 High Expansion Foam Systems for Critical Confined Areas

Preamble

'A small fire which started in a plastic scrap at a warehouse near Sanauri Adda, Patiala on night of st October 31 quickly became a major accident. Plastic scrap acted as a readymade fuel for the fire. Though, no one was hurt in the incident, a major tragedy was averted due to presence of mind and immediate action from local fire services. It took as many as 23 fire tenders around 11 hours to control the blaze.'

A news like this is increasingly finding place in the everyday newspaper. As India is witnessing rapid industrial growth with newer industrial hubs flourishing day by day, the need for fire protection is also increasing significantly. Many of the industries are moving towards larger factories, bigger warehouses and larger confined areas for critical application. High expansion foam systems definitely answers to these constraints and requirement making it one of key system whose time has arrived to make Indian industry safer.

With improvement in India's rank in ease of doing business, new and more industrial hubs are being built and flourishing with increased FDI having favourable environment for industries. With this new trend in industrialization, there is a considerable increase in investment in industries and sectors such as Petrochemical, Chemical, Pharma, Automobile, Aviation, Oil & Gas, and Warehouses etc. As per latest data from GOI's national investment promotion and facilitation agency, India is the th5 largest market in terms of aircraft passengers (domestic and international), we are rd3 largest biotech destination in the Asia Pacific Region having 9 Biotech parks, we are th6 in the world in Chemicals sales and contributes 3% to global chemical industry, we are nd2 largest refiner in Asia having 4.56% CAGR for Gas consumption, we are rd3 largest pharmaceuticals industry in the world by volume and th4 largest vehicle market having 40% share in global R&D. With this there is significant increase in chemical and petrochemical warehouses, aircraft hangers and LNG consumption, automobile manufacturing etc. there are the industries which has large number of critical application and processes including confined areas for machineries, storage of materials and products, process areas etc. Critical industrial applications and process areas are largely confined structures and size of which varies as per process requirement. These are termed critical as they handle the vital process part of any industrial processing and may contain high value machineries, materials, products or process areas etc. Whenever a fire breaks out in any such critical confined area, we depend primarily on a firefighting system that detects & deploys quickly, is effective and safe for personnel. Generally and majorly it includes initial water sprinkler/spray systems that immediately detects the fire on occurrence and deploys the water application quickly. However the purpose of these primary systems is limited to their immediate activation and to contain the further fire spread till any emergency personnel are deployed at site to

HIGH EXPANSION FOAM SYSTEMS

FOR CRITICAL CONFINED AREAS

take the fire further to its complete extinguishment using various applications that includes hand nozzles, monitor equipment etc. Many a times the firefighting at these critical areas with such equipment has limitations of space or resources availability during actual fire scenario.

Understanding the criticality and value of assets protected under these critical areas, there is a need of having a reliable and fixed systems that not only includes detection and initial application but also has an ability to extinguish the fire completely and quickly minimizing the damage to process area saving larger costs.

High expansion foam systems is a perfect solution for such hazards and conditions. High expansion systems include fixed as well as portable equipment and aim to create foam at an expansion ratio in excess of 400:1. As the systems are designed in consideration of actual fire contingency, hence the application and operation of firefighting is available without any resource or space constraints. This helps in faster extinguishment of system and in turn limiting the commercial losses as time a factor that decides quantum of loss in these scenarios. These areas are demand a specialized solution which is fast, effective, and cost efficient.

Conventionally, larger covered/confined areas are protected by deluge sprinkler system or foam water sprinkler system. Both these systems are designed to contain the fire rather than extinguish the fire. Also these conventional system are water intensive thus require large water storage and availability. When in many of the parts of the country, industries are struggling to meet their process water demand, conventional systems stretches this further and intensifies the problem. High expansion foam system is uniquely placed to address these challenges.

Introduction to high expansion foam system

High expansion foam system was first developed and experimented with in Buxton, England through the Safety in Mines Research Establishment in order to cater to a difficult solution of quickly extinguishing fires in coal mines in the year 1950s. The objective of the system was to quickly flood the available space with expanded foam to smother the fire.

High expansion system creates foam at an expansion ratio in excess of 200:1. The effectiveness of High expansion foam systems is very high as it attacks fire in 4 ways - 1. Smothers the fire 2. Insulates of the combustibles from air 3. Penetrating effect of the water/foam solution 4. Cooling

OXYGEN HEAT

CHAIN REACTION FUEL

Fig.1 Fire Triangle and its components

Hence high expansion foam systems are one of the most suitable systems to extinguish three-dimensional fire hazard in most effective way. As high expansion foam system has a very high ratio of foam expansion, this system requires very less amount of water minimizing the overall water damage.

Water vapour Foam crawls slowly to cover complete fuel surface

Dilution effect Cooling Isolation effect

Diesel

Aqueous film Foam layer

Few inches thick foam blanket

Fig.2 Difference showing Low Expansion Vs High Expansion Foam working

Entire void is filled with foam

As the systems are designed in consideration of actual fire contingency, hence the application and operation of firefighting is available without any resource or space constraints. This helps in faster extinguishment of system and in turn limiting the commercial losses as time a factor that decides quantum of loss in these scenarios.

Working Principle & Conclusion

High expansion foam system equipment such as generator works by blowing foam solution against a net or screen, creating many large bubbles, allowing a blanket of foam to take up a large volume. The complete system comprised of storage unit, proportioning unit and discharge units. Storage and proportioning units can be installed closer or away from actual application area depending on space availability and system hydraulic calculations. The storage unit functions for storage of high expansion foam whereas proportioning unit function for proportioning of foam as per foam concentrate composition in a ratio of 1% to 3%. The size and quantity of storage is based on proportioning ratio, operation time, volume of confined area and total foam solution demand of discharge equipment. The capacity of discharge equipment is selected based on minimum operation time to completely fill the volume hence making these system highly effective in quick extinguishment.

Main Hydrant Line

High Exp Foam Generator

Deluge Valve

Fire Detection System Bladder Tank with Proportioner

Fig. 3 Typical System Components of High Expansion Foam System

The environmental impact of the fluorocarbon surfactant used in some firefighting foams has been criticized in recent years. High expansion foams do not contain this surfactant and are overall low in toxicity making them environment friendly. As High expansion foam has large volume it covers a large area quickly. The high expansion foam hence are effective in extinguishing fire and insulation of material surface. Because of presence of large number of bubbles and very light weight nature, it contains a large amount of air and

For generation of High expansion foam, equipment used includes portable and fixed foam generators. The water content in expanded foam compared to low expansion version is minimal. High expansion foams are unique as their expansion ratio is very high - more than 200 times of its original concentrate volume. That means the quantity of foam concentrate required to cover larger space is very little unlike the low expansion foams. In the event of system activation, the entire volume of these spaces are quickly filled with expanded foam in a matter of minutes, eliminating oxygen and cooling the fire. The quick expansion of this foam in these high risk environments can stop and limit major catastrophes, saving lives and assets.

Low expansion foam High expansion foam

1m3 of low-ex foam solution (foam + water) can practically only expand 10m3 of foam (expansion 10) 1m3 of hi-ex foam solution (foam + water) can expand to 1000m3 of foam (expansion 1000)

Fig.4 Difference showing effectiveness of Low Vs High Expansion Foam

Applications

The criticality of highlighting the new trends for high expansion foam system application arises with recent major incidents resulting in large scale damages that includes critical and larger areas such as Aircraft hangars, cellars, and large enclosed spaces, Cable tunnels & ducts, high flammable liquid storage, Gas turbine generators, LNG facilities, Hazardous Chemical and waste storage, Machinery spaces, Mining Paper product & tire warehouses, Power stations, Ship engine rooms, Transformer rooms etc. The applicable generally includes dry product fires or within the premises/contained areas with mixed fire risks (class A and class B fire)

Some major fire incidents recently hit the news headline that includes major fire incidents in chemical warehouses, product storage warehouse, process areas, LNG gas etc. (Refer the news publishing as mentioned in references). Considering the assets under fire, the cumulative effect on operation and losses are huge. High expansion foam system can solve this problem and limit these losses to a larger extent.

Apart from these, high expansion foam systems also finds application in power stations and transformer rooms. Hence overall these systems can act as a solution to wide range of fire scenarios covering multiple industries.

High expansion system is one of the most effective system for suppressing LNG vapours after accidental spill. Foam is an effective method for reducing and controlling fire intensity and decreasing LNG vapour generation. It also has an effective application in suppression of ammonia vapours which is a part of ammonia storage facility in all fertilizer industries.

Medium and high expansion foams are suitable for liquefied gas spills in tank farms both for fire extinguishment and vapour suppression purpose. The surface of the foam in contact with the liquid forms an icy appearing slush which insulates and protects the upper layers of foam, and that in turn acts by reducing the evaporation rate from the liquid. Another important advantage is the relatively low amount of heat transmitted to the liquid by water draining from high expansion foams.

Conclusion

Hence considering the overall reliability, effectiveness & cost implication the high expansion foam systems proves to be highly efficient for fire extinguishment of critical confirmed areas. With the increasing need of high quality and most effective systems, high expansion systems is a need of an hour to protect high assets in confined areas. As the similar systems can be extrapolated for wider industry application, these systems proves to be one of the best in class.

MR. SASMIT PHALAK

Associate Vice President - Sales and Markeng sasmit.phalak@firetechindia.com