OMS Airstream Evoque Regulator, Owner'S Manual

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21
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 fulfill 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.
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 of 30 meters (98ft) carries significant
risks and is not recommended.
Although these minimum requirements only require an Octopus to be tested and restricted
to 30 meters, (98ft) and 10°C (50°F),OMS recognizes that emergencies can happen
beyond these limits.
To ensure OMS products perform well in all conditions in this type of situation, OMS has
designed those products to far exceed the minimum requirements. This means they match
with the performance of the primary demand regulators they are intended to work with, in
water temperatures in 4°C (39.2°F) where stated, and to depths of 50 meters.
When tested in conjunction, the primary regulator and the auxiliary emergency breathing
system meet the requirements according to EN250:2014 Annex B, at a depth of 30 m and
in water temperature of 4°C.