Surface supply diving involves using air from the surface to assist the diver. The standard procedures for surface supply diving are very similar to those used in scuba diving. While many of the procedures are similar for all divers, some are specific to certain equipment or 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 primary connection between the diving system and the diver is the umbilical. 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 diving mask to the top and includes a number of devices to ensure divers are comfortable and safe. The devices include a cable for communication, a thermometer, 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 is designed to increase the pressure of the air used during surface supply diving. This pressure can cause diver to breathe faster and deeper than 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 of breathing, as well as the hydrostatic pressure and cracking pressure. These changes do not affect the oxygen supply to the lungs. Increased pressure allows the diver to extract more carbon dioxide from their air. This improves quality of their breath.
Divers normally inhale via the demand valve. However, 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 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 takes in air, the demand valve will send gas to the remote jawpiece 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 involves diving under the pressure of a saturation accommodation. The divers then return to the surface with a mixture made up of helium and oxygen.
Most commonly, saturation diving is used offshore, near production platforms and drilling platforms, as well as in the contexts of salvage operations. To perform this type of dive, it is important to have precise positioning during the dive. This can be done most often from a specially designed diving support vessel or another suitable vessel. Dynamic positioning is also important, but requires a reliable system.
Diver's fitness for diving
Before surface supply diving, all divers must complete a fitness-to–dive evaluation. 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.
The dive certification agencies set the standards for medical examination. While some require the medical practitioner to conduct an examination, others see it as largely the responsibility of the individual. These standards can be shared between agencies, but they are often similar. These standards are often based on the standards for professional divers. However, they may be slightly relaxed to decrease the incidence of diving-related medical conditions.
Diver's equipment
Surface supply diving equipment doesn't differ much from deep diving equipment. The major difference is the gas used. In surface supply diving, the gas supplied is set at the gas panel. Accordingly, the tank pressure doesn't adjust with the dive 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.
Divers also require a set if voice communication devices to communicate with the surfaces. These devices are connected to the diver's full-face mask or helmet by an umbilical cable. Before diving, ensure that the cable is in good condition.