Frank Water Mist is the name of the fire extinguisher recently engineered by Frank Ryde, member of the International Water Mist Association, founder and CEO of Alpha Fire Services Pvt Ltd., Sri Lanka, founder/shareholding Director and retired CEO of Alpha Fire Services of Bahrain and Qatar.
He is attempting to commercialise the power of low-pressure water mist technology through the use of clever design and high quality, third party-accredited components.
The extinguishing capabilities of water mist are well known and, to summarise, water mist addresses all four elements required for fire to occur. A fire is a chemical reaction that involves rapid oxidation or burning of a fuel and, in order for a fire to occur, fuel, heat and oxygen need to be present for the chemical chain reaction needs to occur. While the removal of any one of these essential elements will result in the fire being extinguished, water mist’s efficacy lies in its ability to address all these elements simultaneously.
As water flashes into steam at the flame front it extracts a large amount of heat from the fire. At the same time, the volumetric expansion of steam at the flame front displaces oxygen that feeds it. Water mist droplets stop heat radiating and limit the spread of the fire while stripping smoke particles from the plume.
These unique properties are the result of the conversion of water into fine water droplets with a diameter below 1,000 microns, which increases the surface area available for heat absorption and evaporation. These droplets are therefore more effective than sprinkler water droplets in absorption, smoke scrubbing and heat blocking. And, given that the droplets are lighter, they remain airborne for longer and are therefore effective over a longer period of time.
One of the greatest advantages of water mist extinguishers lies in their versatility. They can be used on class A, B, F fires and, because water mist droplets are so small that they prevent electricity from travelling through them, class E fires (tested up to 35,000 volts).
‘In the USA, in recognition of its efficacy and superior benefits over CO2-based fire extinguishers, NASA commissioned ADA Technologies to develop high-pressure water mist fire extinguishers to be used on its spacecraft operating in outer space,’ comments Ryde, adding that high pressure water mist fire extinguishers are generally very expensive because thick, heavy, high pressure cylinder systems are required to atomise water to mist. Consequently, he invented water mist extinguisher that is pressurised at only 10 bar, which means that the cylinder is comparatively thin and less costly. The cylinder has already been tested and approved by Apragaz Belgium, TUV Germany and MPA Dresden Germany. The remaining components comprise a rotor, tubes and nozzle that together can produce over 22 billion droplets from a litre of water. Ryde explains how it works: ‘The cylinder or the tank housing maintains the contents of the extinguisher at pressure actuation. When the valve is released by manual action, the water and compressed gas travels towards the rotor via a black tube, controlled by a nozzle assembly. The rotor then starts to rotate, mixing the water and gas which travels via a white tube to the nozzle. Due to the collision of water streams, the water leaves the nozzle at high kinetic energy generating an ultra-fine mist made of water droplets as small as 25 microns in diameter.’
Ryde is convinced that the benefits of low-pressure water mist extinguishers are glaringly obvious: ‘Everywhere in the world you have to use one water and one CO2 extinguisher, or one CO2 and one powder or foam. So you pay for two extinguishers at the beginning, and then throughout its life you pay for the refilling of two extinguishers. And throughout their lives you are using a lot of chemicals – even if they are unused they still have to be topped up. Tonnes of CO2, foam and powder are being dumped continuously in the process of testing, servicing and filling. All that could be done and dusted where one cylinder does all the job.’
The system has received approvals in Sri Lanka for liquid, gas, electrical and cooking fires. ‘What we are looking for then is investment to gain LPCB, Australian, UL and Canadian approvals. I want to take it to the world,’ says Ryde who, although officially retired, is nevertheless currently building an eco-hotel in Sri Lanka.
A keen beekeeper and a man with an obvious affection for the fire protection industry, he regards water mist as a natural next step for him and an environmentally friendly, cost-effective alternative for the market.