SCBA (Passage 6) Flashcards
Of what is the back frame and harness assembly of the SCBA constructed?
A solid, one piece, black, aluminum alloy frame.
Of what does the SCBA harness consist?
Adjustable shoulder and waist straps.
Of what are the adjustable shoulder and waist straps made?
Heavy braided webbing
What joins all the assemblies of SCBA together?
The back frame
How are all the assemblies of SCBA connected?
They are welded.
How is the air cylinder secured to the back frame? (2)
A Kevlar fabric band and a double locking latch.
What air cylinders can be secured by the Kevlar strap?
Air cylinders of 30, 45, or 60 minutes.
With the 2 shoulder straps, through what must the excess slack be pulled?
The 2 alligator clips.
What will prevent fatigue with regard to SCBA?
Carrying the weight of the SCBA on the waist and not the shoulders.
What is located at the bottom of the back frame of the SCBA? (2)
- Pressure reducer and
2. Cylinder housing block
What will you find at the cylinder housing block? (2)
- Universal Air Connector (UAC)
2. Rapid Intervention Crew (RIC) connection
What does UAC stand for?
Universal Air Connector
What is located just right of the pressure reducer?
A pouch which holds the dual Emergency Breathing Support System (EBSS) buddy breathing hose.
What does EBSS stand for?
Emergency Breathing Support System
What is located above the pressure reducer? (2)
- The electronics module with mounted LEDs and sounders
2. A sleeve which contains the batteries for the SCBA
To what is the regulator attached?
To a low pressure hose
Where is the low pressure hose located?
It comes over the left shoulder when the SCBA is donned.
Where is the regulator keeper located?
On the left waist strap.
What is located on the left shoulder of the SCBA?
The low pressure hose.
What is located on the left waist strap of the SCBA?
The regulator keeper.
Where is the remote pressure gauge located?
Over the right shoulder, which allows the user to see how much air is left in the cylinder.
What is located on the right shoulder of the SCBA?
The remote pressure gauge.
Of what are cylinders constructed?
A lightweight, composite material made of an aluminum alloy inner shell, over wrapped with carbon fiber, fiberglass and epoxy resin.
What is the quick-connect fitting called for the cylinder to snap into the SCBA that allows for a quick and efficient bottle exchange?
Hansen valve
What is the Hansen valve?
The quick-connect fitting for the air cylinder to snap into the SCBA.
What do the air bottles have for recharging?
A straight Compressed Gas Association (CGA) male threaded inlet.
What does CGA stand for?
Compressed Gas Association
What is significant about the 60-minute RIC bottles and some isolated air-tool bottles?
They do not have a quick-connect Hansen valve and are connected only through the CGA inlet.
What does the cylinder valve contain?
A dual-reading primary pressure gauge.
What can happen if the cylinder valve is not fully open?
It may induce outlet freezing and prevent air from being provided to the user.
How must the cylinder be closed?
The valve wheel must be simultaneously pushed in and rotated clockwise.
What pressure can the cylinder withstand prior to failure?
Approximately 13,500 psi or 3 times the working pressure of 4,500 psi
What is located within the cylinder valve assembly?
A frangible disc.
What is the purpose of the frangible disc?
It is a safety device and intended to burst and allow gas to escape to prevent rupture of the cylinder
To what is the frangible disc similar and how is it different to that?
It is similar in function to a safety relief valve, however, it has no reset capability.
At what pressure is the frangible disc set to burst?
At 7,500 psi or 5/3 the working pressure of the cylinder.
Where is the pressure reducer assembly located?
On the bottom of the back frame connected to the cylinder housing block, where the air cylinder is connected.
What is the definition of the pressure reducer assembly?
It is a redundant dual path reducing system broken down into the primary and secondary reducer.
During normal operation, what is the path of air from the cylinder?
From the cylinder and valve assembly through the primary reducer to the regulator.
From what to what is the pressure from the cylinder reduced through the primary reducer?
From 4,500 psi to 85-110 psi.
What happens if the primary reducer fails or becomes blocked?
The air supply automatically flows through the secondary reducer to the regulator via the automatic transfer valve.
What does the automatic transfer valve do?
Should the primary reducer fails or becomes blocked, the automatic transfer valve reroutes air to the regulator through the secondary reducer.
What happens when the secondary reducer becomes active?
The Vibralert activates to alert the user the primary reducer has malfunctioned.
From what to what is the pressure from the cylinder reduced through the secondary reducer?
From 4,500 psi to 145-175 psi.
With what is the pressure reducer also equipped?
A low cylinder transfer valve (which activates the Vibralert when the cylinder pressure reaches 25%, approximately 1,100 psi)
When does the low cylinder transfer valve activate the Vibralert?
When the cylinder pressure reaches 25%, approximately 1,100 psi.
Where is the remote pressure gauge located and to what is it attached? (2)
On the right shoulder harness and is attached to the pressure reducer and the electronics module.
What type of gauge is the remote pressure gauge and, generally, what does it show?
It is a mechanical gauge with a glow in the dark backing that indicates to the user how much air is remaining in the system.
The remote pressure gauge must be within how many psi of the primary cylinder gauge?
250 psi
What number readings does the remote pressure gauge have on it?
10, 20, 30, 45
What colors are on the remote pressure gauge?
The first 25% of the gauge is marked in red and the top 25% is marked green denoting full.