10-7. Determine the relief vent areas for the following two-phase fire scenarios. Assume a spherical vessel in each case. a b d 72 Molecular weight Volume, ft Initial mass, lb Set pressure, psia Set temperature, F Maximum pressure, psia Maximum temperature, F Heat of vaporization, Btu/lb 72 5000 30,000 100 220 100 220 130 1.6 0.40 86 5000 15,000 100 220 5000 15,000 100 220 100 220 130 1.6 0.40 86 5000 15,000 100 220 150 275 150 1.6 0.52 130 240 150 1.6 0.52 Vig, ft/1b Cp, Btu/lb F