Six passing valves treated online before gas charging on a new network

The valve and its duty

Six valves on a new city gas network showed medium to heavy passing.

The passing appeared under nitrogen test pressure, ahead of first gas charging.

Nitrogen testing exists to prove isolation before any gas enters a new network.

A valve that passes under test pressure fails that gate and blocks progress.

Six passing valves therefore stood between the project and its gas charging date.

Site conditions

The network was newly built and had not yet carried gas.

New networks often hold construction debris left inside the line during installation.

Debris caught across a seat can stop an otherwise healthy valve from sealing.

Commissioning tests are often the first time these valves see real differential pressure.

The intervention

1. Purge cleaner went in first, and our report recorded passing reduced to a low level.
2. That response indicated line debris inside the valves rather than seat damage.
3. A high-potency cleaner followed, and our report recorded a further reduction.

This is graded escalation: start with the mildest product and read the response.

The response itself becomes the diagnosis, without cutting or removing any valve.

Escalation stops as soon as the response is good enough.

Nothing stronger than necessary went into these six valves.

The response and the client's direction

A written status report documented the treatment and the indicated cause.

Mid-job, the network owner's engineer directed us to service further valves and mobilise immediately.

Written reporting means the operator holds the record of what was found and done.

Debris-driven passing found before gas-in costs far less than the same fault found after.

A cleaner-first result is screening evidence, and the seat test remains the confirmation.

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

Review injection equipment for the guns and pumps behind this work.

Our guide to the valve cleaner's role explains why cleaning comes first.