Base of a Pool Fire
The term “base of a pool fire” usually refers to ground level but could be at any level at which a substantial spill or pool fire could be sustained. Various classes of vessels are operated only partially full. Table 5 gives recommended portions of liquid inventory for use in calculations. Wetted surfaces higher than 7,6 m (25 ft) are normally excluded because pool fire flames are not likely to impinge for long durations above this height. Also, vessel heads protected by support skirts with limited ventilation are normally not included when determining wetted area. The user shall specify whether to include the wetted surface area of connected piping in the wetted area calculation.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global Standards