Alcohol-resistant-type Foam

Information on solubility is important in an emergency situation because a petroleum fire will require the application of a regular-type foam or an alcohol-resistant-type foam for extinguishment or for vapor-suppression purposes. For use on a water-soluble liquid, a good-quality alcohol-resistant foam is generally applied. 

Fluoroprotein and alcohol resistant type AFFF concentrates are suitable for seal protection of open top floating roof tanks. Foam may be applied from fixed chambers in an "over-the-top" fashion or by discharge from "foam chambers" located at the top of the tank shell allowing the foam to run down the inside wall of the tank shell onto the seal area. Subsurface foam on floating tanks is generally not recommended as a sunken roof would block the foam distribution. Typical protection is shown in Table 7-10. 

Class of fire Extinguisher type Water Alcohol-resistant AFFF foam Wet chemical Vaporizing liquid NAFP 3 - commercial use only Ciubon oxide Dry chemical powder AB(E) and B(E) types... 

The type of flammable liquid — determines the t5q>e of foam, e.g. standard or alcohol-resistant grade. Aqueous film-forming foam may be used for rapid knock-down . 

Special alcohol resistant (or compatible) type foam is needed for application to alcohols, esters or ketones type liquids and organic solvents, all of which seriously break down the commonly used foams. Commercially available foam products are now available that can be used on both alcohols and hydrocarbons, only alcohols or only hydrocarbons. It is therefore imperative to design foam systems in a cost effective fashion if several products are in use that may require special foam application requirements. 

Alcohol-resistant foam Alcohols, ketones and esters can break down many types of foam, thus cancelling out the extinguishing action fires involving these materials need to be fought with special foams which do not break down as readily. AFFF-ATC also falls under this category. 

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