Block and Bleed with Line Break

LEVEL 4—BLOCK AND BLEED WITH LINE BREAK [Pg.66]

The key difference between this system and the double block and bleed is that the line connecting the hazardous chemicals to the place of work has a section removed. Therefore there is no way that the chemicals can transit directly to the workers location. The bleed valve is left open so that the workers know if the closed root block valve has started leaking. It can be attached directly to the valve as shown, or it can be attached to the Une leaving the block valve. [Pg.66]

A grounding lead should be installed across the sections of pipe that have been parted to protect against stray currents generating a spark. These currents could be generated by energy sources that have not been properly de-energized, such as cathodic protection of the pipe system or nearby equipment [Pg.66]

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