Venting for Fires External to Process Vessels

More than adequate area exists on the outer wall of the enclosure to accommodate this vent. 

Both vent sizing methods for gases and dusts require values for the deflagration indexes, KG or KSt. We discussed the experimental procedure to determine these values and also provided tables of typical values for gases and dusts in chapter 6. 

Two-phase fire relief equations are available for conservative design. Leung19 presented an equation for the maximum temperature based on an energy balance around the heated vessel. This assumes a constant heat input rate Q  

Cv is the heat capacity at constant volume, m0 is the liquid mass in the vessel, 

The solution to Equation 9-34 for GTA is done by an iterative or trial-and-error technique. Equation 9-34 is likely to produce multiple roots. In this case the correct solution is the minimum mass flux GT. For the special case of no overpressure, Tm = Ts, and Equation 9-34 reduces to 

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