Unplugging a Line

When unplugging underground lines, a line rupture may give the appearance that the plug is dislodged by a sudden drop in pressure. The clearance should be verified by flowing gas or liquid through the line. 

If a line does plug, it may be possible to remove the obstruction by striking the line or by using a drill or augur. Each of these has associated risks striking the line could cause mechanical damage, and the use of a drill means that the equipment has to be opened up. 

Applying pressurized fluid to one side of an obstraction can be an effective 

Check that hoses, regulators, and associated apparatus have an adequate pressure rating. When using compressed gas cylinders, make sure the regulator has the proper threads and pressure rating. The maximum allowable pressure is usually stamped on the regulator s collar. 

Temporary operating and maintenance procedures for the work should be developed. 

---