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Wave Shape

Safe Diving

Waves Shape

Safe Diving

From our training we should all be familiar with BSAC’s Safe Diving Guide which is regularly reviewed and updated-  Safe diving guide – British Sub-Aqua Club (bsac.com)

Please see the qualification / Maximum Depth Restriction advised by BSAC.  These recommendations are designed to minimise risk and maximise safety of the diver and others.

All general club diving should be carried out within these limits.

Divers should dive within their qualification, experience and fitness and not exceed the depth to which they are qualified.    BSAC supports Buddy Diving. No Solo Diving should take place.The maximum depth restriction and should not be considered a target depth for any dive.

The Dive Manager (normally the most senior diver on site or his nominee) should be assured these recommendations are being adhered to.

The Dive Managers Dive Log is now on our Web Site (HERE)  please have a copy with you when heading out for a dive.

Dive leaders can Manage Dives at known locations. Advanced Divers at new locations unless training is to be conducted or inexperienced members are in attendance

AC Qualification Level

Depth Restriction (Air 21%)

Ocean Diver under training

Specific limits for each dive

Ocean Diver Post qualification

Progression to 20m

Sports Diver on qualifying


Sports Diver following progression


Dive Leader on Qualifying


Dive Leader following progression

40m (50m)  **

Advanced Diver

40m (50m)  **

Nitrox Diver

MoD imposed by max ppo2

** most recent advice from BSAC based upon gas density research clearly shows

Using air deeper than 40 metres puts a diver firmly into the increased risk zone

** Dive Leaders and Advanced Divers

In terms of deeper diving for Dive Leaders and Above recent research into gas density has resulted in BSAC amending its advice to divers in terms of maximum depth.  You should be aware –

Increased gas density at depth means that it requires more energy to breathe at depth (work of breathing). This, together with other effects of depth means that it becomes increasingly difficult for your body to remove carbon dioxide.

CO2 retention leads directly to CO2 toxicity and indirectly increases the potential for divers to suffer from oxygen toxicity, inert gas narcosis and decompression illness (DCI). There is also an increased potential for divers to suffer immersion pulmonary oedema (IPO) when breathing gases of elevated gas density underwater.

The effect starts to become increasing important for dives on nitrox or air below 30m and poses increased risk below 40m. Breathing hard at depth as a result of swimming against a current will make the situation considerably worse. 

The research established the following gas density parameters;

· 5.2 g.L-1 (grams per litre) (equivalent to air at 31m) or lower is a recommended safe gas density for use as a diving gas.

· 6.3 g.L-1 is the upper hard limit (equivalent to air at 39m).

Mixed gasses are recommended for deeper diving and the Sports Mixed Gas Diver qualification should be sought



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