IFSTA Aerial Chapter 3 Flashcards
Per NFPA 1901 what are three basic categories of aerial devices
Aerial Ladders
Elevating Platforms
Water Towers
How is the working height of an aerial ladder measured
From the Ground to the Highest ladder rung with the ladder at maximum elevation and extension
what is the minimum floor area for an elevated platform (tower bucket)
14 Sqft
Each platform (Tower bucket) must have a rail completely enclosing the floor area. No opening under the railing can be greater than this many inches
24”
Below the railing of the aerial platform two gates are provided for FF and victim access, what is required at floor level and how high should it be
A kickplate is required at floor level and should be 4 inches high to prevent ff feet from sliding off the platform
All platforms (buckets) are required to have this many operator control stations and where
Two controls one at street level and one on the bucket
per NFPA 1901 a protective water fog curtain nozzle is required at the bottom of the platform. NFPA 1901 requires this nozzle to flow at least how many GPMS
75 gpm
All elevating platforms must have a minimum weight rating of ________ pounds when the aerial is fully ________ at any _______ within its normal ________ of motion with no ______ in the piping
750 lbs
aerial is fully extended at any elevation within its normal range of motion with no water in the piping
When water is added to aerial platform what does the minimum weight rating drop to
500 lbs
Elevated platforms must be capable of discharging atleast ____________ when the aerial device is in any position
1000 gpm
How fast should platforms 110 feet or shorter be able to to be raised
Platforms should be able to be raised from bedded position to its maximum elevation and extension and be rotated 90 degrees in
150 seconds or less
How is the working height of an elevated platform measured
Aerial device at maximum extension and elevation from the GROUND to the top surface of the highest platform handrail
What is Box-Beam construction
Four sides of steel or aluminum welded together to form a box shape with a hollow center
The supporting beams for an aerial device are made of truss construction. What do properly built trusses permit?
Allows for tension and compression stresses to be distributed over the length of the ladder for max strength but minimum weight
Two most common materials that aerial ladders are built with are
Heat-Treated aluminum alloy
Steel
How are the fabricated structural members of the aerial fastened?
Rivets
Entire truss segment may be welded
Heliarced for aluminum alloy
What is the medium by which force is created to move and operate the aerial system
Hydraulic fluid
system is composed of fluid, pump and reservoir
Why is hydraulic fluid used to operate aerial
Fluid is practically incompressible and allows force to be transmitted over a relatively large distance with little loss of power
What is the hydraulic fluid reservoir designed to do
supply the adequate amount of fluid and condition the fluid while it’s stored in the tank
allows for air, heat and foreign matter to be eliminated from fluid before reintroduction into the hydraulic system
Filters and exchange-type coolers are provided to condition the ladder hydraulic fluid, where can the coolers be found
Usually located in front of the vehicles radiator
What type of tubing is used for hydraulic fluid supply through out the system
how much pressure is it rated to withstand
steel tubing and aircraft-type, steel braided hose.
hose must be rated to withstand pressures at least four times greater than normal operating pressure
A number of different valves are used within the hydraulic system,
what do these valves do to the fluid
how are they controlled
Start, Stop, Regulate and direct the flow of hydraulic fluid to control pressure in the system.
Controlled manually, electrically, hydraulically, mechanically or a combination of all of the above
What prevents undesired or unintentional motion of the aerial from its established position
Counterbalance valves
One of the important valves in the system is the “selector valve” also know as the transfer or diverter valve. how is this valve built and how does it function.
Three way valve that directs fluid to either stabilizer controls valves or the aerial control valves
Provides an interlocking mechanism to prevent fluid going to both stabilizers and aerial control valves
