Surface supply diving involves using air from the surface to assist the diver. Many of the standard procedures are identical to scuba diving. Many of these procedures can be used for all divers. Some are more specific to equipment or 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, the surface supply diving equipment and the umbilical of the Diver is through the umbilical. It is responsible for carrying the primary breathing gas from surface to diver's equipment. The umbilical can be either directly attached to the diver, or it can be attached via a bell panel.
The umbilical connects diving mask to the top and includes a number of devices to ensure divers are comfortable and safe. This could include a communication cable or a pneumofathometer. This allows divers to keep track of their depths, and also provides additional air for emergency situations.
Diver's demand valve
The Diver's Demand Valve is designed to increase surface supply diving air pressure. This pressure can cause a diver to breathe more slowly and deeper than he would without the demand valve. The air pressure can vary a lot during diving, whether the diver is aware of it or not. This can increase the work of breathing, as well as the hydrostatic pressure and cracking pressure. However, these changes do not impair the oxygen delivery to the lungs. By raising the pressure, divers' respiratory systems can remove more carbon dioxide from the atmosphere, which improves the quality and quantity of their breathing.
Divers inhale from the demand valve. The regulator controls the main air supply. The regulator usually has a single hose, and is attached to the diver’s mouthpiece. If the diver uses a dual-hose regulator, the demand valve is located in the body of the regulator, which attaches to the cylinder valve or manifold outlet. The demand valve supplies gas at ambient pressure to the remote mouthpiece when the diver inhales.
Saturation spread
It is necessary to have a pressure environment in order to surface supply dive. You have two options: a saturation system, or a "saturation spreading". Saturation diving involves diving under the pressure of a saturation accommodation. The divers then return to the surface with a mixture made up of helium and oxygen.
Most commonly, saturation diving is used offshore, near production platforms and drilling platforms, as well as in the contexts of salvage operations. To perform this type of dive, it is important to have precise positioning during the dive. This can be done most often from a specially designed diving support vessel or another suitable vessel. Dynamic positioning is also important, but requires a reliable system.
Diver's fitness-to dive exam
Divers must pass a complete fitness-to-dive exam before participating in surface supply diving. 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 will need to pass a fitness exam at renewal.
Dive certification organizations specify the standards of medical examination. Some agencies require that a physician examine the diver, while others view the examination as largely a personal responsibility. These standards can be shared between agencies, but they are often similar. Often, these standards are based on those for professional divers, but may be relaxed slightly in order to reduce the incidence of diving-related medical conditions.
Diver's equipment
Surface supply diving equipment doesn't differ much from deep diving equipment. The major difference is the gas used. In surface supply diving, the gas supplied is set at the gas panel. Because of this, the tank's pressure is not adjusted automatically when the depth drops. Some surface supply diving demand Helms may have an additional feature called a “dial-a–breath” system which allows the diver or divers to adjust the level of gas in their tank.
For communication with the surface, divers need more than a tank. An umbilical cable connects these devices to the helmet or full-face mask of the diver. Before diving, ensure that the cable is in good condition.