4.566 10

where:

4.566 x 104 = unit conversion factor [parts per million (ppm) to nanograms and British thermal 

units to joules]

N = nanograms of emitted oxides of nitrogen per joule of heat output

P = concentration of oxides of nitrogen in flue gas in ppm by volume

U = dry volume percent of CO2 in flue gas necessary for stoichiometric combustion

H = gross heating value of fuel, British thermal units per cubic feet at 60°F and 30 inches of 

mercury

C = measured dry volume percent of CO2 in the flue gas, assuming complete combustion and no 

carbon monoxide present

E = efficiency, annual fuel utilization efficiency for natural gas-fired central furnaces or recovery 

efficiency for water heaters as referenced in the Section C definitions for heat output (central 

furnace) or heat output (water heater).

G. Rule Effective Date

This rule is effective on October 20, 2011.