IFSTA - Chapter 16 Flashcards
NFPA 1901
Standard for Automotive Fire Apparatus
- All aerial apparatus must meet the design requirements
- Groups aerials into 3 categories:
1. Aerial Ladders
2. Elevating Platform
3. Water towers
PG 542
Aerial Apparatus
- Fire fighting vehicle equipped with a hydraulically operated ladder, elevating platform, or other similar device for the purpose of placing personnel and/or water streams in elevated positions
PG 543
Aerial Device
General term used to describe the hydraulically operated ladder or elevating platform attached to a specially designed fire apparatus
PG 543
Aerial Ladder
Power-operated ladder, usually employing hydraulics, that is mounted on a special truck
- Can be either rear or midmounted, or on a tillered trailer
- Fully extended (working) length = 50-137ft
PG 543
Tillered Trailer
Trailer equipped with steerable rear wheels
PG 543
Aerial Ladder Truss
Assembly of bracing bars or rods in triangular shapes that form a rigid framework for the aerial device
PG 543
NFPA 1901
Establishes the number of sections and minimum reach required of an aerial apparatus
PG 543
Bed Section
Bottom section of the aerial ladder
PG 544
Fly Section
Extendable section of ground extension or aerial ladder
PG 544
Two most common materials for construction of aerial ladders
1) Head-treated aluminum alloy
2) Steel
PG 544
Base Rails
- AKA Beams
- The lower chords of the aerial ladder to which rungs, trusses, and other portions of the ladder are attached
PG 544
Top Rails
- AKA Handrails
- The top chords to which the opposite ends of the trussing are attached
PG 544
Rungs
The portions that are attached between the two base rails and are used as steps for personnel on the aerial ladder
PG 544
Stabilizers
Device that transfers the center of gravity of an apparatus and prevents it from tipping as the aerial device, hydraulic lifting boom, gin pole, or A-frame is extended away from the centerline as the chassis
- AKA Outrigger
- AKA Stabilizing Jack
PG 546
Four main components of HYDRAULIC SYSTEM
1) Actuators = transforms power into mechanical force
2) Hydraulic Fluid = the medium by which the system transmits force
3) Hydraulic Pump = force is created on the fluid by the hydraulic pump; powered by PTO arrangement off the vehicle’s main engine
4) Hydraulic Reservoir = supplies the hydraulic fluid that is move in and out of the system
PG 547-548
Check Valves
Prevent fluid from flowing backward through a component and act as a safety feature in the event that a leak develops in the system
PG 549
Relief Valves
Limit the pressure built up in the system, thus preventing damage due to overpressurization
PG 549
Counterbalance Valves
Prevent unintentional or undesirable motion of the device from its established position
PG 549
Selector Valve
- AKA Transfer or Diverter Valve
- Three-way valve on aerial apparatus that directs oil to either stabilizer control valves or the aerial device control valves
- Blocks flow to the system not in use, thus acting as an interlock to prevent the stabilization and aerial device systems from operating at the same time
PG 549
Stabilizer Cylinders
- Most modern aerial apparatus are equipped with hydraulically operated stabilizers (AKA Outriggers)
- Each stabilizer is operated by one or two cylinders
- Cylinders force the stabilizer arms outward and down to take weight off the apparatus suspension and make apparatus more stable
PG 550
Aerial Device Hoisting Cylinders
- AKA Elevating or Lifting Cylinders
- Used to lift the aerial device from its bed to a working position
- End of the piston rod outside the cylinder is fitted with a trunnion that is anchored to the aerial device or the turntable
PG 550-551
Trunnion
In a hydraulic cylinder, the pivoting end of the piston rod that is connected to the anchor ear by the heel pin
PG 551
Normal hydraulic pressure
850-3000psi
PG 551
Aerial Device Extension Cylinders
- Dual cylinders fitted on the base section and used to extend the second section of the device
PG 552