Isolation Valves - An Overview

Isolation Valves are valves which are used to isolate a pipeline.  Any type of valve can be used as an isolation valve.  They are named after their functionality.

Consider a skid with two pumps with only one pump running at any given time.  The other pump is a standby pump.  The suction line of both the pumps will be  common.  There will be an isolation valve in the suction line of each pump.

The isolation valve of the main pump will be in the open condition while the isolation valve of the standby pump will be in the closed condition.  The position of the valves needs to be reversed if the standby pump is to be run and the main pump is to be taken offline for maintanence.

Isolation valves can also be provided around measuring instruments such as manometers.  The valve can be opened to connect the instrument to the line and then closed to take it off line.