"True vapor pressure" means the equilibrium partial pressure exerted by a volatile organic liquid as determined in accordance with methods described in American Petroleum Institute Bulletin 2517, "Evaporation Loss From Floating Roof Tanks," second edition, February 1980 (incorporated by reference in 35 Ill. Adm. Code 218.112 and 219.112 ).
Ill. Admin. Code tit. 35, § 211.6770
Added at 17 Ill. Reg. 16504, effective September 27, 1993