Steel or aluminium cylinder can cause damage to the pool bottom if a protective boot isn't worn.

Care should also be taken when placing and removing equipment from the pool and whilst performing deep water entries at pool-side to minimize damage to the pool's edge too.

On the reverse side of the PADI RDP or inside lid of the PADI eRDml you will find the procedures for Emergency Decompression. 

Proper dive planning and execution should remove the need for this action but extraneous circumstances may require you to perform extended stops to come out of unplanned decompression. This is the reason an additional air source should be placed at 5 metres when conducting a deep dive or Deep Diver training. 

The absolute, or total pressure is both the pressure exerted by the water and the air combined.

The best way to work questions out like this in fresh water is to calculate both pressures separately and then add them together.

The constant named on PADI exams for pressure per metre in fresh water is 0.097ATM/m. Multiply this by the depth listed and you have 23x0.097=2.231ATA.

This is the gauge pressure exerted by the water. If we add on the air pressure at sea level - 1ATA we get the absolute pressure 3.23 ATM (to 2 decimal places)

Need assistance with your diving physics? Join my next PADI Instructor Course and Ignite Your Life today!

Although the human body is made up of a series of systems which must all function well for a healthy life such as the nervous, digestive, immune and endocrine systems. Without the ability to diffuse oxygen into the blood and then transport it around the body to organs requiring oxygenating we would be unable to sustain life.

Learn more about physiology in diving on my upcoming profession diver development programs - the PADI Divemaster and PADI Instructor Course.

Although Dry Suit certification isn't required for a course conducted in cold water, orientation to the use of it is required in a confined environment before any open water sessions. 

This can be referenced in Training Standards under Dry Suit.

Some programs such as Sidemount and Tech 40 have a minimum dry suit dive experience requirement before the program can be conducted in a dry suit.

Where are your favorite cold water dive destinations?