Surface supply diving is when air is used to aid 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. These procedures could be slightly different for beginners or for those who have never been certified for diving without 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. It can be attached directly to the diver's apparatus or through a bell panel.
The umbilical connects a diving mask to the surface, and it contains a variety of devices to help divers stay safe and comfortable in the water. 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 to increase surface supply diving air pressure. The demand valve can make a diver breathe slower and deeper than normal. Whether the diver realizes it or not, the air pressure can vary greatly 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. By increasing the pressure, the diver's respiratory system can be more efficient at removing carbon dioxide from the air, and this improves the quality of their breathing.
Divers breathe normally from the demand valve, while the main air supply to the regulator is controlled. 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. When the diver breathes, the demand valve will supply gas to the remote mouthpiece at ambient pressure.
Saturation spread
Surface supply diving requires a pressurized environment. There are several ways to do this, including a saturation system or a "saturation spread." 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.
Saturation diving is most commonly used offshore, near production and drilling platforms, and in the context of salvage operations. To perform this type of dive, it is important to have precise positioning during the dive. This is most often done from a specialised diving support vessel, or a suitable vessel of opportunity. It is important to have reliable systems for dynamic positioning.
Diver's fitness for diving
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 is valid for up to 12 months and must be renewed annually. A fitness test will be required at the renewal.
Dive certification agencies define the standards for medical examination. Some agencies require that a physician examine the diver, while others view the examination as largely a personal responsibility. These standards are almost always the same between different agencies. These standards often reflect those of professional divers. However these standards may be slightly relaxed to reduce the incidences of diving-related conditions.
Diver's equipment
The equipment for surface supply diving doesn't differ significantly from the equipment used by deep divers. The main difference is in the type of breathing gas used. The gas panel controls the gas supply for surface supply diving. Therefore, the pressure in the tank doesn't automatically decrease with depth. 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.
For communication with the surface, divers need more than a tank. These devices are connected by an umbilical cables to the diver's helmet or full-face face mask. Before a dive, the diver should check the cable for sound quality and function.