ABSTRACT
In the middle of the 18th century, compressors became available, and as the principle of underwater ‘diving bell’ was already established, an extension to the underground space was developed, allowing to dry out wells by the application of air pressure and to use airlocks to transfer personnel into the pressurized zone. Among working situations, working under pressure has a special place. Most of the times when a hazard is identified at work, safety requires that the person should be protected against it by preventing actual exposure. This is obtained by removing the hazard, erecting physical barriers like individual protective equipment or confining the source of hazard inside protective cabinets. A professional diver is someone who dives while at work. There are many different working situations that must be considered separately as far as diving methods, organization and safety are concerned.
