Buddy breathing

Last updated April 25, 2024

Buddy breathing is a rescue technique used in scuba diving "out-of-gas" emergencies, when two divers share one demand valve, alternately breathing from it. Techniques have been developed for buddy breathing from both twin-hose and single hose regulators, but to a large extent it has been superseded by safer and more reliable techniques using additional equipment, such as the use of a bailout cylinder or breathing through a secondary demand valve on the rescuer's regulator.^[1]

Running out of breathing gas most commonly happens as a result of poor gas management.^[2] It can also happen due to unforeseen exertion or breathing equipment failure. Equipment failure resulting in the loss of all gas could be caused by failure of a pressure retaining component such as an O-ring or hose in the regulator or, in cold conditions, a freezing of water in the regulator resulting in a free flow from the demand valve.^[3]^[4]

Technique

Buddy breathing is usually initialised by the diver with the "out of air" emergency signalling this to another diver by a standard hand signal "give me air". This signal is made by holding the fingers and thumb of one hand together, pointing them at the mouth and making repeated movements of the finger tips towards the mouth.^[6]

The donor is expected to take a good breath and pass their demand valve (or mouthpiece in the case of a twin-hose regulator) to the recipient, who is expected to take two good breaths and pass it back. In reality the recipient will often take more than two breaths, and the donor should expect this and relax to minimize metabolic rate. The donor should retain a good grip on the demand valve throughout the buddy breathing process, as a panicked recipient may fail to give it back. A reasonably reliable way of keeping control of the demand valve is to grasp the hose firmly in the fist where it connects to the demand valve. This provides good control but allows the recipient to use the purge button if needed.^[7]^[8]

A pattern of two breaths per diver should be established as soon as possible and then terminate the dive and start the ascent as soon as possible, as air consumption while buddy breathing is usually more than double the normal rate. Most demand valves will only drain correctly if the hose is to the user's right, and in these cases the divers should align themselves to allow convenient movement of the demand valve from donor to recipient and back. When the divers need to ascend or swim horizontally, it requires co-ordination and some skill, which is best practiced in a low hazard environment.^[8]

Training

A study by the UCLA Diving Safety Research Project suggests that about 20 successful repetitions of buddy breathing during training of entry level students are needed for a reasonable expectation of success without errors, and retesting after three months without reinforcing practice showed degraded performance and procedural errors. This is a higher level of training than provided by most recreational diver training organisations. For the skill to be reliable in an emergency, periodic reinforcement is necessary, and familiarisation is particularly valuable when buddies are to dive together for the first time.^[7]

Hazards

Buddy breathing is one of the few scuba skills in which the incompetence of one diver can threaten the life of another. Poor buddy breathing performance has resulted in the death of both divers on more than one occasion. The practice has been deprecated by most major recreational training agencies as requiring more practice than the skill is worth, considering that far more effective, safer, and easier to learn methods are available, at the cost of investing in additional equipment. The procedure requires the use of both hands to keep in position and guide the regulator, making buoyancy control during the ascent difficult, though it remains a critical operation if there is a decompression obligation. The task loading is increased if one of the divers must operate a reel for a decompression or surface marker buoy, though this can also simplify buoyancy control. The use of secondary demand valves and bailout cylinders make buddy breathing unnecessary.^[1]

History

Buddy breathing originated from military diving following a prohibition on the training and practice of free ascents.^[7]

The procedure has been used since the beginnings of recreational diving, and along with the free ascent was one of the ways a diver could respond to running out of air at depth. At this time twin-hose regulators were the norm. and it was reasonably easy for two divers in a face-to-face position to share the regulator mouthpiece. Buddy breathing was an important skill before reserve valves and submersible pressure gauges were generally available, and running out of air was so common that it was not considered an emergency. By the mid-1960s the availability of submersible pressure gauges made reliable air supply monitoring possible and running out of air became less common.^[1]

In the late 1960s single-hose regulators started to take over as the standard, and this complicated the buddy breathing procedure. The single hose exhaust valve position at the bottom of most DVs made it necessary to offset the recipient to the right side when face to face, or to the left when side by side. The standard procedure of continuous exhalation during ascent to avoid lung over-pressure injury could leave the diver with insufficient air to clear the regulator, so it was necessary to hold the DV in a way that did not obstruct the recipient from accessing the purge button, as the single hose would not normally free flow when raised above the head. The increasing popularity of the buoyancy compensator was another complication, as it is necessary to periodically vent it during an ascent to avoid a runaway expansion of the contents and an uncontrolled buoyant ascent. This requires the use of one hand. the other is needed to control the regulator and hold on to the other diver, a moderately complex set of simultaneous tasks.^[1] It is possible to coordinate these activities, but this requires greater skill than with the original procedure, and therefore more intensive training to perform reliably. Since running out of air was becoming less common, the procedure was practiced less often, and skills generally deteriorated. The use of a secondary (octopus) second stage or a bailout cylinder removes the necessity for this complex and relatively stressful procedure.

In the 1990s there was also growing concern about the transmission of disease by sharing a mouthpiece, particularly as a better option was available at a reasonable cost. Dive Training magazine ran an article by Alex Brylske in November 1993 detailing the hazards of buddy breathing and the advantages of alternative systems,^[9] and over the following years the practice was phased out of most recreational diver training programmes in favour of the use of secondary second stages and where applicable, a controlled emergency swimming ascent. The most reliable alternative breathing gas supply, the bailout cylinder, has not yet significantly penetrated the recreational diving market, though it is standard equipment for solo diving, and may be required for professional scuba divers in some circumstances.

Alternatives

Most recreational and professional diver training organisations would consider relying on buddy breathing from a single regulator as an unacceptable risk, as the use of a secondary demand valve (octopus) or second regulator, either from an alternative scuba cylinder, or from the primary scuba set, is a far more reliable and safe method of supplying emergency air to a diver who is part of a planned team or buddy dive, and a solo diver should carry their own emergency gas supply. There should never be a situation on a well planned and executed dive where two divers need to share a single demand valve, but the technique is still considered useful by some diving schools as it teaches control and hones skills under difficult circumstances.^[7]

Buddy breathing is discouraged by many training agencies because other more reliable techniques and equipment exist. The technique needs training and regular practice by both divers if it is to be used successfully in a crisis; panic and task loading being the main reasons for it failing. Especially in situations in which one or both of the participants are not well-trained in the technique, the procedure has been criticised for endangering two people instead of one.^[10]

Many divers fit a second demand valve, often called an "octopus", to their diving regulators, for emergency use by another diver. Some go so far as to recognise that the out-of-air diver will want the demand valve they are breathing off at the time, as it is indisputably providing breathing gas, and almost certainly a gas suitable for the current depth. These practice " donating the primary " in recognition of this tendency, and often use an extra-long hose (up to 7 ft long) to facilitate the procedure in tight spaces. These divers often wear the secondary demand valve on a " necklace " which keeps it ready for immediate use under the diver's chin, where it can be retrieved for use without the use of the hands.^[7]

Divers doing deep diving, cave or wreck penetration, or decompression stops may routinely carry a complete, independent bailout scuba set for their own or their buddy's emergency use. This is particularly prevalent in professional diving operations where it is often mandatory.^[11]

Use of other emergency air sources such as octopus second stage, integrated DV/BC inflator units, bailout cylinders etc. also requires the learning of appropriate skills. These procedures are as complex as buddy breathing up to the point of sharing, and the fundamental difference is that the donor and recipient are not required to alternate breathing with a period when no air is available, which can be a big advantage. These alternatives to buddy breathing also require substantial learning and reinforcement to be reliable in a stressful situation.^[7]

Avoidance

In most cases the need for buddy-breathing or other gas related emergency is avoidable. The equipment is highly reliable when in good condition, and though occasionally breakdowns will occur without warning, in most cases user inspection and testing before the dive, combined with a reasonable planned maintenance schedule carried out by a competent person will pick up potential problems before they escalate to an emergency. Realistic gas planning and monitoring of the remaining gas supply in context of the time required to surface safely will prevent almost all out-of gas emergencies.^[12] Carrying a fully redundant emergency gas supply allows the diver to bail out independently of outside assistance if in spite of all precautions, an emergency does occur.

Related Research Articles

A scuba set, originally just scuba, is any breathing apparatus that is entirely carried by an underwater diver and provides the diver with breathing gas at the ambient pressure. Scuba is an anacronym for self-contained underwater breathing apparatus. Although strictly speaking the scuba set is only the diving equipment that is required for providing breathing gas to the diver, general usage includes the harness or rigging by which it is carried and those accessories which are integral parts of the harness and breathing apparatus assembly, such as a jacket or wing style buoyancy compensator and instruments mounted in a combined housing with the pressure gauge. In the looser sense, scuba set has been used to refer to all the diving equipment used by the scuba diver, though this would more commonly and accurately be termed scuba equipment or scuba gear. Scuba is overwhelmingly the most common underwater breathing system used by recreational divers and is also used in professional diving when it provides advantages, usually of mobility and range, over surface-supplied diving systems and is allowed by the relevant legislation and code of practice.

Ice diving is a type of penetration diving where the dive takes place under ice. Because diving under ice places the diver in an overhead environment typically with only a single entry/exit point, it requires special procedures and equipment. Ice diving is done for purposes of recreation, scientific research, public safety and other professional or commercial reasons.

<span class="mw-page-title-main">Surface-supplied diving</span> Underwater diving breathing gas supplied from the surface

Surface-supplied diving is a mode of underwater diving using equipment supplied with breathing gas through a diver's umbilical from the surface, either from the shore or from a diving support vessel, sometimes indirectly via a diving bell. This is different from scuba diving, where the diver's breathing equipment is completely self-contained and there is no essential link to the surface. The primary advantages of conventional surface supplied diving are lower risk of drowning and considerably larger breathing gas supply than scuba, allowing longer working periods and safer decompression. Disadvantages are the absolute limitation on diver mobility imposed by the length of the umbilical, encumbrance by the umbilical, and high logistical and equipment costs compared with scuba. The disadvantages restrict use of this mode of diving to applications where the diver operates within a small area, which is common in commercial diving work.

<span class="mw-page-title-main">Buddy check</span> Pre-dive safety checks carried out by two-diver dive teams

The buddy check is a procedure carried out by scuba divers using the buddy system where each diver checks that the other's diving equipment is configured and functioning correctly just before the start of the dive. A study of pre-dive equipment checks done by individual divers showed that divers often fail to recognize common equipment faults. By checking each other's equipment as well as their own, it is thought to be more likely that these faults will be identified prior to the start of the dive.

<span class="mw-page-title-main">Scuba diving</span> Swimming underwater, breathing gas carried by the diver

Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface breathing gas supply, and therefore has a limited but variable endurance. The name scuba is an anacronym for "Self-Contained Underwater Breathing Apparatus" and was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the effects of nitrogen narcosis during deeper dives.

Solo diving is the practice of self-sufficient underwater diving without a "dive buddy", particularly with reference to scuba diving, but the term is also applied to freediving. Professionally, solo diving has always been an option which depends on operational requirements and risk assessment. Surface supplied diving and atmospheric suit diving are commonly single diver underwater activities but are accompanied by an on-surface support team dedicated to the safety of the diver, including a stand-by diver, and are not considered solo diving in this sense.

Sidemount is a scuba diving equipment configuration which has scuba sets mounted alongside the diver, below the shoulders and along the hips, instead of on the back of the diver. It originated as a configuration for advanced cave diving, as it facilitates penetration of tight sections of cave, allows easy access to cylinder valves, provides easy and reliable gas redundancy, and tanks can be easily removed when necessary. These benefits for operating in confined spaces were also recognized by divers who conducted technical wreck diving penetrations.

Buddy diving is the use of the buddy system by scuba divers. It is a set of safety procedures intended to improve the chances of avoiding or surviving accidents in or under water by having divers dive in a group of two or sometimes three. When using the buddy system, members of the group dive together and co-operate with each other, so that they can help or rescue each other in the event of an emergency. This is most effective if both divers are competent in all relevant skills and sufficiently aware of the situation that they can respond in time, which is a matter of both attitude and competence.

<span class="mw-page-title-main">Pony bottle</span> Small independent scuba cylinder usually carried for emergency gas supply

A pony bottle or pony cylinder is a small diving cylinder which is fitted with an independent regulator, and is usually carried by a scuba diver as an auxiliary scuba set. In an emergency, such as depletion of the diver's main air supply, it can be used as an alternative air source or bailout bottle to allow a normal ascent in place of a controlled emergency swimming ascent. The key attribute of a pony bottle is that it is a totally independent source of breathing gas for the diver.

In underwater diving, an alternative air source, or more generally alternative breathing gas source, is a secondary supply of air or other breathing gas for use by the diver in an emergency. Examples include an auxiliary demand valve, a pony bottle and bailout bottle.

A bailout bottle (BoB) or, more formally, bailout cylinder is a scuba cylinder carried by an underwater diver for use as an emergency supply of breathing gas in the event of a primary gas supply failure. A bailout cylinder may be carried by a scuba diver in addition to the primary scuba set, or by a surface supplied diver using either free-flow or demand systems. The bailout gas is not intended for use during the dive except in an emergency, and would be considered a fully redundant breathing gas supply if used correctly. The term may refer to just the cylinder, or the bailout set or emergency gas supply (EGS), which is the cylinder with the gas delivery system attached. The bailout set or bailout system is the combination of the emergency gas cylinder with the gas delivery system to the diver, which includes a diving regulator with either a demand valve, a bailout block, or a bailout valve (BOV).

An emergency ascent is an ascent to the surface by a diver in an emergency. More specifically, it refers to any of several procedures for reaching the surface in the event of an out-of-air emergency, generally while scuba diving.

Scuba gas management is the aspect of scuba diving which includes the gas planning, blending, filling, analysing, marking, storage, and transportation of gas cylinders for a dive, the monitoring and switching of breathing gases during a dive, efficient and correct use of the gas, and the provision of emergency gas to another member of the dive team. The primary aim is to ensure that everyone has enough to breathe of a gas suitable for the current depth at all times, and is aware of the gas mixture in use and its effect on decompression obligations, nitrogen narcosis, and oxygen toxicity risk. Some of these functions may be delegated to others, such as the filling of cylinders, or transportation to the dive site, but others are the direct responsibility of the diver using the gas.

Scuba skills are skills required to dive safely using self-contained underwater breathing apparatus, known as a scuba set. Most of these skills are relevant to both open-circuit scuba and rebreather scuba, and many also apply to surface-supplied diving. Some scuba skills, which are critical to divers' safety, may require more practice than standard recreational training provides to achieve reliable competence.

Surface-supplied diving equipment (SSDE) is the equipment required for surface-supplied diving. The essential aspect of surface-supplied diving is that breathing gas is supplied from the surface, either from a specialised diving compressor, high-pressure gas storage cylinders, or both. In commercial and military surface-supplied diving, a backup source of surface-supplied breathing gas should always be present in case the primary supply fails. The diver may also wear a bailout cylinder which can provide self-contained breathing gas in an emergency. Thus, the surface-supplied diver is less likely to have an "out-of-air" emergency than a scuba diver using a single gas supply, as there are normally two alternative breathing gas sources available. Surface-supplied diving equipment usually includes communication capability with the surface, which improves the safety and efficiency of the working diver.

The following outline is provided as an overview of and topical guide to underwater diving:

Investigation of diving accidents includes investigations into the causes of reportable incidents in professional diving and recreational diving accidents, usually when there is a fatality or litigation for gross negligence.

The following index is provided as an overview of and topical guide to underwater diving:

Diving procedures are standardised methods of doing things that are commonly useful while diving that are known to work effectively and acceptably safely. Due to the inherent risks of the environment and the necessity to operate the equipment correctly, both under normal conditions and during incidents where failure to respond appropriately and quickly can have fatal consequences, a set of standard procedures are used in preparation of the equipment, preparation to dive, during the dive if all goes according to plan, after the dive, and in the event of a reasonably foreseeable contingency. Standard procedures are not necessarily the only courses of action that produce a satisfactory outcome, but they are generally those procedures that experiment and experience show to work well and reliably in response to given circumstances. All formal diver training is based on the learning of standard skills and procedures, and in many cases the over-learning of the skills until the procedures can be performed without hesitation even when distracting circumstances exist. Where reasonably practicable, checklists may be used to ensure that preparatory and maintenance procedures are carried out in the correct sequence and that no steps are inadvertently omitted.

References

1 2 3 4 Brylske, Alex. "Buddy Breathing: Is it Time for Change?". 25th-anniversary-vintage-articles. dtmag.com. Retrieved 12 January 2017.originally published in Dive Training, November 1993.
↑ Denoble, PJ; Marroni, A; Vann, RD (2011). Annual Fatality Rates and Associated Risk Factors for Recreational Scuba Diving In: Vann RD, Lang MA, eds. Recreational Diving Fatalities. Proceedings of the Divers Alert Network 2010 April 8-10 Workshop. Divers Alert Network. ISBN 978-0-615-54812-8.
↑ Watson, Jim (2013). "Regulator freezes". Diving safety: Safety talk: 2013 listing. Ellesmere Port, Cheshire: British Sub-Aqua Club. Retrieved 30 November 2016.
↑ Ward, Mike (9 April 2014). "Scuba Regulator Freezing Chilling Facts & Risks Associated with Cold Water Diving" (PDF). DL-Regulator Freeze Research Study. Panama City Beach, Florida: Dive Lab, Inc. Retrieved 30 November 2016.
↑ "Dive Links". Archived from the original on 2009-04-14. Retrieved 2009-04-14.
1 2 "Underwater Signals - UKDivers.net". Archived from the original on 2009-04-01. Retrieved 2009-04-14.
1 2 3 4 5 6 Egstrom, Glen H (1992). "Emergency air sharing". South Pacific Underwater Medicine Society Journal. 22 (4). Archived from the original on December 18, 2013. Retrieved 2013-12-18.{{cite journal}}: CS1 maint: unfit URL (link)
1 2 Mike Busuttili; Mike Holbrook; Gordon Ridley; Mike Todd, eds. (1985). Sport diving: The British Sub-Aqua Club Diving Manual (Revised ed.). London: Stanley Paul. ISBN 0-09-163831-3.
↑ Young, Mark. "Buddy Breathing: Is it Time for Change? Editorial comment". 25th-anniversary-vintage-articles. dtmag.com. Retrieved 12 January 2017.
↑ Graver, Dennis (2003). Scuba Diving (3rd ed.). p. 88.
↑ Sheldrake, S; Pedersen, R; Schulze, C; Donohue, S; Humphrey, A (2011). "Use of Tethered Scuba for Scientific Diving". In: Pollock NW, ed. Diving for Science 2011. Proceedings of the American Academy of Underwater Sciences 30th Symposium.
↑ Davis, Andy (7 August 2019). "Don't get gas mugged: A predictable strategy for stress-free air sharing emergencies" . Retrieved 14 January 2020.

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[Brylske_1993-1] 1 2 3 4 Brylske, Alex. "Buddy Breathing: Is it Time for Change?". 25th-anniversary-vintage-articles. dtmag.com. Retrieved 12 January 2017.originally published in Dive Training, November 1993.

[Denoble2011-2] Denoble, PJ; Marroni, A; Vann, RD (2011). Annual Fatality Rates and Associated Risk Factors for Recreational Scuba Diving In: Vann RD, Lang MA, eds. Recreational Diving Fatalities. Proceedings of the Divers Alert Network 2010 April 8-10 Workshop. Divers Alert Network. ISBN 978-0-615-54812-8.

[BSAC_2013-3] Watson, Jim (2013). "Regulator freezes". Diving safety: Safety talk: 2013 listing. Ellesmere Port, Cheshire: British Sub-Aqua Club. Retrieved 30 November 2016.

[Ward_2014-4] Ward, Mike (9 April 2014). "Scuba Regulator Freezing Chilling Facts & Risks Associated with Cold Water Diving" (PDF). DL-Regulator Freeze Research Study. Panama City Beach, Florida: Dive Lab, Inc. Retrieved 30 November 2016.

[dl-5] "Dive Links". Archived from the original on 2009-04-14. Retrieved 2009-04-14.

[uw-6] 1 2 "Underwater Signals - UKDivers.net". Archived from the original on 2009-04-01. Retrieved 2009-04-14.

[Egstrom1992-7] 1 2 3 4 5 6 Egstrom, Glen H (1992). "Emergency air sharing". South Pacific Underwater Medicine Society Journal. 22 (4). Archived from the original on December 18, 2013. Retrieved 2013-12-18.{{cite journal}}: CS1 maint: unfit URL (link)

[BSAC_Manual-8] 1 2 Mike Busuttili; Mike Holbrook; Gordon Ridley; Mike Todd, eds. (1985). Sport diving: The British Sub-Aqua Club Diving Manual (Revised ed.). London: Stanley Paul. ISBN 0-09-163831-3.

[Young-9] Young, Mark. "Buddy Breathing: Is it Time for Change? Editorial comment". 25th-anniversary-vintage-articles. dtmag.com. Retrieved 12 January 2017.

[Graver-10] Graver, Dennis (2003). Scuba Diving (3rd ed.). p. 88.

[RRR10115-11] Sheldrake, S; Pedersen, R; Schulze, C; Donohue, S; Humphrey, A (2011). "Use of Tethered Scuba for Scientific Diving". In: Pollock NW, ed. Diving for Science 2011. Proceedings of the American Academy of Underwater Sciences 30th Symposium.

[Davis_2019-12] Davis, Andy (7 August 2019). "Don't get gas mugged: A predictable strategy for stress-free air sharing emergencies" . Retrieved 14 January 2020.

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