The first section, 60.330, describes what gas turbines are subject to the rule. The rule basically states that any stationary gas turbine with a heat input at peak load equal to or greater than 10.7 gigajoules per hour (10 million Btu/hour), based on the lower heating value of the fuel, must meet the requirements in the rule. The word “stationary” is included in the rule so that aviation gas turbines (i.e. jet engines) will not be affected by the rule.

The rule also mentions the “lower heating value (LHV)” of the fuel. The gross heat that can be acquired from burning a fuel is called the “higher heating value (HHV).” The units of heating value are usually in Btu/lbm (Btu per pound-mass of fuel). The higher heating value includes the heat of vaporization of water, but the lower heating value does not. The higher heating value is therefore larger than the lower heating value. When a fuel is burned, the main exhaust products are carbon dioxide and water. In the LHV, the energy that was used to vaporize the water in the gas is not included. The heating value of the fuel affects the calculations that are made to determine the energy output of a gas turbine.

Section 60.330 (b) states that gas turbines built or modified after October 3, 1977 are subject to the requirements of the rule. However, Section 60.330 (b) refers to two exemptions to this statement listed in Section 60.332 (e) and (j). If construction of a gas turbine commenced before October 3, 1982 and the heat input at peak load is greater than 10 million Btu/hr (10.7 gigajoules/hr) but less than 100 million Btu/hr (107.2 gigajoules per hour), based on the lower heating value of the fuel, the gas turbine is exempt from the NO x requirements of the rule. This exemption is found in Section 60.332(e) of the rule.

The other exemption is for gas turbines that were required by the September 10, 1979 Federal Register (44 FR 52792) to comply with NO x standards. These exempt turbines must have a heat input at peak load greater than 100 million Btu/hr (107.2 gigajoules/hr) and commenced construction or had a modification between October 3, 1977 and January 27, 1982. The exemption does not apply to electric utility stationary gas turbines. Few gas turbines are able to meet the requirements of this exemption, since most gas turbines are used to produce electricity. This exemption is found in Section 60.332(j) of the rule.