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Class A Foam 101

Class A Foam 101. Marysville Division of Fire 2009. Class A vs. Class B Foam. Class B Foam is repelled by hydrocarbons - Oleophobic Class A Foam likes hydrocarbons - Oleophillic . Class A Foam. Contains surfactants which decrease surface tension of water

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Class A Foam 101

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  1. Class A Foam 101 Marysville Division of Fire 2009

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

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

  4. What is surface tension? • Force which makes water bead up • 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. • Increases moisture content • Decreases the temperature

  5. 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.

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

  7. 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)

  8. Proportioning • 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%.

  9. Class A Parameters • Useable from 20o to 120o F, with freezing at 6o • 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.

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

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

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

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

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

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

  16. Hale Foam System • 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

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

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