National Foam Systems

About AFFF Foam Systems

Aqueous Film-Forming Foams (AFFF) are based on combinations of fluoro-chemical surfactants, hydrocarbon surfactants, and solvents. This agent requires a very low energy input to produce a high quality fire fighting foam. Consequently, they can be applied through a wide variety of foam delivery systems. This versatility makes AFFF systems an obvious choice for airports, refineries, manufacturing plants, municipal fire departments, and any other operation involving the transportation, processing, or handling of flammable liquids.

Alcohol Resistant Fire Fighting AFFF Foam Systems

Alcohol-resistant foams are based on AFFF chemistry to which a polymer has been added. ARCs are the most versatile of the fire fighting foam agents in that they are effective on fires involving polar solvents like methanol as well as hydrocarbon fires such as gasoline.

Mixing Foam Systems with Water

A foam system requires proportioning equipment to mix the foam with water in the required concentration. Automatic pressure balancing valves regulate the foam concentrate pressure to match the water pressure.

AFFF Foam System Bladder Tanks

Foam concentrate is often stored in a bladder tank system. In AFFF systems a bladder tank containing a nylon reinforced elastomric bladder is used to store the foam concentrate. System water pressure is used to squeeze the bladder providing fire fighting foam concentrate, at the same pressure, to the proportioner. With bladder tank foam systems, no external power is required, and little maintenance is needed.

Complete Service on Foam Agents, Storage Tanks & Discharge Devices

HEBA Fire provides complete service on your foam agents, storage tanks and discharge devices. We also provide annual inspections, agent testing, bladder replacements and system commissioning.

What is Fire Fighting Foam?

Simply stated, firefighting foam is a stable mass of small, air-filled bubbles with a lower density than oil, gasoline or water. Foam is made up of three ingredients…water, a foam concentrateand air. Water is mixed with a foam concentrate (proportioned) to form a foam solution. This solution is then mixed with air (aspirated) to produce a foam which readily flows over fuel surfaces. Balanced pressure proportioning is the most common method used for foam system applications. The foam concentrate pressure is balanced with the water pressure at the proportioner inlets allowing the proper amount of foam concentrate to be metered into the water stream. With an aspirating discharge device, foam solution passes through an orifice, past air inlets and into an expansion area to produce an expanded foam. With nonaspirating devices, foam solution passes through the orifice and discharge outlet where it mixes with air enroute to the fire.
Types of ‘Class B’ Foams

Aqueous Film-Forming Foam (AFFF): AFFFs are based on combinations of fluoro-chemical surfactants, hydrocarbon surfactants, and solvents. These agents require a very low energy input to produce a high quality foam. Consequently, they can be applied through a wide variety of foam delivery systems. This versatility makes AFFF an obvious choice for airports, refineries, manufacturing plants, municipal fire departments, and any other operation involving the
Alcohol-Resistant Concentrates (ARC):Alcohol-resistant foams are based on AFFF chemistry to which a polymer has been added. ARCs are the most versatile of the foam agents in that they are effective on fires involving polar solvents like methanol as well as hydro-carbon fuels like gasoline. When used on a polar solvent type fuel, the ARC concentrate forms a polymeric membrane which prevents destruction of the foam blanket. When used on hydrocarbon fuels, the alcohol-resistant concentrate produces the same rugged aqueous film as a standard AFFF agent. Alcohol-resistant concentrates provide fast flame knockdown and good burnback.

Types of ‘Class B’ Foams Cont...

Fluoroprotein Foam Concentrates: Fluoroprotein foams are based on hydrolyzed protein, stabilizers, preservatives, and synthetic fluorocarbon surfactants. When compared to protein foams, fluoroproteins provide better control and extinguishment, greater fluidity, and superior resistance to fuel contamination. Fluoroprotein foams are useful for hydrocarbon vapor suppression and have been recognized as very effective fire suppressing agents for sub-surface injection into hydrocarbon fuel storage tanks.

High Expansion Foam Concentrates: High expansion foams are based on combinations of hydrocarbon surfactants and solvents. They are used with foam generators for applying foam to large areas in total flooding and three-dimensional applications such as warehouses, ship cargo holds, and mine shafts. They are especially useful on fuels such as liquefied natural gas (cryogenic fuels) for vapor dispersion and control. In certain concentrations, high expansion foams are effective on hydrocarbon spill fires of most types and in confined areas.

How Foam Systems Work

Fire fighting foam systems suppress fire by separating the fuel from the air (oxygen). Depending on the type of foam system, this is done in several ways:
The following represents operation of a typical foam water sprinkler system.  Although many other types of systems are available; a basic foam system will always require foam agent storage, proportioning equipment, one or more discharge devices, and a manual and/or automatic means of detecting the fire and actuating the system.

  • Fire breaks out in the rack storage area of a flammable liquid warehouse.
  • Rising heat from the fire ruptures the quartzoid bulb(s) in the sprinkler head(s) which starts the flow of water.
  • Flowing water opens the alarm check valve which allows water to open the hydraulic foam concentrate valve and operate the water-motor gong.
  • Foam concentrate flows from the bladder tank into the proportioner where it is mixed with the flowing water at the designed foam solution percentage.
  • Foam is generated as the foam solution discharges through the sprinkler head(s) onto the fire.
 

Pump Skids

  

Pump skids (or balanced pressure pump proportioning systems) are used in combination with atmospheric storage tanks which are typically of polyethylene or fiberglass construction. While foam concentrate is pumped from the storage tank to the proportioner, an automatic pressure balancing valve regulates the foam concentrate pressure to match the water pressure.

Bladder Tank System

  

Bladder tank systems use a pressure-rated tank containing a nylon reinforced   elastomeric bladder to store the foam concentrate. System water pressure is used to squeeze the bladder providing foam concentrate, at the same pressure, to the proportioner. With bladder tank systems, no external power source is required and little maintenance is needed.

Proportioning Equipment

  

Proportioning is the introduction of foam concentrate into a flowing stream of water to produce a foam solution. Although there are several methods of proportioning, fixed foam systems typically use balanced pressure proportioning equipment.

Foam Systems Applications

NF™ foam systems protect virtually any hazard where flammable liquids are present. These hazards are common to a multitude of industries including Petrochemical, Chemical, Oil and Gas, Aviation, Marine/Offshore, Manufacturing, Utilities, Military, and Transportation.

  • Flammable Liquid Storage
  • Loading Racks
  • Processing Areas
  • Refineries
  • Dike Areas
  • Aircraft Hangars
  • Heliports
  • Jet Engine Test Facilities
  • Marine Applications
  • Warehouses

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