Rule 64. Sulfur Content of Fuels

(Adopted 5/23/72, Revised 6/17/80, 9/9/80, 7/5/83, 6/14/94)

A. Applicability

This rule is applicable to any person who burns fuels containing sulfur compounds from any source whatsoever.

B. Requirements

  1. No person shall burn at any time gaseous fuel containing sulfur compounds in excess of 50 grains per 100 cubic feet of gaseous fuel (788 ppmv), except for natural gas which is limited to 15 grains per 100 cubic feet (236 ppmv), calculated as hydrogen sulfide at standard conditions.

  2. No person shall burn at any time any solid or liquid fuel, unless the emissions from the combustion of such fuels are reduced to a level less than the emissions which would occur from the uncontrolled combustion of solid and/or liquid fuels with a sulfur content of 0.5 percent, by weight.

C. Exemptions

The provisions of Sections A and B of this Rule shall not apply to:

  1. The use of solid fuels in any metallurgical process.

  2. The use of fuels where the gaseous products of combustion are used as raw materials for other processes.

  3. The use of liquid or solid fuel to propel or test any vehicle, aircraft, missile, locomotive, boat or ship.

  4. The burning of sewage treatment plant waste gases provided that the fuel used to incinerate such gases does not contain sulfur or sulfur compounds in excess of the amounts specified in this Rule.

  5. Any flare gas combustion, where no useful energy is produced and which is subject to Rule 54, Sulfur Compounds.

D. Test Methods

  1. The sulfur content of gaseous fuels shall be determined by South Coast AQMD Method 307-94 - Determination of Sulfur in a Gaseous Matrix.

  2. The sulfur content of liquid fuels shall be determined by ASTM Method D4294-83 or D2622-87.

E. Definition

  1. "Natural Gas": Natural gas is a gaseous fuel purchased or transported under a Federal Energy Regulatory Commission or a California Public Utility Commission jurisdictional tariff.