FOAM-BASED FIRE SUPRESSION


FOAM-BASED FIRE SUPRESSION


Foam-based fire suppression systems are very suitable for fire protection when flammable and combustible liquids are involved. Foam is generated by mixing water, emulsifier, and air. Depending on its expansion ratio, generation system, and type of emulsifier used, it may be suitable for fire suppression in different kinds of risks.


EXPANSION RATIO

a) Low expansion
The foam / solution expansion ratio is of 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 foam / solution expansion ratio is of up to 1:100; it is basically used in manual nozzles and generators and, in some cases, in special foam sprinklers.

c) High expansion
The foam / solution expansion ratio is of up to 1:1000, i.e., large foam volumes are generated with smaller water content.
Suitable for protecting large-volume spaces where foam may be confined, for example, in hangars. It is applied by means of hydraulic or electric generators


GENERATION SYSTEM

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

b) Balanced Pressure Proportioning System
It consists of a dosing pump and proportioning device, with relief and recirculation valves that take the foam 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. Mechanical system not using an electric pump. The water / emulsifier mixture is achieved through a diaphragm placed inside the storage tank, and a proportioning device, which dose the solution mixture according to system requirements.


EMULSIFIER TYPES

  • Protein
    Suitable 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 suitable for fighting alcohol fires
  • Synthetic Foam (High Expansion)
    Synthetic agent suitable for dosage at 1%-3% , with an expansion ratio of up to 1 :1000
  • Synthetic Foam 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 installations, as well as in the whole product range for these systems.