Commercial diving


Commercial diving may be considered an application of professional diving where the diver engages in underwater work for industrial, construction, engineering, maintenance or other commercial purposes which are similar to work done out of the water, and where the diving is usually secondary to the work.
In some legislation, commercial diving is defined as any diving done by an employee as part of their job, and for legal purposes this may include scientific, public safety, media, and military diving. That is similar to the definition for professional diving, but in those cases the difference is in the status of the diver within the organisation of the diving contractor. This distinction may not exist in other jurisdictions. In South Africa, any person who dives under the control and instructions of another person within the scope of the Occupational Health and Safety Act, 1993, is within the scope of the Diving Regulations, 2009.

Applications of commercial diving

Offshore diving

Offshore diving is a 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, the North Sea in the United Kingdom, and Norway and along the coast of Brazil. The work in this area of the industry includes maintenance of oil platforms and the building of underwater structures used in the production process.
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 whereas North Sea divers need drysuits or even hot water suits due to the temperature of the water.

Civil engineering diving

works are one of the major applications of inshore and inland coastal diving projects. Much of the work is either underwater inspection or engineering construction or repair work. The types of dive sites involved is varied, and divers can be found working in harbours and lakes, on hydroelectric dams, in rivers and around bridges and pontoons, with a large amount of this work being done in freshwater. Divers may be required to inspect and repair outfalls with penetrations exceeding, which require special safety precautions.
The equipment used does depend on the nature of the work and location, but normally surface oriented surface-supplied diving equipment is used. Saturation diving may be used for major projects in deep water, and scuba may occasionally be used for inspections or light work where the regulations or code of practice permit.

Construction and repair

Construction:
Concrete work:
Fixing bolts: Drilling and core drilling
Pipe installation Pipeline support and protection, Mattresses,

Inspection and non-destructive testing

Inspection of underwater structures, installations, and sites is a common diving activity, applicable to planning, installation, and maintenance phases, but the required skills are often specific to the application. Much use is made of video and still photographic evidence, and live video to allow direction of the inspection work by the supervisor and topside specialists. Inspections may also involve surface preparation, often by cleaning, and non-destructive testing. Tactile inspection may be appropriate where visibility is poor.

Hazmat diving

diving is one of the most dangerous branches 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. This leads to special requirements:
  • The divers may need to be vaccinated against diseases such as hepatitis and tetanus.
  • Suitable equipment and competent personnel are required for decontamination of the diver and diving equipment after a dive.
  • Emergency procedures appropriate to the specific hazmat environment must be planned and equipment and personnel in place to safely recover the diver if something goes wrong.
  • Personnel must be monitored after exposure for possible long term effects.
The tasks a diver may be required to do in a contaminated environment include:
  • Essential maintenance of underwater valves and sluice gates.
  • Repairing damaged pipelines.
  • Pollution control work to contain, control and clean up after a pollution incident.
  • Sampling activities, such as those performed by United States Environmental Protection Agency. units specializing in polluted water diving, and the Environmental Response Team dive units.
  • Diving in landfill sites to maintain the pumping equipment, vital in preventing landfill sites from filling up with rainwater and contaminating the water table.
  • Maintenance and repair work inside functioning sewers, sewage treatment works, or working in septic tanks.
  • Maintenance and repair work in nuclear plant.
  • Miscellaneous repairs and finding lost objects.
  • Finding and recovering corpses after crimes, accidents and disasters. - This work is usually done by police divers and public safety divers, though military divers may be called in to assist for major incidents.
Hazmat diving may also be encountered in public safety diving and military diving.

Potable water diving

Potable water diving is diving in a tank for potable water. This is usually done for inspection and cleaning tasks. A person who is trained to do this work may be described as a potable water diver. The risks to the diver associated with potable water diving are related to the access, confined spaces and outlets for the water. The risk of contamination of the water is managed by isolating the diver in a clean dry-suit and helmet or full-face mask which are decontaminated before the dive.

Salvage diving

Salvage diving is the diving work associated with the recovery of all or part of ships, their cargoes, aircraft, and other vehicles and structures which have sunk or fallen into water. In the case of ships it may also refer to repair work done to make an abandoned or distressed but still floating vessel more suitable for towing or propulsion under its own power.
Most salvage diving is commercial work, or military work, depending on the diving contractor and the purpose for the salvage operation, Clearance diving, the removal of obstructions and hazards to navigation, is closely related to salvage diving, but has a different purpose, in that the objects to be removed are not intended to be recovered, just removed or reduced to a condition where they no longer constitute a hazard. Many of the techniques and procedures used in clearance diving are also used in salvage work.

Ships husbandry diving

Ships husbandry is the maintenance, cleaning, and general upkeep of the hull, rigging, and equipment of a ship, and may also refer to aspects of maintenance which are not specifically covered by the technical departments.
Underwater ship husbandry includes:
  • Underwater hull cleaning to remove fouling organisms which increase drag, and therefore reduce top speed and increase fuel consumption. Such cleaning may be of the entire hull or parts thereof, particularly propellers, shafts and thrusters.
  • Non-destructive testing and inspection including fouling surveys, inspection of known or suspected damage to structure, equipment or coatings, and inspection of repairs.
  • Underwater repair of structure, appendages, and equipment, and small areas of paintwork.

    Equipment

Diving suit

Depending on the water temperature, depth and duration of the planned dive, the diver will either use a wetsuit, dry suit or hot water suit. A wetsuit provides thermal insulation by layers of foam neoprene but the diver gets wet. Hot water diving suits are similar to a wetsuit but are flooded with warm water from a surface water heater that is then pumped to the diver via an umbilical. A dry suit is another method of protection, operating by keeping the diver dry under the suit, and relies on either the suit material or the air trapped in thermal undergarments to insulate the diver, and also provides better isolation from environmental contamination. Certain applications require a specific type of dive suit; long dives into deep, cold water normally require a hot water suit or dry suit, whilst diving into potentially contaminated environments requires a dry suit, dry hood, and dry gloves at a minimum, thereby keeping the diver completely isolated from the diving environment.

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. Commercial divers will rarely use scuba equipment for occupational health and safety reasons.

Scuba diving

equipment is occasionally used by commercial divers working on sites where surface supplied equipment is unsuitable, such as around raised structures like a water tower, or in remote locations where it is necessary to carry equipment to the dive site. Normally, for comfort and for 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 are considered safer, as they protect the airway, and can normally be used with surface supplied equipment as well as scuba, reducing the need for contractor to have two different sets of equipment and the spares to service them.