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Friday, April 3, 2015

extinguishing 'fire' by ........ "sound" - believe !!!

A fire accident can reduce a property to rubbles in hours  ~ it can cause damage to property, goods and sometimes to  fatalities and bodily injuries to humans too.  A Fire Insurance Policy provides financial compensation for loss or damage arising out of fire.  Negligence and indifference too contribute a big way and there are potential physical hazards of fire.

While elimination of fire hazard entirely may not be possible, fire safety would reduce to a large extent, the potential hazard of loss caused by fire.  Fire safety measures include those that are intended to prevent ignition of an uncontrolled fire, and those that are used to limit the development and effects of a fire after it starts.   Insurers analyse and rate the risks based on risk potential, probability of occurrence, severity of damage and many other factors.  The method of rating special hazards is more complex.  For better managed risks, they do offer discounts and one of the primary questions in any proposal is about the – fire fighting equipments available and the proximity to a Fire station. 


Portable Fire extinguishers (PFE) are small hand held appliances that are used to put out fires in the very early stage of their inception. There are different types of extinguishers in use and their classification is based on the types of fires on which they are effective. Hence an understanding of the types of fire is very essential in selecting the appropriate type of extinguisher for use in a particular location.

In old theatres, one would have observed bright  red coloured buckets containing sand and water.  A fire extinguisher, is an active fire protection device used to extinguish or control small fires, often in emergency situations. As we all know, Fire needs  “oxygen, heat and fuel” and primarily fire extinguishers put out fire by taking away  one or more elements of the fire triangle.  There are various types of fire – say of wood, cloth, plastics; oil, gas, flammable liquids; electrical and the like.  Depending on the type of fire, the extinguishers also vary – there are : water and foam fire extinguishers; equipments using Carbon Dioxide; dry chemicals; wet chemicals; dry powders and many other agents. 

In some industries, hydrant systems are installed.  As a measure of safety, the primary requirement would be at least  two extinguishers in every area/ room, distributed over the entire floor that they are available within 15 meters. One 9 litre water / sand bucket is to be provided for every 100 square meter of floor area and one 9 litre water type extinguisher is to be provided for every six buckets or part thereof with a minimum of one extinguisher and two buckets per compartment of the building.

While the occurrence of ‘fire’ could be unpredictable, controlling the damage depends on availability of fire fighting equipments, trained personnel, availability of water hydrants, space to reach, emergency exits and the like.  Every Risk Manager would advise that hand equipments are installed in places easily accessible and people trained in using these equipments, in case of a fire.  While the Insurers have been advising on the type of equipment to be kept in the insured premises, this newsitem from MailOnline might change the way of ‘safety equipments’ as fire can be extinguished using ‘SOUND’…. Yes, handheld gadget using pressure waves to remove oxygen from flames. 


Students at George Mason University, Fairfax, Virginia, made the device that works because low frequency noise separates oxygen from fuel !  The report that appeard in MailOnline on 26th Mar 2015 states that the thumping bass lines that go along with rap songs may exasperate some reluctant listeners, but such low noises can be used to put out fires. Two engineering students have built a handheld device that uses sound to extinguish flames - and the breakthrough could one day revolutionise firefighting. It works because the low frequency noise, which they liken to the 'thump' of hip-hop music, separates oxygen from fuel to stop a fire from burning.

A pair of engineering students has built a handheld device that uses sound to extinguish flames, which they claim could one day revolutionise firefighting. It transmits low frequency sound waves between 30 and 60 Hertz from the nozzle. The waves 'agitate' the air to effectively separate oxygen from the fuel.   The 20lb (9kg) device, which would not look out of a place in Ghostbusters film, was created by engineering students Seth Robertson and Viet Tran from George Mason University.  Initially, both students thought big speakers and high frequencies would douse a fire.  ‘But it's low-frequency sounds - like the thump-thump bass in hip-hop that works,’ Mr Tran said. He joked that rappers like 50 Cent could probably douse a fire, explaining that low frequency sound waves between 30 and 60 Hertz work best. When the device is used, humans with hearing between the typical range of 20 to 20,000Hz can hear the blast of sound. In particular, the acoustic field created by sound increases the air velocity around a flame. As this velocity rises it thins what's known as the flame's 'boundary layer'. This layer is where the combustion occurs

Seth Robertson and Viet Tran from George Mason University  were inspired to create their gadget after watching a Defense Advanced Research Projects Agency (DARPA) video showing how two giant tubes of sound waves can put out fire.  However, unlike the agency, the students managed to squeeze the idea into a portable device.  The device is powered by a pack worn on a strap over the shoulder. The new device has benefits such as being free of toxic chemicals and not subjecting buildings to water damage, and not subjecting buildings and other property on fire  to water damage.  Mr Robertson added: ‘Fire is a huge issue in space [where] extinguisher contents spread all over. But you can direct sound waves without gravity’.  The pair built the prototype using $600 (£400) of its own money.  More work will be required because the sound extinguisher has so far only been tested on small controlled blazes, using alcohol as fuel.

Interesting ~ learning for everyone including Insurers

With regards – S. Sampathkumar
27th Mar 2015.


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