Divers Alert Network
Gas management is a fundamental concept in safe diving, but it’s easy to lose sight of its importance in the clatter and din of a busy dive boat. Even with constant reminders to “watch your air,” experienced divers forget how to safely manage their gas supply on dives every year. Thankfully, few of these incidents result in injuries, but they put divers at serious risk and are entirely preventable. Managing your air on a dive is not just about monitoring your SPG and surfacing before you drain your tank, but planning your dive ahead of time and monitoring (and potentially modifying) that plan throughout the dive. Proper air management will make you safer, more relaxed, and better able to enjoy your dive with the knowledge that you have adequately prepared for emergencies.
Check your gauges
It should go without saying, but it is vital to regularly check your gauges during the course of a dive. Monitoring your air, depth and dive time can give you an idea of your air consumption and when you might have to end a dive prematurely, but also whether or not your equipment is functioning properly. A slow leak from a first stage O-ring, for example, might not be obvious on the surface but may become apparent with an abnormally increased air consumption rate underwater.
Factors influencing consumption
There are many factors that can affect your air consumption during the dive, but chief amongst them are depth, weighting, workload and personal fitness. Diving deeper, working harder and carrying more equipment cause your air consumption to increase. A weight check before a dive to remove unnecessary ballast can improve your air consumption, as can diving neutrally buoyant and in trim. Improving your personal fitness, decreasing the amount of equipment you carry, and minimizing your workload can also improve your air consumption, but keep in mind that site conditions like currents or wave action are out of your control and will increase your effort in the water.
Plan your dive, dive your plan
Planning your air consumption is not difficult. A common method known as the“rule of thirds”provides a reasonable level of safety for most diving situations. The rule of thirds is applied by dividing your tank, minus a 500 PSI reserve, into thirds. The first third is used for the descent and working portion of the dive, the second third is used for the ascent and safety stop, and the final third is kept in reserve in case of an emergency. Planning your dive with the rule of thirds adds an extra level of safety to your dive and ensures that you have enough air to help a buddy in an emergency. Always remember to take factors like current, workload and depth into consideration; they may require even more conservative gas planning.
For more information on safe diving practices, visit www.DAN.org.