The increased activity in the offshore sector of the energy industry has led to additional factors that have to be taken into consideration when designing piping systems. Space in these offshore locations is always at a premium and the design of piping systems and their associated components must therefore be more compact. There are structural constraints that are also very important, such as to keep the structure as light as possible, and there are obvious benefits from making components smaller and lighter. Construction labor in offshore locations is also very expensive and any reduction in installation manpower is also beneficial.
The above situation has led to the modification of the patterns of valve components to incorporate savings in space, weight, and labor costs where possible, while still retaining the original function of the valve. Initially these modifications have meant that there is a cost impact, however when installation costs are reduced, the final costs are then comparable with the multi-component option used in the past.
Process isolation philosophy has become more complex as safety issues have to be addressed and the requirement for double block and bleed isolation has become more commonly used, especially in offshore locations. Double block and bleed isolation requires two in-line isolation valves and a bleed valve, used to drain or vent trapped fluid between the two closure elements. Double block and bleed valves are special components, however there are now...
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