Firefighting Flashcards
What are the elements of the ‘Fire Triangle’
Heat, Fuel, Oxygen, Chemical chain reaction
What are the 5 classes of fires, and how would you extinguish them?
Class A: Combustible materials such as Wood, Paper or Fabric to be extinguished by cooling with water, foam or DP.
Class B: Flammable liquids and their vapours to be extinguished by smothering with Foam, DP or CO2.
Class C: Gas fires to be extinguished by first isolating the source and then attacking with Foam or DP. Water can be used to cool the surrounding areas.
Class D: Metal fires to be extinguished by smothering and suffocation using a product such as dry sand but DP can also be used.
Electrical Fires should be extinguished by isolation and then application of CO2 if appropriate.
Class F: Fat or oil fires should be extinguished using a fire blanket or a wet chemical extinguisher.
Explain..
- Conduction
- Convection
- Radiation
Conduction is the transfer of heat energy from one molecule to the next.
Convection is the transfer of heat through the movement of molecules in the air.
Radiation is the transfer of heat through infrared waves emitted by one body and absorbed by the other.
What action should you take on discovery of a fire?
Find the fire
Inform
Restrict the fire
Extinguish
What is the 4th element of the fire triangle and how is it broken down?
chemical chain reaction which is the presence of free radicals, usually broken down with dry powder.
What is the percentage of oxygen in air and the percentage take required to extinguish a fire achieved by smothering?
Normal air 21%, must be reduced to 14%
Explain the term “Flashpoint”
The Flashpoint is the lowest temperature at which a liquid will ignite across its surface.
Explain the term “Firepoint”
The Firepoint is the lowest temperature at which fuel vapour can sustain a flame
explain the term “Auto ignition”
The point at which a fuel will ignite without an ignition source
Describe the characteristics of a flash over
Fully ventilated, powerful radiant heat, flames in gas layer, increased pyrolisation of room contents, lowering of neutral plane.
What may cause a backdraught?
When the atmosphere becomes too rich, reintroducing ventilation into the compartment will allow the atmosphere to dilute into a fuel/air% that can sustain ignition.
What are the main components of structural fire protection?
A vessel will be divided into to vertical fire zones, with the accommodation block being separate from other zones. The theory is to try and contain the fire within that compartment. Large commercial ships are to adhere to Merchant shipping fire protection reg 1988.
What are the 3 Class structures on ships?
Class A: Steel or equivalent offering 60 minutes protection (Red lines on plan)/ Class B: Suitably non combustible material offering 30 minutes protection (Yellow lines on plan) / Class C: Constructed of non combustible material.
What are the main types of automatic fire detection systems?
Ionisation / Optical / Heat / Flame / Aspirating systems
