What type of foam is used for polar solvents?
Alcohol-resistant FFFP foam
Alcohol-resistant FFFP foam When used on polar solvents (or water-miscible fuels), the polysaccharide polymer forms a tough membrane, which separates the foam from the fuel and prevents the destruction of the foam blanket.
What is the difference between AFFF and AR-AFFF?
OFAFFF AND AR-AFFF AFFF and AR-AFFF consist of essentially the same ingredients. These typically include fluorosurfactants, hydrocarbon surfactants, solvents, inorganic salts, corrosion inhibitors, water; and in the case of AR- AFFF, a polymer which is typically a polysaccharide.
What are the four elements of foam tetrahedron?
Four elements are necessary to produce a quality foam blanket. These elements include: foam concentrate, • water, • air, and • aeration (mechanical agitation).
What is firefighting foam made of?
FOAM: A fire fighting foam is simply a stable mass of small air-filled bubbles, which have a lower density than oil, gasoline or water. Foam is made up of three ingredients – water, foam concentrate and air. When mixed in the correct proportions, these three ingredients form a homogeneous foam blanket.
What is polar and nonpolar solvents?
Polar solvents have large dipole moments (aka “partial charges”); they contain bonds between atoms with very different electronegativities, such as oxygen and hydrogen. Non polar solvents contain bonds between atoms with similar electronegativities, such as carbon and hydrogen (think hydrocarbons, such as gasoline).
What is a polar solvent example?
Polar Protic Solvents For our purposes that electronegative atom is almost exclusively oxygen. In other words, polar protic solvents are compounds that can be represented by the general formula ROH. Examples of polar protic solvents are water (HOH), methanol (CH3OH), and acetic acid (CH3CO2H).
How long is AFFF foam good for?
between 20-25 years
If kept in the original unopened and airtight Chemguard supplied container and stored within the temperature range of 35ºF – 120ºF (2ºC – 49ºC) a shelf life of between 20-25 years can be expected.
What class of foam is AFFF?
Class B Foam
Class B Foam (also called AFFF): Used to extinguish Class B materials, which include gasoline, oil, and jet fuel.
What percentage of finished foam is water?
In other words, depending on the type of foam, or the type of fuel, foam concentrate is designed to be mixed with 99 parts water to 1 part concentrate (1 % foam concentrate), 97 parts water to 3 parts (3% foam concentrate), or 94 parts water to 6 parts concentrate (6% foam concentrate).
What is the bank down method of applying foam?
Banking down is a great method when the fire or area to cover is near a wall or near an object. During this technique, the nozzle firefighter deflects the foam stream against the wall and allows the foam to “bank” onto the fire or spill, creating an extinguishing blanket.
What does 3% AFFF mean?
CHEMGUARD C3B 3% AFFF (Aqueous Film-Forming Foam) Concentrate combines fluoro- and hydrocarbon-surfactant technologies to provide superior fire and vapor suppression for Class B hydrocarbon fuel fires. Liquid drains from the foam blanket and forms an aqueous film that suppresses fuel vapor and seals the fuel surface.
What type of foam is AFFF?
Aqueous film forming foams
Aqueous film forming foams (AFFF) are water-based and frequently contain hydrocarbon-based surfactant such as sodium alkyl sulfate, and fluorosurfactant, such as fluorotelomers, perfluorooctanoic acid (PFOA), or perfluorooctanesulfonic acid (PFOS).
How is foam proportioned in a polar solvent?
Typically for hydrocarbons, foam is proportioned at 3 percent: that is three parts foam concentrate to ninety-seven parts water. For polar solvents , foam is usually proportioned at 6 percent: that is six parts foam concentrate to ninety-four parts water.
How does polar solvent destroy fire fighting foam?
Polar solvent/alcohol liquids destroy any foam blanket that has been generated using standard AFFF or fluoroprotein type concentrates. Water in the generated foam blanket mixes with alcohol causing the foam blanket to collapse and disappear until the fuel surface is completely exposed again.
Can a polar solvent fuel mix with water?
Polar solvent fuels are miscible, that is they will mix with water. Polar fuels have a varying attraction for water. For example, acetone has a stronger affinity for water than does rubbing alcohol. Polar solvent fuels are usually dest ructive to foams designed for use on hydrocarbons.
What makes a water molecule a polar solvent?
Why Water Is a Polar Solvent. The slight negative charge near the oxygen atom attracts nearby hydrogen atoms from water or positive-charged regions of other molecules. The slightly positive hydrogen side of each water molecule attracts other oxygen atoms and negatively-charged regions of other molecules.