Foam

Question 1

Low expansion ratio?

Answer 1

2:1 - 20:1

Usually

5:1 - 15:1

Question 2

What percentage of mixture is ARFFFP foam used at?

Answer 2

3% and 6%

Question 3

What must always be used when working in high ex foam?

Answer 3

Guidelines and communication equipment

Question 4

List 7 considerations when applying foam?

Answer 4

Never apply water onto burning liquids

Always open branch away from fire until good supply of foam is produced

If burning liquid is flowing, apply foam to furthest point from fore first

Unless entire surface of fire is covered, heat from fire will eventually break foam down applied.

Surrounding risks should be cooled with covering jets

Once applied, foam blanket should be preserved until flammable liquid has had time to cool.

Care should be taken not to drag hose across foam, as seal of blanket can be disturbed, causing re-ignition.

Question 5

List 4 ways in which foam is applied to a fire?

Answer 5

Gentle application

Rain down

Rolling on

Off wall, in direct application

Question 6

List 7 hazards when working in high ex foam as a firefighter?

Answer 6

Claustrophobia

Disorientation

Severely effected light penetration

Limited audibility of speech, auto distress signals, evac signals, and low pressure whistles

Mini backdraughts and fire explosions due to trapped oxygen and fire gasses

Difficulties determining location of fire and heat.

Difficultly spotting signs of collapse and damage to buildings

Question 7

What form of water from a jet could be used on flammable liquids until foam is available?

Answer 7

Spray or fog

Question 8

What are the processes of foam extinguish a fire? (5)

Answer 8

Diluting (the air surrounding with water vapour)

Isolating. (The fuel from oxygen in air)

Forming (sealing a blanket over fuel)

Intercepting. (Radiant heat from flames, preventing heat reaching surface of fuel)

Cooling. (The fuel)

Question 9

Which fires is 6% ARFFFP foam used?

Answer 9

Fires involving polar solvents (liquids that dissolve in water)

Question 10

What pressure and flow rate should foam be applied when using the delta branch?

Answer 10

400 lpm with 6bar pressure at branch

Question 11

How much foam CAN the foam tank on the appliance carry?

Answer 11

127 litres.

Each light is approx 30 litres of foam

Question 12

How much foam does a BFU (bulk foam unit) carry?

Answer 12

8x1000 litre intermediate bulk container of LOW EX FOAM

1 x 1000 litre of IBC of HIGH EX FOAM

Question 13

What flow rate and pressure should be used when applying foam from a ground monitor?

Answer 13

950 lpm at 7bar at the moniter

Expansion rate should be 12:1

Question 14

When PRODUCING foam, what are three factors than can be varied?

Answer 14

Volume of air mixed with solution

Quantity of foam concentrate added

Size of bubbles. (In medium and high concentrates)

Question 15

On which fires is 3% ARFFFP foam used?

Answer 15

Fires involving hydrocarbons

Question 16

Where should the ground moniter be directed before foam is applied?

Answer 16

Away from fire, until good foam mixture is produced

Question 17

What is low expansion foam (lx) made from?

Answer 17

ARFFFP

Alcohol resistant film forming flouroprotein

Question 18

3 classifications of foam concentrate?

Answer 18

Low expansion

Medium expansion (not used by TFL)

High expansion

Question 19

What does the effectiveness of foam depend on? (4)

Answer 19

Concentrate in good condition

Correct mixture of concentrate used

Good maintenance of equipment

Correct pump pressure used

Question 20

At which locations are the bulk foam units (BFU)?

Answer 20

Barking

Harrow

Kingston

Question 21

How much foam is carried on an appliance?

Answer 21

90 litres.

3 lights.

Prevents breather tube becoming blocked.

Question 22

High expansion ratios?

Answer 22

200:1 - 2000:1

Usually no more than

1200:1