Foam fire suppression

Foam-based fire suppression systems are highly-appropriate for fire protection where flammable and combustible liquids are involved.
The mixture of water, emulsifier and air produces foam which, according to its expansion ratio, generation system and type of emulsifier used, is appropriate to the fire suppression in the different kinds of risks.

EXPANSION RATIO

a) Low expansion
The solution/foam expansion ratio is up to 1:20, and it is mostly used in foam chambers in fuel tanks, containment dike spillways, sprinklers covering truck loading bays, manual nozzles and foam monitors.

 b) Medium expansion
The solution/foam expansion ratio is up to 1:100, basically appropriate for manual nozzles and generators and, in some cases, for special foam sprinklers.

 c) High expansion
The solution/foam expansion ratio is up to 1:1000; therefore, large volumes of foam are generated with smaller water content. Appropriate to protect large-volumes where foam may be confined, e.g., in hangars. It is applied by means of hydraulic or electric generators.

GENERATION SYSTEM

a) Venturi-type feeder
Traditional system for fixed fire suppression installations requiring fixed flow supply, e.g. foam chambers in fuel tanks.

b) Balanced Pressure Supplying System
It consists of a dosing pump and supplying device, with relief and recirculation valves that take the foaming agent from a tank and mix it, with a variable, predetermined flow range; hence it may be used in installations having more than one system.

c) Bladder Tank
Also used in systems with variable demand ranges, but it is mechanical and does not use an electric pump. The water / emulsifier mixture is achieved through a diaphragm placed inside the storage tank and supplying system which doses the solution mixture according to the system requirements.

EMULSIFIER TYPES

  • Protein
    Appropriate for Class B fires.
  • Fluoroprotein
    Proteins with fluoride agents; dosage at 3% or 6%; enhanced foam fluidity and better sealing around obstructions.
  • AFFF
    Aqueous Film Forming Foam concentrate; high resistance against re-ignition; compatible with extinguishing powders; dosage at 3% and 6%.
  • AR AFFF
    Concentrate with features similar to the above, but with physical characteristics and properties appropriate for fighting alcohol fires.
  • Synthetic (High Expansion)
    Synthetic agent appropriate for dosage at 1%-3% , with an expansion ratio of up to 1 :1000.
  • Synthetic for Class A Fires
    Its formulation provides water with more effective wetting and penetrating qualities to fight forest fires, as well as fires involving tires and paper.

MELISAM has an engineering and works department knowledgeable in technical support and standards to design and carry out the different fire suppression system installations, as well as in the whole product range for these systems