Enclosure (6) TO COMDTINST 16478.12
USCG SITE SAFETY PLAN/ATON BATTERY RESPONSE PROJECT
F.3. SAFETY/PHYSICAL HAZARDS:
F.3.a
PRESSURE HAZARDS (DYSBARISM): Descending to work on the bottom
will expose dive personnel to the hazards associated with
diving.
Only currently military certified Coast Guard dive personnel or
contract personnel with suitable certification will dive during
this operation.
Descending and ascending within the water column while
following a dive profile exposes the diver to changes in the
volume of gases in the body. During descent, this pressure
increases and the volume decreases causing squeezes. During
ascent the pressure outside of the body decreases and the
volume of gases within the body increases leading or over
pressure unless compensated for or vented. In any case, the
diver must be in constant pressure equilibrium or suffer from
the effects of dysbarism. An example of a squeeze not
compensated for is an ear squeeze which may lead of tympanic
memnbrane rupture. An example of an over pressure situation not
compensated for would be PULMONARY OVER INFLATION SYNDROME
leading to ARTERIAL GAS EMBOLISM.
Additionally inert gas absorption takes place during diving at
a rate and quantity greater than that for a human on the
surface. Due to laws of physics, NITROGEN (79% of AIR) is
absorbed into tissues readily during descent with pressure
increases over that of the surface. During ascent, this
NITROGEN is off gassed normally as the pressure reduces,
freeing more of the absorbed gas from solution. The lungs act
as a filter here to slowly release the gas from the tissues
during the ascent phase. However, if the depth and duration of
the dive are such that an amount of gas exceeds the limits of
the ability of the lungs to exchange the gas, or the rate of
ascent so rapid as to defeat the lungs ability to filter, than
the NITROGEN will come out of solution in the tissues and not
be allow to be off gassed as part of respiration. In this case
bubbles will be formed in the tissues and DECOMPRESSION
SICKNESS in some form is created.
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