ICAO Levels A, B and C - what's the difference?

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It is mandatory that all foams used in civilian airports must be approved to ICAO Level A, ICAO Level B or ICAO Level C standard. But what is the difference between these standards?

ICAO Level A

In order to obtain ICAO Level A certification the foam concentrate, once proportioned correctly, must extinguish a 2.8m2 hydrocarbon fire within the given specifications (see table below).

The application rate for the ICAO Level A test is 4.1 L/min/m2.

ICAO Level B

In order to obtain ICAO Level B certification the foam concentrate, once proportioned correctly, must extinguish a 4.5m2 hydrocarbon fire within the given specifications (see table below).

The application rate for the ICAO Level B test is 2.5 L/min/m2.

ICAO Level C

In order to obtain ICAO Level C certification the foam concentrate, once proportioned correctly, must extinguish a 7.32m2 hydrocarbon fire within the given specifications (see table below).

The application rate for the ICAO Level C test is 1.75 L/min/m2.

ICAO Level C test has been designed to permit substantially reduced quantities of foam and water to be available on fire trucks (for further information, please refer to the OTAC document on Rescue and Fire-Fighting Management of Extinguishing Agents here.)

Comparison of Test Protocols

Specification

ICAO Level A

ICAO Level B

ICAO Level C

Branch Pipe

“Uni 86” Foam Nozzle

“Uni 86” Foam Nozzle

“Uni 86” Foam Nozzle

Fire Size

2.8m2

4.5m2

7.32m2

Tank Shape

Circular

Circular

Circular

Pre-burn time (seconds)

60

60

60

Application Type

Forceful

Forceful

Forceful

Application Rate (L/min/m2)

4.1

2.5

1.75

Foam Application Time (secs)

120

120

120

Extinguishment Time with flickers (secs)

<60

<60

<60

Full Extinguishment Time (secs)

<120

<120

<120

Burnback Waiting Time (mins)

2

2

2

20% Re-ignition Time (mins)

>5

> 5

> 5

 

ICAO Level C places increased emphasis on

  • Impacts of fluctuating water pressure

  • ARFF vehicle monitor application rates, i.e. regular produced foam testing.

 

 

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