Burning Pools

Pool burning time is defined as tlie time for tlie pool fire to bum itself out. It is ealeulated by... 

Applying Equation (7.2.10) tlie pool burning time is calculated as follow ... 

Determine the percentage of people who will die as a result of burns from pool burning if the probit variable Y is 4.39. Compare results from Table 2-4 and Equation 2-6. 

A burning pool of liquid or a volatile solid fuel will establish a stagnant film height due to the natural convection that ensues. From analogies to heat transfer without mass transfer, a first approximation to the liquid pool burning rate may be written as... 

Equation (5-5) assumes that the burning rate is constant. More detailed pool burning geometry models are available (Spouge, 1999). Circular pools are normally assumed where dikes lead to rectangular shapes, an equivalent diameter is used in the calculation. 

Most oil pools burn at a rate of about 3 to 4 mm per minute, which means that the depth of oil is reduced by 3 to 4 mm a minute. Several tests have shown that this does not vary significantly with the type of oil, the degree of weathering, and the water content of the oil. The standard burn rate is about 5000 L of oil per m2 per day (100 gal per ft2 per day). Thus, the oil spilled from a large tanker and covering an area about the size of the tanker s deck could be burned in about 2 days. The oil from two or three tanks from a typical tanker could be burned under the same conditions in about 6 hours. In-situ oil burning is the only technique that has the potential to remove such large quantities of oil in such a short time. 

In the 1950s, recovery of solvent from air, water or a solvent mixture was almost wholly motivated by the saving of cost it yielded. Destruction by pool burning of waste solvents was an acceptable practice for large respectable firms and solvent-contaminated water was air-stripped to transfer pollution from water to air. 

Burning Rate - Defined as the rate (in millimeters per minute) at which a pool of liquid decreases as the liquid bums. Details of measurements are provided by D. S. Burgess, A. Strasser, and J. Grumer, Diffusive Burning of Liquid Fuels in Open Trays, Fire Research Abstracts and Reviews, 3, 177 (1961). 

The final three phenomena, items 11 through 13, are addressed in the containment performance models of MARCH, accounting for mass and energy additions to the containment, the burning of combustible gases, the effects of core sprays, ice condensers, and suppression pools. MARCH calculates only the containment loads it does not model the containment failure. 

The literature provides little information on the effects of thermal radiation from flash fires, probably because thermal radiation hazards from burning vapor clouds are considered less significant than possible blast effects. Furthermore, flash combustion of a vapor cloud normally lasts no more than a few tens of seconds. Therefore, the total intercepted radiation by an object near a flash fire is substantially lower than in case of a pool fire. 

Combustion behavior differed in some respects between continuous and instantaneous spills, and also between LNG and refrigerated liquid propane. For continuous spills, a short period of premixed burning occurred immediately after ignition. This was characterized by a weakly luminous flame, and was followed by combustion of the fuel-rich portions of the plume, which burned with a rather low, bright yellow flame. Hame height increased markedly as soon as the fire burned back to the liquid pool at the spill point, and assumed the tilted, cylindrical shape that is characteristic of a pool fire. 

Calculate tlie liquid burning rate of an octane ground pool. The pool Itas a diameter of 4.0 m and a deptli of 4 cm. 

Calculate the total burning time of tlie octane pool in Illustrative Exatiiple 3. Calculate tlie peak overpressure of a 50-pound TNT explosion at a distance 200 feet from the ignition point, if tlie peak oi erpressure at 1000 feel is 0.10 psi when 150 pounds of TNT is detonated. 

Other seemingly solid fuel flames such as those from the burning of plastics are actually more like liquid pool flames because the plastic melts and vola-tizes ahead of the advancing flame front. 

The combustion of liquids is a fertile area for further study. Kowledge of the combustion science of individual droplets as well as groups of droplets helps improve performance of devices that rely on spray burning, particularly diesel engines. Understanding of the science of liquid pool fires potentially effects safety during spills. 

Fig. 18. Example of the linear effect of bulk fluid subcooling on burn-out for copper and iron wires with pool boiling of water at atmospheric pressure [from Farber (FI)].

Figure 2. The carbon dynamics of a primary forest prior to and following deforestation and slash burning. Arrows represent the relative magnitude of C flux. In the primary forest (represented by the large box at the top of the figure), the C pool is in a dynamic equilibrium with inputs approximately equalling exports. With deforestation and fire, the balance is altered with exports far exceeding imports.

---