Surface supply diving is when air is used to aid the diver. Many of the standard procedures are identical to scuba diving. Although many of these procedures can be used by all divers, others are only applicable to certain equipment and dive tasks. These procedures can be slightly different for new divers or those who have never dived without scuba equipment.
Diver's umbilical
The Diver's umbilical is the primary connection between the diver and the surface supply diving system. It carries the primary breath gas from the surface to your apparatus. The umbilical can either be directly attached to the diver or attached via a bell panels.
The umbilical connects a diving helmet to the surface. It contains various devices that can help divers stay comfortable and safe in the water. These devices can include a communication cord, a pumpofathometer, or a hot watersuit. 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 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. Whether the diver is conscious or not, the pressure of the air can vary considerably during a dive. This can increase the work required to breathe, and also the cracking pressure and hydrostatic pressure. However, these changes do not impair the oxygen delivery to the lungs. Increased pressure allows the diver to extract more carbon dioxide from their air. This improves quality of their breath.
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. 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 supplies gas at ambient pressure to the remote mouthpiece when the diver inhales.
Saturation spread
A pressurized environment is required for surface supply diving. There are several ways to do this, including a saturation system or a "saturation spread." Saturation diving refers to diving where divers are placed under pressure using a saturation accommodation system and then return to the surface by inhaling a mixture of helium and gas.
Saturation diving is commonly used offshore, close to production and drilling platforms, or in the context of rescue operations. For this type diving, you need to know where you are going and how you will position yourself. This is usually done using a special diving support vessel or other suitable vessel. However, dynamic positioning is essential and requires reliable equipment.
Fitness-to-dive exam for divers
Before diving in surface supply, divers must have a thorough fitness-todive examination. This examination is performed by a diver's medical examiner (AMED), who will assess any underlying health conditions that might pose a risk to their diving ability. The examination can be valid for up 12 months and must always be renewed. The diver will have to pass a fitness check at renewal.
Dive certification agencies specify the medical exam standards. Some agencies require a medical practitioner to perform the exam, while others leave it up to the individual to do the exam. However, these standards are usually similar between different agencies. 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.
Diver's equipment
The equipment used for surface supply diving is not very different from that used by deep divers. The main difference is in the type of breathing gas used. The gas panel is used to control the gas flow. Therefore, the pressure in the tank doesn't automatically decrease with depth. 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.
Divers need to have a set voice communication devices in order to communicate with the surface. These devices are connected by an umbilical cables to the diver's helmet or full-face face mask. The cable should be checked for function and soundness before diving.