Surface supply diving is when air is used to aid the diver. It has many standard procedures that are similar to scuba procedures. Many of these procedures can be used for all divers. Some are more specific to equipment or diving tasks. These procedures may differ slightly for surface supply divers, as well as those who are not certified to use scuba gear.
Diver's umbilical
The primary connection between a diver and his surface supply diving system, the Diver's umbilical. It carries the primary breathing gas from the surface to the diver's apparatus. The umbilical can be either directly attached to the diver, or it can be attached 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. 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 the pressure of the air used during surface supply diving. The demand valve allows a diver's breathing to be more controlled and slow than it would without it. The air pressure can vary a lot during diving, whether the diver is aware of it or not. This can increase the effort required to breathe and may also affect the hydrostatic and cracking pressure. These changes do not affect the oxygen supply to the lungs. By raising the pressure, the diver can make their respiratory system more efficient in removing carbon dioxide. This improves the quality of their respiration.
Divers typically inhale through the demand valve. A regulator controls the main supply of air. The regulator is usually fitted with a single hose and is held by 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 will provide gas to the remote airway at ambient pressure when the diver breathes.
Saturation spread
Surface supply diving requires a pressurized environment. 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.
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 is usually done using a special diving support vessel or other suitable vessel. While dynamic positioning is very important, it requires a reliable system.
Diver's fitness-to dive exam
A comprehensive fitness-to dive examination must be completed before a diver can participate in surface supply diving. An AMED (diver's medical examiner) will perform this exam. They will also assess any other health conditions that may pose a threat to their diving abilities. The examination can be valid for up 12 months and must always be renewed. The diver must also pass a fitness test at renewal.
The dive certification agencies set the standards for medical examination. While some require the medical practitioner to conduct an examination, others see it as largely the responsibility of the individual. 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
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 determines the gas that is supplied for surface supply diving. Because of this, the tank's pressure is not adjusted automatically when the depth drops. Some surface supply diving demand helmets might have an additional feature called a "dial a breath" system. This allows the diver the ability to adjust the tank's gas level.
Divers also require a set if voice communication devices to communicate with the surfaces. These devices are connected to the diver's full-face mask or helmet by an umbilical cable. The cable should be checked for function and soundness before diving.