Surface supply diving is when air is used to aid the diver. The standard procedures for surface supply diving are very similar to those used in 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 Diver's umbilical is the primary connection between the diver and the surface supply diving system. It carries the primary breathing gas from the surface to the diver's apparatus. It can be connected directly to the diver, or via a bell-panel attachment.
The umbilical connects a diving helmet to the surface. It contains various devices that can help divers stay comfortable and safe in the water. This could include a communication cable or a pneumofathometer. These components enable divers to monitor depth and provide air in emergency situations.
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. The pressure of the air can fluctuate during diving, regardless of whether the diver is aware. This can increase work and cause cracking and hydrostatic pressure to rise. These changes will not reduce oxygen delivery to lungs. Increased pressure allows the diver to extract more carbon dioxide from their air. This improves quality of their breath.
Divers breathe normally from the demand valve, while the main air supply to the regulator is controlled. The regulator is usually attached to the diver's mouthpiece and fitted with a single-hose hose. 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
It is necessary to have a pressure environment in order to surface supply dive. 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 commonly used offshore, close to production and drilling platforms, or in the context of rescue 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-to-dive examination
A comprehensive fitness-to dive examination must be completed before a diver can participate in surface supply diving. 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 exam is valid for 12 months, and must be renewed each year. A fitness test will be required at the renewal.
Dive certification agencies specify the medical exam standards. Some agencies require that a physician examine the diver, while others view the examination as largely a personal responsibility. The standards vary between agencies but are generally the same. 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.
Divers equipment
The equipment for surface supply diving doesn't differ significantly from the equipment used by deep divers. The most important difference is the breath 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 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 connect to the mask or helmet of the diver using an umbilical wire. Before diving, it is important to verify the sound quality and functionality of the cable.