COMPRESSED AIR FOAM

SYSTEM (CAFS)

Ulrich Braun

Basics

• To produce extinguishing foam there are two methods:

• Nozzle Aspirated Foam (NAF)

• Compressed Air Foam (CAF)

2

NAFS S 4/15 and M 4/75

3

Medium Expansion Foam

Low Expansion Foam

Foam Concentrates

• In general, foam pumps can work with all foam concentrates (Class A Foam, synthetic foam concentrates, AFFF) without any problems.

• Foam concentrates with low proportioning ratios are recommended.

• Mixing ratios ≤ 0,5 Vol.% reduces logistic problems.

• Environmental pollution?

• AFFF contains Fluortensides

• Class A Foam is free of Fluortensides

• Class A Foam is approved for Class A + B Fires

• Class A Foam is appropriate for urban firefighting

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Technical Requirements

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For urban fire service high-capacity CAFS (i.e. 800 l/min foam solution

from one discharge line) are required:

• 2 or 3 powerful automatic nozzles at the same time from

one appliance or

• one monitor from the ground or

• one monitor from an aerial ladder

CAFS with 800 l/min are suitable for exterior and interior

firefighting.

CAFS 800/2400 according to EN 16327 is conform to this

requirement.

CAFS

• System should be easy to operate (3 steps are enough):

• Engage System (PTO-on)

• Open discharge

• Adjust fire-pump pressure

• Ask for a guarantee that there is no need to flush the

system with Class A Foam.

6

Easy to operate

CAFS

CAFS Pros

CAF - Aerial Attack

CAF - Transitional Fire Attack

Pros

• CAFS allows foam firefighting immediately without any delay .

• CAF stream is a long range powerful extinguishment medium.

• Distance means safety for firefighters.

• Percentage of compressed air in hoses reduces stress (“Wet” >

25% / “Dry” > 50%).

• Persisting white foam blanket signals cooled surfaces. This

reduces water consumption.

• Using automatic branches CAF can be discharged with fog pattern.

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Structural fire attack

• Check transitional fire attack (10 – 30 seconds)

• Start Interior fire attack (after attack was finished)

• Use TIC to show the targets to the nozzle operator

• Use Positive Pressure Ventilation

• Hold radio contact with the chief officer

Aerial:

> Rescue

> Stand byAppliance 2

> Transitional Fire

Attack

> Search and

Rescue

> Positive Pressure

Ventilation

> Firefighting

Standard Operation Procedures

1

2

Appliance 1

> Search and Rescue

> Firefighting

Compressed Air Foam

• Foam bubbles have a huge surface for heat transfer.

• The heat transfer efficiency of these foam bubbles remain

constant for the entire distance. Water fog- vs. Straight stream

droplets.

• Dilution generated by steam: rapid flame knock down (it only

works inside structures).

Charred surface absorbs the water content of the foam blanket

(Penetration). CAF delays re-ignition and is suitable for plastics- and

tire fires.•

•

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Compressed Air Foam

Penetration

Caution: re-ignition!

Lay open pockets of ember and hollow spaces use:• special tools

• special probes.

Pockets of Ember and Hollow Spaces

Special Nozzles

This probe is recommended for pockets of ember and hollow spaces.

Use CAF “Dry”.

Foam Concentrate Consumption

93%

7%

max. 50 l

> 50 l

• Fire Truck Foam Tank ≤ 100 l

• Filling points in each Fire station

• Mobile reserve for big blazes (e.g. roller container)

Foam Logistics

Foam-Logistics

220 l

1,000 l

60 l

Foam-Logistics

• Use only appliances equipped with CAFS

• Don’t use CAF and water together: extinguishing capacity is

reduced.

• CAF may be frequently used to get:

• practice

• experience and

• confidence with CAF

We had no water damage anymore (caused by fire service) .

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Conclusion

Tactics for Class B Fires

08.2013

Hazards

• Rapid increasing temperatures

• Extreme dangerous for firefighters, when exposed indoor

(Heatstroke).

• Complete re-ignition, if the surface was not covered with the foam

blanket to 100%.

• Flammable liquids are fire accelerators for solid combustibles.

• Usually liquid fires are burning in conjunction with solid

combustibles.

08.2013

Tactics

• Always attack from minimum two sides, avoid shadows.

• Work always with an observer and look at him.

• Don`t tear open the foam blanket with the nozzle stream.

08.2013

Bank Down

Rain Down

Summary

• Notice the distance, use solid stream first.

• Don‘t destroy the foam blanket, take the accurate tactics.

• Cover the surfaces with moderate motions.

• Only cool surfaces until foam persists.

• Extinguish border-fire or jet-fire with dry chemical.

• Pay always attention: re-ignition!

08.2013

Class B fire extinguished with Class A Foam

Maximum time to extinguish this fire according to

EN 1568 with Class A Foam:

• Max. 300 seconds

• In this case 55 seconds!