EL DORADO COUNTY AIR QUALITY MANAGEMENT DISTRICT

RULE 239 - NATURAL GAS-FIRED RESIDENTIAL WATER HEATERS

INDEX
 

239.1 GENERAL

  1. PURPOSE
  2. APPLICABILITY
  3. EXEMPTION, LARGE NATURAL GAS-FIREDWATER HEATERS
  4. EXEMPTION, RECREATIONAL VEHICLES 
  5. EXEMPTION, SWIMMING POOLS AND HOT TUBS
  6. EXEMPTION, OTHER FUELS 

239.2 DEFINITIONS

  1. BRITISH THERMAL UNIT (Btu) 
  2. HEAT INPUT
  3. HEAT OUTPUT
  4. MOBILE HOME
  5. MOBILE HOME WATER HEATER 
  6. NATURAL GAS
  7. NATURAL GAS-FIRED WATER HEATER
  8. RATED HEAT INPUT CAPACITY 
  9. RECREATIONAL VEHICLE
  10. SWIMMING POOLS AND HOT TUBS 

239.3 STANDARDS

  1. NITROGEN OXIDES EMISSION LIMIT

239.4 ADMINISTRATIVE REQUIREMENTS

  1. COMPLIANCE SCHEDULE
  2. CERTIFICATION REQUIREMENT
  3. MANUFACTURER'S LABELING REQUIREMENT
  4. CALCULATION FOR DETERMINATION OF HEAT OUTPUT
  5. CALCULATION FOR DETERMINATION OF STORAGE TANK CAPACITY 

239.5 MONITORING AND RECORDKEEPING

  1. TESTING PROCEDURE
  2. DURATION OF RECORDS 


RULE 239 - NATURAL GAS-FIRED RESIDENTIAL WATER HEATERS
ADOPTED: MARCH 24, 1998
 

239.1 GENERAL

  1. PURPOSE: To limit emission of nitrogen oxides (NOx) from natural gas-fired residential water heaters.
  2. APPLICABILITY:
    1. GEOGRAPHIC: The provisions of this rule apply to all of El Dorado County.
    2. GENERAL: This rule shall apply to any person who manufactures, distributes, offers for sale, sells, or installs any natural gas-fired residential water heater with a rated heat input capacity less than 75,000 British thermal units per hour (Btu/hr), for use in this District.
  3. EXEMPTION, LARGE NATURAL GAS-FIRED WATER HEATERS: Water heaters with a rated heat input of 75,000 Btu/hr or greater are exempt from all provisions of this rule.
  4. EXEMPTION, RECREATIONAL VEHICLES: Natural gas-fired water heaters used exclusively in recreational vehicles are exempt from all provisions of this rule.
  5. EXEMPTION, SWIMMING POOLS AND HOT TUBS: Natural gas-fired water heaters used exclusively to heat swimming pools and hot tubs are exempt from all provisions of this rule.
  6. EXEMPTION, OTHER FUELS: Water heaters using any fuel other than natural gas are exempt from all provisions of this rule.

239.2 DEFINITIONS

  1. BRITISH THERMAL UNIT (Btu): The amount of heat energy required to raise the temperature of one pound of water from 59 oF to 60 oF at one atmosphere pressure.
  2. HEAT INPUT: The actual amount of heat energy released by natural gas burned in a natural gas-fired water heater. It is calculated during certification testing in accordance with the test method referenced in Section 239.5 A.
  3. HEAT OUTPUT: The amount of heat energy, Ho, in British thermal units (Btu), absorbed by the water being heated during the process of natural gas-fired water heater testing in accordance with the protocol referenced in Section 239.5 A.
  4. MOBILE HOME: A residential dwelling, designed and manufactured to be movable from site to site as desired by the owner/occupant, and that is not a Recreational Vehicle as defined in Section 239.2 I.
  5. MOBILE HOME WATER HEATER: A natural gas-fired water heater manufactured exclusively for mobile home use.
  6. NATURAL GAS: A mixture of gaseous hydrocarbons containing at least 80 percent methane by volume as determined according to American Standard Test Method (ASTM) D1945-64.
  7. NATURAL GAS-FIRED WATER HEATER: A closed vessel in which water is heated by the combustion of natural gas and is withdrawn for use external to the vessel at pressures not exceeding 160 psig, including the apparatus by which heat is generated and all controls and devices necessary to prevent water temperatures from exceeding 210F (99 oC).
  8. RATED HEAT INPUT CAPACITY: The heat input capacity specified on the nameplate of the combustion 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 actual heat input capacity as certified by the Manufacturer or Certified technician, shall be considered as the rated heat input capacity.
  9. RECREATIONAL VEHICLE: A motor home, travel trailer, truck camper, or camping trailer, with or without motive power, designed for human habitation for recreational, emergency, or other occupancy, which meets all of the following criteria:
    1. contains less than 320 square feet of internal living room area, excluding built-in equipment, including, but not limited to wardrobe, closets, cabinets, kitchen units or fixtures, and bath or toilet rooms;
    2. it contains 400 square feet or less of gross area measured at maximum horizontal projections;
    3. it is built on a single chassis; and
    4. it is either self propelled, truck mounted, or permanently towable on the highways without a permit.
  10. SWIMMING POOLS AND HOT TUBS: Residential only, single-family dwellings, recreational and personal therapeutic equipment, including in-ground swimming pools, above-ground swimming pools, spas and hot tubs.

239.3 STANDARDS:

  1. NITROGEN OXIDES EMISSION LIMIT: No person shall distribute, offer for sale, sell, or install any natural gas-fired residential water heater within the District which does not comply with the following:
    1. A natural gas-fired residential water heater that emits less than or equal to 40 nanograms of nitrogen oxides (calculated as NO2) per joule (93 pounds per billion Btu) of heat output; and is certified in accordance with Section 239.4 B.
    2. A mobile home natural gas-fired water heater that emits less than or equal to 50 nanograms of nitrogen oxides (calculated as NO2) per joules (116 pounds per billion Btu) of heat output; and is certified in accordance with Section 239.4 B.
     

239.4 ADMINISTRATIVE REQUIREMENTS:

  1. COMPLIANCE SCHEDULE: Effective December 1, 1998, no person shall distribute, offer for sale, sell, or install any natural gas-fired residential water heater which does not comply with the requirements of Section 239.3 STANDARDS.
  2. CERTIFICATION REQUIREMENT:
    1. A manufacturer of any natural gas-fired residential water heater subject to Section 239.3 STANDARDS, shall submit to the Air Pollution Control Officer (APCO) at least 30 days prior to sale, a statement obtained from an independent testing laboratory, certifying that the laboratory tested the unit in accordance with the method in Section 239.5 MONITORING AND RECORDKEEPING of this rule, and that it is in compliance with the provisions of Section 239.3 STANDARDS. The statement shall be signed, dated, and shall attest to the accuracy of all information. The statement shall include the brand name, model number, the heat input capacity rating as it appears on the water heater rating plate, and test results in accordance with Section 239.5 MONITORING AND RECORDKEEPING; or
    2. A manufacturer shall submit to this District an approved South Coast Air Quality Management District certification. Any model of natural gas-fired water heater certified as complying with the South Coast Air Quality Management District's Rule 1121 prior to July 1, 1995, need not be recertified to the test protocol specified in Section 239.5 MONITORING AND RECORDKEEPING until such time as required by the South Coast Air Quality Management District.
  3. MANUFACTURER'S LABELING REQUIREMENT: A manufacturer shall display the model number of the water heater complying with Section 239.3 STANDARDS on the shipping carton and on the rating plate of each water heater unit. The manufacturer shall also display the certification status on the shipping carton and on the water heater.
  4. CALCULATION FOR DETERMINATION OF HEAT OUTPUT: The amount of heat energy, Ho, in British thermal units (Btu), absorbed by the water being heated during the process of natural gas-fired water heater testing in accordance with the protocol referenced in Section 239.5 A.. It is calculated using the following equation:
      Ho = MCpi (Tdel - Tin) + VstDnCp2 (Tmax - To) 
      • Where:
      • Ho = heat output, in Btu
      • M = mass of the water withdrawn, in pounds
      • Cpi = specific heat of water at the average temperature [(Tdel + Tin) / 2], Btu per pound per oF
      • Tdel = average delivery temperature, oF
      • Tin = average inlet temperature, oF
      • Vst = storage tank capacity, in gallons, as determined in Section 239.2
      • Dn = density of water at the average temperature [(Tmax + To) / 2], pounds per gallon
      • Cp2 = specific heat of water at the average temperature, [(Tmax + To) / 2], Btu per pound per oF
      • Tmax = maximum mean tank temperature recorded after cutout following the test draw, oF
      • To = maximum mean tank temperature recorded prior to the test draw, oF
       
  5. CALCULATION FOR DETERMINATION OF STORAGE TANK CAPACITY: The capacity of the natural gas-fired water heater in gallons. It is calculated using the following equation:

      Vst = (Wf - Wt) / Ds

      • Where:
      • Vst = storage capacity of the water heater, in gallons
      • Wf = weight of the water heater completely filled with water, in pounds
      • Wt = weight of the empty water heater, in pounds
      • Ds = density of water at the test temperature, in pounds per gallon

239.5 MONITORING AND RECORDKEEPING

  1. TESTING PROCEDURE: Any natural gas-fired water heater distributed, offered for sale, sold, or installed within the District shall be tested in accordance with the South Coast Air Quality Management District Protocol: Nitrogen Oxides Emission Compliance Testing for Natural Gas-Fired Water Heaters and Small Boilers, January 1995.
  2. DURATION OF RECORDS: A manufacturer shall keep test reports and certification records for as long as the water heater model is offered for sale or sold in the District, or for three calendar years after manufacture, whichever is longer. These records shall be made available to the Air Pollution Control Officer upon request.