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Auxiliary Emergency Breathing Systems
For safety reasons when using Self Contained Underwater Breathing
Apparatus (SCUBA), it should always be recommended to use an appropriate alternative breathing air (gas) source/secondary life support system. This recommendation can vary depending on location and training agencies you have received your training from and you must follow how you have been trained. However, it is common practice within recreational diving and during some commercial diving to use an Auxiliary Emergency Breathing System also known as an
Octopus or Alternative Air Source second stage, to fulfil or support this requirement. An Octopus is a secondary demand valve, designed to work in conjunction with the primary demand valve and they are both connected to the first stage pressure reducer. The Octopus provides a backup demand valve in cases of primary demand valve failure and may also act as an Alternative Air Source (AAS) for the diving
Buddy. An AAS does not require the Donor diver to remove their own primary demand valve when supplying gas to a Buddy diver who has experienced regulator failure or an out of gas situation.
By its very nature (other than during training exercises) this type of apparatus is only expected to be used during emergency situations and is therefore likely to experience very high ventilatory demand, as it is required to support two divers breathing at the same time.
SCUBA single demand regulators capable of meeting the breathing performance requirements of BS EN 250:2000 cannot be relied upon to meet the same performance requirements when used as part of an
Octopus system. This is due to requiring twice the performance from the first stage pressure reducer in an already strenuous environment.
Reduced breathing performance of second stage demand valve systems may be experienced when using low performance first stage pressure reducers with poor performing and incompatible second stage demand valves. This may go some way to explaining the number of divers who inexplicably break contact with their buddies during alternative air supply (AAS) ascents using some SCUBA Octopus systems.
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As stated in the minimum safety requirements for such products, using an Octopus, in water temperatures lower than 10°C (50°F) and at depths below 30 metres (98ft) carries significant risks and is not recommended. Although these minimum requirements only require an Octopus to be tested and restricted to 30 metres, (98ft) and 10°C
(50°F), Apeks recognises that emergencies can happen beyond these limits. To ensure Apeks products perform well in all conditions in this type of situation, Apeks has designed and has CE approval for our products to far exceed these minimum requirements. This means they match with the performance of the primary demand regulators they are intended to work with, in water temperatures below 10°C (50°F) where stated, and to depths of 50 metres (164ft).
As a user you can be confident that in an emergency or an out of gas situation, your regulator can cope with the extra demand of your buddy breathing from your Auxiliary Emergency Breathing System (Octopus) and safely supply enough gas for you both in all conditions you may be faced with.
WARNING: If Auxiliary Emergency Breathing Systems
(Octopus) are to be used you must ensure that:
The equipment selected is designed, tested and is CE marked for use with Auxiliary Emergency Breathing Systems with the intended use of water temperature and depth. The equipment is intended and can be used as an escape device by more than one diver at the same time.
Your equipment is maintained in accordance with manufacturers recommendations. Usually annually inspected and serviced. See section Dealer Service and Repair.
NOTE: See section on Markings, which explains how you can identify if your product is suitable for these conditions.
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WARNING:SCUBA regulators and equipment have operational limits when used with, Emergency Auxiliary
Breathing Systems, Alternate Air sharing, Octopus and
Buddy Breathing and increases the risk of serious injury or even death. You must ensure you understand these limitations and you have received the correct level of training and preparation of your equipment before you use Auxiliary
Emergency Breathing Systems.
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