Flashcards in Foam Deck (17)
When would foam be used?
On fires involving flammable liquids or liquefiable solids.
What does foam do? (basic description)
It creates a smothering blanket, cutting of the flammable materials supply of oxygen.
How exactly does foam extinguish a fire? (list of 5)
DILUTES the surrounding air
ISOLATES fuel from oxygen
FORMS a sealing blanket, enclosing vapour
INTERCEPTS radiant heat
COOLS the fuel
What are the three concentrates of foam?
Low expansion (usually between 5:1 and 15:1)
Medium expansion (20-1 and 200-1 -not used by LFB)
High expansion (usually 1200:1)
When would a 3% concentration of high expansion foam be used?
For fires involving hydrocarbons
When would a 6% concentration of high expansion foam be used?
For fires involving polar solvents
What three factors can be varied when producing foam?
1- The volume of air mixed with the volume of solution
2- The quantity of foam concentrate
3- The size of the bubbles
What 4 factors affect the effectiveness of foam produced
1- Good condition concentrate
2- Correct mixture of concentrate
3- Good maintenance of equipment
4- Correct pump pressure
What should the RB101 branch settings be when using foam?
6 bar pressure (from the pump)
400 litres per minute (branch flow ring)
What is the flow rate of the ground monitor when using foam?
950 litres per minute.
What bar pressure should the ground monitor operate at when using foam?
7 bar pressure
What are the four methods of application when using foam?
1- Gentle application
3- Rolling on
4- Off wall (Indirect)
What considerations must be taken when applying foam? (list of 7)
1- Never apply water to a burning liquid
2- Open the branch away from the fire until there is a consistent supply of foam
3- Apply foam to the furthest point of burning liquid
4- Ensure that there is enough foam to blanket the fuel
5- Combat surrounding risks with covering jets
6- Water will break a blanket of foam
7- Do not walk or drag hose on foam
What piece of equipment is used for high expansion foam?
The Angus Turbex MK2
What are the hazards associated with high expansion foam?
Severely affected light penetration.
Limited audibility (Speech, ADSU, warning whistles).
Mini backdraughts and fire gas explosions.
Difficult to determine the location of fire.
Surrounding damage may be obscured.
What must always be used when working in high expansion foam?
Guidelines and communication equipment