Staying too long, diving too deep, working too hard… here are the top 13 ways divers run out of air (and how to avoid them).
As we explore the range of common causes of out-of-air emergencies, we have grouped them into three categories:
- Lack of Awareness
- Procedural Problems
- Equipment Problems
Let’s look at each group in more detail.
Lack of Awareness
Diving too Deep
Gas consumption increases dramatically with depth. Your decompression obligation builds quickly, and you may need more gas for decompression stops. Running out of gas at depth puts you at risk of a hazardous emergency ascent. You can maximise your time at shallower depths and easily reach the surface in the event of an emergency.
Staying too Long
Sooner or later you will consume your gas reserves. Determine in advance the tank pressure at which you will need to turn back and start your ascent. During the dive, actively monitor your tank pressure and turn back on time.
Working too Hard
Fighting a strong current, hunting or lacking buoyancy control can affect gas consumption. Exertion at depth may speed up depletion of your tank up to twenty times. If you are not accustomed to diving in strong currents, seek training prior to diving in these environments.
Not Monitoring Your Pressure Gauge
Be air aware: Monitor your gas supply. Check your pressure gauge regularly and communicate your supplies with your buddy.
Ignoring Anxiety as a Factor
Anxiety changes all calculations and may deplete tank reserves faster than vigorous exercise. Try to maintain normal breathing, but if you do feel anxious, keep a closer eye on your gas supplies; it may dwindle more rapidly than usual.
Starting with Less Than a Full Tank
Regardless of how short an immersion you may contemplate, do not start your dive on less than a full tank. Never descend to retrieve a lost piece of equipment or anchor if the tank is nearly empty.
Not Opening the Tank Valve All the Way
Open the tank valve all the way and check that breathing through the regulator does not cause the pressure indicator to swing with each breath.
Frequent Depth Changes and BCD Adjustments
Yo-yo diving or using your BCD frequently to move up and down in the water column, can quickly deplete your gas supply. Yo-yo diving also increases risk of pulmonary barotrauma and decompression sickness.
Omitting Predive Check and Buddy Checks
Use a printed predive checklist to prevent mental lapses—the mental checklist is an oxymoron. (Check out last week’s post on the importance of Checklists)
Your gas consumption can be affected if…
- Your regulator is hard to breathe from.
- Your secondary regulator has a slow leak.
- Your regulator starts to free-flow due to freezing or debris.
- Your mouthpiece decouples from your regulator.
- Your dive buddy accidentally knocks your regulator out of your mouth.
Take preventative steps…
- Rinse your regulator after diving.
- Conduct regular maintenance on your regulator and have all parts replaced that may have been worn off or are out of date.
- Secure your spare regulator—don’t let it drag on the bottom.
If your regulator starts to free flow, attempt to flush it; this may help if debris is to blame. Remember,
you can still breathe from a free-flowing regulator, but the gas will not last long, so you must initiate the ascent.
Inflator leaks or tears in your BCD can deplete your air. Rinse your BCD after diving and conduct
regular maintenance to prevent leaks.
If your pressure gauge is integrated with your computer, a computer error may also affect the gauge. If your tank pressure does not decrease with time of dive, you have a problem and should safely terminate the dive. Make sure that your gauge is calibrated properly. Some gauges will not indicate zero, even when the tank is empty. To avoid this problem, make sure you return to the surface with the gauge indicating 35 bar or greater.
Burst O-ring or Hose
O-rings should be replaced regularly. Carry your own with you, and if you have a minor leak, replace
the O-ring in question. Do not open your regulator on your own; this should only be done by a certified maintenance professional.
Extracted from DAN’s ‘Smart Guide to Air Consumption’