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
What does the selector valve include that allows drivers to use functions deemed safe by a microprocessor
Electronic interlocks
once the selector valve is switched for either aerial or stabilizer operations, what type of valves are found down the line in the system
monitor, stack, and proportional directional control valves found in four or five way valves
How is hydraulic power from the system turned into mechanical force
Actuators found in the form of hydraulic cylinders that convert energy in the system into line mechanical force or motion
when pressurized fluid is directed into a chamber fitted with a piston into a cylindrical barrel
what are double acting hydraulic cylinders
Used for telescoping or elevation of ladder capable of receiving oil under pressure from both side of the piston so force can be created in either direction
NFPA 1901 requires an aux pump in the event of a failure in the main hydraulic pump. How is the aux pump powered and how many volts is it?
Wired directly to the vehicles battery using 12v DC
What type of cylinders are used to elevate the aerial device
Hoisting ~ Elevating ~ Lift
What is found at the end of each piston rod outside of the cylinder
Trunnion that is anchored to either the aerial device or to the turntable
Extension and retraction cables used to extend and retract the fly sections of the aerial are built with
Corrosion Resistant aircraft quality cable made with plow steel
resistant to abrasion
What is the aerial device turn table decking constructed of
Rigid Metal Plates
Turntables often operate on ________ bearings. One side of the bearing is fastened to the turntable and the other side to the aerial device structure.
Sheer Ball-Type Bearings
Sheer ball type bearings are secured by turntable ________ which should be _________ for manufacturers ______ specifications
Turntable bearing bolts checked periodically for manufacturers torque specifications
What is mounted on the periphery of the turntable that rotates the device
What is it driven by
Gear Teeth engaging gears
driven by a mechanical drive, electric or hydraulic motor
How high does the operator pedestal stand
3.5 feet
How should the aerial controls be positioned
Extension Rotation Elevation control in order from left to right on the pedestal
What are telescoping prepiped water ways made out of
Aluminum or other metal with a general minimu diameter of 4 inches
at what degree must you avoid operating a ladder pipe
90 degrees
Hardened steel nozzle provided to some elevated platforms can poke through what material and be flowed at what rate
Metal Buildings, Aircraft skins, metal roofs
up to 300 gpms
NFPA 1901 requires a _________ communication system
Two - Way comms
Standards to follow by NFPA 1901 if breathing air is equipped in an elevated platform
Number of Firefighters supported by system
Capacity of compressed air cylinders
Pressure Requirements
Low Air Warning alarms
Conformity to government regulations
What NFPA establilshed requirements for the quality of air in breathing air systems
1989
Most common power cord found on portable reels
12 gauges, 3 wire type
NFPA 1901 requires apparatus to be equipped with ________ covers and _____ shovels
multiple salvage covers and two scoop shovels
How are hoisting elevating and lift cylinders built
Heavy, Seamless steel outer shells bored to an extremely smooth inside surface.
Chrome plated on the inside to resist friction and wear.
enclosed at the top and bottom with removable caps
A solid chrome plated piston rod packed and tightly fitted with rings inside the cylinder
