Surface supply diving refers to using surface air to assist the diver. There are many procedures that can be used to supply air from the surface, which is similar to scuba diving. Many of these procedures are the same for all divers, but some are unique to specific equipment and diving tasks. For those new to surface supply diving, or who have never been certified to dive without their scuba gear, these procedures might be slightly different.
Diver's umbilical
The primary connection between the diver's umbilical and the surface supply diving system is the Diver's Umbilical. It carries the primary oxygen from the surface to the divers' apparatus. You can attach the umbilical directly to the diver or via a bell panel.
The umbilical connects the diving mask to the surface and contains many devices that help divers remain safe and comfortable in water. The devices include a cable for communication, a thermometer, and a hot-water suit. These components enable divers to monitor depth and provide air in emergency situations.
Diver's demand valve
The Diver’s demand valve allows for an increase in the air pressure used during surface supply diving. This pressure can cause a diver to breathe more slowly and deeper than he would without the demand valve. Regardless of whether the diver is conscious, the pressure in the air can change significantly during a dive. This can increase the effort required to breathe and may also affect the hydrostatic and cracking pressure. These changes will not reduce oxygen delivery to lungs. The pressure can increase the efficiency of the diver's breathing system in removing carbon dioxide. This improves their quality of breath.
Divers inhale from the demand valve. The regulator controls the main air supply. The regulator is typically fitted with one hose and held in place by the diver's mouthpiece. The demand valve, which attaches either to the manifold outlet or cylinder valve, is found in the regulator's body if the diver uses a dual hose regulator. The demand valve will provide gas to the remote airway at ambient pressure when the diver breathes.
Saturation spread
You need to dive in a pressurized environment for surface supply. This can be done in a variety of ways, including a saturation spread or a saturation system. Saturation diving is a form of diving in which divers are deployed under pressure from a saturation accommodation system, and return to the surface breathing a helium based gas mixture.
The majority of saturation diving is done offshore, on drilling platforms or near production, and when there are salvage operations. For this type diving, you need to know where you are going and how you will position yourself. This can often be done from a specialized diving support vessel (or a vessel suitable for the occasion). A reliable system is required for dynamic positioning.
Diver's fitness-to-dive examination
Before diving in surface supply, divers must have a thorough fitness-todive examination. This is done by an AMED, which will examine any underlying medical conditions that could be a problem for their ability to dive. The examination is valid for up to 12 months and must be renewed annually. The diver must also pass a fitness test at renewal.
The medical examination standards are specified by dive certification agencies. While some require the medical practitioner to conduct an examination, others see it as largely the responsibility of the individual. The standards vary between agencies but are generally the same. These standards are often based upon those for professional divers. However they can be adjusted slightly to decrease the likelihood of diving-related medical problems.
Divers equipment
The equipment used for surface supply diving is not very different from that used by deep divers. The only difference is the use of breathing gas. The gas panel controls the gas supply for surface supply diving. Because of this, the tank's pressure is not adjusted automatically when the depth drops. Some surface supply diving helmets come with an extra feature called a dial-a-breath system, which allows the diver to adjust their tank's gas levels.
Apart from the tank, divers will also require a set of voice communication equipment to communicate with the surface. These devices can be connected to the full-face helmet or mask by an umbilical cord. Before a dive, the diver should check the cable for sound quality and function.