Seat-passing valves treated before first gas-in on a new city gas network

The valve and its duty

A city gas operator found ball valves passing from the seat on a new 8 km steel line.

These ball valves must prove clean isolation before the network takes its first gas.

Gas charging was already scheduled, so the passing threatened the commissioning programme.

Cutting out new valves at that stage would have cost the project its deadline.

Commissioning schedules leave little room for a fault found this late.

Site conditions

The line was newly built and still moving through its commissioning steps.

New networks often hold construction debris, which can hold seats open under test.

Seat passing on a new valve therefore points to contamination before it points to damage.

A new valve that passes is usually a fouled valve, not a worn one.

The fix therefore had to remove the cause without opening the line.

The intervention

1. The operator flew our technicians in and shipped materials to the project office.
2. The team treated the affected valves online, working through each valve in place.
3. No cutting and no valve removal was needed at any point in the work.

Mobilisation speed mattered as much as the treatment itself on this project.

Materials travelling with the plan meant no waiting once the team reached site.

Online treatment kept the valves in the line and the schedule within reach.

The treatment drew on our seat cleaner and sealant product families.

The outcome and the record

The operator confirmed in writing that the work was complete.

It wrote that the attended valves were under observation for a final conclusion. It then asked us to raise the invoice for the job.

Observation before charging is the confirmation step that follows any online treatment.

The line gained no new cuts, joints or welds from the repair work.

The same approach suits any new network that finds passing valves before charging.

See the field results from more live valve work across other settings.

Explore field services for mobilised valve treatment on project timelines.

Our guide to city gas distribution networks covers valve care on new lines.