CHAPTER 7 Scuba Air Diving Operations
explosive projectile. A cylinder charged to 2,000 psi has enough potential
energy to propel itself for some distance, tearing through any obstructions in
Store filled cylinders in a cool, shaded area. Never leave filled cylinders in
Cylinders should always be properly secured aboard ship or in a diving boat.
Predive procedures for scuba operations include equipment preparation, diver
preparation, and conducting a predive inspection before the divers enter the water.
Equipment Preparation. Prior to any dive, all divers must carefully inspect their
own equipment for signs of deterioration, damage, or corrosion. The equipment
must be tested for proper operation. Predive preparation procedures must be stan-
dardized, not altered for convenience, and must be the personal concern of each
Inspect air cylinder exteriors and valves for rust, cracks, dents, and any
evidence of weakness.
Verify that the reserve mechanism is closed (lever in up position) signifying a
filled cylinder ready for use.
Gauge the cylinders according to the following procedure:
Attach pressure gauge to O-ring seal face of the on/off valve.
Close gauge bleed valve and open air reserve mechanism (lever in down
position). Slowly open the cylinder on/off valve, keeping a cloth over the
face of the gauge.
Read pressure gauge. The cylinder must not be used if the pressure is not
sufficient to complete the planned dive.
Close the cylinder on/off valve and open the gauge bleed valve.
When the gauge reads zero, remove the gauge from the cylinder.
Close the air reserve mechanism (lever in up position).
If the pressure in cylinders is 50 psi or greater over rating, open the
cylinder on/off valve to bleed off excess and regauge the cylinder.