The development and the application of Det norske Veritas? Rules for the Construction and Classification of Diving Systems is presented. System requirements and quality criteria are based on main principles of diving technology and physiology, reliability analyses, existing codes and regulations, and experience within industry and certifying bodies, as well as the Society's more than one hundred years experience in ship classification. The rules cover environmental conditions, materials, pressure vessel design, pipes, valves, fittings, manufacture, lire support system, electrical installations, fire protection, control stand, communication, handling system, ballast and stability. Classification provides an international quality assurance throughout the lifetime of the diving system.
The offshore industry needs to observe, inspect and work under water. Manned underwater systems for transportation, production and working operation play an important role in offshore industry today. These systems become even more important as industry moves into deeper and more hostile waters. The depth and endurance capability of commercial underwater operations has been limited, and only the great economical potential of the continental shelves has lead to the rapid expansion of underwater activities and the recent years achievements within offshore industrial diving.
Estimates for the development of manned underwater systems for operation on the North European continental shelves are shown in Fig. 1. The curves indicate a rapid growth in the number of diving systems from about 70 in 1975 to about 210 in 1980. The decreasing rate of growth in the number of diving systems reflects both the total level of activity and the practical depth limitation on diving. The figure also indicates an exponential growth in the number of manned atmospheric systems or submersibles.
What then, about the safety for man and reliability of equipment under water? The industrial diving profession has until recent years accepted a high fatality rate. Official statistics from the North Sea so far show 1 fatal accident per 100 divers per year. For comparison, statistics for commercial diving in The Gulf of Mexico show 0,7% murtality. In 1975 we experienced 10 fatalities among about 700 industrial divers at work on the North European continental shelves. By 1980 the number of professional divers in this area may be three times as high. Is the number of fatal accidents going to increase accordingly?
Diving is by far the most dangerous compared to professions like fishing, flying and professional boxing. At the same time we know that the diving contractors put great emphasis on safety. Accidents .will happen; there will always be a risk connected to manned under water operations and this risk cannot be eliminated. But we must work for increased safety and reduction of the risk.
The escalating cost of offshore industrial activities requires high operational efficiency, and delays due to equipment failure are not acceptable, this naturally leads to increasing requirements for equipment quality and reliability.