Underwater diving , as a human activity, is the practice of descending beneath the surface to interact with the environment. Immersion in water and high exposure to ambient pressure have physiological effects that limit the depth and duration possible in ambient ambient dive. Humans are not physiologically and anatomically well-adapted to the conditions of the dive environment, and various tools have been developed to extend the depth and duration of human diving, and enable different types of work to be done.
In a dive with ambient pressure, the diver is directly exposed to the water pressure around him. The ambient divers can dive on the breath, or use breathing apparatus for scuba diving or surface diving provided, and saturation dive techniques reduce the risk of decompression (DCS) disease after long-term dives. Atmospheric diving suits (ADS) can be used to isolate divers from high ambient pressure. Crewed submersible can extend the depth range, and remote control or robot machines can reduce the risk in humans.
The environment exposes divers to a variety of hazards, and although risk is largely controlled by proper diving skills, the training, the type of equipment and respiratory gas used depends on the mode, depth and diving purpose, remains a relatively harmful activity.. Dive activities are limited to a maximum depth of approximately 40 meters (130Ã, ft) for recreational scuba diving, 530 meters (1,740Ã, ft) for commercial saturation dive, and 610 meters (2,000 feet) wearing atmospheric clothes. Diving is also limited to conditions that are less dangerous, although acceptable levels of risk may vary.
Recreational diving (sometimes called diving or sub-sport) is a popular leisure activity. Diving is technically a form of recreational dive in very challenging conditions. Professional dives (commercial diving, diving for research purposes, or for financial gain) involve underwater work. Diving public safety is undersea work done by law enforcement, fire rescue, and underwater search and recovery dive team. Military dives include combat dive, diving cleansing, and farm vessels. Deep sea diving is underwater diving, usually with equipment provided on the surface, and often refers to the use of standard wetsuits with traditional copper helmets. Hard hat diving is a diving form with a helmet, including standard copper helmet, and other forms of free and light flow helmets. Rescue-breathing history is at least back to classical times, and there is evidence of prehistoric hunting and seafood gathering that may have involved swimming underwater. Technical advances allow the provision of respiratory gas for underwater divers at ambient pressure is recent, and an independent respiratory system developed at an accelerated rate after the Second World War.
Video Underwater diving
Physiological constraints while diving
Immersion in water and exposure to cold water and high pressure have a physiological effect on divers that limits the depth and duration possible in ambient ambient dive. Resistant breathing resistance is a severe limitation, and breathing at high ambient pressure adds further complications, either directly or indirectly. Technological solutions have been developed that can greatly expand the depth and duration of human ambient pressure dives, and enable useful work to be undertaken under water.
Immersion
Immersion of the human body in water affects circulation, kidney system, fluid balance, and breathing, because the hydrostatic pressure of external water provides support to internal blood hydrostatic pressure. This causes a blood shift from the extravascular tissues of the limbs into the chest cavity, and the loss of a fluid known as the immersion diuresis compensates for the blood shift in the hydrated subject immediately after immersion. The hydrostatic pressure on the body from direct immersion causes the respiratory negative pressure that contributes to the blood shift.
Blood shifts cause increased breathing and heart workloads. The stroke volume is not significantly affected by immersion or variation in ambient pressure, but a slowed heart rate reduces overall cardiac output, primarily because of the dive reflex in breath-resistant retention. Lung volume decreases in upright position, due to displacement of the abdominal skull from hydrostatic pressure, and resistance to airflow in the airways is increased due to decreased lung volume. There appears to be an association between pulmonary edema and increased pulmonary blood flow and pressure, resulting in capillary swelling. This can occur during high intensity exercises when immersed or submerged.
Exposure
The cold shock response is the organism's physiological response to sudden cold, especially cold water, and is a common cause of death from immersion in very cold water, such as falling through thin ice. Direct cold shock causes forced inhalation, which if under water can cause drowning. Cold water can also cause heart attacks because of vasoconstriction; the heart must work harder to pump the same blood volume throughout the body, and for people with heart disease, this additional workload can cause the heart to enter into capture. A person who survives in the first minute after falling into cold water can survive for at least thirty minutes provided they do not drown. The ability to survive decreases substantially after about ten minutes when the cold muscle loses strength and coordination.
Diving reflexes are a response to immersion that overrides basic homeostatic reflexes. It optimizes respiration by typically distributing oxygen storage to the heart and brain, allowing a long time under water. Powerfully displayed in water mammals (seals, otters, dolphins and muskrats), and also in other mammals, including humans. Bird divers, like penguins, has a similar dive reflex. The diving reflex is triggered by the coldness of the face and holding the breath. The cardiovascular system constricts the peripheral blood vessels, slows the pulse rate, directs blood to the vital organs to conserve oxygen, releases red blood cells stored in the spleen, and, in humans, causes irregular heart rhythm. Water mammals have evolved physiological adaptations to conserve oxygen during immersion, but apnea, slowing pulse, and vasoconstriction are shared with terrestrial mammals.
Hypothermia is a decrease in body temperature that occurs when the body loses more heat than it produces. Hypothermia is the main limitation for swimming or diving in cold water. Decreasing the dexterity of the fingers due to illness or numbness lowers public safety and work capacity, which in turn increases the risk of other injuries. The body heat dissipates much faster in water than in the air, so the water temperature to be tolerated because outside air temperatures can cause hypothermia, which can cause death from other causes of inadequately protected divers.
Barrier retention limit
Air-breathing by air-breathing animals is limited to the physiological capacity to dive in the available oxygen until it returns to a fresh breathing gas source, usually air on the surface. As the internal oxygen supply diminishes, animals experience increased desire for breathing caused by the buildup of carbon dioxide and lactate in the blood, followed by a loss of consciousness due to hypoxia of the central nervous system. If this happens under water, it will sink.
Freediving outages can occur when the breath is retained long enough for metabolic activity to reduce the partial pressure of oxygen sufficiently to cause loss of consciousness. This is accelerated by exertion, which uses faster oxygen, or by hyperventilation, which reduces the level of carbon dioxide in the blood. Low carbon dioxide levels increase oxygen-hemoglobin affinity, reducing the availability of oxygen to brain tissue towards the end of the dive (Bohr effect); they also suppress the desire to breathe, making it easier to hold their breath to the point of darkness. This can happen at any depth.
Ascent-induced hypoxia is caused by a decrease in the partial pressure of oxygen when ambient pressure is reduced. Partial pressure of oxygen at depth may be sufficient to maintain consciousness but only at that depth and not at reduced pressure near the surface.
Room pressure changed
Barotrauma, an example of dysbarism, is physical damage to body tissues caused by differences in pressure between the inner gas chamber, or contact with the body, and the surrounding gases or fluids. This usually happens when the organism is exposed to major changes in ambient pressure, such as when a diver rises or falls. When diving, the difference in pressure that causes barotrauma is a change in hydrostatic pressure.
The initial damage is usually due to too stretching the network in tension or shear, either directly by the expansion of the gas in the enclosed space, or by the pressure difference transmitted hydrostatically through the network.
Barotrauma generally manifests as sinus or middle ear effects, DCS, pulmonary overpressure injury, and injuries resulting from external blackmail. Barotraumas offspring are caused by preventing the free change of gas volume in enclosed spaces in contact with the diver, resulting in a pressure difference between the tissue and the gas chamber, and the unbalanced force due to this pressure difference causing tissue deformation to produce cell rupture. Barotraumas climbing is also caused when the free change of gas volume in the enclosed space in contact with the diver is prevented. In this case the pressure difference causes the resulting voltage in the surrounding tissue to exceed their tensile strength. In addition to the ruptured tissue, excess pressure can cause the entry of gas into the tissue and further through the circulatory system. This may cause blockage of circulation in distant places, or disrupt the normal functioning of organs by its presence.
Breathe under pressure
The supply of breathing gas at ambient pressure can greatly extend the duration of the dive, but there are other problems that may result from this technological solution. The uptake of metabolically inert gases increases as a function of time and pressure, and these both can produce undesirable effects immediately, as a consequence of their presence in tissues in a soluble state, such as nitrogen narcosis and high-pressure nervous syndrome, or causes of problems when out of solution in the network during decompression.
Another problem arises when the concentration of metabolically active gas increases. This ranges from the effects of oxygen toxicity at high partial pressures, through accumulation of carbon dioxide due to excessive work of breathing, increased dead space, or inefficient removal, to exacerbation of toxic effects of contaminants in respiratory gas due to increased concentrations at high pressure. The difference in hydrostatic pressure between the pulmonary interior and the delivery of respiratory gas, increased respiratory gas density due to ambient pressure, and increased flow resistance due to higher respiratory rate can lead to increased respiratory work and fatigue of respiratory muscles.
Sensory damage
Underwater vision is influenced by the clarity and refractive index of the medium. Underwater visibility is reduced because light passing through water weakens rapidly with distance, leading to lower levels of natural lighting. Underwater objects are also obscured by light scattering between objects and viewers, resulting in lower contrast. This effect varies with the wavelength of light, and the color and turbidity of the water. The human eye is optimized for air vision, and when immersed in direct contact with water, visual acuity is affected by the difference in refractive index between water and air. The provision of air space between the cornea and water can compensate, but causes scale and distance distortion. Artificial lighting can increase visibility at short distances. Stereoscopic acuity, the ability to assess the relative distance of different objects, is greatly reduced underwater, and this is influenced by the field of vision. The narrow field of vision caused by a small viewport on the helm resulted in very reduced stereoacuity, and the apparent movement of the silent object when the head was moved. This effect causes hand-eye coordination worse.
Water has different acoustic properties than air. Sound from underwater sources can propagate relatively freely through body tissues where there is contact with water because of their similar acoustic properties. When the head is exposed to water, some sound is transmitted by the eardrum and middle ear, but the important part reaches the cochlea independently, with bone conduction. Some localization of voice is possible, although difficult. Hearing humans underwater, in cases where the wet-ear is wet, less sensitive than in the air. Underwater frequency sensitivity also differs from that in the air, with consistently higher underwater hearing thresholds; sensitivity to higher frequency sounds is greatly reduced. This type of headgear affects the noise sensitivity and noise hazard depending on whether the transmission is wet or dry. Underwater hearing humans are less sensitive to wet ear than in the air, and neoprene hoods cause substantial damping. When wearing a helmet, auditory sensitivity is similar to a helmet in the air, as it is not so influenced by atmospheric composition or atmospheric gas pressure or space. As the sound moves faster in the heliox than in the air, the sound of the voices is raised, making the diver's speech high and distorted, and elusive to people unfamiliar with it. Increased respiratory gas density under pressure has the same effect and additives.
Tactile sensory perception on divers may be disrupted by environmental protection clothing and low temperatures. The combination of instability, equipment, neutral buoyancy and resistance to movement by the inertial and viscous effects of water weigh on divers. Cold causes loss of sensory and motor function and diverts attention from and interferes with cognitive activity. The ability to exert great and proper power is reduced.
Balance and balance depend on the vestibular function and secondary input of the visual, organic, cutaneous, kinesthetic and sometimes auditory senses processed by the central nervous system to provide a sense of balance. Underwater, some of these inputs may not be present or decrease, making the remaining gestures more important. Conflicting entries can lead to vertigo, disorientation and motion sickness. Vestibular flavor is essential in this condition for fast, complex and accurate movements. Perception-sensitive perceptions make divers aware of personal position and movement, in conjunction with vestibular and visual inputs, and enable divers to function effectively in maintaining a balance of physical and balance. in the water. In water at neutral buoyancy, proprioceptive gestures of position are reduced or absent. This effect can be exacerbated by the divers's settings and other equipment.
Flavors and odors do not really matter to divers in the water but are more important for saturation diver while in accommodation rooms. There is evidence of a slight decrease in the threshold for taste and odor after a long time under pressure.
Maps Underwater diving
Diving Mode
There are several dive modes based on the used dive equipment.
Freediving
The ability to dive and swim underwater while holding your breath is considered a useful emergency skill, an important part of water sports and naval safety training, and fun recreational activities. Underwater diving without respiratory aids can be categorized as underwater swimming, snorkeling and freediving. These categories are highly overlapping. Some competitive underwater sports are practiced without respiratory aids.
Freediving blocks the use of external breathing apparatus, and depends on the ability of the diver to hold his breath until it reappears. The techniques range from simple breathing dives to competitive apnea dives. Fins and diving masks are often used in free dives to improve vision and provide more efficient propulsion. A short breathing tube called a snorkel allows the diver to breathe on the surface when the face goes down. Snorkeling on the surface with no intention of diving is a popular water sport and recreational activities.
Scuba diving
Scuba diving is a dive with an independent underwater breathing apparatus, which is completely independent of the surface supply. Scuba provides diver's mobility and horizontal range far beyond the reach of umbilical hoses attached to substrate provided equipment (SSDE). Scuba divers who are involved in armed operations of secret troops can be referred to as human frogs, combat divers, or swimmers of attack.
The open circuit scuba system releases respiratory gas into the environment when exhaled, and consists of one or more diving cylinders containing respiratory gas at high pressures supplied to divers through a dive regulator. They may include additional cylinders for 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. They considerably extend the time spent underwater compared to open circuits for the same gas consumption. Rebreathers produce fewer bubbles and fewer sounds than scuba that makes them attractive to secret military divers to avoid detection, scientific divers to avoid harassing marine animals, and media divers to avoid bubble glitches.
A dive diver moves underwater by using a fins attached to the foot; External propulsion may be provided by the diver's propulsion vehicle, or towboard drawn from the surface. Other equipment including a diving mask for improved underwater vision, protective submarine, equipment for buoyancy control, and equipment related to the circumstances and special purpose of the dive. Scuba divers are trained in procedures and skills appropriate to their certification level by instructors who are affiliated with the diver certification organization that issues this diver 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, and higher fitness levels may be required for some applications.
Absorption of the provided surface
An alternative to an independent respiratory system is to provide respiratory gas from the surface through a hose. When combined with a communication cable, the pneumofathometer hose and safety line are called umbilical diver's, which may include hot water hoses for heating, video cables and respiratory gas reclamation lines. The more basic equipment that uses only an air hose is called an airline or hookah system. This allows the diver to breathe using an air supply hose from a cylinder or compressor on the surface. Respiratory gas is supplied via a request valve held or a full face mask of light. These are used for jobs such as gastric cleansing and archaeological surveys, for shellfish harvesting, and as snuba, shallow water activities that are usually undertaken by tourists and those not scuba certified.
The saturation of dives allows professional divers live and work under pressure for days or weeks at a time. After working in the water, the diver rests and lives in a dry under pressure underwater habitat or a saturated life support system of pressure chamber on the deck of a dive support vessel, oil base or other floating platform at the same pressure as the working depth. They are transferred between surface accommodation and underwater workplaces within a closed, pressurized bell belt. Decompression at the end of the dive may take several days, but since it is only done once for long periods of exposure, rather than after every shorter exposure, the overall risk of decompression injury to the diver and the total time spent on decompression is reduced. This type of diving enables greater work efficiency and safety.
The commercial diver refers to a diving operation in which the diver starts and completes the dive operation at atmospheric pressure as surface oriented, or diving the reflection. Divers can be deployed from shore or dive support vessels and can be transported on dive stage or diving bell. Diver-supplied surfaces almost always wear a diving helmet or full face diving mask. The lower gas may be air, nitrox, heliox or trimix; gas decompression may be similar, or may include pure oxygen. Decompression procedures include decompression in water or surface decompression in the deck space.
Wet bells with gas-filled dome provide more comfort and control than the stage and allow longer in the water. Wet bells are used for air and gas mixtures, and divers can break down oxygen at 12 meters (40 feet). A small closed bell system has been designed that can be easily mobilized, and includes two-person bells, handling frameworks and space for decompression after transfer under pressure (TUP). Divers can breathe air or mix gas at the bottom and usually recover with air filled space. They decompressed the oxygen provided through a built in breathing system (BIBS) towards the end of decompression. The small bell system supports bounce diving up to 120 meters (390Ã, ft) and for down time up to 2 hours.
A relatively portable surface gas supply system using high pressure gas cylinders for primary and backup gas, but using a full-fledged umbilical system with pneumofathometer and voice communications, is known in the industry as a "scuba substitute".
Dive compressors are the basic method of diving provided surfaces used in some tropical regions such as the Philippines and the Caribbean. Divers swim with half masks and fins and are supplied with air from low-pressure air compressors on boats through plastic tubes. There is no reduction valve; the diver holds the end of the hose in his mouth without a valve or funnel and allows excess air to spill between the lips.
Diving atmospheric pressure
Submersibles and rigid atmospheric diving suits (ADS) allow dives to be performed in a dry environment at normal atmospheric pressure. ADS is a small submarine articulated one that resembles a suit of armor, with a complicated junction to allow bending, while maintaining the internal pressure of one atmosphere. An ADS can be used to dive up to about 700 meters (2,300Ã, ft) for hours. This eliminates most of the physiological hazards associated with deep diving - the inhabitants do not have to decompress, there is no need for a special gas mixture, and there is no danger of nitrogen narcosis - at the expense of higher costs, complicated logistics and loss of dexterity.
Unmanned dive
Automated underwater vehicles (AUVs) and remote-operated underwater vehicles (ROVs) can perform multiple dive functions. They can be placed in greater depths and in more dangerous environments. AUV is a robot that runs under water without requiring real-time input from the operator. AUVs are part of a larger group of unmanned underwater systems, a classification that includes non-autonomous ROVs, controlled and empowered from the surface by the operator/pilot via umbilical or using remote control. In AUV military applications are often referred to as unmanned underwater vehicles (UUVs).
Diving activity range
Diving can be done for various reasons, both personal and professional. Dive pure recreation for fun and have some specialization and technical discipline to provide more space for various activities that specialist training can offer, such as cave diving, submarine diving, deep diving and deep diving.
There are various aspects of professional diving that range from part-time to lifelong career. Professionals in the leisure diving industry include instructor trainers, dive instructors, instructor assistants, divemasters, dive guides, and scuba technicians. Commercial diving is industry-related and includes civil engineering tasks such as in oil exploration, offshore construction, dam maintenance, and port work. Commercial divers can also be employed to perform tasks related to marine activities, such as naval diving, including repair and inspection of ships and vessels, marine rescue or aquaculture.
Other dive diving areas include military dives, with a long history of military frog humans in various roles. They can perform roles including direct combat, infiltration behind enemy lines, placing mines, bombing or engineering operations.
In civilian operations, police forces guard police diving units to conduct search and rescue operations, and to obtain evidence. In some cases rescue divers may also be part of firefighters, paramedical service units or coastguards, and these can be classified as public safety dives. There are also professional divers such as underwater photographers and videographers, who record the underwater world, and scientific divers in the field of study involving the underwater environment, including marine biologists, geologists, hydrologists, oceanographers, and underwater archaeologists.
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 commercial dives, may be limited to equipment supplied by law and codes of practice.
History
Freediving as a means of widespread hunting and gathering, both for food and other valuable resources such as pearls and corals, dates from before 4500 BC. In classical and Roman Greece, commercial diving applications such as sponges and marine rescues were established. Military diving at least until the Peloponnesian War, with recreation and sports applications being the latest developments. Technological developments in ambient pressure dive begin with rock weight (scandalopetra) for rapid descent. Diving bells are one of the earliest types of equipment for underwater work and exploration. Its use was first described by Aristotle in the 4th century BC. In the 16th and 17th centuries, diving bells became more useful when renewable air supply could be supplied to divers deeply, and progressed to the surface of the dive helmet supplied - the effect of miniature bell bells covering the diver head and supplied with compressed air with a pump operated in a manual - which is enhanced by installing waterproof clothes to the helmet. At the beginning of the 19th century it became the standard diving suit, which made far more marine civil engineering and practical diving projects.
Limitations in the mobility of surface-supplied systems led to the development of open circuits and closed-circuit scuba in the 20th century, allowing much larger autonomous divers. It became popular during the Second World War for secret, and post-war military operations for scientific, search and rescue, media diving, recreational and technical diving. The heavy free flow surface supplying the copper helmet evolves into a lightweight, more economical helmet with respiratory gas, essential for deeper dives using expensive helium breathing blends. Submerged saturation reduces the risk of DCS for deep and long exposures.
An alternative approach is the development of ADSs or armors, which isolate the diver from the pressure at depth, at the expense of limited mechanical complexity and agility. This technology was first practiced in the mid-20th century. Isolation of environmental divers is further captured by the development of under-operated long-range underwater vehicles at the end of the 20th century, where operators control ROV from surfaces, and autonomous underwater vehicles, which throw away operators altogether. All of these modes are still in use and each has a variety of applications where it has advantages over the others, although the bell bells have largely been degraded to the means of transportation for divers provided on the surface. In some cases the combination is very effective, such as the use of surface-oriented simultaneous or surface saturation provided by dive equipment and work class or remote-operated observations.
Physiological findings
At the end of the 19th century, when rescue operations deepened and lasted longer, unexplained diseases began to plague the divers; they will have difficulty breathing, dizziness, joint pain and paralysis, sometimes causing death. The problem is well known among workers building tunnels and the footing of the bridge operates under pressure in the caissons and was originally called caisson disease ; it is later renamed bend because joint pain usually causes the sufferer to bend. Initial reports of the disease had been made during Charles Pasley's rescue operation, but scientists still do not know the cause.
The French physiologist, Paul Bert, was the first to understand it as a DCS. His work, La Pression baromÃÆ'Â © Trique (1878), is a comprehensive investigation of the physiological effects of air pressure, both above and below normal. He decided that breathing pressurized air caused nitrogen to dissolve into the bloodstream; Rapid depression will release nitrogen into gaseous form, forming a bubble that can block blood circulation and potentially cause paralysis or death. The oxygen toxicity of the central nervous system is also first described in this publication and is sometimes referred to as the "Bert Bert effect".
John Scott Haldane designed the decompression chamber in 1907, and he produced the first decompression table for the Royal Navy in 1908 after conducting extensive experiments with animals and human subjects. These tables set the decompression method in stages - this remains the basis for the decompression method to this day. Following Haldane's recommendation, the maximum safe operation depth for divers is extended to 61 meters (200 feet).
The US Navy continued research on decompression, and in 1915, the first Decompression Construction and Repair tables were developed by France and Stilson. Experimental dives were conducted in the 1930s, forming the basis for a US Navy air decompression table of 1937. Surface decompression and oxygen use were also studied in the 1930s. The US Naval Tables 1957 was developed to correct the problems found in table 1937.
In 1965, Hugh LeMessurier and Brian Andrew Hills published their paper, The thermodynamic approach arising from the study of Torres Strait dive techniques, which suggests that decompression following a schedule based on conventional models results in the formation of an asymptomatic bubble which must then dissolved on decompression that stops before it can be removed. This is slower than allowing the gas to be removed while still in solution, and demonstrates the importance of minimizing bubble phase gas for efficient decompression.
M.P. Spencer suggests that the Doppler ultrasonic method can detect venous bubbles in asymptomatic divers, and Dr. Andrew Pilmanis points out that safety stops reducing bubble formation. In 1981 D.E. Yount describes the Varying Permeability Model, proposing a bubble formation mechanism. Some other bubble models follow. The pathophysiology of DCS is not fully understood, but the practice of decompression has reached a stage where the risk is quite low, and most incidents are successfully treated with hyperbaric recompression and oxygen therapy. Mixed-respiratory gas is used to reduce the hyperbaric environmental effects on ambient pressure observers.
Diving environment
The diving environment is limited by accessibility and risk, but includes water and sometimes other liquids. Most of the underwater diving is done in shallow shallow seas, and freshwater inland waters, including lakes, dams, quarries, rivers, springs, flooded caves, reservoirs, tanks, swimming pools and canals, but can also be done at large ducting and sewerage, power generation systems, cargo tanks and ship ballasts, and fluid-filled industrial equipment. The environment may affect the configuration of the tooth: for example, fresh water is less dense than saltwater, resulting in fewer additional weights required to achieve a neutral buoyancy in freshwater dives. Water temperature, visibility, and movement also affect dives and dive plans. Diving in liquids other than water can cause special problems due to density, viscosity and chemical compatibility of dive equipment, as well as possible environmental hazards to the dive team.
Benign conditions, sometimes also referred to as limited water, are low-risk environments, where it is highly unlikely or impossible for divers to get lost or trapped, or exposed to dangers other than basic underwater environments. This condition is suitable for initial training in critical survival skills, and includes swimming pools, training tanks, aquarium tanks and some shallow and protected shoreline areas.
Open water is unrestricted water such as sea, lake or puddle of floods, where divers have direct vertical access to the water surface in contact with the atmosphere. Open water diversion implies that if a problem arises, the diver can go up vertically into the atmosphere to breathe the air.
The top diving or penetration environment is where the diver enters the space from which no direct ascending, pure vertical to the safety of the atmospheric breathing on the surface. Dive diving, submarine diving, ice diving and diving within the underwater structure or other natural or artificial enclosure are for example. Restrictions on direct climb increase the risk of dives under the overhead, and this is usually handled by adaptation of procedures and use of equipment such as excessive respiratory gas sources and guidelines to show the route to the exit.
Night diving can allow divers to experience different underwater environments, as many marine animals are active at night. Height diving, for example in mountain lakes, requires modifications to the decompression schedule due to reduced atmospheric pressure.
Depth range
The depth of the recreational dive depth set by EN10153-2/ISO 24801-2 standard 2 "Autonomous Divers" is 20 meters (66 ft). Recommended depth limits for more extensive recreational divers range from 30 meters (98Ã, ft) to PADI divers, (this is the depth at which nitrogen narcosis symptoms generally begin to appear in adults), 40 meters (130Ã, ft) determined by Scuba Training Council, 50 meters (160 feet) for divers from English Sub-Aqua Club and Air-breathing Sub-Aqua Association, and 60 meters (200 feet) for a team of 2 to 3 French Level 3 leisure divers, breathe in air.
For technical divers, the suggested maximum depth is greater on the understanding that they will use less gas mixtures of narcotics. 100 meters (330Ã, ft) is the maximum depth allowed for divers who have completed Trimix Diver certification with IANTD or Advanced Trimix Diver certification with TDI. 332 meters (1,089 ft) is the world depth record in scuba (2014). Commercial diversions use saturation techniques and heliox respiratory gas routinely exceed 100 meters (330 feet), but they are also limited by physiological constraints. Comex Hydra 8 experimental dives achieved an open water depth record of 534 meters (1,752 feet) in 1988. ADS is mainly limited by articulation seal technology, and the US Navy diver has dived to 610 meters (2,000 feet) in one.
Diving site
The general term for a place where one can dive is a dive site. As a general rule, professional diving is done at the place of work to be done, and recreational dives are performed if conditions are suitable. There are many recorded and publicized recreational dive sites known for their convenience, points of interest, and often favorable conditions. Dive training facilities for professional and recreational divers generally use a small number of familiar and comfortable dive sites, and where conditions are predictable and the risks are relatively low.
Diving training
Underwater diving training is usually provided by qualified instructors who are members of one of many dive training institutes or registered with government agencies. Basic diver training requires skills learning required for safe activities in the underwater environment, and includes procedures and skills for the use of dive equipment, safety, self-help and rescue procedures, diving planning, and use of dive tables. Hand diving signals are used to communicate under water. Professional divers will also learn other communication methods.
A beginner-level diver should learn the underwater breathing technique through the demand regulator, including cleaning it out of the water and restoring it if removed from the mouth, and cleaning the mask if it floods. This is a critical survival skill, and if not competent, high-risk diver sinks. The associated skill is sharing respiratory gas with other divers, either as a donor or a recipient. This is usually done with a secondary request valve made for this purpose. Technical and professional divers will also learn how to use the reserve gas supply carried in an independent scuba series, known as emergency gas supply or bailout tube.
To avoid injury while descending, divers must be competent in equating ears, sinuses and masks; they must also learn not to hold their breath while rising, to avoid barotrauma of the lungs. The climbing speed should be controlled to avoid DCS, which requires buoyancy control skills. Good floating controls and trim also allow divers to maneuver and move safely, comfortably and efficiently, using swimfins for propulsion.
Some of the knowledge of physiology and physics of diving is deemed necessary by most divers certification agencies, because the dive environment is foreign and relatively hostile to humans. The necessary knowledge of physics and physiology is fundamental, and it helps divers to understand the impact of the diving environment so that receiving information from the associated risks is possible. Physics is mostly associated with gas under pressure, buoyancy, heat loss, and underwater light. Physiology connects physics with effects on the human body, to provide a basic understanding of the causes and risks of barotrauma, DCS, gas poisoning, hypothermia, drowning and sensory variation. More advanced training often involves first aid and rescue skills, skills related to specialized dive equipment, and underwater work skills. Further training is needed to develop the skills necessary to dive in a wider environment, with specialized equipment, and be competent to undertake a variety of underwater tasks.
Medical aspects of diving
Medical aspects of dive and hyperbaric exposure include dive checks to build dive medical fitness, diagnosis and treatment of diving disorders, hyperbaric oxygen recompression and treatment of hyperbaric oxygen, toxic effects of gases in the hyperbaric environment, and treatment of injuries that occur when diving is not directly related to depth or pressure.
Fitness for diving
The medical fitness for diving is the medical and physical fit of the diver to function safely in the underwater environment using underwater diving equipment and procedures. Depending on the circumstances, it may be stipulated by a statement signed by the diver that he or she has not suffered any of the disqualifying conditions and is capable of managing the usual physical dive requirements, with detailed medical examinations by registered doctors as medical examiners of divers following a procedural checklist determined, as evidenced by legal documents of the suitability for diving issued by the medical examiner and recorded on the national database, or alternatively between these extremes.
Psychological compatibility for diving is usually not evaluated prior to recreational or commercial dives training, but may affect the safety and success of a diving career.
Diving medicine
Diving drugs are the diagnosis, treatment, and prevention of conditions caused by exposing divers to the underwater environment. These include effects on body pressure on gas, diagnosis and treatment of conditions caused by marine dangers and how fitness dives affect the safety of divers. Hyperbaric drugs are another area associated with diving, since recompression in hyperbaric chamber with hyperbaric oxygen therapy is the definitive treatment for two of the most important diving-related diseases, DCS and arterial gas embolism.
Diving medicine deals with medical research on diving issues, diving intrusion prevention, dive injury accident treatment and dive fitness. These fields include effects on the human body's respiratory gas and their contaminants under high pressure, and the relationship between the physical and psychological health of the diver and the safety. In crashes it is common for some disorders to occur together and interact with each other, either causatively or as a complication. Diving drugs are a branch of occupational medicine and sports medicine, and first aid and recognition of symptoms of dive disorders are an important part of divers education.
Risk and security
Risk is a combination of hazards, vulnerabilities and possible occurrences, which may be the probability of an undesirable consequence of harm, or a combination of possible undesirable consequences of all hazards of an activity.
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.
Commercial dive operations can expose dives to more and sometimes greater hazards than recreational dives, but related health and safety laws are less tolerant of risk than recreation, especially technical divers, can be prepared to be accepted. Commercial dive operations are also limited by the physical reality of the operating environment, and expensive engineering solutions are often required to control risk. Hazard identification and formal risk assessment are the standard and necessary parts of planning for commercial dive operations, and this also applies to offshore diving operations. Occupation is essentially dangerous, and large businesses and costs are routinely issued to keep risks within an acceptable range. Standard risk-reduction methods are followed whenever possible.
Injury statistics associated with commercial dives are usually collected by national regulators. In the UK, the Health and Safety Executive (HSE) is responsible for an overview of about 5,000 commercial divers; in Norway, the relevant authority is the Petroleum Safety Authority Norway (PSA), which has maintained the DSYS database since 1985, collecting statistics on more than 50,000 diver-hours of commercial activity per year. The risk of death during recreational, scientific or commercial dives is small, and for scuba diving, death is usually associated with poor gas management, poor buoyancy control, equipment misuse, pitfalls, rough 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. According to a 1972 analysis of North American calendar year 1970 data, the dive, based on working hours, is 96 times more dangerous than driving a car. According to a 2000 Japanese study, every hour of recreational diving was 36 to 62 times more risky than driving.
The death of scuba diving has a huge financial impact by losing revenue, lost business, rising insurance premiums and high litigation costs. Equipment failure is rare in scuba open circuits, and when the cause of death is recorded as drowning, usually the consequences of a series of uncontrollable events where sinking is the end point because it occurs in water, while the initial cause is still unknown. Air embolism is also often referred to as the cause of death, often as a result of other factors leading to uncontrolled and poorly controlled ascent, sometimes worsened by medical conditions. About a quarter of diving deaths are associated with heart events, mostly in older divers. There is considerable data on dive deaths, but in many cases data is poor because of investigative and reporting standards. This inhibits research that can improve the safety of divers.
Artisanal fisheries and marine organism collectors in less developed countries can expose themselves to a relatively high risk of using diving equipment if they do not understand physiological hazards, especially if they use inadequate equipment.
Danger 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.
Human factors
The main factors affecting dive safety are the environment, dive equipment and dive and diving performance. Underwater environments are foreign, both physical and psychological, and usually uncontrollable, although divers can be selective in the conditions in which they are willing to dive. Other factors must be controlled to reduce overall pressure on the diver and allow dives to be completed in acceptable safety. Equipment is essential for safety divers to support life, but is generally reliable, controllable and predictable in performance.
Human factors are the physical or cognitive properties of individuals, or specific social behaviors for humans, that affect the functioning of technological systems as well as the balance of the human environment. Human error is inevitable and everyone makes mistakes at a time, and the consequences of these errors vary and depend on many factors. Most errors are small and do not cause harm, but in high-risk environments, such as in dives, errors are more likely to have disastrous consequences. Examples of human errors that cause accidents are available in large quantities, as it is a direct cause of 60% to 80% of all accidents. Human error and panic are seen as the main cause of diving accidents and death. A study by William P. Morgan showed that more than half of all divers in the survey had undergone panic underwater at some point during their diving career, and these findings were independently corroborated by a survey that suggested 65% of panicked recreational divers were underwater. Panic often causes errors in the assessment or performance of divers, and can cause accidents. The safety of underwater diving operations can be increased by reducing the frequency of human error and the consequences when it occurs.
Only 4.46% of recreational dive victims in the 1997 study were caused by a single cause. The remaining bodies may appear as a result of a progressive sequence of events involving two or more procedural errors or equipment failures, and because procedural errors are generally avoided by trained, intelligent and alert divers, working within organized structures, and not under excessive pressure , it was concluded that the low accident rate in professional scuba diving was due to this factor. The study also concludes that it is impossible to completely eliminate all minor contraindications from scuba diving, as this will produce extraordinary bureaucracy and make all dives stalled.
Risk management
Risk management is derived by ordinary steps in technical control, control and administrative procedures, and personal protective equipment, including hazard identification and risk assessment (HIRA), protective equipment, medical examinations, training, and standard procedures. Professional divers are generally legally required to carry out and officially record these steps, and although recreational divers are not legally required to do many of them, competent recreational divers, and especially technical divers, generally conduct them informally but on a regular basis , and they are important. part of a technical diver training. For example, medical statements or checks for fitness, pre-dive location assessments and briefings, safety drills, thermal protection, equipment redundancy, alternative air sources, friend checks, friend or team dive procedures, diving planning, hand signaling underwater, first and the oxygen administration equipment routinely forms part of the technical dive.
Legal aspects
Commercial and military shipping on land and land is governed by law in many countries. Responsibilities of employers, clients and divers are defined in these cases; Offshore commercial dives can occur in international waters, and are often conducted following voluntary membership organization guidelines such as the International Sea Contractors Association (IMCA), which publishes accepted best practice codes expected to be followed by their member organizations.
The dive leading recreational and dive training is an industry regulated in several countries, and only directly regulated by the government in a subset of them. In the UK, HSE legislation includes recreational diving and dive training leading to prizes; in US and South African industrial regulations are accepted, although non-specific health and safety laws remain in effect. In Israel, diving recreation activities are governed by the Diving Recreation Act, 1979.
The legal liability for a recreational diving service provider is usually limited to the extent possible with the leniency requiring the customer to sign before engaging in any dive activity. The level of responsibility for recreational recreational divers is unclear and has been the subject of considerable litigation. It is possible that it varies between jurisdictions. In spite of this lack of clarity, friend dives are recommended by recreational diving training agencies because it is safer than diving alone, and some service providers insist that customers dive in a friend's partner.
See also
- Glossary of underwater diving terms
Note
References
Source
BenQett, Peter B; Rostain, Jean Claude (2003). "High Pressure Nervous Syndrome". In Brubakk, Alf O.; Neuman, Tom S. Bennett and Elliott physiology and diving medicine, 5th Rev ed . United States: Saunders. pp. 323-57. ISBNÃ, 0-7020-2571-2.
Further reading
- Cousteau J.Y. (1953) Le Monde du Silence , translated as The Silent World , Hamish Hamilton Ltd., London; ASIN B000QRK890
- Lang M.A. & amp; Brubakk A.O. (eds., 2009) Future Diving: 100 Years of Haldane and Outside , Smithsonian Institution Scholarly Press, Washington DC
External links
Media related to Underwater diving in Wikimedia Commons
- The Anthony and Yvonne Pardoe Collection of Diving Helmets and Diving Equipment - illustrated catalogs. A great collection of non-free images of historical equipment from proven origin.
Source of the article : Wikipedia
0 Comments