Ch 14 Hydraulics

Water Additives

Aqueous film-forming foam (AFFF)

concentrated aqueous solution of fluorinated surfactant and foam stabilizers that is capable of producing an aqueous fluorocarbon film on the surface of hydrocarbon fuel, surpassing the vapors

Around-the-pump proportioning (AP) system

fire apparatus mounted system that diverts a portion of the water pumps output from the discharge side of the pump and sends it through an educator to discharge foam

balanced-pressure system

fire app. mounted system that uses a diaphragm-type pressure control valve to send and balance the pressure in the concentrate and water lines to the proportioner

bypass educator

mounted to the pump and can be used for application of water or solution

class A wetting agent

agent that improves the performance of water on ordinary combustible materials

class B foam

class B fires

Compressed air foam system (CAFS)

a system employing compressed air foam discharge nozzles, Type II & III applicators/ devices or hose attached to a fixed piping system through which foam is transported from a mixing chamber

duplex gauge

a gauge on the pump panel that simultainsly monitors both the concentration and water pressure

educator

uses Venturi principle to siphon a liquid into water stream. pressure at throat is below atmospheric

emsulification

mixing 2 dissimilar products to a semi stable mixture

Film-forming fluoroprotein (FFFP) concentrate

protein-foam concrete that uses fluorinated surfactants to produce a fluid aqueous film for suppressing hydrocarbon fuel vapors

foam burn back resistance

ability of the foam blanket to retain aerated moisture and resist destruction by heat or flame

high expansion foam

expansion ratio of 200:1 to 1000:1

low expansion foam

up to 20:1

medium expansion foam

20:1 to 200:1

miscible

redily mixes w water

PFAS ( per- and Poly-fluorniated alkylated substances)

Synthetic chemicals don’t degrade over time, harmful

polar solvent

water soluble

polymer

naturally occurring synthetic compound

wetting agent

when added to water reduces surface tension