Originally Posted by dhnsekaran

How The Foam is mixed with Fire water while fire fighting

Dear sir,

Am new menber to this forum,

am a process safety engineer, am having a doubt regarding the " how the fire fighting foam will be mixed with the fire water when the oil fire is happening.

please send me some notes / explanation regarding this issue to my mail id "dhnsekaran@gmail.com"

advanced thanks

Dhana

Thats easy to explain Dhana,

If you have set up your preferences properly you will recieve notification of any and all responses to you question so no worries there,

The foam fire fire fighting systems use an eductor/venturi to pull the foam concentrate liquid from the five gallon pails and mix it with a small amount of water to be used to make the foam two ways one using a high speed ventilating fan/smoke ejector to create the flood of tiny bubbles to choke the fire out quickly using the foam which is direct by a curtain or tubing to render the fire harmless from one of the three parts of the fire triangle by eliminating oxygen for part of the fuel and cooling the heat source with the foam and water mix

The second is just simple mixing with the water pumper and eductor/venturi.

which is what you see at airports when it is used to create a bed of foam for the aircraft to land on and skid through to prevent or reduce the possibilty of a fire from jet fuel during a landing with no landing gear or disabled landing gear mechanisms that are not fully retracted or stuck and locked in the extended postition etc.

The fan method with the smaller water stream and eductor is used to prevent fires from occuring if petroleum or gasses are involved and also to help stop them quickly where a masive loss of life is imminent, rescuers are trapped, or low water pressure or low water volume is a problem.

The older proven method of mixing water baking soda and a small portion of weak sulfuric acid has been eliminated as a way of making soda stream foam in the soda stream method for many years here in the states-its really to bad as it works well.

You should ask and obtain permission to attend the New York State Fire Academy

in Montout falls, New York USA during a summer short course for your own and your companies benefit as the experience you gain there in field work and class room work will be of great benefit to you and your company.

lzaharis ■

For years, foam has been used as a fire-extinguishing medium for flammable and combustible liquids. Unlike other extinguishing agents - water, dry chemical, CO2, etc., a stable aqueous foam can extinguish a flammable or combustible liquid fire by the combined mechanisms of cooling, separating the flame/ignition source from the product surface, suppressing vapors and smothering. It can also secure for extended periods of time against reflash or reignition. Water, if used on a standard hydrocarbon fuel, is heavier than most of those liquids and if applied directly to the fuel surface, will sink to the bottom having little or no effect on extinguishment or vapor suppression. If the liquid fuel heats above 212ºF, the water may boil below the fuel surface throwing the fuel out of the contained area and spreading the fire. For this reason, foam is the primary fire-extinguishing agent for all potential hazards or areas where flammable liquids are transported, processed, stored or used as an energy source.

Source(S): https://www.sos-safety.com/ ■