for individuals who require glasses. However, once the
TIMER.-- The timer (fig. 5-8) is located at the top
lenses are installed, only the person that the lenses are
of the breastplate assembly so that you can check the
made for can use that spectacle kit. The speaking
amount of time remaining as you go about your duties.
diaphragm allows you to talk to others and to use
The bell of the timer is made to ring for 8-10 seconds
communication devices, such as sound-powered
telephones. The head straps hold the facepiece snug
against your face. If the straps are adjusted properly, no
outside gases can get inside of the facepiece.
Figure 5-8. Timer.
B R E A S T P L AT E
A S S E M B LY. -- T h e
breastplate assembly (fig. 5-5) houses the plunger
assembly, the canister guard and holder, and the
handle. The plunger pierces the copper foil seal of the
Figure 5-6. Facepiece with spectacle kit installed.
canister when the canister is seated in place. The
handle actuates the seating mechanism that positions
BREATHING BAG AND TUBES.-- The OBA
the canister in its housing. The outside of the
has a breathing bag and two breathing tubes to control
breastplate assembly is insulated to protect you from
the oxygen. The breathing bag contains the oxygen that
the heat produced by the oxygen canister.
is generated by the canister for you to breathe. One
breathing tube transports the oxygen from the
COMBINATION VALVE ASSEMBLY.-- The
breathing bag to the facepiece (fig. 5-7); the other
combination valve assembly is shown in figure 5-9. It
transports the exhaled air back to the canister. Both
directs the flow of air through the canister to the
tubes are made of corrugated rubber. They control the
flow of air and help cool the air for your comfort when
you wear the OBA. The tubes are a quick-disconnect
type. The tube couplings are color coded, and the
supply tube is of a different size than the exhaust tube.
This prevents the possibility of connecting the tubes to
Figure 5-9. Combination valve assembly.
OBA QUICK-STARTING CANISTER.-- The
quick-starting canister (fig. 5-10, views A and B) is
painted green. This is the only canister that you will use
aboard ship. The rubber gasket provides an airtight seal
when the canister is in the operating position in the
OBA. The copper foil seal protects the chemicals from
moisture until the canister is ready for use. The
chlorate candle, which is built into the canister,
produces oxygen for about 5 minutes until normal
Figure 5-7. Breathing tubes.
oxygen generation begins. You will be able to breathe