Pool fire example

Class 1B flammable liquid, if released at atmospheric pressure and ambient temperatures, forms a pool of flammable liquid that, if ignited, develops into a pool fire. If delayed ignition occurs, experience has shown a flash fire may result. For the example under consideration, explosions are extremely unlikely because ... 

Efficient fire protection is also based on the consideration of product or scenario-specific hazards, which may lead to very specific materials development goals. Examples are the combination of impacts, such as vandalism and ignition source for seats in railway vehicles, or a preceding shock wave before the fire impact in navy applications. Some more product-specific phenomena of such kind are related directly to material properties, such as building up an increased risk for pool fires through burning thermoplastic plastics or dripping foams, and thus have become topics in the development of some flame-retarded materials.103... 

The difference between RANS and LES is depicted in Figure 20.1, which shows the temperature fields of a pool fire flame. While the RANS result shows smooth variations and looks like a laminar flame, the LES result clearly illustrates the large-scale eddies. Both results are the correct solutions of the corresponding equations. However, the time accuracy of LES is also essential for the quantitative accuracy of the buoyancy-driven flows. As Rehm and Baum have shown [10], the dynamic motions or eddies are responsible for most of the air entrainment into the fire plumes. Because these motions cannot be captured by RANS, LES is usually better suited for fire-driven flow. LES typically requires a finer spatial resolution than RANS. Examples of RANS-based fire CFD models are JASMINE, KAMELEON [11], SMARTFIRE [12], SOFIE [13], ISIS [14], and ISIS-3D [15]. Examples of LES models are the FDS [4,5] and SMAFS [16], developed at Lund University. Fire simulations using LES have also been performed by Cheung et al. [17] and Gao et al. [18],... 

The product, conditions on the line, and conditions in the surroundings affect consequences. For example, high-pressure gas lines, which may fail by rupture, can result in a jet fire that is usually oriented vertically. The fire burns with intense heat and the primary threat is from the heat radiation within a certain distance from the fire. Flammable liquids can also burn by jet fires, but also offer the potential for a pool fire. The potential for a specific type of fire (or even a vapor explosion) varies with a number of conditions, including product... 

Data in Table 11.10 from the Cone Calorimeter indicate that the burning behaviors of polymers are similar to those indicated by the data in Table 11.9 from the Fire Propagation Apparatus. Ordinary polymers (which are thermoplastics and melt easily) have very high heat release rates in the range predicted for the liquid pool fires. For example, for the boiling liquid pool fires of PE, PP, nylon 6, and ABS, 2di values at 50 kW/m are in the range of 1133-1304 kW/m from the Cone Calorimeter (Table 11.10) and 1004-1341 kW/m from the Fire Propagation Apparatus (Table 11.9). 

If the release forms a vapor cloud that premixes with air before ignition occurs, and turbulence is developed (for example, by the flame front propagating through a process structure), the flame speed can accelerate sufficiently to cause a blast. This event is referred to as a vapor cloud explosion. In addition to blast effects, radiant heat and flame contact effects may also occur. Flashback to the source may cause a pool and/or jet fire. 

Identifying and analyzing fire hazards and scenarios is the next step in a fire risk assessment. The hazard identification should be structured, systematic, audit-able, and address all fire hazards, including nonprocess fires. The result of the hazard identification is a list of potential fire hazards that may occur at the facility, for example, jet, pool, flash, BLEVE, electrical, or Class A fires. This list should also include the location where each fire could occur. Hazard identification techniques used to identify potential hazards are shown in Table 6-1. 

Dilution is used to mitigate hazardous releases, especially releases that form liquid pools. If properly implemented, the addition of an appropriate diluent to a liquid spill can have beneficial effects. Dilution can be employed to reduce the vapor pressure of the spilled hazardous material. It may also chemically combine with the hazardous material and render it nonhazardous. An example of this would be the use of water to dilute spills of a water-soluble material, such as acetone. Acetone is very soluble in water, and as it is diluted, the vapor pressure of the acetone above the mixture is reduced, commensurately reducing the potential for ignition and fire. However, to be effective there must be adequate volume available to obtain a satisfactory dilution and a way to dispose of the acetone-water mixture in an environmentally sound manner after the initial crisis has passed. 

How can matters improve when 10 percent or less of the applications for faculty openings in chemistry come from women, although the candidate pool is at 33 percent One way is to stop accepting the male dictionary as the operative lexicon. Women and men must challenge the standard terms and patterns and expectations. For example, most university faculty search committees are not really search committees they are manila-envelope-opening committees. These committees do not seek out new life forms (i.e., women and minorities). If a life form sends in a manila envelope, the committee will open it, but the members of the committee are not going out there to search for new life forms. Universities understand that to build competitive functional teams, recruitment is absolutely vital—they would fire their basketball coach if he didn t do it. Chemistry departments also have to recruit what they need, and they need women. Chemistry departments already recruit the men they want as faculty. 

Finally, an oxyradical can have two less oxygen atoms than the base state. The oxyradical name will now have a hypo prefix and the suffix will be ite. An example would be aluminum hypophosphite. In the following example, calcium is combined with the oxyradical hypochlorite the resulting compound is calcium hypochlorite, a common swimming pool chlorinator. Calcium hypochlorite is an oxidizer and a fire risk when in contact with organic materials. 

It is difficult to identify effective lagging indicators for use with process safety. The most obvious problem is that major PSIs do not occur frequently enough to develop a statistically significant trend such as that shown in Figure 2.3. If many facilities and companies pool their data it may be possible to that some trending results can be developed. However, such results are always open to doubt, not least because different organizations define terms differently. For example, the Baker report (Baker, 2007) provides a list of events that fall under the term fire. That list includes a fault in a motor control center. It is questionable as to how many organizations would call such an event a fire unless it resulted in actual flames. 

The spiff mix contains sodium carbonate (soda ash, often available from swimming pools), bentonite (clay cat litter), and dry sand (Armour et al., 1999). The rationale for choosing these components for the spiff mix was as follows. The sodium carbonate at least partially neutralizes any acid in the spiff, thus rapidly reducing the corrosive impact of the acid on the surface where the spill occurred. The bentonite absorbs liquid and vapors effectively, and the sand moderates and helps to smother any reaction that may occur (for example, in a spill of a solution of lithium aluminum hydride in ether, there is a risk of fire). 

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