superiority of simplicity
Details of a high-end foam system
With its immediate and overpowered reaction, the FoamFatale storage tank foam system makes a huge step forward in protecting the environment against the damaging effects of storage tank fires.
1. Abstract
The highest level of protecting the environment is provided by successful prevention.
The fire itself causes the primary environmental effect. In addition to the value of the material destroyed by the fire, the environment, as such, our common treasure, also suffers. In most cases, combustion products are highly damaging to our health. By burning fossil fuels, the atmosphere’s composition changes since carbon stored for millions of years in solid or liquid form is again released into the atmosphere as carbon dioxide gas. And since uncontrolled fires always result in incomplete combustion, all kinds of by-products are also released into the atmosphere.
Using extinguishing materials causes the secondary environmental effect of the storage tank fire extinguishing.
Using vast quantities of firewater can cause environmental damage when the polluted water use cannot be appropriately collected afterward and treated before it is released into the environment. The use of artificial extinguishing materials always causes environmental pollution.
The level of pollution, i.e., the secondary environmental effect, depends mainly on the quality of the extinguishing material used and the application technology because these two factors define the quantity of the material necessary to extinguish a given fire.
Depending on the degree and speed of natural decomposition of the used extinguishing materials into harmless components, the period the environment is under strain is determined.
We call a storage tank foam system “environmentally friendly” when it uses only natural extinguishing materials (water and gases, like nitrogen or argon, which are extracted from the air).
We call a storage tank fire extinguishing technology “environmentally aware” when it uses artificial (but not hazardous) materials for the extinguishment, but when compared to other technologies, the application will result in:
- the shortest period between the outbreak of the fire and extinguishment
- highly efficient and effective use of the smallest possible amount of extinguishing agent
Setting up and managing proper storage tank fire extinguishing facilities on hydrocarbon storage facilities operating under extreme conditions nearly always requires a non-traditional approach.
The traditional method is not suitable when there are no firewater sources available.
Examples are sites operating a substantial part of the year under very low ambient temperatures and storage sites in arid desert areas. Other examples are mobile military fuel storage facilities without access to a high-performance firewater network.
Sometimes, the owner has no choice but to operate without fire protection.
Building, maintaining, and operating firewater networks with heated reservoirs and pipelines in very low-temperature situations would be prohibitively expensive. Such facilities are typically required when using the traditional fire protection methods as recommended by, e.g., NFPA.
2. Conventional foam systems, the reason for a low success rate
The traditional approach is to apply foam with mobile, semi-fixed, and fixed equipment.
Foam proportioning
To create the foam, the foam concentrate must be mixed with water in the correct proportion. However, the operating range of the equipment used for this process is always limited, and it can be challenging to achieve the desired mix. Additionally, the proportioner may not respond well to sudden changes in flow. Various proportioning systems range from simple but unreliable to sophisticated but delicate electronic systems.
Foam generation
Enrolling air into the foam solution stream is necessary to make expanded foam. Venturi-type aspirating devices are typically used for this purpose. The delicate balance between flow rate, upstream pressure, and backpressure determines the proper functioning of such a device. Optimum performance can only be achieved in a relatively narrow operating range. Blockage, or partial blockage, of the small-bore air inlet often occurs in fixed systems in locations where maintenance is not optimal. This results in malfunctioning.
Dependence on water
Firewater availability is essential in conventional storage tank fire extinguishing foam systems (including the CAFS). Several steps are required to convert foam concentrate, water, and air into expanded foam. The expanded foam can subsequently be applied onto the burning surface. In the majority of cases, these activities take place close to the scene of the fire. A trained workforce is required to set up these relatively complicated systems. Given the stressful situation during any fire, mistakes are likely to be made, resulting in the mal-performance of the system. Unmanned storage sites cannot count on a turnout of sufficient firefighters within a reasonable time.
Over the past decades, the user had no choice but to accept these complicated and expensive systems. Sites that had no access to adequate water were left without protection. The owners/management, the Fire Administration, and the Environment Protection Authorities had to accept the situation.
Conclusion
There are sites where:
- The implementation of conventional fire protection systems is facing serious technical problems
- The cost to set up an installation complying with NFPA recommendations is too high
- There is insufficient workforce available at short notice to operate a labor-intensive mobile or semi-fixed system
- There is a need for an acceptable level of reliability
A different foam-making and application method was developed, solving the foam intensity and firewater-related problems described above.
The automatic and autonomous storage tank fire extinguishing system responds with full power immediately after the ignition without requiring any external water or energy supply. It is considered to be representative of the Best Available Technology (BAT) today. The closed foam blanket covers the fire surface for a maximum of two minutes from the ignition. Thus, there is no time for developing environmentally dangerous smoke or soot, and a significant part of the stored material is also saved.
This is FoamFatale
2. Description of the high-performance automatic and autonomous foam system
Storage tank fire extinguishing by superintensive foam flooding
- FoamFatale is a revolutionary storage tank foam system with a high application rate. It is called Superintensive Foam Flooding (SFF)
- The new foam introduction device provides a high foam flow rate, accommodating the massive foam flow and preventing excessive velocities in the nozzle. It is called a Continuous Linear Nozzle (CLN). The CLN provides an ideal curtain-like foam application pattern, thus providing substantial and continuous cooling of the tank wall
- One of the advantages of the Self Expanding Foam (SEF®)concept is that it has no release rate limitations. Combining the method with the high-capacity CLN makes achieving 20-40 liters/minute/square meter application rates easy. This can fulfill the requirements of the Dynamic Tactical Rules.
- The result of this combination is a highly efficient system. The system’s reliability is very high; the valve is the only moving part.
- The SEF® storage vessel can be stationary in the vicinity but at a safe distance from the hydrocarbon tank. An alternative option, requiring some intervention by human resources, can be a mobile SEF® storage vessel mounted on a truck.
The method eliminates the limitations of outdated foam systems
Foam Supply Device: the FoamFatale Pressure Vessel (FFPV)
- Self Expanding Foam is prepared in advance, under calm and controlled conditions, during the installation of the FoamFatale foam system. This eliminates the probability of an off-spec composition of the foam
- The pre-mixed foam is stored in a pressure vessel until the moment of use
- The foam remains homogenous for at least ten years, as experience has shown
- There are other pressurized storage units available
Dimensions of SEF® vessels
- Static SEF® pressure vessels can be massive. The maximum amount of foam stored is limited only by mechanical manufacturing constraints.
- Another limiting factor is likely to be the maximum size of the transporting vehicle and the total axle load allowed on the road network to be used.
- Larger amounts of foam premix can be stored in multiple pressure vessels connected if needed.
Foam Introduction Device: the Continous Linear Nozzle (CLN)
- FoamFatale uses another proprietary innovation: the Continuous Linear Nozzle, instead of point-like foam introduction devices such as discrete nozzles. This “nozzle” is actually an orifice cut into a ring-shaped tube that is mounted around the top rim of the storage tank, all over its circumference
- CLN provides the ideal foam flow pattern that was never seen before. Unlike the point-like pattern, the curtain-like foam introduction on the whole perimeter of the tank shell immediately exerts its protective effect: it flows down the tank wall, cooling it immediately, thus protecting the most vulnerable part of the storage tank: its shell from the damaging effects of heat, and reaching the surface of the burning liquid, the foam front moves inwards from the tank shell, keeping flames and heat away from the tank wall from the very first moment of the extinguishing
- Another essential advantage of CLN is that, unlike other nozzles, there is no chance of clogging
- If we calculate the total area of the orifice, we can immediately understand why there is no upper limit to the foam intensity
Let the foam flow
- On release of the SEF®, the pressurized foam will expand. This, in turn, eliminates the need for aspirating devices
- The release rate of the foam from the vessel is not bound by conventional limitations, like aspirating devices and such
- The expansion ratio of the foam is independent of the flow rate; the pressure in the foam vessel is the only factor determining the expansion
Operation of the system
- The operation of the whole system is effortless. All that is required is to open the isolation valve between the pressurized SEF® storage vessel and the foam application device
- The simplicity eliminates the need for specialists to operate the system successfully
Advantages of the FoamFatale™ system over other systems
- Can provide any desired foam intensity, thus forming a closed foam blanket even in the most intense fire
- Its reliability level is very high: the CLN can hardly be damaged by explosions or fire
- It is sabotage-proof; the fire protection system of a tank farm built by our method has no common elements, like a fire water system, which, when destroyed, would cause the malfunction of fire protection systems using firewater
- Environmentally aware: FoamFatale doesn’t use more foam than is necessary for safe extinguishment. None of a drop of foam gets outside the storage tank
- Requires considerably lower CAPEX
- Requires considerably lower OPEX
- The system is fully autonomous
- Does not require firewater at all
- It does not require external energy sources, like a fire truck or electric pump
- It is so simple that mistakes under stressful fire conditions are unlikely
- Automatic operation of the system further reduces air pollution caused by the fire
- Its simplicity eliminates the need for specialists to operate and maintain the system
- It uses perfectly proportioned foam mixed under calm and controlled conditions
- The foam is stored under pressure; no pump or other pressure-raising source is required
- The pressure of the container determines the expansion; no aspirating device is required
- Produces optimum quality foam at all flow rates
- Provides total safety at a modest cost
- Has only a few key elements requiring regular inspection
Real fire demonstration
Live demonstrations of this 500 m2 gasoline fire repeatedly proved that after 40 seconds, the fire went out so abruptly as if it had been cut off. An automatic version of such a storage tank fire extinguishing system will extinguish massive tank fires within two minutes of ignition without intervention from any person.
3. Some other applications where the FoamFatale® concept can be used
