Ch 16. Inteoduction To Aerial Apparatus Flashcards
What are the three basic categories of Ariel Apparatus?
Ariel ladders, elevating platforms, and water towers
Per IFSTA, what are the three classifications of elevating platform Apparatus? (Refers to the design of the aerial device)
Aerial ladder platforms,
Telescoping aerial platforms,
Articulating aerial platforms
What types of chassis are found on Ariel ladders?
Aerial ladder devices may be mounted on a straight chassis in either a rear or midmount configuration, or on a tillered trailer.
How are the supporting beans of an aerial ladder constructed?
The supporting beams of the aerial ladder are of aerial ladder truss construction
What are the sections of an aerial ladder referred as?
Bed section and fly sections
What are the two most common materials for construction of Ariel ladders?
The two most common materials are heat treated aluminum alloy and steel
What are three ways that the fabricated structural members of an aerial ladder are fastened together?
The fabricated structural members may be fastened by rivets or may be welded or Heliarced (aluminum alloy)
What are the three main portions of an aerial ladder to which firefighters commonly refer?
Bed rails, top rails, and rungs. The base rails, are commonly called the beams. The top rails are commonly called handrails
Why are Ariel ladders designed and built with K bracing as a standard feature?
K bracing provides greater strength than older designs
What is the stabilizer on an aerial Apparatus?
Stabilizer is the device that transfers the center of gravity of an apparatus and prevents it from tipping as the aerial device, hydraulic lifting boom or A-frame is extended away from the centerline of the chassis. Also called outriggers
How are virtually all stabilizers or outriggers activated a new Ariel devices?
Hydraulic systems
What are the four main components of hydraulic systems?
Actuators
hydraulic fluid
hydraulic pump
hydraulic reservoir
What does a hydraulic actuator do?
The actuator transforms power into mechanical force
What is the medium by which the hydraulic actuator system transmits force?
Hydraulic fluid
In a hydraulic system how is force created on the hydraulic fluid?
Buy a hydraulic pump
How are hydraulic pumps powered on a Ariel Apparatus?
The pump is powered by a PTO arrangement of the vehicles main engine
What types of hydraulic pumps may be used in the hydraulic system?
The pumps used for the hydraulic system may be either load sensing piston pump, rotary vane pump or rotary gear positive displacement pumps
Hydraulic fluid is practically incompressible. In aerial apparatus the fluid may be under pressures of up to ________ psi?
3500
What part supplies or stores the hydraulic fluid in a hydraulic system?
The hydraulic fluid reservoir
Tubes and hoses supply hydraulic fluid throughout the system. What are these hoses typically made of?
Most manufacturers use steel tubing and aircraft tape, steel braided hose
What is the rating standard (strength rating) for steel tubing and aircraft type, steel braded hose?
Steel tubing and steel braided hose must be related to withstand pressures of at least 4x the normal operating pressures
The flow of hydraulic fluid through a system are regulated through a number of different _____________ that open or close to allow fluid movement.
Valves
What valves in a hydraulic system prevent fluid from flowing backwards through a component and act as a safety feature in the event that a leak develops in the system?
Check valves
What valves in a hydraulic system limit the pressure built up within the system?
Relief valves
What valves in a hydraulic system prevent unintentional or undesirable motion of the device from his established position?
Counterbalance valves
What important three-way valve directs fluid to either the stabilizer control valves or the aerial device control valves?
The selector valve a.k.a. the transfer or diverter valve
What unsafe action do selector valves prevent an aerial apparatus?
The selector valve prevents the stabilization and aerial device systems from operating at the same time. This system is governed by a microprocessor or other system
The hydraulic cylinders used for elevation and telescopic control of the aerial device are double acting. What does this allow?
Double acting cylinders are capable of receiving oil pressure from both sides of the piston so that force can be created in either direction
There are two rotary motor systems in Ariel apparatus. What do these rotary motors control?
One rotary motor rotates the aerial device through a ring opinion drive. The other rotary motor operates a winch drive to extend and retract the ladder.
What cylinders are used to operate stabilizers or outriggers?
Stabilizer cylinders
What type of cylinders are used to elevate the aerial device from its stowed position?
Hoisting cylinders a.k.a. elevating or lift cylinders
Hoisting cylinders are often constructed of what material to resist friction and where?
Chrome plating
In a hydraulic cylinder, what is the pivoting end of the piston rod that is connected to the anchor ear by the heel pin called?
Trunnion
Hoisting cylinders are attached to the aerial device or turntable by a ________?
Trunnion
What is the normal hydraulic pressure in the large pistons used in the lifting cylinders?
850 to 3000 psi
What do many new hoisting cylinders come equipped with that lock and hold the cylinder in the event of a leak or a blowout?
Integral safety valves
Many new apparatus are equipped with dual cylinders fitted on the base section used to extend what?
Used to extend the second section of the device.
What is the primary function of the turntable on an aerial ladder device?
The primary function of the turntable is to provide rotation to the aerial device
What are the normal fully extended length ranges, in feet on aerial ladders common in North America?
From 50 to 137 feet
What are the main uses of Ariel ladders?
The main uses of aerial ladders are rescue, ventilation, elevated master Stream application and gaining access to upper levels of an emergency scene
How is the working height for Ariel ladders measured?
The working height for aerial ladders is measured from the ground to the highest ladder rung with the ladder at maximum elevation and extension
What is an elevating platform?
A work platform attached to the end of an articulating or telescoping Ariel device