Positive isolation methods are those that provide a safe environment for performing maintenance, repair or replacement operations on process facilities. These isolations remain effective even if there is an equipment failure or operator error.
There are many ways of isolating equipment. Each offers different levels of security. They include:
·Level 1 Closed Valve
·Level 2 Closed Valve with Open Bleeder
·Level 3 Double Block and Bleed
·Level 4 Block and Bleed with Line Break
·Level 5 Block, Bleed, and Spectacle Blind
·Level 6 Double Block and Bleed with Blind
·Level 7 Double Block and Bleed with Line Break