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Rescuing A Ccr/scr Diver In Distress


New Member
Oct 5, 2007
By: Thomas Hanaway

Seeing as how CCR/SCR diver's are becoming more commonplace these days, my self being one of them I thought it would be a good time to refresh everyone's minds on how t effectively help out a CCR/SCR diver in distree.

First off is a small glossary of the teminology we use in rebreather diving:

The LOOP: This term refers to the available gases that are available in the system for the diver to breathe.The loop consists of the 2 counterlungs,the scrubber canister,the amount of available gas in the hoses,the O2 tank, the diluent tank, and the dead space that is in the system.

The SCRUBBER: This refers to the canister that contains a chemical that effectively removes the CO2 from a diver's exhaled breath.The scrubber unit is filled with a chemical,(Sofnolime being one of the choices) that extracts the CO2 from the breath as it passes over and through it.

The COUNTERLUNGS: These are the 2 bags that contain the gas to be inhaled by the diver, and the expired gas from the diver.

The ppO2 sensors: The units, which are usually mounted on the diver's hands, that give a true time reading of the ppO2 that is in the breathing gas mixture at that point in time.

The OXYGEN SENSORS: These are located inside the rebreather unit and work by producing a very minute charge of electricity thereby reading the amount of O2. Most modern Rebreathers contain 3 of these sensors which are locatef in the electrical component area of the unit.

The ADV: Refers to the automatic diluent valve on rebreathr's that adds an amount of your diluent gas to the O2 that is in your loop bringing the level of O2 to a sustainable life giving mixture. Too much O2 can kill you, as can too little.

The ONE WAY VALVES: As the name implies, a valve that allows the flow of a gas in one direction only.

The "MUSHROOM" Valve: Is the one way valve that is located in the diver's moutnpiece allowing the gas to flow in one direction only."From the inhalation bag,to the mouthpiece, from the mouthpiece, to the exhalation bag.

The rescue/help scenario:

Upon arriving at the diver:

First check to see if the diver is breathing.This can be done by placing your hand on his/her chest or looking for the counterlungs to be inflating/deflating.

Check to see if the mouthpiece is in place and secure.If it is not and the diver is unresposive do NOT waste time trying to replace it.

If the diver is alert/responsive but the loop is malfunctioning offer your octo. or the diver's bail out OC regulator.

If the diver has retained the mouthpiece check to see if there is a breathable gas mixture in the breathing loop.This can be done by checking the hand readouts.

If there is not a sufficent breathing gas/volume you can add gas to the loop by placing the diver slightly on their left side and manually adding diluent to the loop by using the ADV overide feature.This will flush the loop and ensure that gas is available.There is an overpressurization release valve on the counterlung that will automatically activate, or you can activate it by hand much like a drysuit valve.


Approach the victim from behind using your right hand to keep the neck flexed backwards to avoid trapping any air in the lungs, airways, while you ascend.Using your left hand grip the diver's BCD and dump valve, keeping the dump valve open as you rise.

Never ascend faster than the recommended rate of 25 fpm.

If the diver's mouthpiece is in place use your right hand to secure it in the mouth while applying slight back pressure to flex the neck ensuring a constant release of gas from the respiratory system.

If the mouthpiece is out make sure you close the mushroom valve on it to prevent the loop from flooding any further as this extra weight adds a significant amount to negative buoyancy!!


Once on the surface you can start mouth to mouth breathing if required.Once you have the diver on land you should perform CPR as needed.

Make sure that somebody has called for the EMT's if they are not on scene.

Secure the CCR/SCR unit the same way as you would a scuba unit by closing off the valves to the O2 tank and diluent tank.Make sure the mushroom valve on the mouthpiece is also closed to prevent contaminents from the area around from getting in. NEVER lay the rebreathjer unit on its back as moisture/water from the exhaltion bag can flow into the scrubber unit causing a caustic cocktail to form in the scrubber making analysis of the unit much more difficult, should the need arise.

Administer oxygen to the diver as this can only do more good than harm.If O2 is unavailable at the scene and the diver is breathing on their own you can use the O2 in the unit by turning off the diluent valve and fully opening the valve on the O2 tank.There won't be a lot of volume in the tank but any is better than none at this point!It should last at least 6-10 minutes.You will have to keep the manually add O2 button depressed at all times.

I hope this small article has helped in some way if a CCR/SCR rescue is required.
SAFE DIVING everyone!!
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