Class A Foam 101 Marysville Division of Fire 2009

Class A vs. Class B Foam Class B Foam is repelled by hydrocarbons - Oleophobic Class B Foam is repelled by hydrocarbons - Oleophobic Class A Foam likes hydrocarbons - Oleophillic Class A Foam likes hydrocarbons - Oleophillic

Class A Foam Contains surfactants which decrease surface tension of water Contains surfactants which decrease surface tension of water Contains emulsifiers which enhance “stickiness” to organic molecules Contains emulsifiers which enhance “stickiness” to organic molecules Similar to Class B foam in that it contains ingredients which make tiny bubbles Similar to Class B foam in that it contains ingredients which make tiny bubbles Biodegradable Biodegradable

What is surface tension? Force which makes water bead up Force which makes water bead up Surfactants decrease surface tension Surfactants decrease surface tension Reduction of surface tension allows the water to spread out more on a surface and more likely to soak into that surface. Reduction of surface tension allows the water to spread out more on a surface and more likely to soak into that surface. –Increases moisture content –Decreases the temperature

What does an emulsifier do? Emulsifiers (in foam) bind with hydrocarbon fuels and work to break them down into smaller droplets and encapsulate them. So, when a Class A fuel burns, the emulsifier binds with the burnt surface. Emulsifiers (in foam) bind with hydrocarbon fuels and work to break them down into smaller droplets and encapsulate them. So, when a Class A fuel burns, the emulsifier binds with the burnt surface.

Advantages of Class A Foam Spreads out and soaks into fuels Spreads out and soaks into fuels Binds with fuel Binds with fuel Covers the fuel with a cooling blanket Covers the fuel with a cooling blanket “Sticky Water” “Sticky Water”

Why don’t we use Class A foam on gasoline too? Class A foam does not work well on liquids that have polar solvents. (i.e. ethanol) Class A foam does not work well on liquids that have polar solvents. (i.e. ethanol)

Proportioning Class A foam is typically proportioned from 0.3% to 1%. Class A foam is typically proportioned from 0.3% to 1%. Our default will be to initiate at 0.5% and titrate to desired effect up to 1%. Our default will be to initiate at 0.5% and titrate to desired effect up to 1%.

Class A Parameters Useable from 20 o to 120 o F, with freezing at 6 o Useable from 20 o to 120 o F, with freezing at 6 o 20 Yr shelf life if stored in sealed container, 1 yr if stored in apparatus reservoir tank. 20 Yr shelf life if stored in sealed container, 1 yr if stored in apparatus reservoir tank. Avoid mixing with Class B foam, it congeals into a sludge. Avoid mixing with Class B foam, it congeals into a sludge.

Class A Foam uses Class A foam has been used for years on initial attack, overhaul and exposure protection. Class A foam has been used for years on initial attack, overhaul and exposure protection. –Permeates voids and cavities –Increases moisture content

Hale Foam System Hale Foam Logix System Hale Foam Logix System –30 gallon Class A Foam Concentrate –Default at 0.5% foam at 150 GPM

Hale Foam System Red Button: On/Off Red Button: On/Off When turned “on” a red light will come on the bar graph under the numerical display When turned “on” a red light will come on the bar graph under the numerical display

Hale Foam System “I” Button: Mode button. Switch between flow, %, total flow and total foam “I” Button: Mode button. Switch between flow, %, total flow and total foam

Hale Foam System ↓ and ↑ button: change foam percentage ↓ and ↑ button: change foam percentage We will default at.5%, but can be increased for deep seated fires or increased effect.

Hale Foam System If the display reads “0” or “Lo A”, the concentrate is nearing empty or is empty If the display reads “0” or “Lo A”, the concentrate is nearing empty or is empty

Hale Foam System When done with the foam: When done with the foam: –Turn off (red button (light goes out)) –Flush the hose line until only water come out –Reload hose and refill Class A Foam tank

Questions? Based on NFPA 1145, Use of Class A Foam in Manual Structural Firefighting, 2006 Edition Based on NFPA 1145, Use of Class A Foam in Manual Structural Firefighting, 2006 Edition