Surface supply diving uses air from the surface to help the diver. It uses many of the same procedures as 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 Diver's umbilical is the primary connection between the diver and the surface supply diving system. 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 to a diving mask to surface. It has a variety devices that assist divers in staying safe and comfortable in the sea. These devices may include a communication cable, a pneumofathometer, and a hot water suit. All of these components make it possible for divers to monitor their depth and provide additional air in case of an emergency.
Diver's demand-valve
The Diver’s demand Valve is designed for increasing the pressure of air used in surface supply diving. The demand valve allows a diver's breathing to be more controlled and slow than it would without it. Regardless of whether the diver is conscious, the pressure in the air can change significantly during a dive. This can increase both the work of breathing and the hydrostatic pressure. These changes will not reduce oxygen delivery to 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 typically inhale through the demand valve. A regulator controls the main supply of air. The regulator usually has a single hose, and is attached to the diver’s mouthpiece. If the diver is using a dual-hose regulator the demand valve is located inside the regulator. It attaches to either the cylinder valve outlet or the manifold outlet. The demand valve is activated when the diver breathes. It will provide gas to remote mouthpiece at ambient temperature.
Saturation spread
Surface supply diving requires a pressurized environment. There are two ways to achieve this: a saturation set or a "saturation spread". Saturation dive is when divers are put under pressure by a saturation accommodation and then returned to the surface using a helium-based gas mixture.
Saturation diving is most commonly used offshore, near production and drilling platforms, and in the context of salvage operations. It is crucial to be precise during a dive for this type of diving. This is most often done from a specialised diving support vessel, or a suitable vessel of opportunity. Dynamic positioning is also important, but requires a reliable system.
Diver's fitness for diving
Before diving in surface supply, divers must have a thorough fitness-todive examination. The AMED, a medical examiner for divers, will perform the examination. This will determine if there are any conditions that could affect their diving ability. The exam is valid for 12 months, and must be renewed each year. The diver will need to pass a fitness exam at renewal.
Dive certification organizations specify the standards of medical examination. While some require the medical practitioner to conduct an examination, others see it as largely the responsibility of the individual. These standards are almost always the same 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
Surface supply diving equipment doesn't differ much from deep diving equipment. The main difference is in the type of breathing gas used. In surface supply diving, the gas supplied is set at the gas panel. The tank's pressure does not adjust automatically as the water level drops. Some surface supply diving demand helmets have an extra feature called "dial-a breath" that allows the diver adjust the gas level in their tank.
Apart from the tank, divers will also require a set of voice communication equipment to communicate with the surface. These devices connect to the mask or helmet of the diver using an umbilical wire. Before diving, make sure to check the function and sound quality of the cable.