Cross Connection on Park Road, Hayes: 3 Inch to 6 Inch Network Reinforcement

The brief

Affinity Water engaged us to install a cross connection on Park Road in Hayes, Greater London. The job joined a 3 inch main into a 6 inch main as part of a wider network reinforcement plan. Connecting a smaller main into a larger distribution main is how a water utility feeds pressure and flow into a part of the network that needs more of both. Once connected, the 3 inch main benefits from the stronger upstream supply, which improves reliability and headroom for customers downstream.

The works had to be delivered live, as most cross connections do. Taking a section of main out of service to install the fitting would have put customers off supply, which is the opposite of what a reinforcement scheme is trying to achieve.

Our approach

Ian and DJ carried out the works. The cross connection was installed using under-pressure drilling to tap into both the 3 inch and the 6 inch mains without depressurising either side. Valves were installed to allow Affinity’s operational teams to open or close the new connection as required by the wider network strategy. Pipework was jointed, pressure tested, and commissioned into service on completion.

A live cross connection of this type is a textbook piece of water network construction work: under-pressure drilling on two different diameter mains, fabrication between them, valve install, test, commission. It’s the kind of job that sits squarely inside the scope of what the Network Construction Operations (Water) scheme exists to measure.

NCO site audit: independent sign-off

This job was also the practical site audit for Ian and DJ’s NCO (Water) registration. The Network Construction Operations (Water) scheme is the industry’s nationally recognised competency scheme for water network operatives, held by the Energy and Utility Skills Register (EUSR) and accepted by LRQA as evidence of competence for the Water Industry Registration Scheme (WIRS). It’s the qualification water companies and WIRS auditors look for when asking who is allowed to touch their network.

Jo Parker carried out the audit. Ian and DJ passed. That means the works on Park Road served a dual purpose: the network got its reinforced cross connection, and two more members of our crew carry nationally recognised, independently audited competency to work on potable water networks. Both of those are useful outcomes.

Outcome

Cross connection installed and commissioned live, 3 inch main now reinforced from the 6 inch main, no customer off-supply during the works. Ian and DJ’s NCO (Water) registration successfully signed off by the auditor on the basis of the work delivered. Affinity Water got the network reinforcement they scoped; we got two more NCO-registered operatives on the books.

For the technique in more depth see our under pressure drilling capability page. The service context sits under water mains repair and maintenance for water companies.