Fire Testing of Experimental

Siloxane-Based AFFF

Results from New Experiments

SupDet 2015

03.-06.03.2015

Ralf Hetzer2

05.03.2015

AFFF

AFFF = Aqueous Film Forming Foam

Ralf Hetzer3

05.03.2015

The Aqueous Film

The Aqueous Film…

• cools the fuel surface

• acts as vapor barrier

• operates in areas without foam

• autonomously closes

perforations of the foam

• works as buffer between fire

and foam

AFFF is the most effective agent

for pool fires!

Ralf Hetzer4

05.03.2015

Environmental Problems

Environmental Problems of AFFF:

- AFFF use PFC (polyfluorinated

compounds) to establish the water

film.

- PFC are persistent.

- PFC are strictly regulated in Germany.

Quelle: www.derwesten-recherche.org, abgerufen am 21.05.14.

Ralf Hetzer5

05.03.2015

Definition of the spreading coefficient

S = SFTF - (SFTA + IFT)

S Spreading Coefficient

SFTF Surface Tension of the Fuel

SFTA Surface Tension of the Extinguishing Agent

IFT Interfacial Tension between the Fuel and the

AqueousPhase

If S > 0, an aqueous film is formed.(S > 0 is a necessary, but not a sufficient condition.)

Ralf Hetzer6

05.03.2015

Militarily Important Fuels

Fuel SFTF (24 °C) Sample Origin

Diesel 28,3 mN/m BP Refinery Emsland, Germany

Jet fuel 26,7 mN/m BP Refinery Emsland, Germany

F-34 25,8 mN/m Bundeswehr (NATO Standard Fuel)

Cyclohexan 24,9 mN/m Reference substance

S = SFTF - (SFTA + IFT)

=> (SFTA + IFT) < 25 mN/m

Ralf Hetzer7

05.03.2015

Surfactant Types

Surfactant Type min. SFTA (20 °C)

1. Fluorosurfactants (PFC) 15 mN/m

2. Siloxane surfactants 20 mN/m

4. Alkylsurfactants 28 mN/m

5. no surfactant (pure water) 73 mN/m

S = SFTF - (SFTA + IFT)

(SFTA + IFT) < 25 mN/m

=> SFTA <<25 mN/m

Ralf Hetzer8

05.03.2015

Siloxane Surfactant T-C3-Malt

T-C3-Malt

Ralf Hetzer9

05.03.2015

Synthesis of T-C3-Malt

Problems: time consuming and low yields.

Ralf Hetzer10

05.03.2015

Interfacial Characteristics T-C3-Malt

Chemical CompositionSFTA

[mN/m]

IFT#

[mN/m]

S#

[mN/m]

Film on

Cyclohexane

Film on

F-34

16.8 g/l Glucopon 215 CS UP

2.5 g/l BDG28.5 1.0 - 4.5 No No

2

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

0.25 g/l T-C3-Malt

25.8 0.8 - 1.6 No Yes*

3

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

0.50 g/l T-C3-Malt

24.1 0.7 0.2 Yes Yes

4

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

1.00 g/l T-C3-Malt

23.5 0.5 1.0 Yes Yes

5

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

2.00 g/l T-C3-Malt

22.2 0.4 2.4 Yes Yes

#: based on Cyclohexane (SFTF=25.0 mN/m);

*: small area film formation, recontracting after a short term.

Ralf Hetzer11

05.03.2015

Foam Characteristics

Experimental Setup

Foaming Device: Micro Foam Unit, MFU

V-25, (Jürgen Arens,

Cologne, Germany).

Nozzle: Low Expansion

(also Jürgen Arens).

Discharge Rate: 1.06 Kg/min.

Working Pressure: 4,5 bar.

Graduated Cylinder : 2000 ml nominal volume,

2330 ml total volume.

Electronic Balance and Stop Watch.

Ralf Hetzer12

05.03.2015

Foam Characteristics of T-C3-Malt

Chemical Composition Expansion Factor50%-Drainage Time

[min]

1

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG10.66 ± 0.16 05:39 ± 0:03

2

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

0.25 g/l T-C3-Malt

10.76 ± 0.08 5:44 ± 0:02

3

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

0.50 g/l T-C3-Malt

10.89 ± 0.15 5:36 ± 0:02

4

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

1.0 g/l T-C3-Malt

10.80 ± 0.09 6:00 ± 0:05

5

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

2.00 g/l T-C3-Malt

10.88 ± 0.11 6:05 ± 0:03

Ralf Hetzer13

05.03.2015

Commercially Available Foams

Commercial

Firefighting foam

PFC-

containing

Concentration

in Water [%]Expansion

50%-Drainage

Time [min]

1 AFFF 1 Yes 3 10.09 ± 0.16 6:38 ± 0:04

2 AFFF 2 Yes 3 10.29 ± 0.05 6:09 ± 0:06

3PFC-free

Class B Foam 1No 3 9.50 ± 0.06 15:21 ± 0:21

4PFC-free

Class B Foam 2No 3 9.85 ± 0.03 21:16 ± 0:22

5PFC-free

Class B Foam 3No 3 9.28 ± 0.29 2:26 ± 0:06

Chemical Composition Expansion Factor50%-Drainage Time

[min]

16.8 g/l Glucopon 215 CS UP2.5 g/l BDG

10.66 ± 0.16 05:39 ± 0:03

26.8 g/l Glucopon 215 CS UP

2.5 g/l BDG0.25 g/l T-C3-Malt

10.76 ± 0.08 5:44 ± 0:02

36.8 g/l Glucopon 215 CS UP

2.5 g/l BDG0.50 g/l T-C3-Malt

10.89 ± 0.15 5:36 ± 0:02

46.8 g/l Glucopon 215 CS UP

2.5 g/l BDG1.0 g/l T-C3-Malt

10.80 ± 0.09 6:00 ± 0:05

56.8 g/l Glucopon 215 CS UP

2.5 g/l BDG2.00 g/l T-C3-Malt

10.88 ± 0.11 6:05 ± 0:03

Ralf Hetzer14

05.03.2015

Small Scale Fire Tests

Experimental Setup

Pan: EN 3-7,

55B (0.8 – 1.8 kg/min×m²)

21B (>1.8 kg/min×m²).

Water Buffer: 3 cm

Fuel: F-34 (10 l)

Nozzle: Low Expansion

Foam: Premixed Solution

Discharge Rate: 1.06 Kg/min

Foam Solution Reservoir: 25 l (premix)

Working Pressure: 4,5 bar

Burn Back Pot: Height: 10.0 cm

Radius: 5.8 cm

Fuel: Heptane

Ralf Hetzer15

05.03.2015

Small Scale Fire Tests – 99% Extinguishing Time

0

100

200

300

400

500

0.5 1 1.5 2 2.5 3 3.5

99

% E

xtin

gusi

hin

g Ti

me

[s]

Application Rate [kg / (min x m²)]

AFFF 1 AFFF 2

PFC-free Class B Foam 1 PFC-free Class B Foam 2

PFC-free Class B Foam 3 6.8 g/l Glucopon, 2.5 g/l BDG

6.8 g/l Glucopon, 2.5 g/l BDG, 0.25 g/l T-C3-Malt 6.8 g/l Glucopon, 2.5 g/l BDG, 0.50 g/l T-C3-Malt

6.8 g/l Glucopon, 2.5 g/l BDG, 1.00 g/l T-C3-Malt

Ralf Hetzer16

05.03.2015

Small Scale Fire Tests – 100% Extinguishing Time

0

100

200

300

400

500

0.5 1 1.5 2 2.5 3 3.5

10

0%

Ext

ingu

sih

ing

Tim

e [

s]

Application Rate [kg / (min x m²)

AFFF 1 AFFF 2PFC-free Class B Foam 1 PFC-free Class B Foam 2PFC-free Class B Foam 3 6.8 g/l Glucopon, 2.5 g/l BDG, 1.00 g/l T-C3-Malt6.8 g/l Glucopon, 2.5 g/l BDG, 0.50 g/l T-C3-Malt 6.8 g/l Glucopon, 2.5 g/l BDG, 0.25 g/l T-C3-Malt6.8 g/l Glucopon, 2.5 g/l BDG

Ralf Hetzer17

05.03.2015

Burn Back Experiments

0

200

400

600

800

1000

1200

1400

0.5 1 1.5 2 2.5 3 3.5

25

% R

eig

nit

ion

Tim

e [

s]

Application Rate [kg / (min x m²)]

AFFF 1 PFC-free Class B Foam 1

PFC-free Class B Foam 2 AFFF 2

6.8 g/l Glucopon, 2.5 g/l BDG, 1.00 g/l T-C3-Malt 6.8 g/l Glucopon, 2.5 g/l BDG, 0.50 g/l T-C3-Malt

6.8 g/l Glucopon, 2.5 g/l BDG, 0.25 g/l T-C3-Malt 6.8 g/l Glucopon, 2.5 g/l BDG

Ralf Hetzer18

05.03.2015

Revised ICAO Test Protocol

Source: ICAO AIRPORT SERVICE MANUAL, Doc 9137-AN/901 Part 1 (07.2013).

Ralf Hetzer19

05.03.2015

ICAO Fire Test

99%-Extinguishing Time (only flickers left) Burn Back Experiment

Experimental Set-Up Start Foam Application

Ralf Hetzer20

05.03.2015

Results of ICAO B Fire Tests

Type of Foam

Solution

Chemical Composition /

Commercial FoamExtinguishing Time [s]

25%-Burn

Back Time [s]

Requirements ≤ 60 (99%) ≤ 120 (100%) ≥ 300

PFC-free

siloxane based foam

solution

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

2.0 g/l new siloxane surfactant

42 70 641

45 66 660

6.8 g/l Glucopon 215 CS UP

2.5 g/l BDG

2.0 g/l new siloxane surfactant

0.15 g/l Xanthan gum

45 60 n.d.

47 60 n.d.

PFC-containing

AFFF

according to

TL 4210-0112

AFFF 1 59 88 573

53 98 604

AFFF 2 41 87 756

43 82 779

AFFF 342 78 863

50 75 752

Ralf Hetzer21

05.03.2015

Conclusions

Conclusions

• The new siloxane surfactants form aqueous films on cyclohexane and

militarily important fuels.

• These siloxane surfactants are compatible with foam forming glyscoside

surfactants.

• In fire test the perfomance of the siloxanes based foams is only surpassed by

the fluorine-containing AFFF.

• Fluorine-free Class B foams are clearly performing less good than the

siloxane-containing blends.

Future work

• Further fire tests according to international standards, e.g. ICAO B and C.

• Formulation of a long-term storable concentrate based on the

experimental siloxane

Ralf Hetzer22

12 February 2014

AFFF

Thank you for

your kind

attention.

Questions?

Ralf Hetzer23

05.03.2015