HSD storage tanks fabrication & fueling system

rowing global concern for the ecology, resulting in the worldwide ban on the production of the principal halogenated fire suppressants, has stimulated extensive research of new, environmentally acceptable substances. However, it has evidently been very difficult to create a chemical agent that meets all the desirable, and often contradictory, properties.

An ideal agent naturally must be highly effective at ignition and flame suppression, yet also be environmentally friendly, stable, and non-toxic for humans during and after application.

Fire prevention and control has long dealt with the familiar fire “triangle” consisting of heat, fuel, and oxygen, all three of which are required to initiate and support combustion.

It is also well established that nitrogen, constituting 79% of atmospheric air, can significantly influence combustion. Nitrogen molecules at common flame temperatures (lower than 1100 C) do not return the absorbed thermal radiation. Rather, it is continuously removed from the combustion zone by the convection process. Because of this, an increase of Nitrogen concentration in the air causes a mass – proportional increase in the total loss of emitted thermal energy, which inhibits combustion. Furthermore, increasing the nitrogen content in the gaseous mixture affects its molecular kinetic properties, reducing the availability of oxygen molecules for combustion.

The invention of FirePASS® is based on a discovery made during research conducted in the Hypoxic Room System manufactured by Hypoxico Inc. (www.hypoxico.eu) in New York. It was discovered that the processes of ignition and combustion in a normobaric, hypoxic environment are far different from the ignition and combustion process that occurs in a hypobaric natural altitude environment with the same partial pressure of oxygen (ie up a mountain).

For example, air with a 4.51″ (114.5 mm of mercury) partial pressure of oxygen at an altitude of 9,000’ (2700 m) can easily support the burning of a candle or the ignition of paper. However, if a corresponding normobaric environment is created with the same partial pressure of oxygen (4.51” or 114.5 mm of mercury), a candle will not burn and paper will not ignite. Even a match will be instantly extinguished after the depletion of the oxygen-carrying chemicals on its tip. Consequently, any fire that is introduced into this breathable normobaric, hypoxic atmosphere is instantly extinguished. Kerosene fuel, gas lighter or propane gas torch will not ignite in this environment either.

This surprising observation leads to an obvious question: “Why do two environments which contain identical partial pressures of oxygen (ie the same number of oxygen molecules per specific volume) affect the processes of ignition and combustion so differently?”

The answer is simple: “The difference in oxygen concentration in these two environments diminishes the availability of oxygen to support combustion. This happens due to the increased number of nitrogen molecules interfering with the kinetic properties of oxygen molecules”. In other words, the increased density of nitrogen molecules in the normobaric environment creates a “buffer zone” that obstructs the availability of oxygen molecules for combustion. When the kinetic properties of both gases are compared it is revealed that nitrogen molecules are both slower and have a lower penetration rate (by a factor of 2.5) than oxygen molecules.


Figure 1 presents a schematic view of the density of oxygen and nitrogen molecules in a hypobaric or natural environment at an altitude of 9,000’ or 2.7 km. (All other atmospheric gases are disregarded in order to simplify the following explanations). Blue circles represent oxygen molecules, and green circles represent nitrogen molecules.

Figure 2 shows the density of molecules in a hypoxic environment with the same partial pressure of oxygen (4.51” or 114.5 mm of mercury), but at a standard atmospheric pressure of 760 mm of mercury. This environment contains approximately 15% of oxygen by volume, which is perfectly suitable for human life, but is not sufficient to support combustion.
As can be seen, both environments contain identical amounts of oxygen molecules per specific volume. However, the relative amount of nitrogen molecules versus oxygen molecules is approximately 6:1 in the second case (Figure 2) compare to 4:1 in the altitude air (Figure 1).

 

Figure 3 shows ambient air at sea level with the greater partial pressure (159.16 mm of mercury) of oxygen than in the air found at an altitude of 9,000’ or 2.7 km (114.5 mm). It should be noted that ambient air in any portion of the Earth’s atmosphere (from sea level to the top Mount Everest) has an oxygen concentration of 20.94% by volume. However, the ambient air at sea level is under a substantially higher pressure: As the number of gas molecules per specific volume increases, so the distance between the gas molecules is reduced, and the availability of oxygen to support combustion is unaffected.