Surface supply diving uses air from the surface to help the diver. There are many procedures that can be used to supply air from the surface, which is similar to scuba diving. These procedures are generally the same for all divers. However, some of them are tailored to specific equipment or diving tasks. These procedures can be slightly different for new divers or those who have never dived without scuba equipment.
Diver's umbilical
The primary connection between the diver's umbilical and the surface supply diving system is the Diver's Umbilical. It carries the primary breath gas from the surface to your 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. Some of these devices could include a communications cable, a pneumofathometer and a hot water suit. These components allow divers to monitor their depths and supply additional air in an emergency.
Diver's demand lever
The Diver’s demand valve allows for an increase in the air pressure used during surface supply diving. This pressure can cause diver to breathe faster and deeper than without the demand valve. Whether the diver realizes it or not, the air pressure can vary greatly during a dive. This can increase work and cause cracking and hydrostatic pressure to rise. These changes don't affect 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 is usually fitted with a single hose and is held by the diver's mouthpiece. If the diver uses an dual-hose regulator, then the demand valve is attached to the cylinder outlet. When the diver takes in air, the demand valve will send gas to the remote jawpiece at ambient pressure.
Saturation spread
The environment must be pressurized for surface supply diving. You have two options: a saturation system, or a "saturation spreading". Saturation diving allows divers to dive under pressure. They are then able to return to the surface and inhale a mixture of helium, helium, or both.
Saturation diving can be used most often offshore, near production or drilling platforms, and within the context of salvage operations. To perform this type of dive, it is important to have precise positioning during the dive. This can often be done from a specialized diving support vessel (or a vessel suitable for the occasion). A reliable system is required for dynamic positioning.
Diver's fitness-to dive exam
Divers must pass a complete fitness-to-dive exam before participating in surface supply diving. 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. A fitness test will be required at the renewal.
Dive certification organizations specify the standards of medical examination. Some require an examination by a medical practitioner, while others make the exam entirely up to the examinee. 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.
Divers equipment
The equipment for surface supply diving doesn't differ significantly from the equipment used by deep divers. The major difference is the gas used. The gas panel determines the gas that is supplied for surface supply diving. 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. Before diving, ensure that the cable is in good condition.