In the Oil & Gas industry, pipelines often handle fluids which may be hazardous, flammable and/or toxic. Any interruption to operations for unplanned maintenance or operation activities is considered a risk of release of harmful energy or materials into the work area.

Proper isolation of equipment is selected considering the nature of work activity, materials involved, and piping arrangement. Positive isolation (blinding) of process lines and equipment is used to prevent the release of harmful energy or materials to the work area during maintenance or construction activities. However, cases can arise where this option is not always achievable or cannot be placed safely because of leaking valves, and operators require other methods of isolation.

Double Block and Vacuum is an option that can be used to enhance an isolation procedure and permit continuous monitoring throughout the isolation period.

This paper presents the performance of DBV isolation during a field trial in a gas pipeline application.