It may sound far-fetched but one day sound may be the method of choice for putting out fires.
A recent feature on BBC’s The One Show programme demonstrated how certain low frequency sound waves can be used to extinguish flames. The clip featured a large sound system that produced low pitched bass notes. The idea was that the sound from the speakers would be used to put out the candles on a birthday cake.
When the sound was played, it took a few seconds but eventually the flames began to flicker and then went out completely. This proved the theory that sound waves could be effective as a new approach to firefighting, although it’s still early days.
There are safety concerns with this method, as at this frequency sound is more felt than heard and may pose a potential risk to health, particularly if people are exposed to it over a long period of time.
How sound waves extinguish flames
The US Defence Advanced Research Projects Agency (DARPA) has been investigating the potential of sound waves to fight fires. In a video issued by them, after fewer than 10 seconds of being exposed to a low frequency sound you can clearly see the flame is extinguished.
How this works is that the sound waves disrupt the flame by increasing air speed and thinning the layer where combustion occurs. The acoustics also disturb the surface of fuel, increasing vaporisation resulting in the flame widening and temperatures inside the flame cooling.
Cooling the temperature of a flame removes heat, which is one of the essential elements that keep a fire burning. Without heat present a fire will go out. This factor is used by water based fire extinguishers which put out fires by cooling them down.
It may take some time to find a practical way to use this effect and turn it into an effective alternative to current fire extinguishers, but the research is looking promising.
So who knows… perhaps in a few years from now, sound fire extinguishers will be the next big thing.
You heard it here first…Tags: fire extinguishers, new fire fighting technology, putting out fires, the one show
The British Standards feature a set of recommendations on the fire alarm and detection systems for businesses and other commercial properties.
Here’s a summary of the recommendations specified by the British Standards
British Standards Recommendations for Commercial Fire Alarm Systems
a) The category of fire detection and alarm system required should be stated in recommendations from the relevant enforcing authorities or insurers. This is so that there is no ambiguity over the most appropriate category of fire alarm system for a property.
b) The person responsible for purchasing of an alarm system for a commercial property should inform the system’s designer of the category of detection system required. This should for example be stated in tender specifications.
c) When no category is set in the requirements, it is the responsibility of the system designer to make it clear to the purchaser as to which category of system is proposed.
d) In situations a, b and c – further information as to the location of where fire detectors should be placed in a building should be provided. The only exceptions are for L1 or P1 systems
e) Category L1, L2, L3 and L4 fire detection systems (which are for the protection of life) should also satisfy the recommendations of a Category M system. A Category M system is one that is defined as needing manual operation/human input to activate the alarm.
f) In some cases, Category M manual fire detection systems may be required in conjunction with a Category P1, P2 or L5 system. Under these circumstances these will be named as follows:
- Category P1/M
- Category P2/M
- Category L5/M
g) When more than one category of system is required to satisfy your building’s fire alarm system requirements, this should be referred to in the following way:
- Category L2/P2
- Category L3/P2
h) The system design certificate is a document that should state the category of fire detection and alarm system designed. It should also include details on the areas of a building that are protected by automatic fire detectors. This is excepted in the cases where Category M, L1 or P1 systems are installed.Tags: british standards, commercial fire alarms, fire alarm systems, fire detection, fire protection