Hot tapping 3" connection on gas pipework
Client: Jaguar Landrover, Liverpool
The problem:
JLR required a new 3” gas supply to feed a commercial steam boiler.
As the system was in continual use for production, shutting off the gas supply was not an option.
Therefore, our hot tapping engineers were contracted to perform a live tapping intervention to avoid any shutdowns or downtime.
Our solution:
Before arriving on site, our engineers fabricated a 3” connection to suit the profile of a mild steel 14” pipe.
For safety, an ultrasonic thickness test of the 14” main was taken in order to identify if the existing pipework was thick enough to weld onto.
We then welded a flanged saddle in the position specified by the client.
An important element of hot tapping is to use a full-bore valve in order for the under-pressure drill to have clear access.
For example, a butterfly valve would not be suitable due to the obstruction of the internal paddle.
Thus, our engineers fitted a full-bore gate valve appropriate for natural gas.
We then pressurised the connection and valve in order to identify any leaks.
After the successful test, the under-pressure drill was attached with a special retaining pilot so the coupon could be extracted.
Drilling the 14” pipe was then undertaken using a bi-metal hole saw with specific dimensions.
Choosing the right hole saw comes with experience, the right width and depth has to be considered in order for the rig to be extractable and the hole to be fully cut.
Once the drilling was complete a safety blank was fitted to the new valve and the works were completed in under four hours.
Tasks involved:
Hot tapping / under pressure drilling on chilled water, mild steel pipework
Positional welding
