Firefighting Foams, Dry Columns, and Fire Types

Firefighting Foams Characteristics

• Fluency and Sealing: Ensures quick and effective surface coverage, preventing fuel vapor escape.
• Heat Resistance: Maintains cooling properties under mechanical stress and heat.
• Durability: Resists heat, flames, and wind; regenerates if surface cracks occur.
• Contamination Resistance: Maintains a uniform bubble structure when exposed to liquid fuels.
• Thickness: Holds enough water to withstand contact with hot surfaces of non-liquid or solid fuel.
• Oxygen Separation: Physically separates oxygen from the air above the ignited fuel surface.
• Heat Absorption: Absorbs heat from the fuel and adjacent solid surfaces.
• Radiation Prevention: Prevents heat transmission from flames via radiation.

Dry Columns: Function and Operation

A dry column is a facility for Public Service Termination, consisting of an empty vertical shaft with connection openings on each floor and electrical outlets for connecting fire extinguishing utilities.

The purpose of dry columns is to ensure fire services can operate effectively in tall buildings where their own extinguishing media may be insufficient.

To operate, it connects to a fire vehicle via a front power socket, providing water to each floor's outlets. This allows firefighters to enter the building and attach their hoses on the floors where they need to fight the fire.

Fire Types and Extinguishing Methods

Fires are classified based on the physical state of the fuel:

• Type A: Fires involving solid fuels like wood, paper, and textiles.
• Type B: Fires involving liquid fuels such as gasoline, alcohol, and liquefiable solids like paraffin waxes.
• Type C: Fires involving gaseous fuels like methane, propane, and butane.
• Type D: Fires involving combustible metals like magnesium, sodium, aluminum, and zinc.

Extinguishing Methods

Extinguishing a fire requires stopping the oxidation reaction by removing one of the four elements of the fire tetrahedron:

• Fuel Removal (Desalimentación): Eliminating the fuel source. Fuel vapors ignite when their concentration is within the lower and upper flammable limits (flash range).
• Suffocation: Isolating the combustion from air or oxygen, preventing fuel vapors from contacting it.
• Cooling: Reducing the fuel temperature to prevent sufficient vapor production for combustion.
• Breaking the Chain Reaction: Introducing catalysts to prevent heat transmission between fuel particles and the reaction between free radicals.