25 Pa. Code § 145.3
Measurements, abbreviations and acronyms used in this subchapter are defined as follows:
Btu—British thermal unit.
hr—Hour.
Kw—Kilowatt electrical.
Kwh—Kilowatt hour.
lb—Pounds.
mmBtu—Million Btu.
MWe—Megawatt electrical.
Ton—2,000 pounds.
CO2—Carbon dioxide.
NOx—Nitrogen oxides.
O2—Oxygen.
This section cited in 25 Pa. Code § 145.4 (relating to applicability); 25 Pa. Code § 145.5 (relating to retired unit exemption); and 25 Pa. Code § 145.81 (relating to opt-in source general provisions).