OP 015: Fixed Installations Flashcards
Name some common fixed installations?
Eleven answers
Automatic fire alarms (AFA) Automatic sprinklers Drenchers Water spray projectors Dry rising mains Wet rising mains Fire lifts Foam inlets Roller shutters Hosereel installations Extinguishers
What are the three functions of an AFA?
Detect a fire
Raise an audible alarm
Indicate the whereabouts of the alarm at a central control remote from the building
What are the five main types of detector heads on AFAs?
Ionisation - detects small smoke particles
Optical - detects large smoke particles
Radiation - detects infrared radiation
Heat - detects heat
Sampling detector - detects smoke by sampling the air through a series of pipes with small holes
What are the three types of automatic sprinkler?
Wet system - all pipes are permanently filled with water
Dry system - the pipes have air under pressure to hold back water
Alternate system - switches between wet or dry
How are sprinkler heads sealed?
Two answers
Quartzoid bulb - expands and break with heat
Fusible link - two pieces of metal joined with a solder which melts
How can single sprinkler heads temporarily be dealt with to reduce water damage?
Tying the female coupling of a 70mm hose under it
What are drenchers?
Sprinklers on the outside of the building to prevent fire spread occuring from neighbouring buildings
Manual or automatic
What are water spray projectors?
High velocity sprinklers used to protect equipment, such as electrical transformers, from oil fires
The water hits the oil and breaks it up, then forms an emulsion
What are the advantages of rising mains?
Five answers
Reduces the amount of hose required to reach the fire
Reduced frictional loss in the delivery supply
Lessening the amount of equipment needed
Leaving staircases clear of hose
Reducing the effort required by staff
What is the height at which buildings are required to have rising mains?
Dry riser - 18m
Wet riser - 60m
What is the pressure at which fixed installation hosereels work at?
7 BAR, low pressure hosereels
140lpm flow rate
What happens on the operation of the fire lift switch?
Three answers
The lift automatically returns to ground level
Deactivates the landing call buttons
Enables firefighter only to control the lift from inside the lift
How do roller shutters work?
Mainly used in factories or large warehouses
Provide compartment fire separation
Weighted to automatically close when the cables or links that hold them melt
