Instructor Manual
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Ocean Diver
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Adapting to the underwater world
Copyright © BSAC 2017
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stages are a common method of identifying this backup system. Regulator
first stages manufactured after 2014 will be stamped with an “A” if they are
compatible to be fitted with an alternative supply.
As a backup system, an alternative supply second stage should be of equal
standard to the primary second stage. This alternative supply is for use in an
emergency, usually by the diver’s buddy.
Note: The latest version of the regulator standard EN250 (2014) advises that an
octopus rig is not a preferred option if the depth is greater than 30m or the water
temperature is less than 10°C, instead an alternative fully independent gas
supply is advised.
• Contents/pressure gauge
Divers need to know how much gas is in their cylinder at all times throughout
their dive, so a contents gauge is connected via a hose to the first stage. This
has to be a high-pressure hose as it delivers high-pressure gas for the gauge
to “read”. This contents gauge is sometimes mounted in a console that also
includes a depth gauge and possibly a compass.
Types
• Cold water (less than 10°C)
Many entry-level regulators are designed for water at a temperature above
10°C. EN250 (2014) compliant regulator first stages which are not designed for
cold-water performance are marked with “>10°C”. Regulator first stages may
be marked with a lower working temperature if specified by the manufacturer.
• Nitrox
Regulators used with nitrox should be in oxygen service. A regulator is in
oxygen service when all its internal components are compatible with high
oxygen levels and have been cleansed of hydrocarbons.
Care
• Rinse in fresh water
Regulators should be rinsed in fresh water after use. It is good practice to rinse
regulators while still attached to a cylinder and pressurised.
Warn about not pressing the purge button while rinsing a regulator that is not
under pressure, as water can enter the hoses and first stage. Also the first stage
should not be submerged in water unless sealed with an adequate cover; some
first stage covers are only dustproof and not watertight.
• Dry before storing
Regulators should be dry before storing and should be stored without placing
strain on the hoses.
