"True vapor pressure" means the equilibrium partial pressure exerted by a VOL as determined in accordance with methods described in American Petroleum Institute (API) Chapter 19.2, "Evaporative Loss From Floating Roof Tanks", second edition, September 2003.
N.H. Admin. Code § Env-A 1204.53
(See Revision Note at chapter heading for Env-A 1200) #9933, eff 6-1-11