Line Stopping: Warburtons

LINE STOPPING CASE STUDY

Client:  Warburtons, best-selling bread makers based in Nottingham

The problem:

Warburtons were replacing an industrial gas oven in their bakery plant in Nottingham, which necessitated the decommissioning of an existing gas installation. Any downtime to the bakery production was unfeasible, so shutting off the gas main was not possible.

Due to these constraints, the plant required a line stop on three branches to form temporary in-line valves while allowing the rest of the gas main to remain live.

Our solution:

Firstly, ultrasonic thickness tests were undertaken to test if welding onto the pipes would be safe. After the successful test, custom made 4” on 4” saddles were welded on. To check the integrity of the welds and valves, a pressure test of 2bar was performed.

Upon finding no leaks, our engineers hot tapped the existing pipework to form purge points and to insert the line stopping paddles.

Upon establishing the paddles were not letting-by, we purged out the branches, cut the existing pipework and then welded positional flanges to attach valves and blanks. 

 
Tasks involved 

• Ultrasonic thickness test
• Welding
• Pressure test 
• Hot tapping/Under pressure drilling
• Line Stopping/Bagging off
• Indirect Purge 
• Gas Safe purge certificate 

What were the benefits of Line Stooping / Bagging Off? 

• No system down time 
• Cost saving
• Avoid purging gas for the entire site 
• Avoid gas testing the entire site 
• No gas leak or waste
• Time efficient