Chp 16 Flashcards
Selection criteria
Maneuverability Most common tasks required Equipment to be carried Budgets, planning depts Number of crew
Aerial definition
Hydrolic ladder, platform for placing personnel or water streams in elevated positions
NFPA requirement
1901 Standard for Automotive Fire Apparatus
IFSTA categories
Aerial ladder Elevating platform -Aerial ladder platform: -Telescoping aerial platform -Articulating aerial platform Water tower
Aerial ladder
Power operated ladder, usually hydrolic
Rear or mid mount or tillered trailer
Aerial ladder truss
Assembly of bracing bars or rods in a triangular pattern that forms a rigid framework for the aerial device
Fly section
Extendable section
Not the base (first section)
Aerial material
Heat treated aluminium alloy (heliarced)
Steel (welded)
Or rivets holding it together
Aerial parts
Base rails or beams: lower chords to which rungs are attached
Top rails: hand rails or top chords
Rungs: attached to two base rails
K bracing
New design which has greater strength
On the rungs
Stabilizer
Transfers center of gravity to prevent tipping as aerial is extended. Aka outrigger or stabilizing jack
Hydraulic system components
Actuators: transforms power to mechanical force
Hydraulic fluid: medium to transmit force
Pump: creates force via power take off
Reservoir: removes air, heat and particles from fluid
Types of hydraulic pumps
Load sensing piston pump
Rotary vane pump
Rotary gear positive-displacement pump
Hydraulic fluid pressure
Up to 3,500 psi
So its always important to check for leaks
Hydraulic hose
Steel tubing
or aircraft type steel braided hose
Must handle pressure 4x normal operating
Valves
Start and stop hydraulic fluid
May be manual, electric, or hydraulic
Selector Valve
aka transfer or diverter valve
3 way valve that directs fluid to stabilizers or aerial
Interlock so blocks fluid to one while supplier the other
Double acting cylinder
Can receive pressurized fluid from both sides so force can be created both directions
For elevation and telescopic control of aerial and stabilizers
Hydraulic motors
Convert energy in the system to rotary motion.
Two on the rig: rotate aerial device through ring and pinion and winch drive to extend/retract aerial
Auxillary hydraulic pump
Required by NFPA 1901
Usually 12 volt DC, connected to battery (some are 110v or combustion)
Only use to bed ladder. Overheat if used more than 1 min in 1:1 rest ratio
Hoisting cylinder
Aka elevating or lift cylinder
Raise an aerial
Chrome plated with top and bottom removable caps
Trunnion
The pivoting end of the piston rod that is connected to the anchor ear by the heel pin
Normal hydraulic pressure
850 to 3,000 kPa
Safety valves
On hoisting cylinder it locks oil in cylinder if a leak or blowout.
Can only be lowered manually with bleeder valve in that case.
Extension cylinders
On new aerials
Dual cylinder on base section used to extend second section or pulleys
Aerial
2 types, aerial ladder, tillered trucks
Most common apparatus
Range 50 to 137 ft
Working height
Ground to highest ladder rung at maximum elevation and extension
Aerial functions
Rescue ventilation Elevated master stream Access to upper levels Exposure protection Also access to lower floors or rescue areas
Aerial ladder platform def
Power operated ladder usually employing hydraulics with a passenger carrying device attached to the end of the ladder
Telescoping aerial platform def
Elevating platform equipped with piping systems and nozzles for elevated master stream
Not meant to be climbed; only have a small ladder used for escape
Articulating aerial platform def
Device with two or more booms with hinges that fold with passenger platform at the working end
All elevating platform requirements
Leveling system
14 sq ft floor area
Enclosed rail system with no opening >24”
2 gates with inward swinging doors (or up)
4” kick plate (separate drain)
Two sets of controls (base can override tip)
Backup hydraulic system
Heat shield (age, dirt damage affect effectiveness)
Fog curtain nozzle at bottom at 75 gpm or more
Load capacity 750 lbs dry at any angle
500 lbs flowing
1000 gpm at 100 psi in any position
If <110’, bed to fully extended, rotate 90* in 150 seconds
Elevating platform equipment
1 or 2 master streams Roof ladder at fly, platform, or base station Electrical, air and hydraulic outlets Communication system Floodlights Forcible entry Handline outlets Safety attachment point
Aerial ladder platforms
Climbable ladder with working platform
Height from ground to top of highest handrail
Common 85-110’
Straight chassis, 3 axle, rear mount is most common
Telescoping aerial platform
Same per NFPA but these have smaller escape ladder only
Common 75-100’
2 or more sections of box beam or tubular truss beam
Tubular steel is welded to form a box shape using cantilever or triangular truss design
Huck bolt
Mechanically applied rivet used on aerials.
Can only be removed by drilling.
Articulating aerial platforms
Built the same as telescoping but with hinges instead
Standard is 55-85’
Also combination with telescoping and aerials (90-174’)
Water tower
Articulating or telescoping aerial primarily for deploying an elevated master stream, not climbing
Go from 0-90*
50-130’
Flow 1000-5000 gpm
Quint
Pump, tank, supply and attack hose, ground ladders, aerial
Can be customized
Can supply its own elevated MS
Can protect itself from radiant heat
Cable and pulley system
Corrosion resistant aircraft quality cables of plow steel,abrasion resistant
Or can use a dual chain drive
Main cable drum can be hydraulic, electric, or mechanical
Turntable
Rotational structural component
Generally large shear ball bearings secured by bearing bolts
Gear teeth engage rotating grears
Control pedestal
On the turntable
Some small water towers or quints may be on the back
For platforms must have two sets
3 levers for elevate, rotate, extend from right to left
Some have joysticks
Also has high idle, light switch, override switches and a bunch of others
Designed for all heights with a sloped panel
Interlock
Combination of mechanical limit switches or algorithms that prevent a component from functioning when another one is.
Interlock types
Aerial/stabilizer
Body collision: won’t hit cab
Rotational interlock (short jack): won’t go off short jack side
Maximum elevation slow down
Retraction
Nozzle stow: won’t cradle
Aerial function interlocks: aerial won’t go without brake etc
Cab interlock: cab won’t raise with engine running
Tiller: deadman
Water delivery systems (waterways)
Pre-piped: bed ladder system or telescoping
Bed ladder: non telescoping, 3-3.5” on underside of bed section via Siamese, old, manually operated, solid stream
Telescoping: on ladders 110’ go to tip, 4” min diameter, flow up to 1000 gpm
Pinnable telescoping
Detachable ladder pipe
Elevationg platform
Detachable ladder pipe
ladder pipe
3-3.5” fire hose placed in middle to avoid torsion, other end rests on the ground
Straps secure 2-3 times
Siamese fed by 2-3 2.5-3” hoses or LDH with 3-way wye; clamped on top 2 rungs of fly
Solid or fog, controlled at tip or by ropes
750 max gpm
15* rotation limit to avoid nozzle reaction torsion
Elevating platform waterway systems
Same as pre-piped aerial ladder system
But nozzle is located in the platform, rather than the end of the ladder
Greater load capacity
200 gpm flow
Some have 2 nozzles and on 2.5” discharge
Water tower systems
Designed for master stream deployment
Usually pumped from the apparatus
Controlled from the ground
May have camera or TIC or piercing nozzle (flows 300 gpm)
Communication systems
Hands free at tip, one at platform (maybe one at pump panel)
Breathing air systems
Some have, not required by NFPA 1901
Do regulate # of ff, capacity, pressure, low air warning, and govt regulations
Test annually, moisture filters have specific pressure
Generator
Portable: 110-220; gas or diesel; works in compartment or remotely
Mounted: larger capacity; portable equipment and floodlights; fuel or PTO driven; noisy; have breaker panel;
Inverter
When generator is not required Used for vehicle mounted floodlights Steps 12v of vehicle to 110-220 volt AC Efficient, low noise Small capacity, limited mobility
GFI
Ground fault circuit interrupter: protects against shock
When grounding occurs, opens a circuit to stop flow of electricity
Scene lighting
Portable: corded or self powered; handles and telescopes
Fixed: for overall scene lighting; raise lower or turn; or booms with bank of lights;
Power distribution equipment
Power cords: 200 ft; examine daily for insulated, ground wire, waterproof, exposed wires
Junction boxes: for multiple connections; have locator light
Adapters: for mutual aid responses
Hydraulic extrication tools
Spreaders, shears, combination, rams
Hoses should be 100’ or less
Portable equipment
Ground ladders: attic roof and extension required (40’ is a pole ladder with bangors)
Forcible entry: plaster hook, crow bar, wrenches
Ventilation: exhaust/smoke ejector or PPV fans
Salvage/overhaul: covers, scoop shovel required, also infrared detector, TIC, blocks, saws
Tiller inspection
Many steering linkages
Make sure pin is removed
Inspect air bag suspension
Coupling is lubed
Aerial inspection general
Check cable systems
Hydraulic systems, cold when all are stowed
Slides and rollers, extend is preferred to bedded
Stabilizing systems
Breathing air systems
Communication systems
Need to test as well as visually inspect
Aerial operational inspection
Tests and refreshes operator
Pre-power transfer refer to owner’s manual
If leaning with stabilizers, you may have a leak
Some automatically tfer to aerial mode if stabilizers deployed
Testing EPU disengage main hydraulic system and open control valve to prevent dead hanging
Deadhanging
Operating a hydraulic pump without fluid flowing through the system
Aerial apparatus testing
Preservice
Service: inspect and test stabilizers, torque box, aerial device and water system
NFPA 1911
Nondestructive testing done 5 years, after accident, unusual stress or major repairs, some do annually
After interlock engaged
Once aerial or stabilizers are shut down: actuator valves, monitor valves, stack valves, proportional directional control valves all sued to direct and control power.
Many 4 or 5 way valves to operate actuators both directions
Actuators are cylinders or hydraulic motors
