Professional diving
From Wikipedia, the free encyclopedia
Professional Diving is a type of diving where the diver is paid for their work. There are several branches of professional diving, the most well known of which is probably commercial diving. Any person wishing to become a professional diver normally requires specific training that satisfies legislation, such as that set by the United Kingdom Health and Safety Executive[1]. Due to the demanding nature and danger of some professional diving disciplines, specialized equipment is often required or demanded by law, normally diver to surface communications systems.
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[edit] Equipment
[edit] Diving Suit
Depending on the water temperature and length of dive, the diver will either use a wetsuit, where neoprene provides thermal insulation but the diver gets wet, a hot water diving suit which is similar to a wetsuit but is flooded with warm water from the surface through an umbilical, or a drysuit, which keeps the diver totally dry and relies on either the suit material or the air trapped in thermal undergarments to insulate the diver. Certain applications require a specific type of dive suit, long dives into deep, cold water normally require a hot water suit, whilst diving into potentially contaminated environments normally requires a drysuit.[2]
[edit] Breathing Apparatus
A number of factors dictate the type of breathing apparatus used by the diver, typical considerations include the length of the dive, water contamination, space constraints and vehicle access for support vehicles. Some disciplines will very rarely use surface supplied diving, such as military clearance divers, whilst commercial divers will rarely use SCUBA equipment.
[edit] SCUBA
SCUBA equipment is normally used by media and military divers, often using specialist equipment such as rebreathers, closed circuit SCUBA equipment, which is has a duration, efficient decompression and doesn't release any bubbles into the water, making it ideal for covert use behind enemy lines, mine clearance where a bubble could potentially set off an explosion, and for the observation of animals in the wild.
Open circuit SCUBA equipment is occasionally used by commercial divers working on sites where surface supplied equipment is unsuitable, raised structures such as water towers, or remote locations where the equipment has to be carried to the dive site. Normally, for comfort and practicality, a full face mask, such as those manufactured by Kirby Morgan will be used to allow torches and video cameras to be mounted onto the mask. The benefit of full-face masks is that they can normally also be used with surface supplied equipment, removing the need for the diver or the company to have two sets of expensive equipment.
[edit] Surface Supplied
This is, perhaps, the most common type of equipment used in professional diving, and the one most recognised by the public, made familiar through films such as The Abyss.
Surface Supplied equipment can be used with full face masks or diving helmets. Helmets are normally to be found fitted with diver to surface communication equipment, and often with light sources and video equipment. The use of a full-face mask or a full diving helmet is down to requirements and personal preference, however the impact protection and warmth offered by a full diving helmet makes it popular for underwater construction sites and cold water work.
Breathing gas for the diver is piped down from the surface, through a long, flexible hose, called an umbilical. In addition to breathing gas, the umbilical may have additional hoses and cables for such things as communications equipment or hot water should the diver be using a hot water suit. The diver's breathing gas can is pumped down from either high pressure tanks or through a gas compressor.
If the diver is to be working at extreme depths for a long period, the diver may live in a special underwater habitat called a diving bell. This type of surface supplied diving is known as saturation diving. The same technique for supplying breathing gas as regular surface supplied diving is used, with the diving bell receiving breathing gas and electricity from a diving support vessel on the surface. Due to the often extreme depths the diver is working at, specialised helium-based breathing gas mixtures are often used to prevent both nitrogen narcosis and oxygen toxicity which occurs at these extreme depths.
[edit] Branches of professional diving
[edit] Commercial diving
[edit] Offshore diving
Offshore diving is the most well known branch of commercial diving, with divers working in support of the exploration and production sector of the oil and gas industry in places such as the Gulf of Mexico in the United States and the North Sea in the United Kingdom. The work in this area of the industry typically revolves around the maintenance of oil platforms and the building of underwater structures used in the production process.
For many newly qualified divers, this is the entry point to the industry, the lack of experienced divers and the excess of qualified divers within the industry push down wages for younger, less experienced divers beginning their careers.[1] The low wages, relative inexperience of the workforce combined with difficult and dangerous operating conditions make offshore diving the most dangerous area of employment for professional divers.
Equipment used for offshore diving tends to be surface supplied equipment but this does vary depending on the nature of the work and location, for instance Gulf of Mexico based divers may use wetsuits whilst North Sea divers need drysuits or even hot water suits due to the temperature of the water.
[edit] Inland / Onshore diving
Inland or onshore diving is very similar to offshore diving in terms of the nature of work and the equipment used, the work often being in support of land based civil engineering projects, with the majority of the work either underwater survey or engineering work. The number of dive sites this covers is varied however, and divers can be found working in harbours and lakes, in rivers and around bridges and pontoons, with the bulk of this work being undertaken in freshwater. Onshore divers typically earn less per hour than their colleagues who work offshore, but the ability to work from home for many divers is an advantage.
The equipment used does depend on the nature of the work and location, but normally a mixture of SCUBA and Surface supplied diving equipment is used by divers and their employers.
[edit] Nuclear / HAZMAT diving
HAZMAT diving is widely regarded as the most dangerous branch of the commercial diving industry, employing highly skilled and experienced staff.
Typical work involves diving into raw sewage or dangerous chemicals, such as paper pulp, liquid cement or oil sludge, to do this, divers need to be vaccinated against diseases such as hepatitis and tetanus, the dive company needs to have specialist plans in place for decontamination of the diver and equipment following a dive, and procedures for recovery of the diver if something goes wrong.
The main tasks a diver can be found to be doing include essential maintenance of underwater valves and sluice gates, repairs to damaged pipelines, and pollution control work to contain, control and clean up after a pollution incident. Some divers are required to dive into landfill sites in order to maintain the pumping equipment, vital in preventing landfill sites from filling up with rainwater and contaminating the water table, other divers can be found welding inside live sewers or working in septic tanks.
Sewer diving is often considered the most dangerous of all the HAZMAT jobs due to the diseases contained in raw sewage coupled with the fact syringes and glass find their way into the raw sewage, creating risks of both contracting diseases should the diver be injured by a needle, and also damaging the drysuit.
Divers working in an environment harmful to their health will always wear a full drysuit with thick gloves which are attached directly to the suit, the helmet and boots will also attach directly to the drysuit, this allows the gloves, boots, suit and helmet to be pressured in order to prevent ingress of liquid should a puncture occur. Normally, to achieve this, a diver will use a free flow diving helmet which continually supplies enough air for the diver to breathe plus an additional amount to pressurise the suit, a free flow helmet has a much lower chance of leakage through the exhaust valve compared with a demand helmet where the exhaust valve is dormant during the inhalation stage of the diver breathing.
The drysuit will be made from a material resistant to whatever hazard the diver faces, normally this will see the diver wear a vulcanised rubber drysuit, but occasionally a neoprene or tri-laminate suit is required. Often, a diver will wear additional protection over their drysuit to decrease the chance of a puncture, leather, PVC and nylon coveralls are used for this purpose.
Nuclear diving is similar to HAZMAT diving, the difference is the exposure to radiation instead of a water borne contaminant. To this end certain different precautions are required for nuclear diving, mainly the use of equipment which will not absorb radiation and pose a disposal problem after multiple dives. Heat stress can also be a danger for the diver, in which case a cold water suit may be used, the cold water suit is a special canvas coverall which floods the outside of the divers drysuit with chilled water, countering the dangerously high ambient water temperature. A dosimeter is used to ensure the diver doesn't receive a dangerous dose of radiation during the dive, assisting in calculating the maximum length of the dive. In addition the dosimeter can also be used to find radiation hotspots, which can indicate areas in need of repair.
[edit] Scientific diving
Scientific diving is the use of divers to study underwater what would normally be studied by scientists on land, therefore scientific divers are normally qualified scientists first and divers second, using diving equipment and techniques to get to the location of their fieldwork. Underwater archaeology, marine biology and geology are examples of sciences persued underwater. Some scientific diving is carried out by universities in support of undergraduate or postgraduate research programs, with a few universities offering scientific diving modules as part of their degree courses.[3]
Government bodies such as the United States Environmental Protection Agency and the UK Environment Agency carry out scientific diving to recover samples of water, marine organisms and sea, lake or riverbed material to examine for signs of pollution.
Experimental diving, such as that carried out by the US Navy's Experimental Diving Unit (NEDU) falls loosely under the auspices of Scientific Diving. Experimental diving is the research and development of diving practices and diving equipment, testing new types equipment and finding new and safer ways to perform dives and related activities. The US NEDU was responsible for much of the early experimental diving work to calculate decompression tables and has since worked on such developments as heated diving suits powered by radioactive isotopes and mixed gas diving equipment, while the British equivalent perfected the Mark 10 submarine escape suits utilised by both the Royal Navy and the US Navy.[4]
Equipment used varies widely in this field, but surface supplied equipment is quite uncommon here, the short number of dives made by scientific divers in normally quite shallow water and the need for easy transportation make surface supplied equipment uneconomic and undesirable. Experimental diving equipment will, as the name implies, often be new types of equipment, being tested for military service by Armed Forces, or new types of equipment being tested before being going into production.
[edit] Media Diving
Media Diving is a term that covers underwater photography and underwater filming. Media Diving is often carried out in support of television documentaries, such as the BBC series Planet Earth or Hollywood blockbusters, with feature films such as Titanic and The Perfect Storm featuring underwater photography or footage. Media divers are normally highly trained camera operators who use diving as a method to reach their workplace, although some underwater photographers may start as recreational divers and move on to make a living from their hobby.
Equipment in this field is varied with SCUBA and surface supplied equipment used, depending on requirements, but rebreathers are often used for wildlife related work as they are normally quiet, release few or no bubbles and allow the diver a lengthy bottom time with a reduced risk of frightening off the subject at hand.
[edit] Military and Naval Diving
Military Diving covers all types of diving carried out by military personnel. There are a number of different specialisations for a military diver to choose, some depend on which branch of the military they've joined or where the military needs more divers. Typical offensive activities include underwater demolition, infiltration and sabotage, this being the type of work elite regiments such as the UK Special Boat Service or the USA Navy Seals carry out. Defensive activities are centered around countering the threat of enemy special forces and enemy anti-shipping measures, and typically involve defusing mines, searching for explosive devices attached to the hulls of ships, and locating enemy frogmen in the water.
Military divers need equipment which hides their position and prevents explosives from being set-off, and to this end, they use rebreathers which produce few or no bubbles on the surface, and which contain no magnetic components, this continues down to the design of their diving suit, which will normally have a non-magnetic zip, and the face-mask may be fitted with special anti-reflective glass. Some navies have gone further and given their divers special contact lenses instead of large face-masks to cut down on the risk of a reflection.
Naval diving is the military term for commercial diving, and is drastically different to military diving. Naval divers work to support maintenance and repair operations on ships and military installations. Typical tasks include changing propellers or fitting replacement anodes. Naval divers may also work to recover downed aircraft, submarines, missiles and other military hardware. Their equipment is derived from commercially available equipment, with the US Navy using versions of the Kirby Morgan helmets and full-face masks amongst other equipment.
[edit] Police Diving
Police divers are normally police officers who have been trained in the use of diving techniques to recover evidence and occasionally bodies from rivers, canals and the sea. They may also be employed in searching shipping for contraband substances fitted to the outside of hulls to avoid detection. The equipment they use depends on requirements, but the requirement for communications at some sites does often require the use of full-face masks with communication equipment, either with SCUBA or surface supplied equipment.
[edit] Dive Instruction
There are two differing types of dive instructor. Some train recreational divers while others train professional divers.
Recreational dive instructors differ from other types of professional divers as they normally don't require a professional level qualification, but a relevant recreational qualification from a recognised training agency such as PADI or BSAC, which permits them to teach. Dive instructors teach a wide variety of skills from entry-level diver training for beginners, to diver rescue for intermediate level divers and technical diving for more experienced divers. They often operate from dedicated dive centres at coastal sites or through hotels in popular holiday resorts or simply from local swimming pools. Initial training is carried out mainly on conventional SCUBA equipment but with the increasing use of rebreathers, their use is also taught. Not all dive instructors are professionals; most BSAC instructors are amateurs with careers outside the diving industry.
Commercial dive instructors normally required to have professional diving qualifications. They typically teach trainee commercial divers how to operate types of diving equipment and typical underwater tools they will use in the course of their work. Commercial dive instructors will use similar equipment to commercial divers in the course of their work.
[edit] Training
Training to become a professional diver is expensive, with courses around £10,000 (around $20,000)[5] although the earning potential is broadly in-line with that of university graduates and the overall cost of training is substantially lower (taking into account tuition fees and debt in the UK).
In the UK, any person diving at work is required to hold a relevant qualification approved by the Health and Safety Executive (HSE). In the UK, diving schools work towards a standard HSE approved qualification, whilst divers who have trained overseas may find their existing qualifications meet the necessary HSE standards, if not, additional training may be required. HSE approved qualifications are well known around the world and due to the stringent requirements of HSE qualifications, most diving qualifications around the world are designed to meet HSE standards, allowing any trained diver to work in the UK, an important location due to the North Sea oil industry. The stringent requirements of the HSE qualifications make then a common requirement around the world for employers looking for new staff.
There are several different HSE qualifications, each focusing on a different type of equipment or type of diving activity, for instance the HSE Scuba qualification allows the holder to use only SCUBA equipment.
Training usually takes place at a residential school, with courses taking anything between 9 and 13 weeks[5] although divers with existing qualifications, such as former military divers can take 'Top Up' courses which build on their existing knowledge and experience. During training, divers will be taught how to use common types of diving equipment (nearly every school trains divers to use the Kirby Morgan equipment) and how to carry out underwater construction techniques such as welding and cutting.
In addition to physical training, there is a large amount of classroom work, with divers being trained subjects such as basic gas laws and decompression tables. First Aid courses are normally also a requirement for trainee divers, with the emphasis placed on dealing with decompression and other diving related injuries.
[edit] References
[edit] See Also
For scientific and archaeological applications for which diving is needed see:
For other diving activities
