SVI PE Branch Saddles and Under Pressure Drill Technology used on new connections at Sellafield

January 26, 2021

SVI were contracted by One Aim – Jacobs, on behalf of Sellafield, the Infrastructure Strategic Alliance (ISA), to install a large diameter PE branch saddle on a 315mm HDPE pipe raw watermain diversion approximately 130 metres in length.

The new connection was required so that a new building, under construction, at the Sellafield site could be included in the site fire hydrant network in case of fire. A branch saddle operation was chosen because it was deemed too high risk to fully shut down the hydrant network while a new connection was installed.

The advantage of a PE branch saddle is that it can be installed under ‘live’ conditions. The PE branch saddle was clamped to the existing PE pipe and then electro fused prior to the attachment of a full-bore valve. The fitting and valve were then pressure tested in situ at 1.5 times network working pressure. Once the pressure testing was carried out successfully, the drilling operation was performed using SVI under pressure drill technology. The entire operation was completed within one working day.

One Aim – Jacobs staff were then able to connect the new hydrant pipeline into the new PE branch connection valve at their own convenience.

Ian Campbell, Mechanical Site Engineer for One Aim – Jacobs commented,

“We contacted Steve Vick International because they had been used successfully on previous installations of branch connections at Sellafield. The branch saddle technique they use alleviates any issues during the commissioning of the new raw water main diversion and ensures the main header pipework is fully purged and free of any trapped air before going into full operational service. The knowledgeable and efficient service SVI provided was excellent and allowed us to achieve a key project milestone, allowing for other disciplined work scopes to be completed.”

Making Live Connections

SVI can offer private utility network owners a solution to connecting into existing utilities pipelines without the requirement for a network shut down or line stop. A range of services are available depending on what the pipe material, diameter and running pressure dictates.

For PE gas and water networks, SVI can install and commission PE branch saddles using electrofusion welding.

For metallic gas and water networks, SVI can install and commission mechanical Under Pressure Tee (UPT) branch connections.

There is no need to lower pressures, line stop, close valves to isolate or shut down the network for either of these operations as they can both be performed “live”.

For full details on all our Nuclear products and services please contact Richard Ditte or Andy Hutchison  on 01225 864864.