SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT

RULE 474 - FUEL BURNING EQUIPMENT - OXIDES OF NITROGEN
(Adopted May 7, 1976)(Amended October 8, 1976)(Amended December 4, 1981)

(a) A person shall not discharge into the atmosphere from any non-mobile fuel burning equipment, oxides of nitrogen, expressed as nitrogen dioxide (NO2), calculated at three percent oxygen on a dry basis averaged over a minimum of 15 consecutive minutes, in excess of the concentrations shown in the following table:

Maximum Gross Heat Input Rate in Millions Per Hour

Fuel Kilogram - Calories British Thermal Units Kilogram - Calories British Thermal Units Kilogram - Calories British Thermal Units
  140 or more but less than 450 555 or more but less than 1786 450 or more but less than 540 1786 or more but less than 2143 540 or more 2143 or more
Gas

300 ppm NOx

225 ppm NOx

125 ppm NOx

Liquid or Solid

400 ppm NOx

325 ppm NOx

225 ppm NOx

(b) A person shall not discharge into the atmosphere from steam generating equipment, oxides of nitrogen dioxide (NO2), calculated at three percent oxygen on dry basis averaged over a minimum of 15 minutes, in excess of the concentrations shown in the following table:

Maximum Gross Heat Input Rate in Millions per Hour

 

Kilogram - Calories

British Thermal Units

 

140 or more

555 or more

Gas

125 ppm NOx

Liquid or Solid

225 ppm NOx

The provisions of this subsection shall be effective only in San Bernardino and Riverside Counties.

(c) When more than one type of fuel is used, the allowable concentration shall be determined by proportioning the gross heat input for each fuel to its respective allowable concentration.

(d) Notwithstanding the provisions of subsection (a), a person operating a supercritical steam generating unit with a maximum gross heat input exceeding 2143 million BTUs per hour may discharge oxides of nitrogen into the atmosphere not to exceed 400 ppm calculated at three percent oxygen on a dry basis averaged over a minimum of 15 consecutive minutes during the pressure ramp periods of the boiler startup operations.

(e) For the purpose of this rule:

  1. FUEL BURNING EQUIPMENT shall be comprised of the minimum numbers of boilers, furnaces, jet engines or other fuel burning equipment, the simultaneous operations of which are required for the production of useful heat or power.
  2. A SUPERCRITICAL STEAM GENERATING UNIT is a steam boiler which normally operates above the water critical temperature (705oF) and critical pressure (3210 psia) where water can exist only in the gaseous phase.
  3. PRESSURE RAMPS are two steam pressure build-up periods, after a heat-soak period at 400 psia in the startup of a supercritical steam generating unit:

    (A) Low pressure, 400 psia to 1000 psia, and

    (B) High pressure, 1000 psia to 3500 psia.