Maintenance is an essential undertaking as part of our role to keep the high pressure gas National Transmission System (NTS) safe, fit for purpose and operating efficiently and economically, in line with our obligations.

In order to work on the NTS, it is sometimes necessary to take an outage of a part of the network or reduce the flexibility available (e.g. where steady flows may be required). This may affect one or more parties connected to the network including:

  • gas fired power stations and large industrial consumers connected to the NTS;

  • gas storage facilities;

  • gas entry facilities; or

  • distribution networks.

We are also incentivised on some aspects of our maintenance activities.

Types of maintenance

Customers may be affected as a result of:

  • routine maintenance;

  • asset replacement;

  • pipeline and defect inspections;

  • emergencies and faults; or

  • work to facilitate investment in the network which may be as a result of a new connection or capacity requirement (common maintenance types).


We aim to minimise the impact of our maintenance on customers by being transparent about what we do, aligning our work with their outages as appropriate, and facilitating customer needs for flexibility.

Each year, we ask when our customers' outages will take place, so we can align works. If your outages move, please email us ([email protected]) as early as possible, so we can consider if we can realign our works to reduce impact.

Minor works agreement

We can help parties to agree different maintenance approaches through a mutual contract with directly connected customers.

Minor works

Maintenance plans

When working with our customers to plan our system access requirements, we consider maintenance requirements, forecast supply, and demand patterns, as well as outage programmes from relevant and affected industry parties. This facilitates the alignment of work where feasible to reduce its impact.  

If the dates of your planned outages change, please contact us as early as possible so that we can consider whether we can also realign our works to reduce any impacts. 

Grey gas pipeline exposed at the ground at North Rigton

Gas network maps and routes

You can find out more about gas pipeline routes--including maps--by going to the Gas network routes page.

Find out more