Scuba diving is an underwater diving mode where divers use fully-scaled underwater scuba tools (scuba) that are completely independent of the surface supply, to breathe under water. Scuba divers carry their own respiratory gas source, usually compressed air, which allows them to be freer and free to move than a surface-supplied diver, and a longer underwater duration than a breath-holding diver. The open-circuit scuba system removes respiratory gas into the environment when exhaled, and consists of one or more diving cylinders containing respiratory gas at high pressure supplied to the diver through the regulator. They may include additional cylinders for extended range, decompression gas or emergency respiratory gas. The schematic rebreather system of closed or semi-enclosed circuits allows recycling of exhaled gases. The volume of gas used is reduced compared to the open circuit, so a smaller cylinder or cylinder can be used for equivalent dive durations. Rebreathers extend the time spent underwater compared to open circuits for the same gas consumption; they produce fewer bubbles and less noise than open-circuit scuba that makes them attractive to secret military divers to avoid detection, scientific divers to avoid marine animal intrusion, and media divers to avoid bubble distractions.
Scuba diving can be done recreationally or professionally in a number of applications, including scientific, military and public safety roles, but most commercial dives use the currently available practical on-the-surface dive equipment. Scuba divers who are involved in armed operations of secret troops can be referred to as human frogs, combat divers, or swimmers of attack.
A scuba divers mainly moves underwater by using a fins attached to the foot, but external propulsion can be provided by a diver propulsion vehicle, or a sled drawn from the surface. Other tools include masks for improving underwater vision, exposure protection, equipment for buoyancy control, and equipment related to the circumstances and special purpose of the dive. Some divers use snorkels while swimming on the surface. Scuba divers are trained in procedures and skills appropriate to their certification level by instructors who are affiliated with the certification organization of the divers who issued this certification. This includes standard operating procedures for using equipment and dealing with the common dangers of the underwater environment, and emergency procedures for self-help and diver assistance with full equipment that has problems. Minimum fitness and health levels are required by most training organizations, but a higher level of fitness may be appropriate for some apps.
Video Scuba diving
History
The history of scuba diving is closely linked to the history of scuba equipment. At the turn of the 20th century, two basic architectures for underwater breathing equipment have been pioneered; the open surface equipment provided in which the gas inhaled diver is directly discharged into the water, and a closed-circuit breathing apparatus in which the dioxide of the diver is filtered from unused oxygen, which is then recycled. Closed circuit equipment is more easily adapted to scuba because of the absence of reliable, portable, and economical high pressure gas storage vessels. In the mid-twentieth century, high pressure cylinders were available and two systems for scuba had emerged: open-circuit scuba where breaths inhaled by divers were released directly into the water, and scuba closed circuits in which carbon dioxide was removed from the exhaled diver. breath that has oxygen added and recirculated. The oxygen boiler is very limited because of the risk of oxygen toxicity, which increases with depth, and the system available for mixed gas rebreathers is large enough and is designed for use with a diving helmet. The first commercially designed rebarthher scuba designed and built by engineer Henry Fleuss in 1878, while working for Siebe Gorman in London. The self-contained breathing apparatus comprises a rubber mask connected to the breathing bag, with an estimated 50-60% of the oxygen supplied from the copper and carbon dioxide tanks released by passing it through a bundle of string strings soaked in an acoustic potash solution, the system providing the duration of diving up about three hours. This equipment has no way of measuring the composition of gases during use. During the 1930s and during World War II, Britain, Italy and Germany developed and extensively used oxygen rebreathers to supplement the first frog. Britain adapted the Davis Submerged Escape Apparatus and the Germans adapted the submarine crew of the DrÃÆ'¤ger escape, to their frogs humans during the war. In the US Major Christian J. Lambertsen invented the free oxygen rebreather swimming in nature in 1939, which was received by the Office of Strategic Services. In 1952 he patented his equipment modification, this time named SCUBA, (an acronym for "self-help underwater breathing apparatus"), which became the common English word for autonomous breathing apparatus for diving, and then for activity using equipment. After World War II, the military frogs continued to use rebreathers because they did not make bubbles that would provide the divers's presence. The high percentage of oxygen used by this early rebreather system limits the depth at which they can be used because of the risk of seizures caused by acute oxygen toxicity.
Although the demand-management system was discovered in 1864 by Auguste Denayrouze and BenoÃÆ'®t Rouquayrol, the first open-circuit scuba system developed in 1925 by Yves Le Prieur in France was a manually adjusted free flow system with low endurance, which was limited practical use. In 1942, during the German occupation of France, Jacques-Yves Cousteau and ÃÆ' € Gagnan miles designed the first successful and safe open-circuit scuba, known as Aqua-Lung. Their systems combine enhanced demand regulators with high-pressure air tanks. It was patented in 1945. To sell its regulators in English-speaking countries, Cousteau registered the Aqua-Lung trademark, which was first licensed to the US Diver, and in 1948 to Siebe Gorman of England. Siebe Gorman was allowed to sell in Commonwealth countries, but had difficulty meeting US requests and patents preventing others from making products. The patent was circumvented by Ted Eldred of Melbourne, Australia, which developed a single-hose open-circuit scuba system, which separates the first stage and the pressure regulator request valve with a low pressure hose, locates the demand valve in the mouth dive, and releases the exhaled gas through the demand valve casing. Eldred sold the first Scuba Porpoise Model CA single hose in early 1952.
Early scuba devices are usually equipped with shoulder straps and waist belts. The waist belt buckle is usually released quickly, and the shoulder straps sometimes have adjustable or removable loose buckles. Many reins do not have back plates, and cylinders lean against the backs of divers. Scuba divers early diving without the help of buoyancy. In an emergency they have to throw away their burden. In the 1960s a customized floating life jacket (ABLJ) became available, which could be used to compensate for the loss of buoyancy in depth due to compression of the neoprene wetsuit and as a lifejacket that would hold unconscious divers facing upward on the surface, and which could by fast increase. The first version is pumped from a small disposable carbon dioxide tube, then with a small direct air cylinder. The low pressure feed from the first stage regulator to the valve inflation/deflation valve of the oral inflation and exhaust valve allows the volume of ABLJ to be controlled as a buoyancy aid. In 1971 the stabilizer jacket was introduced by ScubaPro. This floating power assist class is known as a floating control device or a float compensator.
Backplates and wings are an alternative configuration of scuba harness with a floating compensated bladder known as a "wing" mounted behind a diver, flanked between the back plate and the cylinder or cylinder. Unlike a stabilizer jacket, the backplate and wing are modular systems, which are made up of components that can be separated. This arrangement became popular with cave divers making long or deep dives, which need to carry some extra cylinders, as it cleans the front and sides of the diver for other equipment to be installed in easily accessible areas. This additional equipment is usually hung from a harness or carried in a pocket on an exposure suit. Sidemount is a scuba-diving equipment configuration that has a basic scuba set, each consisting of a single cylinder with a special regulator and a pressure gauge, mounted next to a diver, clamped into the harness below the shoulders and along the hips instead of at the back of the diver. It originated as a sophisticated cave diving configuration, as it facilitates the penetration of tight cave sections, since sets can be easily removed and recreated if needed. The configuration allows easy access to the cylinder valves, and provides easy and reliable gas redundancy. This benefit to operate in confined spaces is also recognized by divers who make the penetration of diving accidents. Sidemount diving has grown in popularity in the technical dive community for general decompression dives, and has become a popular specialty for recreational diving.
In the 1950s the US Navy (USN) documented an enriched oxygen gas procedure for military use of what we now call nitrox, and in 1970, Morgan Wells, of (NOAA) began instituting diving procedures for oxygen-rich air. In 1979 NOAA published the procedure for the use of nitrox scientific in NOAA's Diving Manual. In 1985 IAND (International Association of Nitrox Divers) began teaching the use of nitrox for recreational diving. This is considered dangerous by some people, and is met with severe skepticism by the diving community. Nevertheless, in 1992 NAUI became the first major recreational dive training institute to sanction nitrox, and finally, in 1996, the Association of Professional Diving Instructors (PADI) announced full nitrox education support. The use of a single nitrox blend has been part of recreational diving, and some common gas mixtures in technical dive to reduce overall decompression time.
Technical diving is a recreational scuba diving that exceeds the commonly accepted recreational limits, and may expose divers to outside hazards that are typically associated with recreational dives, and the risk of injury or death is greater. These risks can be reduced by appropriate skills, knowledge and experience, and by appropriate tools and procedures. The concept and the term are both relatively recent introductions, though divers are already involved in what is now often referred to as technical dives for decades. One widespread definition is that any dive that at some point of the planned profile is not physically or physiologically acceptable to make a direct and undisturbed vertical ascent to the surface is a technical dive. This equipment often involves respiratory gas in addition to a standard air or nitrox mixture, different gas sources, and different equipment configurations. Over time, some equipment and techniques developed for technical dive have become more widely accepted for recreational diving.
Narcotic nitrogen limits the depth that can be achieved by underwater divers when inhaling a nitrox mixture. In 1924 the US Navy began investigating the possibility of using helium and after experiments on animals, human subjects inhaled heliox 20/80 (20% oxygen, 80% helium) were decompressed from deep dives. In 1963 saturation of diving using trimix was done during Project Genesis , and in 1979 a team of researchers at the Hyperbarik Laboratory of Duke University Medical Center began work that identified the use of trimix to prevent the symptoms of high-pressure nerve syndrome. The cave divers began to use the trimix to allow deeper dives and was used extensively in the 1987 Wakulla Springs Project and spread to the North American-eastern crash diving community.
Deeper dive challenges and longer penetration and the large amount of respiratory gas required for these dive profiles and the availability of oxygen sensing cells that were ready to begin in the late 1980s led to a reappearance of interest in rebreather diving. By accurately measuring the partial pressure of oxygen, it becomes possible to maintain and accurately monitor the breathing gas mixture in a circle at any depth. In the mid-1990s, semi-closed rebreathers became available for the recreational scuba market, followed by rebreathers around the turn of the millennium. Current rebreathers (2018) are produced for military, technical and recreational scuba markets.
Maps Scuba diving
Tools
Breathing apparatus
The equipment used by scuba diver is eponymous scuba, a self-contained underwater breathing apparatus that allows divers to breathe while diving, and transported by divers.
When one descends, in addition to normal atmospheric pressure on the surface, water provides an increased hydrostatic pressure of about 1 bar (14.7 pounds per square inch) for every 10 m (33 ft) depth. The breath pressure inhaled should balance the ambient or ambient pressure to allow lung inflation. It is almost impossible to breathe air at normal atmospheric pressure through a tube under three feet underwater.
Most recreational scuba diving is done using a half mask covering the eyes and nose of the diver, and a funnel to supply the respiratory gas from the demand valve or rebreather. Inhaling from the regulator funnel becomes second nature very quickly. Another common setting is a full face mask that covers the eyes, nose and mouth, and often allows the diver to breathe through the nose. Professional divers are more likely to use a full face mask, which protects the diver's breath if the diver loses consciousness.
Open circuit
Scuba open circuits have no provision for using respiratory gas more than once for respiration. The gas inhaled from the scuba apparatus is exhaled into the environment, or sometimes to other equipment items for special purposes, typically to increase the buoyancy of the lifter such as float compensators, buoys of the inflatable surface markers or small lifter bags. Respiratory gas is generally provided from high pressure dive cylinders through scuba regulators. By always providing the appropriate breathing gas at ambient pressure, the valve regulator demands that the diver can breathe and exhale naturally and without excessive effort, regardless of its depth, as and when required.
The most commonly used scuba set uses a single-hose "open-circuit" 2-stage demand regulator, connected to a single-backed high-pressure gas cylinder, with the first stage connected to the cylinder valve and the second stage of the funnel. This arrangement differs from the original 1940's "twin-hose" design Gagnan and Jacques Cousteau, known as Aqua-lung, where the cylinder pressure is reduced to ambient pressure in one or two stages that are all in a housing mounted to a cylinder or manifold valve. The "single hose" system has a significant advantage over the original system for most applications.
In a two-stage "single-hose" design, the first-stage regulator reduces cylinder pressure to about 300 bar (4,400 psi) to an intermediate pressure (IP) of 8 to 10 bar (120 to 150 psi) above ambient pressure. The second stage request valve regulator, supplied by a low pressure hose from the first stage, sends breathing gas at ambient pressure to the diver's mouth. The exhausted gas directly into the environment as waste through the valve does not return to the second stage house. The first stage usually has at least one outlet port that sends gas at full tank pressure connected to a submersible diver or submersible dive pressure gauge, to show how much gas is left in the cylinder.
Rebreather
Less common are closed circuits (CCRs) and semi-closed rebreathers (SCRs) which, unlike open circuits that release all exhaled gas, process all or part of each exhaled breath for reuse by removing carbon dioxide and replacing the oxygen that used by divers. Rebreathers release little or no gas bubbles into the water, and use less volume of stored gas, for equivalent depth and time because oxygen exhaled has recovered; it has advantages for research, military, photography, and other applications. Rebreathers are more complex and more expensive than open-circuit scuba, and proper training and proper maintenance are required so that they can be used safely, due to greater variations of potential failure modes.
In rebreather closed circuits, the partial pressure of oxygen on the rebreather is controlled, so it can be maintained at a safe continuous maximum, which reduces the inert gas partial pressure (nitrogen and/or helium) in the respiratory loop. Minimizing the loading of inert gas from the diver tissue for a given dive profile reduces the decompression obligation. This requires continuous monitoring of actual partial pressures with time and for maximum effectiveness requiring real-time computer processing by decompression computer divers. Decompression can be much lower than the fixed ratio gas mixture used in other scuba systems and, as a result, divers can stay longer or require less time to decompress. Semi-closed circuit rebreather injects constant mass flow from the respiratory gas mixture into the respiratory ring, or replaces a certain percentage of the breathing volume, so that the oxygen partial pressure at any time during the dive depends on the diver's oxygen consumption and/or respiratory rate. Planning decompression requirements requires a more conservative approach to SCR than CCR, but decompression computers with real time oxygen partial pressure inputs can optimize decompression for these systems. Because rebreathers produce very few bubbles, they do not interfere with marine life or make the existence of divers known on the surface; this is useful for underwater photography, and for secret work.
Mixed gas
For some dives, a mixture of gases other than normal atmospheric air (21% oxygen, 78% nitrogen, 1% gas footprint) can be used, as long as the diver is competent in its use. The most commonly used mixture is nitrox, also called Enriched Air Nitrox (EAN), which is air with extra oxygen, often with 32% or 36% oxygen, and thus less nitrogen, reduces the risk of decompression or allows longer exposure. to the same pressure for the same risk. Decreased nitrogen also allows no stops or shorter stop decompression times or shorter surface intervals between dives. A common misconception is that nitrox may reduce anesthesia, but studies have shown that oxygen is also narcotic.
Increased oxygen partial pressure due to higher nitrox oxygen content increases the risk of oxygen toxicity, which becomes unacceptable under the maximum operating depth of the mixture. To replace nitrogen without increasing oxygen concentration, other diluent gases may be used, usually helium, when the resulting gas mixture is called a trimix, and when nitrogen is completely replaced by helium, heliox.
For dives requiring long decompression stops, divers can carry cylinders containing different gas mixtures for different dive phases, commonly referred to as Travel, Down, and Decompression gas. These different gas mixtures can be used to extend down time, reduce the effects of inert gas narcotics, and reduce decompression time.
Divers mobility
To take advantage of the freedom of movement provided by dive equipment, divers must move underwater. Personal mobility is enhanced by swimfins and optionally outperforms propulsion vehicles. The fin has a large blade area and uses stronger leg muscles, so it is much more efficient for propulsion and manoeuvering propulsion than hand and arm movement, but requires skill to provide good control. Several types of fins are available, some of which may be more suitable for manoeuvering, alternative kick styles, speed, endurance, reduced effort or roughness. Streamline dive equipment will reduce barriers and improve mobility. A balanced trim that allows the diver to align in the desired direction also improves the simplification by presenting the smallest part of the area to the direction of movement and allows the propulsion drive to be used more efficiently.
Sometimes a diver can be pulled using a "sled", an unmanned device pulled behind a surface ship that saves the diver's energy and allows more distance to be covered for given air consumption and down time. Its depth is usually controlled by divers by using a dive plane or by tilting the entire sled. Some sleds are given faired to reduce drag on the diver.
Floating and floating controls
To dive safely, divers should control their decline and climbing rates in water and can maintain a constant depth at sea. Ignoring other forces such as water currents and swimming, the overall buoyancy of the diver determines whether they are up or down. Equipment such as diving weighing systems, wetsuits (wet, dry or semi-dry clothing used depending on water temperature) and buoyant compensators can be used to adjust the overall buoyancy. When divers want to remain at a constant depth, they try to achieve a neutral buoyancy. This minimizes the effort of swimming to maintain depth and therefore reduces gas consumption.
The buoyancy force on the diver is the weight of the volume of fluid that they and their equipment substitute less the weight of the diver and their equipment; if the result is positive, force it up. The buoyancy of any object immersed in water is also affected by the water density. Freshwater density is about 3% less than sea water. Therefore, divers that float neutrally at one diving destination (eg freshwater lake) is expected to positively or negatively float when using the same equipment at the destination with different water densities (eg tropical coral reefs). Removal ("skipping" or "shedding") from the dive-weighting system can be used to reduce the weight of divers and lead to a soaring ascent in case of an emergency.
Dive clothing made of compressed materials decreases in volume as the diver falls, and flourishes as the diver rises, causing buoyancy to change. Diving in different environments also requires adjustments in the amount of weight carried to achieve neutral buoyancy. Divers can inject air into dry clothing to counteract compression and pressing effects. The buoyancy compensator allows easy and smooth adjustment in the overall volume of divers and hence buoyancy.
The neutral buoyancy in the diver is an unstable condition. This is altered by small differences in ambient pressure caused by profound changes, and changes have a positive feedback effect. Small breeds will increase the pressure, which will condense the gas filled space and reduce the total volume of divers and equipment. This will further reduce the buoyancy, and unless it neutralizes, will cause the sink to sink faster. Equal effects apply to small climbs, which will trigger an increase in buoyancy and will result in accelerated climbing unless they are eliminated. Divers should continue to adjust the buoyancy or depth to remain neutral. Good control of buoyancy can be achieved by controlling the average lung volume in open-circuit scuba, but this feature is not available for closed-circuit refreather diver, as the exhaled gas remains in the breathing circle. This is a skill that increases with practice until it becomes second nature.
The buoyant force changes with depth variation is proportional to the compressive volume portion of the diver and the equipment, and the proportional change in pressure, which is greater per unit depth near the surface. Minimizing the volume of gas required in the float compensator will minimize flotation of buoyancy with depth change. This can be achieved by accurate ballast weight selection, which should be the minimum to allow neutral buoyancy with an exhausted gas supply at the end of the dive unless there is operational requirements for greater negative buoyancy during dives. Floating and trim styles can significantly affect drag divers. The effect of swimming with an upward head angle of about 15 Â °, as is common enough in poorly trimmed divers, can be an increase in drag in the order of 50%.
The ability to rise at a controlled level and stay at a constant depth is important for true decompression. Recreational divers who are not subjected to decompression can escape with imperfect buoyancy control, but when long decompression stops at a certain depth is required, the risk of decompression disease is increased by the depth variation at the time of stopping. Decompression stops are usually performed when the cylindrical breathing gas is widely used, and the reduction of the cylinder weight increases the buoyancy of the diver. Adequate weights should be made to allow the diver to decompress at the end of the dive with an almost empty cylinder.
Underwater vision
Water has a refractive index that is higher than air - similar to the cornea of ​​the eye. The light entering the cornea from the water is hardly refracted at all, leaving only the crystal lens of the eye to focus light. This causes very severe hypermethropia. People with severe myopia, therefore, can see better underwater without a mask than normal-looking people. Masks and diving helmets solve this problem by providing an air space in front of the diver's eyes. The refracting mistakes made by water are mostly corrected when the light moves from water to air through a flat lens, unless the objects appear about 34% larger and 25% closer in water than they really are. The faceplate mask is supported by frames and skirts, which are opaque or translucent, therefore the total field of view is significantly reduced and hand-eye coordination must be adjusted.
Divers who need corrective lenses to see clearly outside the water usually require the same recipe when wearing a mask. Generic corrective lens is available from the shelf for some two-window masks, and special lenses can be glued to a mask that has one front window or two windows.
When a diver descends, they must periodically exhale through their noses to equate the internal pressure of the mask with the water around it. Swimming glasses are not suitable for diving because it only covers the eyes and thus does not allow for equalization. Failure to equalize the pressure inside the mask can lead to a form of barotrauma known as a squeeze mask.
Masks tend to be foggy when the warm air is exhaled air condenses on the cold inside of the front plate. To prevent fogging many spit divers into a dry mask before use, spread the saliva around the inside of the glass and rinse with a little water. Salivary residues allow condensation to wet the glass and form a continuous film, rather than small droplets. There are some commercial products that can be used as an alternative to saliva, some of which are more effective and last longer, but there is a risk of getting anti-fog agents in the eye.
Diving light
Water weakens the light with selective absorption. Pure water specializes in red light, and at lower levels, yellow and green, so the most absorbed color is blue light. The dissolved substance can also absorb the color selectively in addition to the absorption by the water itself. In other words, as divers are deeper in dive, more colors are absorbed by water, and in clear color water becomes blue with depth. Color vision is also affected by turbidity that tends to reduce contrast. Artificial light is useful for giving light in the dark, returning contrast at close range, and returning the natural color lost to absorption.
Environmental protection
Protection from heat loss in cold water is usually provided by wetsuits or dry clothing. It also provides protection from sunburn, abrasion and stings from some marine organisms. Where thermal insulation is not important, lycra/leather clothing may be enough.
Wetsuits are clothing, usually made of frothy neoprene, which provides thermal insulation, abrasion resistance and buoyancy. The insulating properties depend on the gas bubbles inside the material, which reduces its ability to heat. Bubbles also give wetsuit low density, providing buoyancy in water. Clothes range from thin (2 mm or less) "shortie", covering only the torso, to a full 8 mm semi-dry, usually equipped with neoprene shoes, gloves and hoods. A good fit and some zippers help the clothing to remain impermeable and reduce rinsing - replacement of water trapped between suit and body with cold water from the outside. The upgraded seals on the neck, wrist and ankle and baffles beneath the entrance result in a suit known as "semi-dry".
The dry suit also provides thermal insulation to the wearer when immersed in water, and usually protects the whole body except the head, hands, and sometimes the feet. In some configurations, this is also discussed. The dry setting is usually used where the water temperature is below 15Ã, Â ° C (60Ã, Â ° F) or for an extended water immersion above 15Ã, Â ° C (60Ã, Â ° F), where the wetsuit user will be cold , and with integral helmets, boots, and gloves for personal protection while diving in contaminated water. Dry clothes are designed to prevent water from entering. This usually allows better isolation making them more suitable for use in cold water. They can become uncomfortable heat in warm or hot air, and are usually more expensive and more complex to don. For divers, they add some degree of complexity as the suit has to be pumped and reduced with profound changes to avoid "pressure" on an uncontrolled rapid decline or ascent due to excessive buoyancy.
Unless the maximum depth of water is known, and quite shallow, a diver should monitor the depth and duration of the dive to avoid decompression. Traditionally this is done using depth gauges and dive hours, but electronic dive computers are now used in general, as they are programmed to perform real time decompression modeling for diving, and automatically allow surface intervals. Much can be arranged for the gas mixture to be used on the dive, and some can accept changes in the gas mixture during the dive. Most dive computers provide a fairly conservative decompression model, and the level of conservatism can be user-selected within limits. Most computer decompresses can also be set to altitude compensation to some extent.
If dive sites and diving plans require diver to navigate, a compass can be done, and where route tracking is essential, such as in a cave or breakdown, the guide lines are laid out from the scroll. In less critical conditions, many divers simply navigate by landmarks and memory, a procedure also known as guided or natural navigation. Diver diving should always be alert to the remaining supply of respiratory gas, and the duration of the dive time to be safely supported, taking into consideration the time it takes to surface safely and allow for unexpected possibility. These are usually monitored by using a submersible pressure gauge on each cylinder.
Security equipment
Cutting tools such as knives, line cutters or scissors are often carried by divers to cut loosely from windings in nets or lines. The buoy of surface marker on the line held by the diver shows the diver's position to the surface personnel. This may be the inflatable marker used by divers at the end of the dive, or sealed float, which is drawn for the entire dive. The surface marker also allows easy and accurate rate control of climbing and stopping depth for safer decompression. A bailout cylinder provides enough breathing gas for a safe emergency ascent.
Various surface detection devices can be performed to help surface personnel where the diver after the ascent. In addition to buoy float buoys, divers can carry mirrors, lights, lights, whistles, beacons or emergency seek beacons.
Accessories
Divers can bring underwater photography or video equipment, or tools for specific applications other than diving equipment.
Procedures
Underwater environment is unusual and dangerous, and to ensure safety divers, simple procedure, but need to be followed. A certain level of minimum attention to detail and acceptance of responsibility for personal safety and security is essential. Most of the procedures are simple and straightforward, and are second nature to experienced divers, but must be learned, and take some practice to be automatic and perfect, such as the ability to walk or talk. Most safety procedures are intended to reduce the risk of drowning, and much of the rest to reduce the risk of barotrauma and decompression diseases. In some applications getting lost is a serious danger, and special procedures to minimize risk are followed.
Prepare for diving
The purpose of diving planning is to ensure that divers do not exceed their comfort zone or skill level, or the secure capacity of their equipment, and include scuba gas planning to ensure that the amount of respiratory gas carried is sufficient to allow for a predictable contingency. Before embarking on a dive, divers and their buddy perform equipment checks to make sure everything is going well and available. Recreational divers are responsible for planning their own dives, except in training, when the instructor is responsible. Divemasters can provide useful information and advice to help divers, but are generally not responsible for the details unless specifically employed to do so. In a professional dive team, all team members are usually expected to contribute in planning and to check the equipment they will use, but the overall responsibility for team safety lies with the supervisor as a representative at the designated place of the employer.
Standard diving procedure
Some common procedures for almost any scuba dive, or are used to manage very common possibilities. These are studied at the beginner level and may be highly standardized to allow for efficient cooperation between divers trained in schools.
- The procedure of entry and drop of water is done first to enter water without injury or loss/damage of equipment. This procedure also includes a way down in place, time, and right value; with the correct gas breathing available; and without losing contact with other divers in the group.
- Equal pressure in the gas chamber to avoid barotraumas. Expansion or compression of enclosed air space may cause discomfort or injury while diving. Critically, the lungs are susceptible to excessive expansion and then collapse if the diver holds breath as it rises: as long as the training divers is taught to never hold his breath while diving. Ear cleansing is another important equity procedure, usually requiring conscious intervention by divers.
- Regulator masks and cleaning may be necessary to ensure the ability to see and breathe in the event of a flood. This can easily happen and is not considered an emergency.
- Floating and trim controls require periodic adjustments (especially during depth changes) to ensure safe and comfortable underwater mobility during dives.
- Peer checks, respiratory gas monitoring, and monitoring of decompression status are carried out to ensure that diving plans are followed and group members are safe and available to help each other in an emergency.
- Ascent, decompression, and surface: to ensure that dissolved gases are safely released, barotraumas climbing is avoided, and safe to emerge.
- Exit procedure: to leave the water again unscathed, lost, or damaged equipment.
- Underwater communication: Divers can not speak under water unless they wear full face masks and electronic communications equipment, but they can communicate basic and emergency information using hand signals, light signals and rope signals, and more complex messages can written on a waterproof whiteboard.
Decompression
The inert gas component of the dive breathing gas accumulates in the tissue during high-pressure exposure during the dive, and must be removed during the ascent to avoid the formation of symptomatic bubbles in tissues where the concentration is too high for the gas to remain in solution.. This process is called decompression. Most recreational and professional scuba divers avoids the mandatory decompression cessation by following a dive profile that requires only a limited climbing rate to decompress, but it will usually also perform an optional short shallow decompression known as a security stop to reduce the risk even further before it surfaces. In some cases, especially in technical dives, more complex decompression procedures are required. Decompression can follow a series of pre-planned hikes that are stopped by dismissal, or can be monitored by a personal decompression computer.
Post-diving procedure
This includes debriefing if necessary, and equipment maintenance, to ensure that equipment is kept in good condition for later use.
Buddy, team or diving solo
Peer-to-peer diving procedures are meant to ensure that recreational underwater recreational divers are in the presence of people with complete equipment who understand and can provide assistance. Divers are trained to assist in emergencies specified in training standards for their certification, and are asked to demonstrate competence in a set of assisting buddy's prescribed skills. The friend/team's safety basics are centered on divers communication, equipment redundancy and respiratory gas by sharing with friends, and additional situational perspectives of other divers.
The solo diver is responsible for their own safety and compensates for the absence of a friend with the appropriate skills, vigilance, and equipment. Like a friend or team diver, a properly equipped soloist relies on the redundancy of critical dive articles that may include at least two independent gas supply and ensures that there is always enough available to safely end the dive if one of the supplies fails. The difference between the two practices is that this redundancy is done and managed by a solo diver rather than a friend. Certifying agents for solo diving require candidates to have a high-level diving experience - usually about 100 dives or more.
Since the start of scuba, there has been an ongoing debate about the solo diving policy with strong opinions on both sides of the problem. This debate is complicated by the fact that the line separating the solo divers from the team/team divers is not always clear. For example, should a scuba instructor (who supports a friend's system) be considered a solo diver if their students have no knowledge or experience to assist the instructor through unexpected scuba emergencies? Should buddy underwater photographers consider themselves as effective divers because their friend (photographer) gives most or all of their attention to the subject of the photo? This debate has motivated some of the leading scuba agencies such as Global Underwater Explorers (GUE) to emphasize that its members only dive in teams and "remain aware of team members' location and safety at all times." Other institutions such as Scuba Diving International (SDI) and Professional Diving Instructor Association (PADI) have taken the position that divers may find themselves (by choice or coincidence) and have created certification courses such as "SDI Solo Diver Course" and "PADI Self- Reliant Diver Course "to train divers to handle such possibilities.
Emergency procedures
The most urgent underwater emergency usually involves disturbed gas supply. Divers are trained in procedures to donate and receive respiratory gas from each other in an emergency, and can bring alternative air sources independently if they do not choose to rely on a friend. Divers may need to make an emergency ascent in case of respiratory gas loss that can not be managed in depth. The controlled emergency assault is almost always a consequence of respiratory gas loss, whereas uncontrolled climbing is usually the result of a failure of buoyancy control.
Divers can be trained in procedures approved by training institutions for the recovery of unresponsive divers, where it is possible to manage first aid. Not all recreational divers have this training because some agencies do not include it in beginner level training. Professional divers may be required by law or code of practice to have the diver ready at every dive operation, competent and available to try to rescue the troubled diver.
Two basic types of traps are significant dangers to scuba divers: Inability to get out of enclosed spaces, and physical traps that prevent diver from leaving the site. The first case can usually be avoided by staying outside the enclosed space, and when diving destinations include the penetration of enclosed spaces, take precautions such as the use of lights and guidelines, for which specialized training is provided in standard procedures. The most common forms of physical trap are cranes, lines or nets, and the use of cutting tools is the standard method for solving problems. The risk of con fi guration can be reduced by careful equipment configuration to minimize fragile parts, and allow for easier decomposition. Other forms of trap like being squeezed in a narrow space can often be avoided, but otherwise should be dealt with when it happens. A friend's help can help if possible.
Scuba diving in relatively harmful environments such as caves and shipwrecks, areas of strong water movement, relatively large depths, with decompression obligations, with equipment having more complex failure modes, and with unsafe gas for breathing in all depths of diving require special security and emergency procedures tailored to specific hazards, and often special equipment. This condition is generally associated with diving techniques.
Depth range
The depth range applicable to scuba diving depends on the application and training. The world's largest recreational diver agency considers 130 feet (40 m) as the limit for recreational diving. British and European institutions, including BSAC and SAA, recommend a maximum depth of 50 meters (160 feet). The thrust limit is recommended for young, inexperienced, or under-diving divers. Diving technically extends this depth limit through changes in training, equipment, and gas mixtures used. The maximum depth that is considered safe is controversial and varies between agency and instructor, but there are programs that train divers to dive up to 120 meters (390 feet).
Professional dives usually limit the planned decompression allowed, depending on the code of practice, operational directives, or legal restrictions. Depth limit depends on the jurisdiction, and the maximum allowable depth ranges from 30 meters (100 feet) to more than 50 meters (160 feet), depending on the respiratory gas used and the availability of decompression space nearby or on site. Commercial dives using scuba are generally restricted for occupational health and safety reasons. Surface-supplied dives enable better control of operations and eliminate or significantly reduce the risk of loss of respiratory gas supply and loss of divers. Scientific and media diving applications may be excluded from commercial diving constraints, based on acceptable practice codes and self-regulatory systems.
Apps
Scuba diving can be done for a number of reasons, both personal and professional. Diving recreation is done purely for fun and has a number of technical disciplines to increase the underwater interest, such as diving in caves, submarine diving, deep diving and deep diving. Underwater tours are mostly done in scuba and related guides should follow suit.
Divers can be employed professionally to perform underwater tasks. Some of these tasks are suitable for scuba.
There are divers who work, full or part-time, in recreational diving communities as instructors, instructor assistants, divemasters, and dive guides. In some jurisdictions, professional nature, with specific reference to responsibility for client health and safety, recreational diving instruction, diving leadership for awards and diving guidance are recognized and regulated by national laws.
Other dive diving areas include military dives, with a long history of military frog troops in various roles. Their roles include direct combat, infiltration behind enemy lines, placing mines or using manned torpedoes, bomb disposal or engineering operations. In civilian operations, many police forces operate police diving teams to conduct "search and recovery" or "search and rescue" operations and to help detect crimes that may involve water bodies. In some cases rescue divers may also be part of firefighters, paramedical services units or coastguards, and may be classified as public service dives.
Underwater breeding and research in large aquariums and fish farms, and harvesting marine biological resources such as fish, abalone, crabs, lobsters, shellfish, and sea lobsters can be done on scuba. Boats and ships inspection boats, cleaning and some maintenance aspects (livestock boats) can be performed on scuba by commercial divers and boat owners or crew.
Finally, there are professional divers engaged in underwater environments, such as underwater photographers or underwater videographers, who document the underwater world, or scientific dive, including marine biology, geology, hydrology, oceanography, and underwater archeology. This work is usually done on scuba because it provides the necessary mobility. Rebreathers can be used when open circuit noise will alert the subject or bubbles may interfere with the image. Scientific diving under the liberation of OSHA (USA) has been defined as diving work done by people with, and using, scientific expertise to observe, or collect data on, natural phenomena or systems to generate non-exclusive information, data, knowledge or other products as an important part of scientific, research, or educational activities, following the guidance of safety dive guidance and safety diving board.
The choice between scuba diving equipment and the provided surfaces is based on legal and logistical restrictions. Where divers are in need of mobility and a large range of movement, scuba is usually an option if safety and legal restrictions permit. High-risk jobs, particularly in commercial dives, may be limited to equipment supplied by law and codes of practice.
Security
The safety of submarine dives depends on four factors: the environment, the equipment, the behavior of individual divers, and the performance of the dive team. Underwater environments can provide heavy physical and psychological pressure on divers, and most are beyond the control of divers. Scuba equipment allows divers to operate under water for a limited period of time, and reliable functioning of some equipment is essential even for short-term survival. Other equipment allows divers to operate in comfort and relative efficiency. The performance of individual divers depends on the skills learned, many of which are not intuitive, and team performance depends on communication and common goals.
There are a large number of dangers that can be exposed by divers. These each have related consequences and risks, which must be taken into account during dive planning. If the risks are marginally acceptable, it is possible to reduce the consequences by establishing the possibility and contingency plan, so that damage can be minimized where feasible. Acceptable risk levels vary depending on laws, codes of practice and personal choice, with recreational divers who have greater freedom of choice.
Dangers
Divers operate in an environment unsuitable for the human body. They face special physical and health risks when they walk underwater or use high-pressure gas respiration. The consequences of dive incidents range from mere interruptions to rapidly fatal results, and the results often depend on the equipment, skills, response and fitness of divers and divers team. Hazards include aquatic environments, use of respiratory equipment in an underwater environment, exposure to pressurized environments and pressure changes, especially changes in pressure during down and rising, and respiratory gas at high ambient pressure. Diving tools other than respirators are usually reliable, but are known to be failing, and loss of buoyancy control or thermal protection can be a huge burden that can lead to more serious problems. There are also certain environmental hazards of dives, and the dangers associated with access to and exit from water, which vary from place to place, and may also vary over time. The dangers attached to divers include previously pre-existing physiological and psychological conditions as well as personal behavior and individual competencies. For those who pursue other activities while diving, there are additional dangers of task loading, diving assignments and special equipment related to the task.
The presence of a combination of several hazards simultaneously is common in diving, and the effect generally increases the risk for divers, especially when an incident occurs because one danger triggers another with a cascade generated from the incident. Many dive victims are the result of a cascade of incidents that plagued divers, who must be able to manage any predictable incidents. While there are many dangers involved in scuba diving, divers can reduce risk through proper procedures and equipment. The required skills are gained by training and education, and honed by practice. The open water certification program highlights the physiology of dives, safe diving practices, and dive hazards, but does not provide divers with enough practice to be truly proficient.
Scuba divers by definition carry their respiratory gas supply during dives, and this limited amount should return it safely to the surface. Pre-dive planning of suitable gas supplies for the intended dive profile allows divers to allow sufficient breathing gas for planned dives and contingencies. They are not connected to umbilical surface control points, such as the use of the supplied surface divers, and the freedom of movement that allows this, it also allows divers to penetrate the overhead environment in ice diving, cavern diving and dive accidents to the extent that divers may get lost and can not find a way Exit. This problem is exacerbated by the limited supply of breathing gas, which gives limited time before the diver will sink if it can not surface. The standard procedure for managing these risks is to lay a continuous guideline line from open water, allowing divers to ensure surface routes.
Most scuba diving, especially recreational scuba, uses a respiratory gas supply conglomer that is gripped by divers gear, and which can be released relatively easily by impact. This is generally easy to fix unless the diver is incapable, and the associated skills are part of the beginner level training. The problem becomes severe and immediately life-threatening if the divers loses consciousness and funnel. A funnel rebreather that opens when it comes out of the mouth can allow water that can flood the loop, allowing them to not provide respiratory gas, and will lose buoyancy as the gas escapes, thereby placing divers in two simultaneously threatening lives. problem. Skills to manage this situation are an important part of training for specific configurations. A full-face mask reduces this risk and is generally preferred for professional scuba diving, but can make emergency gas distribution difficult, and less popular with recreational divers that often relies on gas sharing with a friend as their respiratory gas redundancy option.
Risk
The risk of death during recreational, scientific or small commercial dives, and scuba, death is usually associated with poor gas management, poor buoyancy control, equipment misuse, pitfalls, poor water conditions and pre-existing health problems. Some casualties are inevitable and are caused by unexpected situations that rise beyond control, but most deaths from diving can be attributed to human error on the part of the victim. Equipment failure is rare in open circuit scuba.
According to the death certificate, more than 80% of deaths are ultimately linked to sinking, but other factors are usually combined to immobilize divers in a series of culminating events, which are more of a consequence of media where accidents occur than actual accidents. Scuba divers should not drown unless there are other contributing factors as they carry gas supply of breathing and equipment designed to provide gas on demand. Drowning occurs as a result of previous problems such as uncontrolled stress, heart disease, pulmonary barotrauma, unconsciousness of any cause, water aspiration, trauma, environmental hazards, equipment difficulties, improper response to emergencies or failure to manage gas supplies. and often obscures the true cause of death. Air embolism is also commonly referred to as the cause of death, and it is also a consequence of other factors leading to uncontrolled and poorly controlled ascent, possibly exacerbated by medical conditions. About a quarter of diving deaths are associated with heart events, mostly in older divers. There is considerable data about deaths from dives, but in many cases, data is poor because of investigative and reporting standards. This inhibits research that can improve the safety of divers.
The mortality rate is proportional to jogging (13 deaths per 100,000 people per year) and is in the range where reduction is desired by the Health and Safety Executive (HSE) criteria, the most common cause for diving death is exhaust or low gas. Other factors cited include buoyancy control, entanglement or trapping, rough water, equipment misuse or problems and emergency ascent. The most common injuries and causes of death are drowning or asphyxia by inhaling water, air embolism and cardiac events. The risk of cardiac arrest is greater for older divers, and greater for men than women, although the risk is the same at age 65.
Some plausible opinions have been put forward but have not been empirically validated. Recommended causative factors include experience, rare dives, inadequate supervision, inadequate predicate summaries, separation of friends and diving conditions beyond the training, experience or physical capacity of the diver.
Decompression diseases and arterial gas embolisms in diving recreation have been linked to certain demographic, environmental, and diving factors. A statistical study published in 2005 tested potential risk factors: age, asthma, body mass index, sex, smoking, cardiovascular disease, diabetes, previous decompression disease, years since certification, number of dives in the previous year, respectively, the number of dives in a repetitive series, the depth of the previous dive, the use of nitrox as a respiratory gas, and the use of a dry suit. There was no significant association with the risk of decompression or embolic artery disease found for asthma, body mass index, cardiovascular disease, diabetes or smoking. Greater diving depths, previous decompression sickness, number of consecutive days of diving, and male biological gender were associated with higher risk for decompression and embolism of arterial gases. The use of dry clothes and nitrox breathing gas, greater diving frequencies in the previous year, greater age, and more years since certification are associated with lower risk, may be a broader indicator of training and experience.
Risk management has three main aspects besides equipment and training: Risk assessment, emergency planning and insurance closure. Risk assessment for diving is primarily a planning activity, and can range in formality from part of a pre-dive check for recreational divers, to security files with professional risk assessment and detailed emergency plans for professional diving projects. Some forms of pre-dive briefing are a habit with organized recreational dives, and this usually includes divemaster readings of known and predicted hazards, significant risks associated with, and procedures to be followed in reasonably suspected cases of an associated emergency with them. Insurance cover for diving accidents may not be included in the standard policy. There are several organizations that focus exclusively on safety and insurance divers, such as the International Diver Network
Training and certification
Scuba training is usually provided by qualified instructors who are members of one or more certification bodies or registered with government agencies. Basic diver training requires skill learning required to carry out safe activities in the environment b
Source of the article : Wikipedia
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