Line Stopping: BT

LINE STOPPING CASE STUDY

Client: Allied, on behalf of BT Supply Chain

The problem:

One of BT’s warehouses required part of their gas main to be purged, decommissioned and cut off. 

Their industrial gas installation was large and complex. Turning the gas off to the entire site was problematic because the old gas pipework may not have passed a tightness test. 

What’s more, BT required their gas to remain live in order to avoid any downtime or disruption.

Our solution: 

To avoid turning off appliances and tightness testing, a line stopping procedure was recommended in order to form a temporary inline valve.   

Our commercial Gas Safe engineers were brought in to assist in line stopping the steel 4” gas pipework. 

Hot tapping a 1” connection was also required in order to form a purge point.

We welded a 4” and 1” branch to the existing gas pipework. 

Once the gas supply was isolated, we nitrogen purged the existing pipework.

The decommissioned pipework was then disconnected and a Gas Safe certificate was issued. 

Tasks involved:

• Line stopping 
• Hot tapping/under pressure drilling
• Welding 
• Indirect gas purge 
• Commercial Gas Safe certificate