Life support equipment

by | Oct 24, 2009 | Equipment

Regulators
While divers spend a great deal of money, time and commitment to get the best training possible it is amazing to see that there are a lot of dives out there who use inferior regulators and do not see the point of the regulator being life support equipment in a otherwise hostile environment. It is the regulators that deliver our breathing gas to us from our tanks and as we progress from recreational to advanced forms of diving with limited or no access to the surface, or changing diving environments from moderate to cold water diving we must reconsider our choice of regulators.

Regulators fall into a variety of categories ranging from a primary regulator that is our main regulator we are breathing from, to the secondary regulator or backup regulator that is hanging on a bungee around the divers neck, to the stage regulator used on stage tanks to extend cave penetration or extending bottom time to the decompression tank regulator who is used for nitrox mixtures or pure oxygen up to argon regulators used to feed argon from small tanks into our dry suits to enhance thermal comfort.

Each one of these regulators has his own specific requirements regarding balanced or unbalanced first stage or second stage, oxygen clean or not and second stages that can be adjusted or not. Downstream type regulators are preferred over upstream type regulators and all hoses should be interchangeable without any special hose or connector diameter. The use of 90 degree turn pieces is discouraged to prevent restriction in gas flow along with any type of adapter that is going in-between a hose connector and first or second stage.

In an extreme emergency one can breathe from the BCD while inflating the BCD with the power inflator and breathe the gas coming from the right post tank valve. A rare case of closing the left control knob while being in contact with a cave or wreck ceiling and then breaking the valve control know off would still enable us to have access to this last resort while accessing the right post valve and low pressure inflator hose including the ability to inflate the BCD while sharing gas with the long hose.

Balanced versus Non Balanced
First or second stages are either balanced or unbalanced. A balanced regulator is compensated for the environmental pressure and it takes the same effort to take a breath if the tank is either full or empty. Balanced first stages are a must for advanced forms of diving such as wreck, technical or cave diving with a choice of adding the breathing comfort of a balanced second stage. The extra performance and comfort comes with a price and more complexity in the design of balanced first or second stages. The balanced regulators provide ease of breathing with maximum performance while unbalanced regulators are less performing but of a more durable design.

Piston versus Diaphragm
Named after their internal design and working principle the first stages do either have a piston or a diaphragm that is in contact with the ambient pressure and water in order to regulate the intermediate pressure and gas flow to the second stage. Cold water divers prefer diaphragm first stages due to a higher resistance of regulator freeze up while other divers prefer the diaphragm first stage for the ease of gas delivery. While piston regulators have a tendency to freeze up easier in cold water conditions the manufacturers offer anti freeze kits to prevent that problem successfully.

Hoses
Hoses should be of the exact custom length for the individual diver with high quality materials used and providing maximum gas flow. The hoses must be checked regularly and replaced as soon as any wear or tear manifest itself.

The second stage hose of recreational divers is usually 32 ‘’ while many diver find that it is easier to share gas when the donating diver is using a 5-7 foot/1.5-2 Meter hose instead of the 40‘’ regular octopus hose when using the Hogarthian configuration based on the long hose looping under the waist band or under the primary light if one is used.

If participating in more advanced forms of diving such as wreck, technical or cave diving a 7 foot/2 Meter long hose is a must when the divers either have to swim or scooter any horizontal distance, are engaged in decompression diving or have to pass through small passages and being forced into single file. Any shorter hose then 7 feet/2 meters will not allow the divers to facilitate an effective and proficient gas sharing, and exit while passing through restrictions.

The primary regulator has a clip attached with a break away connection, close to the end of the long hose right next to the second stage. If the long hose is not in use during decompression when using another regulator and breathing gas or during an out of gas situation and gas sharing operation the long hose is clipped of to the right chest d-ring to prevent entanglement, regulator and environmental damage.

When diving in double tanks the primary long hose regulator is coming of the right hand post enabling the user to get the full length of the hose out for singe file exits. Of that same right hand post is coming the inflator hose, crossing behind our head to the left and feeding the BCD inflator. The left hand post is accommodating the short hose backup regulator, crossing behind our head to the right and coming over our arm below our chin to be attached to a bungee cord necklace hanging around our neck. The same left hand post is accommodating the pressure gauge hose leading down to  our waist band d-ring.

The advantage of having the long hose on the right post beyond getting the full length out of it is the fact that the right post control knob is rolling open and if breaking off in the open position it will stay open with the long hose enabled. If the left post rolls shut and possibly breaks off when diving close to a ice, wreck or cave ceiling with the long hose is attached to it, the left post will stay close and the long hose will be lost to the team. Gas sharing scenarios where the out of air diver will most likely leading out, passing a restriction there is no way for the out of air diver to signal the donor behind him that he is out of air, and drowning will result.

DIN versus Yoke
There are two ways to connect a first stage the tank valve, one is the DIN (Deutsche Industrie Norm) and the second one is the Yoke or A clamp. The Yoke connector is used mainly by recreational divers due to ease of use but has the disadvantage that this connection often leaks gas and is not as streamlined as the DIN connector due to its large clamp surrounding the valve. The o-ring of the Yoke connection is located on the tank valve being subject to much more abuse then the DIN o-ring. The DIN connector is a very streamlined design and construction with the o-ring located inside the first stage stem connector and when assembled is embedded inside the valve for maximum o-ring sealing and protection.

Pressure Gauge
Following the concept of streamlining, keeping it clean, gear and environmental protection the best place for the pressure gauge is for the hose to come down from the left post, having the exact length to connect and be clipped into the left waist d-ring. This configuration provides the cleanest and most protective approach. Some divers prefer to have the pressure gauge coming under the arm and clipping it into the left or right shoulder d-ring to facilitate the reading of the gauge specially with a lot of additional gear and stage tanks. The use of two pressure gauges is over-redundancy and not needed since we will abort the dive inside turn around pressures including reserve volumes. All a second pressure gauge does is creating more failure points in our life support system. Any boot or console increases drag and a greater chance of environmental impact or entanglement.

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